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mrpaul152

81 turbo that once engine is warmed up it is a real pain in the a** to get going again. Once you get it started it runs fine. You guys were great in last post thanks again!! Any thoughts on this one. I am taking it to get painted tomorrow.
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1981 924 turbo

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Could be:

Fuel Pump Check Valve
Fuel Accumulator
Warm-Up (Control Pressure) Regulator
Primary Fuel Pressure Regulator
Aux Air Valve
CSV and Related (thermo-switch)
Leaking Injectors
Vacuum Leak(s)

Hmm, did I forget anything? The first step is to check your system and control pressures, cold and hot. You could also remove the screw from the bottom of your accumulator and see if fuel runs out. . .that is what was causing my hot start issues.

Good luck,

rasta
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Smoothie · Posted: Wed Aug 29, 2007 2:01 am Post subject:

mrpaul152 · Posted: Wed Aug 29, 2007 3:42 am Post subject:

Smoothie,
That is exactly the deal... If I hold or pump the pedal it will start. Very slowly but it will start. I was reading on another post that you could put a switch on the cold start injector to aid in getting started. Don't mind doing for now because it will be going in for paint tomorrow and would be best if it ran. But I do want to get it going right after it comes out. It does have 2 new fuel pumps and filter. Does anyone remember to install the temp switch on the neg side of injector (RED and White wire)? Also after warm up my oil pressure is dropping extremely. Could the ball and spring on the oil pump have anything to do with that? If so do you just clean and reinstall?

Rasta,
I will check this evening on the accumulator. What does it mean if fuel runs out?
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1981 924 turbo

Buwani 931 · Joined: 31 May 2004 Posts: 308 Location: Napa California

You might want to check that oring you just replaced in the pressure regulator. If it is not correct or you have pieces of the incorrect oring still in there, you will be loosing residual pressure causing hot start problems.

A pressure test gauge would your best starting point in my opinion.

Shawn
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1980 931
That's thirty minutes away. I'll be there in ten.

mrpaul152 · Posted: Wed Aug 29, 2007 4:30 am Post subject:

Shawn,
I cleaned out as much of the old oring as I could even flushed out with fuel. You know what now that you mention it I did not even put a oring back in I don't think. I put the needle back in to flush fuel through lines and did not remove and put oring back in. I will check tonight. I hate to remove again because it is running pretty darn good now. This is the first actual turbo car I have driven. Does the boost normally come in about 3000rpm? It feels like a Chevette before boost then like a V8. Any thoughts on the Oil pressure?
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1981 924 turbo

Buwani 931 · Joined: 31 May 2004 Posts: 308 Location: Napa California

That would defanetly cause a problem.If you,( or anyone ) need that oring for the pressure regulator , just send me your address and I will drop them in the mail. I got 50 of each ( cost like .02 each ) so I still have 49 of each left. I am 98% certain they are are correct in size and material but unfornatly I have to wait a few more weeks until I put mine back together and test it out.Funny how my Durango, Ranger, Rabbit and 931 all needed attention this month.
I have never (knock on wood) had oil pressure issues so I have never really looked into it.
On mine, at 3000 rpm ,I am well beyond the just kicking in stage.

Shawn
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1980 931
That's thirty minutes away. I'll be there in ten.

Smoothie · Posted: Wed Aug 29, 2007 5:03 am Post subject:

There's a rubber bladder or diaphragm in the accumulator. If fuel runs out when you remove the screw from the bottom, that means the bladder is torn, and the accum is ng.

That o-ring on the pressure regulator is one of the several things that hold fuel pressure in the lines after shutdown. Rasta and myself listed the others above. Definitely need that o-ring - its' being missing, by itself would cause the hot start problem. As Buwani mentioned, don't use just any olde black rubber o-ring - you need one made of stuff that's fuel resistant. "Viton" is one material they can be made of if I'm not mistaken'.

Oil pressure - yeah, mine's been doing that more lately, even after switching to 5W-40 oil. It might be the oil pressure regulator. Might also be the oil cooler thermostat...? I'll be checking the pressure regulator on mine soon. -But I'm recalling a few more discussions about this lately - if some of them were 924NA owners, that might reasonably rule-out the oil cooler thermostat because the 924NA doesn't have one. Probably about time I installed an oil temp gauge...
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

Smoothie · Posted: Wed Aug 29, 2007 5:09 am Post subject:

For that Chevette to V8 thing at 3k rpm, I'd review the vacuum lines and their routing, especially to the ignition distributor.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

mrpaul152 · Posted: Wed Aug 29, 2007 5:15 am Post subject:

Smoothie,
The Oring that I found before was an A\C oring. Right size but as advised might not be fuel tollerant. That was an understatment. I checked on it the next day and it was almost compleley disolved. I flushed all that stuff out (I hope). I will replace with a fuel injection oring tonight and check the accumulator.

I have put 20 50 in and it still goes very low. Light was flashing before and does not now but I am still worried.

Shawn,

I think I will take you up on that offer so I know I have the right oring. I will be most happy to send you whatever the cost. I do not want you to be out of pocket or anyone else for that matter. All of your advices are worth much more than I can afford. Thanks to all!!!!

Does anyone have a parts car with the A\C and Heater Controllers they would like to part with? My center piece is broken off and I cannot turn on. It gets mighty hot in Corpus without Air Conditioning.
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1981 924 turbo

Smoothie · Posted: Wed Aug 29, 2007 5:23 am Post subject:

Oh yeah, you're that other guy we were already talking to in another topic about the o-ring.

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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

mrpaul152 · Posted: Wed Aug 29, 2007 5:29 am Post subject:

Around what rpm should the boost kick in?
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1981 924 turbo

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

I have 5 psi at about 2400 RPM, full boost before 2900. Oh yeah, and I spent a couple hundie on new intake rubber. . .

On the oil pressure, the manual says falshing at tidel after hard driving (in the Texas August heat) is nothing to worry about. The kicker is your pressure at 2750 RPM, should be 75 PSI (around 5 Bar).
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

johnathan1 · Joined: 08 Oct 2007 Posts: 308 Location: Downey, Ca

I just started having starting problems too...

Seems better to just ad to this thread...

When cold, the engine starts perfectly, but it doesn't want to idle, and I has to hold the gas pedal slightly to keep the rpms up, otherwise it will idle very low and act like it wants to stall.

And occasionally when hot, it will just crank and crank...a couple times until the battery is dead. Sometimes it will be hard to start, and then run roughly for a few seconds, then it runs fine... And then sometimes, it starts and runs perfectly when hot...strange that it is so intermittent. Would this point at any particular part going bad?

I also just replaced both of my fuel accumuators. (Those things are spendy!

)
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-1977 924, 4-Spd...Gone
-1987 Toyota Supra Turbo, Pearl White, BPU, 300RWHP @ 10psi.
-1989 Mercedes-Benz 300SEL

WARNING: MAY CONTAIN TRACES OF AUDI OR VW!

Buwani 931 · Joined: 31 May 2004 Posts: 308 Location: Napa California

Have you tested the fuel pressure?

Shawn
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1980 931
That's thirty minutes away. I'll be there in ten.