924Board.org

[bigjnson_2000]

I am having a problem with my 81 924. It was not getting any fuel previously because of a bad fuel relay. The owner before me put in new fuel pumps and sending unit. The car will start then idle irratically and shut down. If I press on the gas it bogs out imeadiatly. It will run for about 30-60 secound otherwise. I tuned up the car thinking bad spark, but still have the same issue. I was thinking it might be bad gas buildup on the injectors but it has been 10 years since I worked on a german injected car. Felt best to get some advise before tackling into something not needed.
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1981 924 Paid $950 WOO HOO!

[Smoothie]

Need more info - How long did the car sit unused? (CIS injection needs to be used regularly, otherwise things can get clogged up.)
During those brief periods when you do have it running, is black smoke coming out the tailpipe? Just a puff? No smoke at all? -Have someone look.
The cold start valve and thermo-time switch system will inject extra fuel for up to roughly 10 seconds if the key is held in the start position. That can be used to inject extra fuel - try that to see if it behaves any differently, runs longer, shorter, etc. (obviously don't re-activate the starter after it's running - just hold the key in start during starting, then for a few more seconds after it's started)
You could also try holding the throttle to the floor while starting, then let up and regulate it if/when the engine starts. (When my own settings were off, pressing lightly on the throttle would cause it to die, while flooring it caused it to pick up and run.)
Your problem could be a clog somewhere, bad WUR or AAV, ignition parts or timing, bad fuel/water in the fuel, vacuum leak/s, idle and/or mixture settings off, mice or the snake that ate them in the intake, etc.
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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

[bigjnson_2000]

I couldn't tell you how long it sat for. I bought it 3 months ago and have been working on it since. It did need a new fuel sending unit because the old one was clogged with gas deposits. The is no bad emmisions from the exaust they come out normal. I have attempted to hold the key longer it does not make a differance. The position of the throttle does not effect it either unless I don't hold it, start the car, and then push on the gas the car bogs down mediately and shuts off. The fuel has no water or sediments. I drained it out and refilled it when I bought it thinking the same thing. But just in case since it has sat 3 months with me I still did a sample test everything ok. I have not check cold start valve, thermo-time switch, or the cis injection. Is there one you feel would be best to check first?
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1981 924 Paid $950 WOO HOO!

[gohim]

The 1981 cars are different from earlier 924 models. Troubleshooting procedures are different because of the higly sensitive nature of the relationships between the ignition, fuel and emissions control systems.

DO NOT TOUCH THE IDLE SPEED OR IDLE MIXTURE CONTROLS UNTIL AFTER ALL THE PRELIMINARY WORK HAS BEEN DONE.

I have written several extensive posts to others that detail a procedure to set up 81 and later 924 cars several times. It is a simple, easy, proven procedure. Search the site archives to find one of the posts.

Most probably someone/s have screwed up the idle speed and idle mixture adjustments trying to compensate for leaking vacuum lines, without knowing that the idle speed stabilizer must be disabled or disconnected first.

It is possible to get the adjustments so screwed up that the car will not start, or will not start when hot, or will start when cold, and will not idle when cold but will run well when hot, or will start when cold, will idle/run when cold, but not idle when hot.

You have to replace the broken or worn-out stuff first, then adjust the engine to run, then adjust the engine to run correctly. after you take care of the bad stuff, if the car will not start, you can adjust disconnect the idle speed stabilizer, and adjust the idle speed screw and idle speed mixture to default initial settings, get the car started, and warmed up, then adjust the engine to run correctly both hot and cold.

[bigjnson_2000]

First I would like to thank eveyone for their ideas these are great things to start with. I have replaced everything from the fuel filter bac, and I was kinda hoping not to need to replace the injectors. I will have to pull them out and inspect them I think to check for faults there. I that does not flow I have printed a previous adjustment thread. Please feel free to give me more ideas. I will check them all.
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1981 924 Paid $950 WOO HOO!