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My 92 C2 Turbo has the stock ignition replaced with dual plug, crank fire , Electromotive XDI2.
I have Stock CIS except modified WUR and modified Fuel head(lambda circuit removed). with a single 044 pump up front.
I don't remember mine running for 5 seconds after shutdown with stock ignition.
but whats more interesting is that there isn't a consistent view of what is right vs wrong across our community.
You need to think about this statement.
Everyone here is trying to help you over the internet, with data supplied by you. What do you honestly expect? If that's how you feel, don't ask for advice.
In the end, you either have to fix the car yourself or rely on a shop.
News to me but I still stand by what I said about worn, leaky injectors. I imagine that feature is a safety feature to protect the cylinders from being washed by fuel from a leaky injectors.
I have seen that in the service manual before, I agree with Paul that its a safety feature. As I mentioned before when my fuel pressure was just a tad off it caused the same issue. You changed out everything that I would have suggested. I would not worry about it. It should work itself out. Your run-on issue isn't that bad.
Someone might have tried to make adjustments to the fuel mixture in your cars past to compensate for the staring issue when it was most likely the fuel accumulator going bad. Most likely the idle mixture or your system pressure valve might have been shimmed. If you have service history on your check there. Just a thought. Again nothing to worry about.
@Metal Guru - sorry if that came across as anything other than an observation. There is nothing but gratitude from my side for everyone on this forum who has been generous with their time. I appreciate all of the assistance and opinions without any reservation. What I do find interesting is that the “official” porsche document suggests the car do something that no one on this forum has experienced. Sorry but that is strange. I was not, for one second, trying to minimize anyone’s experience with these cars or their technical acumen.
Ok Ian,we're cool.
Since you replaced the accumulator, the other thing that could allow fuel to bleed the system is one or more leaky injectors. That's the other component at the other end of the fuel delivery system.
Buy three things: CIS test gage (around $130 from Ebay;I have the one in the link below), a Mityvac vacuum/pressure hand pump ($75) and make a jumper switch that you can trigger the fuel pumps with (toggle switch with blade connectors. You stick the blades into where the fuel pump relay is and then you can stand at the back of the car and run the fuel pumps from there).
You want to know how fast the system pressure decays after you shut the engine off. Minimum pressure after 10 minutes is 1.6 bar, 1.4 after 20 minutes.
Are you in spec?
Well the Porsche doc says the ignition stays on for 5 seconds. Doesn’t say they engine should run on.
another datapoint: my ‘91 - which is in excellent running order - would not hesitate to drive it cross country on 5 minutes notice - does not do that. Shuts down clean. Rebuilt WUR, somewhat recent accumulator and filter, Professionally tested and cleaned injectors (replaced 1).
@urquattro20Vt Thanks for adding to this. At this point I haven't come across anyone whose car runs on for 4-5 seconds and based on the collective experience of this group I would be surprised to find anything different. Paul's comment is the most spot on as I do think it poses a safety issue. Can you imagine telling the product liability attorney at Porsche "I've designed a car that stays on after you turn if off"......
Perhaps you're on to something about the definition of 'ignition staying on for 5 seconds' that is different than 'engine continues to run on'? Interesting to look at 930 forums for this as there seems to be a similar set of questions.
At this point I'm going to take my new fuel pump and accumulator as a win and set my sights on working through my fuel injectors. With that said does anyone have an opinion on Porsche OEM vs Bosch injectors (they are listed as the OEM supplier on Pelican Parts)? My experience with non-OEM parts (whatever they may be) has been mixed to say the least.
Brandon's observation is correct. The factory manual says, "...the ignition remains on for approximately five seconds..." after the engine is shut off. Nothing in the manual says that the engine continues to run, or diesel, for five seconds. For reference, my '89 turbo runs on for about a second after key off.
In the 930, this ignition delay relay is in the relay panel on the driver side of the engine compartment, behind the CDI box. This photo, left to right, shows the yellow overboost relay, ignition delay relay, lambda circuit relay, and rear defogger relay. Note: I do not recall who this car belongs to, or I would give credit where credit is due.
@urquattro20Vt Thanks for adding to this. At this point I haven't come across anyone whose car runs on for 4-5 seconds and based on the collective experience of this group I would be surprised to find anything different. Paul's comment is the most spot on as I do think it poses a safety issue. Can you imagine telling the product liability attorney at Porsche "I've designed a car that stays on after you turn if off"......
Perhaps you're on to something about the definition of 'ignition staying on for 5 seconds' that is different than 'engine continues to run on'? Interesting to look at 930 forums for this as there seems to be a similar set of questions.
At this point I'm going to take my new fuel pump and accumulator as a win and set my sights on working through my fuel injectors. With that said does anyone have an opinion on Porsche OEM vs Bosch injectors (they are listed as the OEM supplier on Pelican Parts)? My experience with non-OEM parts (whatever they may be) has been mixed to say the least.
Thanks,
Ian
Replacing the fuel injectors is straight forward until you try to get number cyl 3 injector off, you will need a diesel injector removal tool to make the job easier. it's a PITA
@heliolps2 Curious about the diesel injector removal tool you referenced in your post. Can you elaborate on what the tool is and where you got yours? Is it the kind that is like a slide hammer?
@heliolps2 Curious about the diesel injector removal tool you referenced in your post. Can you elaborate on what the tool is and where you got yours? Is it the kind that is like a slide hammer?
Thanks,
Ian
Here's an example, I forget what size you need, I think it's 14mm, but double-check. Getting the line off is easy, it's getting to the injector with the air pump in place is very difficult without the tool. You may have to grind down the wall of the socket to get to fit in that area. it's tight. Click on the Amazon link below
10-09-2020, 10:49 AM
