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Wayne,
another way to look at this and segment is to list what has been replaced or temporarily changed out w/o effect. Let's assume the the chance of a swapped part (e.g. loaner DME) having the exact same failure as the original one is very small. This produces a pretty extensive list what doesn't appear to be root cause: - DME - Injectors (once you swap left side with right side) - Fuel rails, fuel damper, fuel pressure regulator - O2 sensor? - Exhaust? - cap, rotor, spark plugs, plug wires? - 90 degree elbow in intake - AFM (not sure if that's done already Short of swapping the entire short block I would start to look to what might make one side a more effective pump than the other: How about taking a borescope and look into the barrels? Take the intake off and inspect/change the gaskets. And I am still wondering about the cams, maybe one side is flat or a different type. Re-check valve lash, etc. Ingo |
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Infra-red thermometer on the headers is a good way to check for that. Another thing; after a certain point, too rich will read lean on a wideband; rich misfire == incomplete combustion == unburnt oxygen in the exhaust. And the excess fuel can contaminate the sensor/shorten the life; bonus. With an aftermarket ECU, the tell-tale is that the sensor gives lambda numbers going further above 1.0 as you fatten up fuel trim... You may not be able to tell from listening to it, especially if you have a "hot" spark. |
Background:
- The stock 3.2 Carrera engine came out of a 1984 911 with about 65,000 miles that had been in an accident. In 2003, when I bought the engine, I was able to hear it run in the car. - The engine was installed into the car around 2008 by another builder. The ECU, harness and other fuel injection equipment appears to be non-original to a 1984 car. The ECU is a 1987 unit with the 24-pin inside. In addition, the engine harness is a late late harness with the late-style 3-pronged round oxygen sensor connector. Here are photos of the build: https://rdwdevelopmentcom-my.sharepoint.com/:f:/g/personal/wayne_dempseymotorsports_com/Enx6Otn2nxhGh-cpzqJ86l8B5r7YHL3uEpLxmA5qkirtgA?e=ErEAst - The car was returned to me around 2008 and it never quite ran correctly. It hunted at idle quite a bit when cold and when warm. As a result of the car not running terribly well (and other various factors), the car was parked for about 8 years and driven maybe 100-200 miles over that eight years. Around 2016, the car was stolen from the garage it was parked in. After two years of investigative work, the car was recovered, the thief ended up (back) in jail, and the car and I were reunited. the fuel tank was emptied, the fuel filter was replaced (May 2018), and fresh fuel was used to start and run the engine for approximately 20 min. I did not take a video of the engine, nor did I pay close attention to how well it was running, but it did hunt just like it did nearly a decade prior. Over the next year and a half, the car was prepped and painted blue. The paint job was done in the fall of 2019, and reassembly has been ongoing and almost is almost completed. - I knew that the engine never had run properly, and would take some work to get it running well. When started up in February 2020 (and driven to the Pelican Parts open house), it exhibited the same hunting issue that it has had for more than 12 years. It also had a high idle (around 1,100 or so). It also had quite a bit of air whistling, which I attributed to the odd/custom air-intake setup on the car. March 2020: - Before I messed with anything, the car was missing (I remember hearing it while driving it a few times back from the shop). Since I wasn't actively listening for a miss at that point, I didn't stick my ear near the tailpipe or take a video, but I heard the engine "thunking" very lightly from the driver's seat while it was idling and I was pulling it into the garage. So, the problem with missing existed prior to me changing the idle and mixture. My mindset during this period was to get the car ready for the Pelican Open House, and get it running enough so it would drive there - smoothy running was a "I'll fix that later" item. - I started by adjusting the idle and mixture using the idle air screw and the mixture to try to get it to run properly without hunting at the proper idle (using the LM-1 handheld air/fuel mixture meter). Lowering the idle down to the proper range made the missing problem more obvious. I believe that if I raise the idle