924Board.org

[oldmanwintersret]

Before I going diving into things am asking for assistance on my 924. It barely runs. History of the car since I owned it. Bought it non running.replaced the timing belt, ignition module (new), dizzy (used then a new one which was not the right one) and it ran fine for a week then quit due to a bad fuel pump. Replaced pump car ran rich. Took it to a shop that played around with the A/F ratio as it was running rich. Advised me to replace the WUR and that they were not sure if that was the issue. Not going there again. Three weeks later car died. Now over a year later finally got the car to run again, but it is very weak. The dizzy has been professionally rebuilt. Three of the wires going to the coil have been replaced, The WUR has been replaced along with the ignition switch.

Today, I finally got the car to barely idle under it's own power. If I give it fuel it wants to quit. If I play with the timing it does not help. I am thinking as the plugs were originally running rich in replacing them, and draining the fuel out as it sat for over a year. Are there any other suggestions?
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1982 Porsche N/A

[datatrain]

Here's some advice I got from Smoothie a couple of years ago when my car barely ran.

With an ear near the fuel distributor, jumper the fuel pump relay 30-87 (maybe wire yourself up a switch on a long wire with two 1/4" male spade connectors at the opposite end). If you hear fuel rushing through with the air metering plate in the neutral position, the screw is already too far clockwise (too rich), so back it out just until you hear the fuel flow stop. Then back it out another 1/2 turn. Obviously if you don't hear the fuel flow, turn the mix adjustment clockwise until you do, then back it out 1/2 turn.
This should give you a good starting point to get it running.
If it takes more than a few seconds, and much fuel's been squirted into the engine while not running, you'll also need to change the oil.


After following this advice I chased the timing and mixture for about 10 minutes before it ran nicely.

Maybe this will help.
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'78 924 NA with Collector plate
33 year old car, with me for 21 yrs
Mint '92 318i BMW
Near mint '98 Buick LeSabre
VE7HFR

[oldmanwintersret]

Thanks. It helped have the car running just enough now to take it to a Bosche mechanic on the other side of town for fine tuning. Wish there was a competent one on my side though.
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1982 Porsche N/A

[gohim]

Glad to read that you finally got it running. The idle speed and idle mixture screws are probably hopelessly screwed up.

Don't try the idle speed, idle mixture adjustment process for a 80 and earlier car on a 81 and later car. It won't work right, and will make idle speed and flat spot off idle problems worse.

Before you take the car across town, try setting the idle speed and mixture back to the initial start setting, and see if you can get it to run better yourself.

This will only work weel if you've taken care of the vacuum leaks. Screw the idle speed screw on the front of the throttle body all the way back in (clockwise). Make a note (on paper) of where it was when you screw it back in, incase something bad happens. Now do the same thing with the mixture screw (all the way clockwise, write down where it was when you started, then turn it out 2.5 turns).

The idle stabilizer disable (on the left inner fender) must be unplugged, or the idle stabilizer plugs must be plugged into each other bypassing the idle stabilizer.

Now start the engine, and let it warm up to normal temperature. You can't adjust the idle speed with the engine cold, or it will be screwed up when the engine is warm.

Adjust the idle speed to 900 rpm using the idle speed adjustment on the throttle body. Now turn the mixture screw 1/4 turn clockwise, then 1/2 turn counter clockwise to see what the engine is going to do. Did the engine speed vary greatly (almost die, or jump way up)? If it did, then there's room for improvement. If it tried to die, which way was it when it happened? That is the direction that you don't want to turn the mixture screw. It ran better going the other way, right? So turn the mixture screw 1/4 turn farther than you did previously, in the direction that the engine ran better. Adjust the idle speed to 900 rpm using the idle speed screw on the throttle body. Now do the 1/4 turn test in both directions, and watch to see if you get a major change with the mixture change.

The idea is to set the mixture screw at a point where a 1/4 turn in either direction will not yield a large change in the way that the engine is idling (find the center of the sweet spot). When you find the center of the sweet spot, set the idle speed to 900, and check the ignition timing to make sure it's at spec. You will be where you're supposed to have all of the adjustments when the ignition timing is correct, at the 900 rpm, with the mixture screw in the sweet spot. I actually like to run my 81 924 engine just to the rich side of the sweet spot (1/8 to 1/4 turn clockwise) to help with emissions (NOX). When you have everything happy, then shut the engine off, and enable the idle stabilization. Then you should be able to restart the engine (idle speed should be about 50-100rpm lower), and blip the throttle, without a flat spot (engine warm) just off idle. Let the engine cool, and confirm that the engine still idles normally with cold coolant temperature.