I hope your plugs for the cold start injector and the sensor plate switch, are not swapped over by accident.

Hi Ren

After adjustment my WUR is at 1.4bar at 10 deg C with vacuum applied. Prior to adjustment I was at 0.9 bar, or just below the specification

http://forums.pelicanparts.com/uploa...1701809377.jpg

It sounds like you are already on the lean side of the chart (2 bar at 20 deg C without vacuum). For reference, my pressure changes by about 8 psi/0.55 bar when vacuum is applied

John

Ren: I feel your frustration. BTDT. It takes slow methodical troubleshooting to solve. That's not comforting, but it's reality.

The fuel accumulator should not make a difference in cold start, but I just went back through this thread to see if it has been tested or replaced and did not see whether that had been done. Does it hold pressure for at least 1/2 hour after shut down? Or does it not leak when running the pump with the drain line disconnected (and drain line plugged)? If the FA is original, I can guarantee that it is leaking, or soon will.

Yes, an O2 sensor and AFR meter is very helpful. Now that I have one, I wonder how the hell I managed to tune and monitor engines without one. I would even say it's worth pulling out one heat exchanger and welding in a bung and then installing an AFR meter. It will help answer a lot of the questions you are asking. FYI, AEM sells a clamp-on bung that doesn't need to be welded in. You do need to drill the hole, and then install this thing, which is like a wide SS hose clamp with the bung welded onto it. The sensor then screws into that.

Hard cold starting: Well, it could be too rich, or too lean. You have indicated that you thought it was too rich. Why? Does it blow black smoke when it starts?

Based on what you have said, it sounds to me like it is not getting enough fuel for the first 8 seconds of cranking, which makes me want to troubleshoot the cold start valve and thermo time switch. If the CSV squirts fuel for a couple seconds, the engine should fire almost immediately. It may then die from lack of fuel or air, but it should fire. In fact, a quick test of whether you lack fuel during a cold start is to squirt starting fluid into the intake. If it fires almost immediately, that indicates you don't have enough fuel. I'll bet that is what you find out.

Have you or Karl verified that the cold start valve is working correctly and shutting off after a few seconds? That of course requires testing the thermo time switch as well (it should shut off current to the CSV in only a few seconds). Have you or Karl removed and watched the operation of the auxiliary air valve to see that it closes gradually after 12 volts is connected to it? Does the fuel pump run while you crank the engine? I'm wondering if the fuel pump safety switch in the air metering unit is faulty. Lifting the sensor plate slightly off the rest position should make it run.

Have you checked that the injectors do not squirt fuel with the fuel pump running and the sensor plate in the rest position? Pull out one injector and check it. Is the rest position correct? (if not, refer the excellent info Schulisco has provided in a parallel thread about the initial settings of the CIS).

Do not mess with the WUR that Tony sent to you. He set it right in the middle of the specs, so it should not be responsible for the cold starting issues. Don't complicate your troubleshooting by introducing more variables.

Note: I added stuff to this posting several times after I first posted it, to add other things I subsequently thought of, so re-read the whole thing.

One other thing about the WURs. I have a spare 033 WUR too. It has a strange behavior. When I apply the specified vacuum, it changes the CP by 12 psi, but if I apply more vacuum, it drops back to 10 psi. Odd. I would think that the CP should increase for greater vacuum, or just top out at the specified checking value. But it doesn't, at least not on mine. I have not checked the 089 WUR for this behavior yet. That small 2 psi difference should not affect cold start behavior, but keep it in the back of your mind for other running characteristics. .

CIS Troubleshooting……………
 

Ren,

I have provided more than 200 WUR’s to fellow Pelicanparts members over the years and not a single one failed except for those motors with significant unmetered air going into the system. Once the air leaks sources were corrected they all ran well. At this point, if you are having problem starting the motor, you have unmetered air.

Not because you can not locate any air leak does not mean you have none. The smoke test has to be done correctly to be effective. Secondly, test and verify that the AAV and decel valve are good and working. I can’t remember if I tested your CSV (?). Plus your system pressure at 5.3 bar is out of spec.

I will be back home next week. Please do not tinker or alter the WUR.That is not contributing to your starting problem. It is something else we have to identify. Thanks.

