2.7 will not run well after CIS rebuild

[Ginger77]

Hi Thomas,

Thanks for your elaborate reply. I hope I'm near to having the engine run properly. I've invested nearly €2500 in parts and it's unbelievable that the engine still runs worse than when I started with bad rubber seals and gaskets, broken injector sleeves, leaking injectors, incorrectly routed vacuum hoses and the list goes on.

I want to focus on the check valve here because I did a lot of research before purchasing the Pierburg pump. I got the 7.21659.70.0 from the E3T series as they call them. These pumps are supposed to have an internal check valve, see the first paragraph in the left upper corner in the attached screenshot of documentation.

Also, I was quite happy with the way the AAR closed. Mind you it was tested when it came out of the freezer and thus was frozen at -20C.

I'm hoping to test fuel deliver pressure soon and install the FA when it arrives later this week.

[Ginger77]

I got ill last week so I was out for a few days. In the meantime a nice new silver Bosch fuel accumulator arrived. As well as the M14x1.5 to M12x1.5 fitting to test the check valve. I finally got a chance to go out today.

My conclusion is that (1) the check valves passes the test. A few seconds of the fuel pump on gave over 6 bar of pressure. That slowly dropped to 2 bar and per 5 minutes the pressure dropped 0.05 bar to 1.8 bar after 20 minutes.



And (2) CIS is still fighting me in every possible way. I then spent over an hour to install the fuel accumulator. The main problem was to get the hard line to the filter to seal. I eventually took out the fuel filter and assembled both on the floor. But to no avail. After many attempts I still get a wet fitting.



That would be the center fitting or left in the photo. The one that seems to screw on further than the line from the pump. Am I doing something wrong. Believe me: they are on tight. I removed all the fuel lines several times and none of them leak except for this one.

Also, I let the fuel pump run for a few seconds to check the cold pressure. Unfortunately I was just under 1 bar. I had hoped it to be higher due to the old fuel accumulator losing pressure but OK. I also heard some squeeking injectors. Remember, they are new and did not open at this low pressure before. What is going here?

[Ginger77]

Well, I slept on it... but it still doesn't make any sense. There are no fiber rings or crush rings missing because there should be none.

I suppose I'd best take the assembly (filter and acc.) out and inspect it on the work bench. I'll check to see if the ball of the hard line is undamaged because that's what's supposed to seat in the accumulator fitting. I did notice the surface was hard to mate especially compared to a cone fitting. The ball seat tends to wiggle.

I'd rather not resort to thread sealant unless anyone would advise me to. I have Permatex PTFE sealant and Loctite 574 at hand. Or I could use some PTFE tape. But I can't see how that should be necessary.

[Ginger77]

I took the assembly out and to the workbench. It seems the ball seat of the hardline is OK.



But the inlet has a hairline scratch that took me 3 photos to capture but must be the culprit of the leak. Could this be a manufacturing error?

[Showdown]

Wow that’s a tiny scratch!! I’d bet that with some 800 grit you could eliminate it.

[boyt911sc]

Diederick,

Did the the new fuel accumulator come like that? The compression fitting of the outlet is not even close to the smoothness of the inlet. I would contact the vendor and show the picture of the fuel accumulator. They might replace it. That is certainly a poor quality merchandise. You would be lucky to make it leak-free.

Tony

[Ginger77]

Hi Tony, yes it came like this. New Bosch item though sealed in plastic and a Bosch box. I contacted the vendor indeed. Hopefully they'll have good customer service and will replace it.

Just another example of my bad luck with CIS. If it weren't a $180 item I'd place another order right away and get back at it. But I'll wait for their answer first.

I'm a little hesistant to sand the outlet. I wouldn't want to get particles in the FA.

[boyt911sc]

Originally Posted by Ginger77

Hi Tony, yes it came like this. New Bosch item though sealed in plastic and a Bosch box. I contacted the vendor indeed. Hopefully they'll have good customer service and will replace it.

Just another example of my bad luck with CIS. If it weren't a $180 item I'd place another order right away and get back at it. But I'll wait for their answer first.

I'm a little hesistant to sand the outlet. I wouldn't want to get particles in the FA.

Diederick,

What ever metallic particles you created fixing the fuel accumulator would be filtered. Blow compressed air to the FA after sanding or position the FA upside down and perform the sanding operation. Wipe clean the fitting and you are done.

