Ok I have just about given up on the engine . Its in my offroader and I posted here a while ago with a few issues .

It is running very rich at idle . What causes this ? Send me your ideas and I will check them .

It comes right at about 2500 - 3000 rpm , I suspect at this point it is reading the oxy sensor and correcting for it .

It is so rich it will not run without throttle manipulation etc .

Changed all coils and harness , power transistor . These all checked ok . Pulled injectors and leak checked , ok . resistance check shows all at 13.8 ohms and no leak to earth . Throttle position sensor resistance good , airflow meter changed . Temp sensor good .

Compression check good , all 170 and even .

What now , any ideas

thanks

Chris Weaver

Has throttle position sensor been moved/adjusted? If there are any scratches around the mounting bolts, then readjust it according to the manual.

The ECU test light should come on at 400rpm above idle. The TPS test might be in the mode IV test mode..but you'll have to confirm that.

Could also be that the oxygen sensor is buggered.

Chris

Have you tried unplugging the oxy sensor?

I believe it goes out of closed loop mode when you do that.

Have you checked every possible location for an air leak?

if their was an air leak wouldnt it run leaner (considering the intake stroke creates a low pressure area within the combustion chamber) therefore sucking more air in?????

Quote:

Yeah I guess so. I'm still in forced induction mode. What I said would only be accurate on boost.

lol im not old enough to appreciate boost yet lol

definatley take the oxy sensor out.

even check the cold start injector, it may be getting a false signal, and the ecu mite b holding it open for too long.

engine temp sender, knock sensor. if any of these are reading false then you will get poor engine operation.

Ok I will pull the oxy sensor out and see what happens , have a couple here so can swap it if nececary . I would guess its working as it sorts itself out about 2500 or so , ie in closed loop . Will give it a try thou .
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Ok so no different with oxy sensor unplugged .
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Also have had sugested an air leak but this would lean it out I think .

Temp sensor checks ok , 3.0 k ohms , was below 20 deg .
The detonation sencor should just move ignition I thought but will pull it to check . wire off it will not detect etc .

Cold start injector ? Have not come acrss that , any more info ?

Also someone has suggested a EGR valve put I do not think it has this either , can anyone confirm ?

Thanks

Chris

not EGR.

have you tuned the TPS? You haven't confirmed that yet.

My car stalled once in traffic, after I played around with the TPS. The reason is, that the engine thinks it is in off-idle, so enriches the fuel charge. So make sure that's set properly, straightening it up so it looks good will make it do this...

No such thing as a cold start injector on a CA.

Temp sensor is important so if it reads ok, then it's not that. Bad temp sensors tend to play with 'ignition timing' more than fuel mix.

Don't pull out the 02 sensor, just disconnect it for this test.

If the engine is not blowing petrol smoke, but won't idle, it could be that the IAC/AAC valves are clogged up, or IACV (Cold Idle) valve is clogged up with oily crap.

If you haven't had your injectors cleaned, it's very possible they are leaking. which mainly affects idle fuel mixtures.

check the fuel pressure regulator, sometimes the diaphragm splits and suck fuel directly into the intake manifold.