up to 1,100 it will disguise the main problem (perhaps this was what was done 12 years ago, who knows). - Since the car sat for a long time and had been out of my control for more than two years, I figured that everything was suspect and/or should be overhauled as one would do with a car that has been basically sitting for 12 years, has never really run right, and has been stolen! Description of the problem: - When you start the car up, it runs fine for about a minute or two (two min if stone cold, less if warmer). The idle goes up to about 1,100 or so. Smooth running, no misses. Then, after about a minute or two, the idle drops down to about 850 or so, and starts missing (seemingly random missing). If you rev the engine just a little bit off of idle, the car revs okay, but the car is still flubbing / missing at this point. The car is drivable, but it seems to have less power than it should, and you can hear it missing at idle when you're in the car. Video of the problem from cold start to crappy running: https://www.youtube.com/watch?v=JAyihnlTo2g What's been done so far: ENGINE MECHANICAL: - Compression check (seems good): 1- 170 psi, 2- 168 psi, 3- 175 psi, 4- 175 psi, 5- 172 psi, 6- 175 psi - Leakdown (I was only able to do one cylinder before my 17-year old tester broke, I have a new one coming today, I will update this post with the results) 6- 2-3% - Emptied the oil. No surprises there. The oil hadn't been changed in 12 years, but it also only had maybe 300-500 miles on it. Oil looked very fresh - some "air cooled smell", but very light in color. Photo here: http://forums.pelicanparts.com/uploads26/IMG_11601589747198.jpg - Spot-checked the cam timing. I placed a dial gauge on the left and right cams and rotated the engine through TDC and TDC overlap. It's very difficult to do this with the engine in the car on a 914 - it's nearly impossible to find absolute TDC using the mirror on the left and right side, etc. Heck, it's really difficult just to turn the motor over (have to use the wheel with the transmission in gear). Cam timing specs as measured: 0.046" = 1.16mm (cylinders 1-3), 0.054" = 1.37mm (cylinders 4-6). Spec is 1.1 - 1.4mm with ideally the timing being set at about 1.25mm. It's probably closer than this, but this is pretty much the best I could with the engine still in the car. - Checked the upper valve clearances. The lower ones would pretty much require removal of the entire exhaust. The engine is not clicking badly like one would see with loose valves, and the upper ones were all within spec, so it is my assumption that the lower valve clearances are good. If I drop the engine out, I will of course check them, but I didn't think it was necessary to spend 4-5 hours on this right now when there were no clues that it might be causing a problem. - Checked the orientation of the distributor. TDC for #1 matches when Z1 is at TDC on the pulley. ENGINE IGNITION: - Replaced: spark plugs, plug wires, distributor cap, rotor, swapped out ignition coil. The cap and rotor looked fine. The plug wires I was not happy with, went with the stock BERU wires which feel more solid and higher quality. - Checked TDC timing with a timing light. There were no drops seen in the ignition signal. Pulled the plugs wires off on one side and inserted plugs into them and grounded them - no issues with sparks were found (video: https://youtu.be/AKkHlykF1YQ ) - Ran an inductive probe on each cylinder and then hooked it up to the oscilloscope. Sample scope output from one cylinder: http://forums.pelicanparts.com/uploads26/IMG_0616_JPEG1588489309.JPG - Pulled the spark plugs. Some definitely look better than others. The plugs show that there is an issue somewhere, but they don't really point to any one particular issue. Cylinder number six has been the dirtiest (on the right in the photo): http://forums.pelicanparts.com/uploads26/IMG_09701589181184.jpg FUEL INJECTION: - Replaced fuel filter, cylinder head temperature sensor. - Tested TDC sensor, looks good: http://forums.pelicanparts.com/uploads26/IMG_07391588574046.jpg - Tested RPM sensor, looks good: http://forums.pelicanparts.com/uploads26/IMG_07271588574046.jpg - Tested fuel pressure, looks a bit high. Ran the car and unplugged the vacuum line from the fuel pressure regulator / fuel damper - the pressure went from about 2 bar to a bit over 2.5 - made no difference in the running of the engine. Fuel pressure static: http://forums.pelicanparts.com/uploads26/IMG_07161588575570.jpg Fuel prssure running: http://forums.pelicanparts.com/uploads26/IMG_07221588574046.jpg - Tested both the fuel pressure regulator and the fuel damper to make sure they held vacuum (they did). Swapped out the fuel pressure damper with a used one on loan from Steve W. - made no difference. - Fuel injectors were sent out to R.C. injection for a full cleaning and overhaul. Fuel Injector report: http://forums.pelicanparts.com/uploads26/RC_Injection1588709576.JPG - Air Fuel Meter: Took it off and took a look at it, it has been opened. Tested the resistor strip with an oscilloscope, tested fine (see image). No clue as to whether the spring pressure is correct. Ordered a new 964 one due to arrive early this week because the resistor strip on this one looked worn and looked like it could be causing problems in the future. Ambient air temperator sensor tested within spec. Flapper door test: http://forums.pelicanparts.com/uploads26/IMG_06611588489309.jpg - Air intake boot - removed the goofy 180-degree bend on the intake (made no change). - Fuel tank - emptied the tank out (twice) - gas looked clear and clean. Refilled the tank with about 5 gallons of fuel. Jumpered the pump at the DME relay. Listened to the pump recirculate - you can hear the fuel flying back into the tank at a high rate of velocity. Very smooth when the tank is full of fuel. - Fuel pump - sometimes makes some odd noises when the tank is less-than-full, but pressures are good in the engine bay, so I don't think the pump is the issue. - Cylinder head temp sensor tested out of spec, replaced. - Tested high altitude sensor -> tested okay - Ran several smoke tests on the system -> fixed a small leak at the airflow meter found after the first test. Subsequent tests (done cold and also warm) revealed no leaks at the boots, the injectors, or the intake manifold / cylinder head connection. - Idle control valve - removed, inspected, and electrically tested. Also checked the pulse signal going to the valve: http://forums.pelicanparts.com/uploads26/IMG_06151588489309.jpg - Replaced the O2 sensor. Also checked the voltage coming out of both the new and old sensor, and it matches what was indicated on the wideband LM-1 meter. |
[continued]
ENGINE ELECTRICAL: - Replaced the DME relay - Swapped out a replacement ECU from Steve W. - Tested the resistance in the injector harness - found some high resistance in injectors #5 and #6 - cleaned the contacts and that went away. Also swapped out the injector harness with one borrowed from Steve W. Wired 12V directly to the injector harness to see if a low-current issue was causing any problems. - Checked the idle position switch -> operating okay. - Checked the wide-open-throttle switch -> found an issue with the harness (connectors were recessed causing a loss of contact). Replaced both the switch (it broke trying to remove), and repaired the harness. Tested okay now. - Alternator - the alternator has a common "exciter problem" where it doesn't start charging until the engine is revved. Not sure if this a symptom of something else. - Checked resistance to grounds, ground connections are attached to intake (1) and there is also a big ground going from that manifold point directly to the negative strap on the battery (2). Transmission ground strap in place (3). - Cleaned connections to the fuse box located in the trunk. Tested proper power to the DME / DME relay. - Checked injector pulse signal - matches left/right seems correct, even and consistent: http://forums.pelicanparts.com/uploads26/IMG_10621589425305.jpg http://forums.pelicanparts.com/uploads26/Injector_Pulses_both_channels1588747387.JPG - Checked / verified that the tachometer signal is property setup to drive the Carrera tach in the gauge cluster TEST CONDITIONS: - Running the engine while measuring exhaust temps has revealed various issues at times. In particular cylinder number six seemed to be running a bit colder than the rest of the cylidners. This has changed since cleaning injector harness contacts and swapping injectors around. Also, cylinder #3 seems to run slightly colder, but it may be the orientation of the header, as the distribution of heat in the header is slightly different than in the other two next to it. This may be related to the issue seen on #6 (they are symetrical sides of the engine, and symetrical headers). It's difficult to tell without reference measurements from when the car was running well. Photos here: http://forums.pelicanparts.com/porsche-911-technical-forum/1059924-need-some-input-problem-3-2-translant-going-lean-misfiring-after-two-min-7.html#post10860179 - Disconnecting injectors on one side completely (so it only runs on three cylinders, for example 1-2-3) seems to make the car idle consistently (but only on three cylinders 1-2-3). Plugging in the other three, 4-5-6 (running on all six) makes the car run inconsistently, but when you then unplug 1-2-3, the car runs consistently on 4-5-6. This is weird, but it's also a weird test that may or may not reveal anything useful. - Taking the muffler off and measuring air-fuel mixture independently on each bank revealed that 4-5-6 was running leaner than 1-2-3. This could be a missing cylinder on 4-5-6, or less fuel getting to 4-5-6, or an air leak somewhere on the 4-5-6 side. This mismatch was also confirmed when the LM-1 mixture meter was plugged directly into the 1-2-3 side, and the tailpipe measured a significantly leaner mixture than the reading on the 1-2-3 side. PUZZLING QUESTIONS: - Why does the car seem to run so much better when it's cold and then when it warms up, it just starts misfiring like crazy? I would think, if there were any big mechanical issues then they would show up within the first second of starting the car. It could be an air leak that only happens when the car warms up, but I did smoke test it when it was still warm, and nothing showed up. NEXT POSSIBLE STEPS: - Swap out injectors with the ones that Steve W. lent me. - Disconnect alternator belt to see if the alternator is interfering (what a huge pain on the 914.) - Remove each fuel rail and fuel line from the car and check for blockages. - Figure out a way to check fuel pressure on the 4-5-6 of the engine (I think I have this figured out) - Remove manifold and look closer at it - not sure if I can get it off / out without dropping the engine, bare minimum, would have to remove the rear trunk lid and engine lid (pain) - Run leakdown test when the tester arrives this afternoon -Wayne |
Hi,i was wondering .i think i asked before..did you ever check the ref-speed sensors distance at the flywheel.0,8...?
Ivan |
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-Wayne |
Okay, I've finally given up on the premise that this would be solved quickly, so me and my two sons removed the rear trunk lid and the engine lid. More room to work -> what a luxury.
Two more data points. I removed the fuel pressure gauge and gathered the fuel emptying out of the rails into a cut-off water bottle. Strange thing happened - the mini one filled up, so I put it on the curb, and then used a larger one to catch the other half of the fuel. Same fuel, same moment, same everything. But one looks cloudy and the other doesn't. It might be due to excess water in the smaller one. I've never seen that before, but I've also never really paid close attention either. http://forums.pelicanparts.com/uploa...1589758350.jpg Probably nothing (it's a brand new fuel filter), and the fuel looks perfectly clear on the left, but I'm questioning *everything* that looks a bit weird these days. 2nd data point. I removed the #6 injector and stuffed some fuel hose attached to my pressure gauge into the fuel rail and then started the pump to get a pressure reading. Reads the same as the other side. Although I do feel like it took a bit longer to build up pressure than the other side. This basically shows that there is not a super-major blockage to the 4-5-6 side - the pressure reading was exactly the same. Particularly at idle, I wouldn't think that there would be any issues fuel flow rates anyways, even if there were a blockage. Still, nice to have another data point. http://forums.pelicanparts.com/uploa...1589758596.jpg -Wayne |
Wayne, the sample on the right looks like ^$%^#@& (like someone submitted a sample for a drug test). Can you clarify where that came from and are you even sure it's gas :eek:
You do know that fuel can turn into jelly right. It polymerizes almost like epoxy glue or silicone. I've had this on a motorcycle that sat for a long time. It's next to impossible to clean that stuff out. |
Do a fuel delivery rate test, just put a length hose on the fuel pressure port and feed it into a 1 gallon clear milk container. Then jumper the fuel pump fuse on for exactly 1 minute you must have more than 1/2 gallon in 1 minute. A healthy 3.2L setup delivers 3/4 gallon per minute. But I doubt this is your issue. Then simply test fuel pressure at idle should be 30-32PSI then at idle remove vacuum line from the FPR and FP should read 36-38PSI if you pass these simple FP tests and the delivery rate then it's not the FP nor the delivery rate, move on and diagnose other areas. Read on as I have other suggestions for testing.