Think positive and you could overcome more challenging problems in life. You might as well fix the ball section of the S-tube between the fuel accumulator and fuel filter to improve the sealing and eliminate the leak. Summer is coming very soon and good driving season on your calendar.

Tony

[Ginger77]

Thanks for your positivity, Tony! I'm off to a father and son evening after work and see Eric Clapton perform tonight. But tomorrow I'll get some 800 grit and sand the ball section of the S tube and outlet of the FA and report back.

[Showdown]

Given how small that scratch is, I don’t think it’ll take much effort to get a nice surface.

You could also use a drill or dremel tool with a conical polishing bit to address the entire surface.

Like Tony said- this is simple and you’ve totally got this!!

Edit: a thought:
Isn’t the FA, port agnostic in that it doesn’t matter which is the input and which is the output? If that’s the case (can’t remember and not at my car to check) then you could flip it to see if indeed that scratch is the culprit or if it’s the female part of the cohline fitting… not sure if that’s more work than just nicking off the scratch but a thought none the less.

[Bobboloo]

I'm late to the discussion and confess I haven't read all the replies but I read your initial post and that all looks good.
Check your timing. Make sure your distributor isn't 180 degrees out of time. That your sensor plate dances makes me think your out of time and intake valves are still open when they should be closed.

[Ginger77]

Hello one and all! It took me a few days due to busy family life and, if truth be told, it's a little hard sometimes to find the energy to go out for the so manieth time to get the CIS sorted.

However, I put the filter and accumulator assembly back in place after having carefully and meticulously mated the two on the work bench - away from the car. My 911 is not parked at my house so I often go back and forth with parts and tools. When the lines were on and tight I grabbed my remote fuel pump switch, connected the battery, turned the key and flicked the switch.

I heard fuel and pressure building... and an odd whistle. I waited a second or two and at that point fuel came squirting out of the fuel line that runs from the filter to the CSV and FD. F***. The FA kept dry and all seemed well. But now a new issue has risen.



I'm pretty sure I didn't break the line during the dismantling of the filter and accumulator. I admit it's a little stretched and could point to the right rear. But I suppose this was going to happen at some point. This line looks particularly brittle and the rest seem fine. And in that perspective I'm glad it happened now and not while driving.

What's the best next step here? I found it's part number 93011057000 and like $200. Do I have any other options? Should I have the polyamide of my original line replaced?

[OSC911]

I got Len Cummings to make me one - mine leaked also after moving it to replace the accumulator.

len.cummings@verizon.net

[boyt911sc]

Diederick,

I could offer you one of my spare delivery fuel lines but they are old too. Not worth paying the shipping cost across the Atlantic. Just spoke to Len an hour ago and he is very busy.

I am traveling to Europe next month and if you could have Len make the delivery fuel line, I would be more than happy to take it with me and mail it from Barcelona. Len could use the fittings of my fuel lines if needed. Or find someone local with experience.



Or you can have one of my spares for FREE that I will pressure test and mail it to you if you could wait till mid July. Arriving at Barcelona on the 16th. Contact Len Cummings ASAP.

Tony

[otto_kretschmer]

Not sure if someone mentioned it but you may want to pull the tank out and clean it and replace the screen. I'm doing that right now.

[Ginger77]

Hi Otto, replacing the tank screen is on my list. However my fuel delivery and flow test were good.

Tony, thanks so much for offering your help. I slept on it and decided to place an order with a Dutch company that sells the fuel line new. I'm hoping to receive the line later this week and test my luck once more.

[boyt911sc]

Originally Posted by Ginger77

For reference. The control pressures are as follows for my 1977 2.7 033 WUR.
CCP 1 bar (13 degrees C = 55F) 15 PSI
WCP 2.9 bar (takes about 6 minutes) 42 PSI
WCP 3.3 bar with vacuum 48 PSI
These are according to spec given the workshop info I'm using.

Diederick,

I don’t know how we missed these data from your initial post (#1). Except for the WCP w/o vac, the CP and [B]WCP w/ vac are OUT OF SPEC for WUR-033. From what control fuel pressure chart/s did you get them from? Have you corrected the fluttering behavior of the AFM arm? Check the cold control pressures versus time at 1 min. intervals until the CCP settles to WCP.