Tony

Thanks for the input, folks. I hesitated to share the details of the cold start condition until we sort it out first-hand. The car has only been started & driven five times now, and Karl needed me to take the car and drive it until next time it goes in, which gave him garage space to drop two turbo engines for work. I will report back on this cold starting condition after I drive it more and it goes in again. He is confident it will be sorted out before too long. All things noted above have been checked, and they will be re-checked at next visit.

Tony- Thank you again for your assistance. Your WUR works perfectly! We are aware the System Pressure is a tenth of a bar higher than spec. When we reflect that my engine itself is quite a bit out of spec, with its larger displacement, hotter cams, larger exhaust and overall increased performance, that 1/10bar is not suspicious at this time. And CIS Flowtech recommended it this way for my application, based upon their experience. We may return to it in future as we circle back with re-checks.

John & Pete- Thanks for your ideas and data points. You and I are not far apart when temperature differences are taken into account. Do you have any pressures and AFRs to share re: Warm Control Pressures both with and without vacuum? I was hoping at the end of all this to have some data points for others to use when using a similar engine combination. Your data might help us arrive faster if available.

Give me a bit more time and practice cold starting- I've only done it once. I don't think I opened the throttle while cranking, but rather I waited until it fired. That may account for the extra-long cranking time. But with more time, driving and cold starts, I should have more to share in the near future. Again, thanks for the help!

Cold Start………..
 

Ren,

Put the gear in neutral and don’t even get into the car. Reach over the driver side window to reach the ignition switch and start the motor. If your motor fails to start and idle the first attempt, there is something wrong with your CIS.

I will be away from home for 5 weeks and when I get back home from vacation, I usually go straight to the garage for inspection. Set the house and water heater temperature from vacation mode in the basement and back to the garage. I expect the 911 cars to start on the first attempt or worse, a second try without getting into the car/s.

Tony

500 Mile Update
 

Just a brief update here, and to correct a previous comment I made RE: Cold Start. I have made 5 nice drives of about 100 miles each, and I am getting a better feel for this newly rebuilt engine. I dropped it off this morning at Karl's shop for an oil change and some adjustments.

The cold start is not nearly as bad as I had indicated previously. After sitting 3 weeks, she started up this morning within two seconds, albeit with a slight crack in throttle opening. I was giving it way too much throttle on my first and second cold starts, and that was making things worse- sorry for misleading with my earlier observations. I still have Tony's loaner WUR installed, and after this shop visit, I plan to send my original unit to Tony for the adjustment modification and re-calibration. Then do a final swap-out when it's received.

Two things stand out to me about this new engine: It's pretty loud, and it really wants to GO! I won't say it's obnoxious in the neighborhood, but some might think so, even with easy throttle. I'm still keeping max revs at about 4K, I can tell this baby wants to go way past that. Karl will adjust the valves and change the oil/filter again at 1000 miles, and after that, I should be OK to open her up. Then I will offer a more detailed report. A recurring theme: With these cams, this engine feels like it needs to be at or over 2000RPM for gears 3,4 & 5. And it's really happy over 3000RPM. I have modified my driving style a bit to downshift more and avoid gently lugging it in traffic like I did with the original factory cams. They were more tolerant and torquey down below 2000 revs, but I wouldn't trade back these Melissa M1 cams for those....I'm having way too much fun now!

Ren: Thanks for the update. Glad you are enjoying it. Although the M1 cam in my engine does increase torque above 3000 RPM, and especially around 4000 RPM, I can still floor the pedal at 1200 RPM in higher gears and it pulls cleanly with no hesitation or lugging all the way up the rev range. That's with the SC RoW CIS on it. Yours is a 3.2SS, whereas, mine is a 3.2 long stoke. However, the cam should have pretty much the same characteristics in both engines. Did you keep the stock clutch and flywheel, or switch to lighter versions?

I know you want to follow Karl's recommendations, but you don't need to wait until 1000 miles to let her rip! 500 miles is plenty for break-in. :D

Even if you do keep your right foot in check for 1000 miles, definitely do a few runs to redline and full throttle at the 1000 mark and before you get the oil changed and valves adjusted.

Stay at 4000 rpm until it is up to 150 degrees and start beating the engine like a rented mule.

Thanks for the responses. Pete, if I recall, your cam timing was set with less of a measurement? I think that would give you more torque earlier in the rev range and explain the difference we have?

