ECU, wot switch, check injector rail wiring for cracks
This weekend I wanted to treat my G60 which has been all good for me. So I changed the plugs / wires / cap /rotor. Being there I popped the timing light and retimed it on 6* on the dot.
It ran like a champ all weekend and all week. This morning went out to start the car. Now the thing did not want to start unless I hold the gas to have it start and keep it at 2000rpm. If I let go the gas it stalls. Once its warm, it wont go out of open loop. Pulls 20hg of vacuum. And the idle is super low all the time... Even with timing advance it still runs low (500 rpm ish)
When running, once it hits boost, it wont go under 13 AFR. Usually when I blip the gas it hits 10-11 AFR instantly. When going on idle it goes to 12 AFR and slowly creeps to 15.
Today, I changed the CTS sensor, unplugged and bypassed the ISV, double and tripple check the timing. Also checked for vacuum leaks. but souldnt it run higher idle if there is a vacuum leak?
I just dont know where to look now... could someone point me in a good direction?
Did u re adjust ur idle after setting the timing thats always good practice. Check that the dizzy hasnt moved.
Check cam and crank timing also.
u have done most of the common stuff so maybe time to check resistance at the injectors or even take them out and crank the car to check if they are firing.
all good earths? co pot setting?
Idle and wot switch working?
So since the last post, I've been for a while...
Now I've swaped O2 sensors. Got better but still does it... I've put a new vaccuum line from the intake to the ECU... I've even took out the whole harness and checked every single wire. I've found that the center wire from the CO pot was out of the harness... I've clipped it back to where it goes...
I then went for a ride and the problem is still there... Could it be possible that i fried the ECU by running the car with a CO pot with a wire missing in it?
Today changed the injector harness... and created a new engine ground... the car ran so good after but still that issue where the car wont make the mixture rich when boost is present...
I've noticed today that when I stop at a light it idles at 1000 rpm and 12 AFR... then after a couple of seconds the car realises that its at idle... it drops to 800 rpm and goes to closed loop... I doubt that the idle switch is the culprit since when I unplug it while the car is running the car idles even worst...
I've been doing some more testing. I've tried with a new ECU and it still does the same thing. Replaced the CO pot and still does it... I've decided to bite the bullet and push it. Up until 5 psi the car stays in closed loop and does steady 14,7 AFR. But at 5 psi it goes in open loop and AFR are normal 11-12. What could stop the ECU to go into open loop since Stage 5 SNS chips are supposed to hit open loop at 1 psi...
A leak or restriction between the throttle body and the ECU pressure sensor. Have you looked inside the ECU and changed the little hose inside there? Any leak will bleed off pressure and the pressure sensor will not see the correct pressure. If it doesn't neither will the ECU and it will transition late to open loop fueling.
A restriction will also delay the signal from getting to the sensor.
Runs a lot better now than it did before... must be all the parts that I changed... The car used to run pig rich with a 3.0bar FPR... Now even with my 4.0bar FPR, it runs near 12.5 at full boost (17psi) in 5th gear... elsewhere I might see a 13.0... I know that 12.5 is the maximum safe you can go... but I was used to seeing 11.0 even in the 10s.
When the CO pot took a crap I used the IAT attached to the aba intake I had on the car (running the ABA intake + head) and used a simple resistance for the CO pot. Now that the IAT is in the intake and not in the intake tube after the intercooler I'm wondering if this could have an impact on the AFRs.
Anyone as any experience with the placement of the IAT on AFRs?