ok, today after work i start the car and it was shaking really bad and the wideband shows 18 after like 30sec and was still going up, but i was affraid so i shut the car off. my fuel pressure read good pressure at 40psi (normal)
so what can cause that? can it be a bad O2? i have no code by the way. i think it might be the injectors.
I'll bring my tools tomorrow to swap the injector with my stock one, but i wanna check all options here.
if you have any idea of what can cause that, please let me know, thanx!!
Could be a bad MAF. Isn't registering the actual air passing through it so in turn doesn't provide enough gas for it.
i had a problem simular to that. checked all the vacuum lines and the fuel pump all were good. it turned out that two guides on the timing chain were broken (Cheap Plastic) threw the timing off just enough tomake it idle rough as hell. it was running extra lean and smelled like gas from the exhaust. the timing chain could be your problem. this problem was in a 96 Z24 2.4. hope this is helpful.
well today it ran fine and i went home with the car. after 15-20mins it start to do it again. i parked, restart and was fine. but on idle it still goes up to 15.5 and then go back to 14.7....
i just swapped the injectors with stock one and for now it seems to run fine. i'll seee tomorrow.
i dont think its the timing, it has brand new timing componentfrom the built and its not soing this all the time, if it were the timing it would do it all the time right???
can it be the O2 sensor?
thanx for helping
ok, this morning, it starts to do it again.... so i swapped the MAF woth the sunfire one and went to work with no problem at all. but after work, it did it again. I tried to unhook the O2 sensor and it runs rich at about 13, so i went home with it unplugged. at least it wasn't bogging.
So i think its the O2.
anyone have any idea?
thanx
sounds like a bad fuel pump
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
If you find a MAF sensor on the Ld2 Ld9 I'll buy you a beer.
It's not a bad fuel pump. Does it just go leaner and leaner at idle or does it jump? You'd be suprise how lean you can get at idle. If you push on the gas does it come back to normal A/F?
Gilles
2.3 Ho
its not the fuel pump, thats for sure!!!
i didn't know we didn't have a maf sensor. i thought that the sensor under the manifold was that lol
yes, at idle it goes leaner and leaner, and sometimes it jump to only like 15.5 and go back to 14.7 without touching the gaz. the other day, i was driving and the a/f was at like 17-18 it was bogging really hard.
What kind of O2 sensor do you have, one wire or four? Running rich is caused by high voltages on the O2 sensor. Usually dead sensors don't provide enough voltage and cause the engine to run rich. The ECU reads the O2 sensor against ground. If the ground on the engine is a bit high vs the ECU, it will run rich because the voltage is consistently higher than it should be. If it idles lean, I'd strongly suspect the O2 sensor. If it just started doing this all of a sudden, maybe it will correct over time. Maybe pulling the battery for a while will help you.
2002 Cavalier 2200 5spd
Oops, I meant running rich is caused by low voltages, and lean is caused by high voltages.
2002 Cavalier 2200 5spd
voltages?..lol
you could have a t/b or intake manifold leak causing u to run pretty lean..
Quote:
voltages?..lol
you could have a t/b or intake manifold leak causing u to run pretty lean..
Yes, as in the signal the O2 sensor sends to the ECU, the end of the feedback loop. Since manifold and, T/B and leaks are contained within this feedback loop, it would correct itself before long.
Make sure the ECU knows the car is running lean by measuring the O2 sensor. Under a lean condition, the voltage should be less than 0.4v. If you know for a fact that you're running lean and the O2 reads >0.5v the O2 sensor/grounding is at fault. Also make sure your engine block and negative battery terminal are very close (<0.2v). Bad grounds can do funny things to cars. If the grounds are bad, run a low gauge wire from the block to the battery -.
2002 Cavalier 2200 5spd