I suspect a bad injector (possibly 2) that are acting up at very low pulse widths, like at idle. During code start the pulse width is around 2milliseconds but once warm up happens the idle mixture leans out a bit and the pulse widths drop to the 1.2ms range, injectors that have bad spray patterns or other issues act up at low pulse widths. Try these simple test to see if they make things better at warm idle: 1) Fully warm remove the vacuum line from the fuel pressure regulator (FPR) and plug the vacuum line so it's not a vacuum leak. This causes fuel pressure to increase from 30PSI to 36PSI and this will richen the mixture a bit. See if this makes the idle any better. It's just another data point. 2) Warm idle remove the air cleaner or any ducting to the AFM inlet so you can actually reach in and push the door open a bit further by hand with engine at idle. Simply with engine at idle reach into the inlet side of the AFM and slightly push on the door, this will cause the mixture to go richer and the injection pulse width will increase. Does the engine like it when you do this? If either of those 2 tests help the idle condition it indicates you are running lean in some cyls. Next up try this. Engine fully warm and at idle, observe the WBO2 mixture. Unplug the ICV so it will not alter idle speed. Then unplug each injector while running, test each injector by unplugging it and observe that AFR and make a note of it for that cyl. Plug the injector back in and move to the next one and repeat. This is called a cyl balance test and as you unplug each injector pay attention to the AFR, the idle speed and the exhaust tone. Each injector should have the same effect on the idle quality as you unplug it. If you get to a cyl that sounds different you have a good hint. You can then move that injector from that problem cyl to an adjacent cyl and repeat. Using this method is decent way to find a problematic injector at idle. In a typical 3.2L at idle the AFR should be around 14.0 +/- 0.2 with O2 disconnected, when you unplug one injector while monitoring AFR at the tail pipe the AFR will typically lean out to the high 15s to low 17s, so you have a reference point from other cars I've done this on. Another worthy item is remove all 6 spark plugs and compare them to each other, look at the color of the white ceramic and such. Does one or 2 look worse or different than the others? I suspect you have clogged injector(s) especially after seeing the color of that fuel in you prior post! If you need help with a set of test injectors just PM me. I have all sorts of spare test items for the 3.2L DME system. |
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And, we ran the pump through the system for about 10-20 seconds after installing the pressure gauge on the 4-5-6 rail too, so it's not like this fuel was sitting anywhere for any length of time. So, once again, this doesn't make any sense to me. -Wayne |
I'm not 100% sure what made the fuel turn that color - maybe it was the bottle with water in it, maybe it was the hot sun. I borrowed a 2-liter Pepsi bottle from my neighbor and had my son hold it while we used the pump to fill it from the *exact* same point on the car. Here's the video:
<iframe width="560" height="315" src="https://www.youtube.com/embed/sQ4wXLrFVPo" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe> Also, the really cloudy bottle of fuel magically became less cloudy when the sun went away. I just turned a brownish color: http://forums.pelicanparts.com/uploa...1589774370.jpg I'm not as convinced that there is a fuel contamination problem? As I mentioned before, I've emptied the tank several times and used fresh fuel, and changed the filter, etc. The 2-liter coke bottle shows the fuel delivery rate to be very quick, and the fuel to be crystal clear. I'm not sure why that fuel that dribbled out that time changing the injectors happened to turn brown. Yet another mystery surrounding this car. More to come... -Wayne |
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I haven't had a chance yet to document what happened today. More on that soon... -Wayne |
I pulled the injectors that I had cleaned the other day. All six looked pretty terrible to me, for only being in the engine a very short period of time. Each pintle cap has some crap and crud on it that I cannot really explain. I did use a *very* small amount of grease to gently smooth the installation of the injectors, but I doubt this is from that (really, really light amount of grease - like I just rubbed my fingers with it and then rubbed the o-rings). These injectors look like they've been in an engine for thousands of miles. It almost feels like something in the intake manifold is disintegrating or breaking down. Even if there were a fuel contamination issue, then I don't necessarily think the tips of the injectors (and in particular, the base rims of the pintle caps) would show this much crap.
