924Board.org

[Mike77]

I just got done building the cold start injector push button described in the tech section, and the engine still won't start. It does sputter a little when I push the button, but no start. The odd thing is that the engine will start if I remove the boot at the throttle body. I then dies quickly but the I reattach the boot and it fires up and runs. What does this mean? My injectors are new so I don't think I'm loosing pressure there and if it was the accumlator, it still wouldn't start when I remove the boot, right?
Maybe a bad cold start injector?

Thank

[Benski]

I'm guessing that's fuel vapor lock. For some reason (small leak in the fuel system), fuel vapors accumulate in the intake system and the car won't start. When you remove the intake boot, you let the vapors out of the system.

Does it smell of gas when you take the intake boot off?

This is just a guess but it's a possibility. If it is the case, it's probably a bad check valve in the fuel pump or bad accumulators.

[dpw928]

Your hot start problem is caused by a fuel pressure leakdown somewhere in your system. The most common cause is a leaking fuel injector. If those are alright your fuel accumulator or check valve may be faulty.

Dennis

[924 turbo]

Make sure you check the mixture too, it might be off.

[Paul]

Having owned 924's since 77, many of them had this problem. The problem is usually due to the lack of fuel in the injection system due to leakdown due to a faulty check valve or a leaking accumulator. Once the pressure is gone the remaining gas boils and thus all you have is gas vapor in the injection system.

My favorite trick is to turn the ignition on to the run position, listen for the fuel pumps to run and then shutdown, turn the igntion off, wait 30 seconds, repeat, wait 30 seconds, repeat. Then crank it and it will usually fire up.