Could you make the motor starts and run for a few seconds before stalling? Where are you now as far as start up? Did you check for unmetered air? Have you verified if the CSV is spraying during initial start? Keep us posted.

Tony

[Ginger77]

Tony, thanks for being so thorough and I know you troubleshoot many threads at the same time but we're revisiting some bits here. The pressure you quoted are from last year - before Ruben rebuilt my FD and WUR. This rebuild also solved the fluttering AFM arm. I posted the current pressures on page 3 and they are:

Cold pressure is 0.8 @15C
Warm pressure is 3.3 w/o and 3.7 with vacuum.
System pressure is 4.5 bar

I use the following for reference:





As stated on page 3 cold and warm pressures are a little too far apart. Cold could be higher and warm should be lower. However, I will revisit the pressure test once the fuel line is in place and I'll see if the new FA makes any difference.

Also I mentioned on page 3 that I used my diagnostic leak tester and found no leaks.

My order for a new fuel line got cancelled because it's NLA according to company of the link I posted. So I tried my luck with the local Amsterdam Porsche dealership and they'll have it in the morning - which should be great!

I can start the engine and drive laps in the underground parking garage. My AEM UEGO AFR gauge showed lean AFR when driving 1st gear. Then the engine would stall if I'd rev in neutral after which I would be unable to start the engine. This was all pre FA replacement. I'm hoping to achieve different results after dumping another $400 into the bottomless CIS pit for the FA and fuel line.

[boyt911sc]

Originally Posted by Ginger77

Cold pressure is 0.8 @15C
Warm pressure is 3.3 w/o and 3.7 with vacuum.
System pressure is 4.5

Since you had the WUR rebuilt, the enrichment between 3.7 to 3.3 bar is only 0.4 bar (5.8 psi.) and the system pressure is only 4.5 bar/65.3 psi. These values should have been adjusted higher but if you are happy with these numbers, leave them alone.

My interest is how you did the smoke test because many had done the test incorrectly. Without knowing how it was done, there is a likely hood it was not correctly done. But I will give you the benefit of the doubt that it was correctly tested.

Is the engine running satisfactorily now? If NOT, something is not right. So you are back to square one.

Tony

[Ginger77]

Tony, I purchased a diagnostic smoke tester and hooked it up to the brake booster outlet on the air box. Then I used the assortment of caps and plugs that came with the kit to close off the TB and the 90 deg pipe coming off the AAV. The tester requires 12v and some baby oil and produces enough smoke to find leaks. In the past I found tiny leaks but I sorted those out. I should also note that I purchased a tube of DC high vacuum grease a while back and I smeared it on virtually all gaskets and seals.

Today I picked up my new fuel hose. I replaced the old one. But I couldn't get the banjo fitting at the CSV to seal. Very odd. I used new copper washers and tightened the bolt using my 1/4" ratchet that I use for all the 12mm banjo bolts of the CIS. I'd like to say that I've developed a feel for how tight to go. Plus a 1/4" ratchet is still on the safe side because it doesn't provide too much leverage. Initially I went tight, then tighter but that didn't solve the spillage.

I then wondered whether the CSV or red plastic was giving issues. While taking the CSV off I wondered whether I was going to regret this because it's going to be a pain to put those two Allen bolts back in. I didn't crush or damage the copper washers and the CSV looked fine. The red plastic was still connected to the pipe at the back and I did not dare to take it off so it's staying.

I took the CSV home and hooked it up to a battery. It clicks alright. Sprayed some carb cleaner in and I wouldn't say it sprays but it sorta drips. Actually I have a spare that came with CIS parts some time ago. I tried that one too and it showed similar performance. So I guess the spray is tiny? Not like a modern injector that has a V shaped spray pattern. Am I right? Anyway I'm soaking both overnight in some Liqui Moly diesel cleaner that I have left from when I tried to clean and salvage my old injectors - that was unsuccessful and I currently have new ones installed.

Something I still can't wrap my head around is that right now I randomly hear injectors squeel and open. I haven't run the engine for 2 weeks now or so. So I'm talking while I run the fuel pump and see a cold pressure of around 1 bar. I have new injectors and a rebuilt FD. Why would they stay closed until the prescribed 2.5 bar?