Photos: http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg http://forums.pelicanparts.com/uploa...1589794182.jpg |
So, here's what happened today:
- I installed the six injectors that Steve W. lent to me this past week and started the car up. When the car first started up, it ran like it typically runs for the first two minutes. Except this time it was for about 3-4 minutes. It seemed to run well with no missing, but it felt like it was running on only 4 or 5 cylinders. Then all of a sudden, it surged and started running better (like a stuck injector had woken up). So, it was running evenly, but not completely on six cylinders (my guess - I didn't have the thermal camera on at that time). But the muffler wasn't completely attached, and I wanted to make sure that the gaskets were in there and tight, so I took off for a bike ride and let the car cool down. When I came back, I installed the muffler back on, and started it up again. Instead of lean, it's now running much richer I plugged in the O2 sensor, and the car started running lean again I checked the temperatures of each exhaust pipe, and now cylinder #1 is running cold. I took a video of this, but I haven't had time to review it. I may have swapped one set of clogged injectors for another set. At the end of this session, the car started running poorly again, and was running like it was on the other injectors. What does all this mean? Swapping out / changing injectors definitely changed the way the car runs. I'm not sure it changed it for the better, it just changed it differently. So, that gives a clue that this is fuel-related and not really ignition. If it were ignition related, then swapping injectors would show no difference? This also hints at whether there is a fuel contamination problem or not? Was the car running on 5 or so injectors, got one "unstuck" (I did the tap on the side of the injector with a small hammer trick), and then did they get clogged by something shortly thereafter? I didn't think that the issue was necessarily an injector issue because I had them cleaned and tested, and also they were not clogged when I did my "injector in a bottle" test the other day. Of course that doesn't show fuel flow or fuel patterns, etc. Hmm, it makes one wonder out loud if it's even something silly like the fuel pump being plumbed backwards (where the supply line and return line are switched). Hmm, probably not, as the check valve and pressure regulator wouldn't hold pressure against each other after the car is turned off (they do)? I have a video from today, but it's a bit confusing and haphazard. I'll make a better one tomorrow. I guess the "good" news is that the problem is dancing around (cylinder number one is "cold" on the temps today. That still tends to indicate the problem lies not with the long block but with the fuel / ignition system. Also the fact that injectors made a big difference (which is what Sal said today, and Steve W. said the other day) hints further at those being the issue. Ha - I just realized that a replacement gas tank for a 914 is $160 (Dansk). Man, that is super-cheap, at that price, it's way cheaper than having the original one sent out for reconditioning (heck it would cost that much just to ship it somewhere and back). Also, I was just looking at the injectors on my desk, and I was wondering if I could see if any of them were clogged or not simply by powering them up and blowing air through them. Turns out that does work - I have the connector harness and powered them up with my bench power supply and then just blew through them with my mouth. It was really easy to tell that four were pretty easy to blow through, one not so much, and one hardly at all. I think I have a new strategy: - Empty tank - Replace fuel tank, screen and fuel filter (again). - Replace injectors with new ones (preferred) or have these cleaned again. - For testing purposes pick the six best "flowing" ones that I have on hand (from the original ones and Steve W.'s) and see if they work in the car -Wayne |
Wayne, I just went through the entire thread and earlier in the thread you have pictures of the spark plugs. Plug #3 has some big issues, that plugs is completely white at the ceramic, that cyl is running far leaner than all the others. Is this still the case? #3 cyl is very interesting and has my attention. Could it be this setup in the 914 never ran correctly? At the top of intake runner #3 is the large vacuum port that feeds the brake booster and special brass pipe that's part of a vacuum venturi setup. Can you take pictures of that port just under the FPR? I want to see what they plumed to the port and where the other end of the brass tube goes? I need to see pictures of the entire intake track that was altered.
Let's take a step back and double check what/how this transplant was done. You have a lot of smart folks looking at this and I'm really suspecting something may have been messed up from day one with the transplant. |
Wayne,
At the start of this thread you had this picture, where/how did they plum this brass tube? Looks like one end goes to the cyl3 intake runner port. Where does the other end go? http://forums.pelicanparts.com/uploa...1589802875.jpg |
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- This transplant indeed has never run correctly. It's one of the reasons why it was parked for so long - I got a bit pissed off at it. For many years (12+) it hunted at idle. There were other issues too besides the engine, and I'm slowing going through those as well. - YES - #3 has appeared to always be running a little colder than 1-2 next to it. This has been relatively consistent. I'm not sure if this temperature differential is due to the header design or not though, as some sections of the header pipe are just as hot as #2 and #1. In general, this side, 1-2-3 has been running richer than 4-5-6 though, so that's a bit confusing... - The intake was simply plugged up - there's no need for vacuum pressure anywhere on the 914. Here's a photo I just took for you: http://forums.pelicanparts.com/uploa...1589804656.jpg As for your question in the next post about what is connected there, sorry for the confusion, that is simply my smoke machine funnel plugged into the inlet: http://forums.pelicanparts.com/uploa...1589804656.jpg Thanks! -Wayne |
Glad that vacuum port for brake boost is plugged.
