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fault chasing on a subie
pete wood - May 2nd, 2005 at 09:31 PM

Got to faults at the mo with my subie, both of them are hard to trace, and the ECU isn't registering any fault codes.

Fault 1;
car won't idle. you have to ride the throttle or it dies. this is really annoying at the lights. Changed both fuel filters so it's not them.

Fault 2;
if I stop for more than about 10 minutes the car will not fire again using the starter. however it can be clutch started easily with a decent push. Could this be heat soak into the fuel lines causing vapour lock, or what?

Please, any ideas to help solve these issues would be great.

Stopping at the lights is a pain and stopping for petrol involves asking strangers for a push afterwards. They are always decent and help, but its not very cool. :o


helbus - May 2nd, 2005 at 10:41 PM

Have you got a VSS installed? Vehicle Speed Sensor.
I am installing one as it lets the computer know when you are slowing down speedwise and helps it go to idle mode.

Buggy Brad can assist with ideas on this one.

The second one may be starter/ earth related. The starter itself is somehow drawing too much current for the earth that is available to be able to allow enough power to run the injectors????

This would explain why it would only happen when using the starter and not when push starting.

Also if it only happens when it warms up a bit this also shows earthing as hotter = less earthing.

You may have to take the earth strap off the gearbox and clean both ends and both mounting points. If this still does not help at all, chech to see if the starter its self is earthing/ bolted tight

These may not be the solutions, but they may be a start or lead to the final conclusion.

Hope I have been of assistance


Brad - May 3rd, 2005 at 07:58 AM

mmm although it is hard without seeing your car... Has it just started or has it been there for ever ?

If it has just started then something must have changed to cause it to begin.

Prob 1 - Check you air flow meter and all your vacum / seal lines. It sounds very much like an air leak between the air flow meter and the throttle body sensor. Also check your PCV valve and vacum lines.

Prob 2 - When you say not fire again what do you mean ? Will not kick over or kicks over and does not fire. If you mean does not turn over then it is something to do with you starter and not engine. If you mean will not fire but starts when pushed I would be looking at your wire that tells the ECU the starter is turning over.

More info please ..


ratbug - May 3rd, 2005 at 06:32 PM

Hey pete,

You checked the idle solenoid and associated piping? I had a few dramas way back, similar symptoms and turned out the hose running from the idle valve to the intake pipe was getting kinked.
Also one thing i've noticed with my subi, if i deliberately disable a sensor (unplug it etc) it doesnt register straight away, takes half an hour or so of driving for the light to come on. Often if you do an ecu diagnosis, it will come up with the codes way before the warning light comes on permanently telling you there is a problem.


pete wood - May 3rd, 2005 at 07:58 PM

For fault no.2;
the starter turns the motor fine, but the motor will not fire. It's been happening for a while now. It only happens when the motor has warmed up abit.

BTW, thanx for the tips guys, helps me keep trying to fix it. I've been driving it about 100kms a day since sunday, and having it not idle in traffic is excruciating. I'll go and have another look at stuff now.

[Edited on 3/5/2005 by pete wood]


pete wood - May 3rd, 2005 at 09:08 PM

It idles now! yay! :thumb

Turns out that the ICV motor I got to replace the original unit I thought was faulty was in fact faulty itself. I put the old one back on, adjusted it higher and now it's all hunky dorry.

Now I just have to figure out the restarting issue. It definitely has to do with heat. Just can't figure out how still.

Gonna check the earthing to begin with.


Brad - May 4th, 2005 at 08:48 AM

check your fuel lines are cool and your return line is clear.


pete wood - May 4th, 2005 at 10:06 AM

so the fuel lines should be cool all the time?

they do feel a bit warm when it's sitting there after running, is that not good?


Brad - May 4th, 2005 at 10:22 AM

Feed should be cold, rtn will get a little warm


speedster356 - May 4th, 2005 at 10:30 AM

You will find that the return line gets warm after idling for a period due to very little fuel usage and the majority of the fuel being regulated back to the tank. My surge tank is warm also after a run.
My fuel lines run to and from the tank run right next to the radiator (up along side the end tank) then across the engine in the stock pipes so it sees plenty of heat soak when the engine is off but doesn't appear to have any problems with fuel vapourising. I would imagine that my under bonnet temps are much greater than what would be in a buggy.
I wonder if your fuel reg is kaput?


pete wood - May 4th, 2005 at 08:50 PM

seems to be much better today, aside of the starter solenoid wire falling off, it started without fail. I even filled up with fuel on the way home and it started straight up after sitting for a few minutes. Maybe cleaning the earths up and changing the main ECU really has solved all the issues. Certainly seems to have.

Thanx for all the help guys. :kiss