grev1

Hey

I bought a 87' N/A in October 09, and before I parked it in a nice warm garage for the winter I discovered a strange coldstart issue. I have searched the forum, but can't find something similar.

The previous owner removed the airpump, installed a RB exhaust all the way except the rear silencers. He also hooked up a switch on the fuelpump. Engine was rebuilt about 20k km or 12k miles ago. The car itself has about 118k km or 73k miles.

I didn't have much time to find out about the issue at the time, because I had to park the car (rented a garagespace).

So to the problem:

Within about a day or so the car starts fine, but the idle bounces between about 1k and 1,5k RPM when cold. When the engine gets warm the idle is fine. If I turn off and on the engine when its warm, the idle is fine. The engine has no hotstart issues.

When the car sits for several days I must crank very long before it starts, but if I switch off the pump the car is much easier to start. The idle when cold is still bouncing, but is fine when the engine gets warm.

Also if I touch the throttle and let it go, the engine can hold the RPM, but start to bounce again after a short time.

The engine never stalls on coldstart.

My guessing with the coldstart is that the engine gets flooded because of leaky injectors. But that wouldn't explain the bouncing idle.

The temprature outside at the time was between 0-10C or 32-50F.

Thanks for all help, and an extremely informative forum!

Cheers from Norway!!

midnightbluefc

iTrader: (19)

i have this same issue it idles weird like that but then after warm it idles nice. i really havent looked into it hopefully mt turbo swap goes well...

calpatriot

Some candidates include:
1) vacuum leaks
2) operation of BAC valve
3) operation of AWS/water thermo sensor
4) fast idle cam/thermowax
5) double throtte diaphram

The temperature dependent nature of the problem you describe suggests the water thermo sensor, fast idle cam or double throttle system. The FSM has good troubleshooting procedures for each.

It could be as simple as a perforated diaphram in the double throttle system; it has vacuum only in cold (post start) conditions; the thermovalve shuts off the vaccum once it warms up. Until then the perforated diaphram might be acting as a vacuum leak, causing the erratic idle.

Check the resistance of the water thermosensor per the FSM, and the voltage for it at the connector to the ECU.

Verify proper operation of the fast idle cam/thermowax.

RTRx7

iTrader: (2)

You are describing dirty injector problems.
Send them to witchhunter performance and have them serviced.
If that doesn't fix it, you should do a compression test because the long cranking could indicate low compression. Good luck.

grev1

Tnx for the replies
I will check all this as soon as I get the car out of the garage!