I was a bit confused with spark plug pictures and the ordering of them, if you pull the plugs now do you see any of them really clean and white? If so do the cyl balance testing I outlined earlier so you can maybe prove that the cyls with white plugs are indeed and issue. I also agree with you that making sure all fuel lines, screens and filters are clean is a good idea. Can you also intentionally force the engine rich by the methods I outlined earlier to see if it helps idle quality? One more thing, what's the system charge voltage at idle? needs to be 12.8 to 14.8vdc range. |
The way your injectors look, it's as if the insides of your intake manifold are full of crud, and/or some type of material or sealant used on those intake boots is disintegrating. Maybe time to pull off the intake manifolds, check and clean everything up, maybe even get the TB rebored.
Sure the insides of your gas tank doesn't have any rust in it? Did water ever get in the fuel system (i.e. sitting outside without the gas cap on in the rain)? Also how much and what type of fuel hose is in your system, and how old are they? Are they ethanol rated? |
So something downstream from the fuel filter acts as contamination source and plugs the injectors. That’s in agreement with the yellow stuff you called fuel the other day.
I’m not too familiar with the 3.2 but assume it also has a fuel feed line and a fuel return line to the tank. Does the 914 have the same layout? I’m still concerned that a car sitting for years might have created a form of reservoir of broken down fuel inside the fuel system downstream from the fuel filter. That might be what’s going through the injectors. The black stuff that’s on the tips of the injectors is from where they’re exposed to the air from the intake runners. How is the oil breathing system realized and is it possible the stuff on the injectors tips comes from there. I don’t think it’ll plug their internals though. |
After reviving my car from a 15 year slumber, I ran a new fuel filter for 1000 miles then cut it open like an oil filter to visually check for debris.
Might be worth cutting your filter open. |
Flush each injector port at the rail, Lift the rail and remove one injector, put a length of hose on that injector port into as catch can. Run the pump to flush.
Repeat for all injector ports till fuel is clear. But you will likely have contaminated filter screens in the injectors, they will need to be cleaned again. |
How long has the fuel been in the tank? If it's E10 the ethanol may have separated and you now have it sitting at the bottom of the tank? Why not just run the pump and use the hose to fully empty the tank, then fill with 5gal fresh 91 or 93 octane fuel.
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-Wayne |
I do not know the 914 tank setup but the 911 has a screen at the bottom that gets really clogged with crud and such. I agree that if the tank looks bad it should be replaced/fixed.
What I have learned from other 3.2L that sat a long time is that they ussually have multiple things wrong and that really complicates things. The reason I often see multiple problems is that some time in the past the Engine develops and issue and someone band-aids a solution. For example, we are running lean so someone fixes this by loosing the spring tension in the AFM or they decide to crush the FPR in a vise to increase fuel pressure, I've seen both examples done! Then things get worse and the car no longer runs. Now we start figuring things out and you need to undo all the previous band-aids. I mention this because you may fix the fuel system and still have some other issue. You already found evidence of the spring tension possibly altered in the AFM, you need to keep notes on all the findings that seem like someone messed with something. But dirty fuel like in your photos needs to be fixed first. Quote:
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Hello from Spain, I use a google translator, sorry for the mistakes.
I want to give some restraints. 1º Check if the alternator charge is correct and check if it allows a lot of current to pass through the battery. 2º That so white color in the number 3 plug is proof of a poor mixture, with excess air, that's why in cold when the injection time is higher it hides the failure. Check for possible air intake. Thank y |
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- Goofy 180-degree bend on the MAF mount - WOT throttle switch not working due to recessed connectors in the harness - Ignition wires that look like they've been melted - Cylinder head temp sensor out of spec - MAF sensor that is worn and has been obviously messed with - Intake boot leak (small one) In addition, the other following issues due to age: - Possible fuel system contamination - Possible sealant breakdown or something in the intake manifold I guess this type of crap is what kept Pelican in business for the 20+ years I owned it, so I can't really complain *too* much, right? SmileWavy -Wayne |
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With the clog found in the injectors, I think that is a big clue though for the moment... -Wayne |
Did you happen to see any smoke coming out the fan, however minute? The lower intake gaskets, when they suck in or blow out would show smoke under the shroud, being the lower gasket is way down against the head. That's why you can spray stuff around the runners till the cows come home and it won't show an issue.
