Too much fuel

**Gremlyn** · 01-03-2006, 12:30 PM

Correct that is what should happen.

What is happening is that the car will idle and run reasonably ok when the AFM is unplugged i have had the car idling for about 30mins and it did not stall. Still rins a little rough.

In fact i have driven it to the servo and back in first gear just fine, only when you push the pedal down to quick it stalls out.

My first guess was injectors leaking but had a mechanic come out who ruled this out. prehaps he was full of it.. is there anyway to tell for sure with out pulling them out first.

**CrUZida** · 01-03-2006, 12:36 PM

No way that I know of to test them without pulling them out.

Check the resistance of the temp sensor, make sure thats fine.
Try another ECU if you have one handy?
And then get the injectors cleaned.
Fuel rail pressure is another possibility mentioned.

mic* · 02-03-2006, 12:31 AM

Cruz, electrically, how are the fuel pump and AFM connected? Relay, ECU?

Say there was an open circuit in the AFM wiring, could the ECU employ a "limp home" mode? TPS & CAS? - to explain 30 minutes of operation with AFM unplugged...?

If it ran for 30 minutes, you would have to assume that the pump still had power to it somwhow. And having replaced it a couple of times with no change, rule out the AFM itself?

Perhaps the wiring (resistance) is the issue, and when connected the AFM gives an erroneous signal coz thereof?

Im scratchin, but i beleive that knowing why the fuel pump works when Cruz says it shouldnt holds some answers...

**CrUZida** · 02-03-2006, 02:01 AM

On every vane/flap type AFM car I've had/worked on, the fuel pump is triggered by START, and triggered by the AFM. (through the circuit opening relay)
The ECU does not trigger the pump.

You can clearly see how it should be setup from the wiring diagrams.

**TTMX83** · 02-03-2006, 02:24 AM

Had exactly the same problem with my 1JZ-GTE Cressida, would get 30 min out of it then it would overfuel it really bad. My bet is the injectors, well the injectors themselves or the o-rings. I replaced my injectors and it is all fine now.

Couldn't drive mine either, killed the plugs after 100kays, got 50k out of $30 of fuel.... Still, check all sensors are working properly and make sure fuel pressure is not too high. I'm still a bit iffy on my fuel pressure regualtor...

Cheers Brad.