Broken down

mlambert1987 · 04-08-2010, 08:03 PM

So the car has been running great, then today it died on me. Whenever i try and run it, it will start up and then die after 2-3 seconds or idle really rough and reeks of unburnt gasoline. Both fuel pumps are at least running as i can hear them both engaging. Any thoughts or suggestions? I am thinking warm up regulator, or something to do with fuel injection/pumps? If i slowly work her up to 3k she runs well after that, but thats only if i have it in neutral. I pulled one fuel pump relay and on one pump she ran much better for a bit if that helps narrow anything down. Unfortunately im not near my normal mechanic so I had to bring it to a place where he is not too familiar with 911 motors, only having worked on csi in the old vw's

Thanks for the help,
Mike
1988 turbo

cl8ton · 04-09-2010, 12:16 AM

Mike I have nothing to add here, but thought I would bump a new members thread!
Welcome!

jwasbury · 04-09-2010, 05:19 AM

Hook up fuel pressure gauge to verify system pressure and control pressure. This will tell you if the problem is with the WUR and/or fuel pumps. For Engine type 930/66 (not positive if this is what you have, but values should be close) system pressure should test within 6.0-6.7 bar. Cold control pressure will vary depending upon ambient temps...at 20 celcius, it should be around 1.25-1.50bar. Warm control pressure should be 3.65 bar +/- 0.2

Your problem may also be ignition related or an intake leak.

Turboo934 · 04-09-2010, 06:18 AM

If it reeks of gas could be the fuel accumlater next to the fuel filter .

mlambert1987 · 04-09-2010, 07:12 AM

Ok so I will stop by the shop I had it towed to and hopefully check the fuel pressure today, unfortunately I'm not back home where I could bring it somewhere I have tools to check stuff or to the mechanic we normally use, so it is sitting at a mechanic I only vaguely know. Like i was saying it runs really well over 3k so. How could I check the fuel accumulator for proper function? also could the warm up regulator contribute to any of these problems? when it does run it runs real low rpm wise and doesnt want to rev when u push the gas, but it will gradually climb to 3k and then run smooth up at that range.

thanks again guys,
Mike

mlambert1987 · 04-12-2010, 11:23 AM

Test fuel pressure seemed fine, Could the fuel accumulator be getting perfect fuel pressure and be screwed up or?

Thanks,
Mike

mark houghton · 04-12-2010, 11:59 AM

I'm not sure a bad fuel ammumulator will cause your symtoms. Aren't they primarly there to dampen pressure fluctuations and provide a pressure reserve when re-starting the car? Something like that anyway.

Since your control and system pressures seem to be in line then, there is one more thing that will cause a pig-rich rough running car...an air leak before the throttle body. Remember, that's metered air which has already set up the fuel delivery rate in your CIS fuel head when it deflect the metering plate. If you let that air escape before it gets to the intake manifold, it will throw your mixture to the way rich side. Also, something about your other comment of it running better with one of the fuel pumps taken out of the loop...that's a clue and it's telling us something. Could it be with only one pump you still get the fuel pressure required, but get less volume to the injectors, thus leaning things out a little to compensate for an overly rich condition???? Just a thought.

Turbo hose connections and IC o'rings and hoses....look at them, spray carb cleaner around to see if the rpm's change, pretty painless exercise.

Otherwise, ignition problems maybe. Go after the obvious first (wires, connections, etc).

mlambert1987 · 04-12-2010, 12:30 PM

thanks a lot i will definitely try that after work today when i stop by the shop

mlambert1987 · 04-14-2010, 08:35 AM

Update is that the fuel regulator is not getting any juice through the wires. Fuel pressure was 90 psi. Back tracking the regulator today

RarlyL8 · RarlyL8's Garage

Those symptoms would be consistant with a WUR not getting power. Is this what you meant by fuel regulator?
System pressure will be ~90psi. Your WUR cold pressure will remain at 20-25psi if there is no power going to it. Warm pressure should raise to ~40psi or so.

mark houghton · 04-14-2010, 10:00 AM

Quote:

Originally Posted by RarlyL8

Those symptoms would be consistant with a WUR not getting power. Is this what you meant by fuel regulator?
System pressure will be ~90psi. Your WUR cold pressure will remain at 20-25psi if there is no power going to it. Warm pressure should raise to ~40psi or so.

Mike, one more point to add to this - in case you're not aware. When testing for electrical power in the line to the WUR, you won't find any juice there unless the fuel pumps are running.
Please disregard if this is common knowledge.

mlambert1987 · 04-14-2010, 10:22 AM

No no thats definitely helpful, if I have the key in the run position without the vehicle actually running that would qualify as pumps running correct? I can hear them engaging.

Mike

fletcher0780 · fletcher0780's Garage

Quote:

Originally Posted by mlambert1987

No no thats definitely helpful, if I have the key in the run position without the vehicle actually running that would qualify as pumps running correct? I can hear them engaging.

Mike

I thought the pumps only ran when the metering plate was pressed down?

mlambert1987 · 04-14-2010, 11:38 AM

Update* with the key in the run position the wur didn't seem to be getting power. So I will go and check the fuse associated with it and see if power is going to that etc.

jwasbury · 04-14-2010, 11:44 AM

Quote:

Originally Posted by fletcher0780

I thought the pumps only ran when the metering plate was pressed down?

This is supposed to be true. If the micro-switch at the air meter housing is disconnected, pumps will go with the key in the run position.

mark houghton · 04-14-2010, 12:05 PM

Quote:

Originally Posted by jwasbury

This is supposed to be true. If the micro-switch at the air meter housing is disconnected, pumps will go with the key in the run position.

Yepper, that would be correct. The key point being that there will be no power to the WUR unless the pumps are running...whether they run with the key on/engine off or not.

mlambert1987 · 04-14-2010, 07:38 PM

Ok so after removing that switch we do in fact have power to the WUR. Now I am even more confused. The mechanic up here is not familiar at all with this which makes it even more difficult. So its running rough on one pump not at all on two. WUR is getting juice but the car smells overly rich. So check around for air leaks I guess, right?

mlambert1987 · 04-14-2010, 07:38 PM

p.s
The mechanic said it could be the ignition coil?

It has fairly new wires and distributor to my knowledge.

mark houghton · 04-14-2010, 08:14 PM

Frustrating, I know. So, you have confirmed power to the WUR....that's good. And you've confirmed 90 psi "system" pressure....that's good too. Do you have the gauge setup to check control pressures as well? Those (control pressures) are what really determine how well your WUR is working.

Yes, I would still check for the obvious air leaks. Elliminate the most simple and obvious stuff first so you don't chase your tail. Yes, it could be poor spark. Have you checked that? You should get a good healthy spark when holding a plug wire close to ground...we're talking like at least a half inch spark.

mlambert1987 · 04-15-2010, 05:26 AM

Yeah super frustrating because this guy doesn't know much about the car and I can't get her home to my garage. I will have him test the spark. To test control pressure I'll have to see if he knows what to look for. Thanks for all the advice and options guys if anything else that could be causing it pops into mind let me know.

Mike