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Knowing my luck, I'll probably create a vacuum leak by disturbing it! -Wayne |
Might as well put new gaskets in there if you take the intake off.
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It can come out in two pieces, so you should be able to deal with it in situ.
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Since you're going to pull the manifolds, now is the time to replace those 35+ y.o. fuel lines, especially that big T line that can't be replaced without removing the right manifold. These are the ones that go bad and seep fuel, leave your garage smelling like gas, and bad enough there have been instances of the car going up in flames. The hoses harden also degrade from ethanol and you can tell how leaky they are by how easily the fittings spin around the crimps - they shouldn't. There are several options here, from OEM, to Griffiths or Len Cummings, to custom PTFE. My preference is the latter, as PTFE lines are the best and forever like polyamide tubing and will never degrade with exposure to ethanol and most any chemical, unlike rubber lines which will degrade and need to be replaced after 15 years. I had all mine rebuilt by Mesa Hose in Costa Mesa.
Speaking of which, on rubber hoses, you want at minimum fuel injection hoses rated SAE J30R9 or something like Gates Barricade J30R14. These are rubber hoses rated to withstand ethanol in fuel longer than standard hose. If this isn't the type of hose in your fuel system, the ethanol can degrade and dissolve the inner layer of rubber into your fuel system, clogging filters, injectors etc. If there's any rubber hose submersed such as inside your fuel tank (i.e. prepump), make sure it's submersible rated, or you'll get the same problem with the outer layer of the rubber hose degrading and dissolving into the fuel. If you take paint thinner and rub the outside of nonsubmersible standard fuel injection hose, you'll see the black rubber dissolve right before your eyes. Fuel hoses are typically layered with as much as 5 layers of different plastics and rubbers, each having a specific property and function. I don't know anything about the 914 fuel system and the lines from the tank to the engine and back, but pay attention to anything that is not polyamide. |
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-Wayne |
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-Wayne |
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I emptied the tank today, saw some stuff in there, but didn't get a good, close look, as it's not completely empty. I will remove the tank tomorrow and take a closer look. The injectors and fuel rails go to RC Injection for cleaning tomorrow as well... -Wayne |
Isn't there a guy here that makes the lines? I was thinking a member did that.
Also there's this https://members.rennlist.com/imcarthur/fuel-lines.htm Edit: Found it! Len at autosportengineering.com (boxsterGT here on PP) Here's a thread with his work go to post 10 http://forums.pelicanparts.com/porsche-911-technical-forum/952176-88-carrera-fuel-line.html ^^ that thread has a couple of nice options. Len's solution and one called the Feeler kit link below https://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/1011141-feeler-fuel-lines-3-2l-stainless-teflon.html A thought on the fuel, if you're worried about contamination from the tank, couldn't you place an inline filter at the tank temporarily along with the one back in the engine bay? I'd think that double filtration would rule out contamination from the tank. I'd think that draining and filling several times like you have would dilute whatever contaminant might be in the tank. I'm assuming the 914 has the bung in the bottom of the tank that everything tapers to like the 911 does so I'd think unless it's a gelled mass that is in the tank, you'd have it cleared by now. If I was questioning the fuel I think I'd try to plumb the suction side of the pump into a clean can of fuel for testing purposes. I haven't looked at how the lines plumb into the tank from the pump but I would think in a pinch for troubleshooting that it could be done. Something guys do on diesel engines is plumb the return to the tank into a clear glass and run the pump. This shows what's flowing through the system. I'd think you could do the same on this car since it has a return line.. right? |
Gracias, buenas observaciones. Hicimos una prueba de humo (4 veces), y eso volvió bien. La carga del alternador es buena, creo que ya lo probé / verifiqué, pero no puedo recordarlo por completo. Sin embargo, está en la lista.
Con la obstrucción encontrada en los inyectores, creo que es una gran pista por el momento ... -Wayne Delighted to be able to collaborate in this interesting thread. Alternator current, I mean to check with meter the alternating current input to the battery Cheers |
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