I set mine to William's ideal measurement, and he indicated to me before it was set that the torque before 2K or so would not be impressive, but after 2K or 2.5K, power and torque would be great all the way up. He was right (of course).

Karl's concern on limiting the revs revolves around the valve adjustment. Yesterday he said it's OK to rev up to 4.5K or even 5K sometimes, but don't flog it until he adjusts the valves at around 1000 miles. Hope this offers a bit more information and reasoning.

No, I set mine to William's spec. I did not deliberately advance or retard the cams. I have tighter deck height and squish clearances because I eliminated the cylinder base shims, which resulted in closer clearances of about .030 or a bit more. That does not change the cam timing.

I understand Karl's conservatism. I would still run it hard at least a few times before the oil change and adjustment. Get everything settled before the adjustment. Do you have any loud valves?

Update Following Full Break-In
 

I know it's been a while since my last update, but this has been a busy year so far. I am really impressed with this engine! It's now past the 1,000 mile break-in, and I am extremely pleased with the result. First, I'll offer updates to the previous issues and impressions I reported in the first 1,000 miles.

Cold Start: Much better now than previous. Tony enriched the Warm Control Pressure with No Vacuum (Full Throttle), and Karl adjusted the fuel injection a touch. We also replaced the Thermo-Air Valve on the CIS, which had lost its delay function, and the cold starting now is overall good. The only caveat is that I need to open the throttle just a bit with my foot to nurse the warm-up for the first 3 minutes, until it holds an idle. I think this must be a by-product of the M1 cams, and it's only a minor inconvenience to me. Karl says this could be eliminated with either a hand throttle, or adjustable ignition timing (like 123 Ignition), or a full EFI setup. And the idle could come down to a more stock-ish level. But none of those is on my radar at this time.

Warm-Up: After about 3 minutes nursing the throttle just a bit, the engine holds an adle, and I can drive off normally. We shall see how it does in cold weather.

Idle: Works fine at about 1050RPM without complaint. I don't notice any kind of stumble anymore.

Drivability Below 2000RPM: After enriching the WUR setting, this is now similar to my original 3.0L engine. But this 3.2SS engine is still happier above 2000RPM than below it. She just wants to run, and these cams just wanted more fuel.

Engine Characteristics: Overall, I'm happy to say I still recognize my old 3.0L, it just has MORE of everything, everywhere above 2000RPM. It's about the same up to 2000RPM, and it continues gaining power noticeably and smoothly. William Knight described these M1 cams as very 'Linear' in power delivery, and I agree. I get a little bump about 3200RPM, and another larger bump about 4,300RPM, running strong up to the time I backed off today at 6000RPM. I'll take her up to 7000RPM when I get a good opportunity, but she gave no sign of giving up, like the original engine did at about 5500RPM. And it's pretty loud too, in a good way- not obnoxious.

Oil Temperature: I confirmed in today's 93*F weather the oil temperature runs similarly to the old 3.0L. She cruised at 185*F and increased to 195*F when thrashed a bit. Then, in slow traffic, she crept up to 210*F. I am very happy with these temps, all of which occurred with the air conditioning on. Strangely enough, these temps were about the same in the cooler Spring weather. That surprised me.

Overall: This car is SPORTY now! It sounds and drives sporty, which is exactly what I was seeking. The Dansk muffler with the larger SSIs still have a recognizably similar sound to the factory 911s, and I see that as a plus (I've always loved that sound). The sound is now deeper and meaner, but it's quite recognizable as a 911. I'm emphasizing the term 'sporty' here, as the car is not 'racy' in that sense. This is a sporty street car. Todd Uhl's 300HP 3.2SS was super-sporty and even a little scary to me over 4000RPM in 2nd gear. Mine is certainly short of that- more like undeniably exhilarating- I think I'll leave it there. Yes, this is a sporty street car now- perfect for me. If not for the loud exhaust, the car would appear stock, and I like that, too.

The only thing remaining a the moment is to install Porterfield R4S brake pads, which will happen soon enough. My currently-installed ATE pads will certainly continue doing fine until then. I'm also looking forward to the cooler, crisper air of Winter- these engines love it. That's all for now. Feel free to ask questions if considering a similar project.

Thanks for the update. More positive returns on the M1.

Ren, great to hear you are pst the break-in. Now, drive it like you mean it!