Jay P.

Cobalt ss t/c problems.
Does anybody know if a bad fuel pump can instead of giving out , just sen excessive fuel to injector then to spark plugs?

Slowbalt2000

iTrader: (1)

No that is impossible. The pcm controls the amount of time the injectors spray for. Even if your fuel pump magically started flowing more volume, it would see that and cut back the trims.

Jay P.

I am still having trouble with the cobalt I took it today to the dealer they changed out one plug that was missfiring and they test drove the car and it was working fine..but as soon as I took my balt back from them at the last hour before them closing it worked kinda good until I got to my house it stared messing up again..a guy from the dealer highly recommend for me to get ngk iridium which I already have but the one he recommended are laser ngk's

I can smell all the fuek which is not being completly burned.. I believe that plugs are getting over filled with fuel and carbonized and start to fail which makes the misfire and problem has to be fuel not being in controled?

Jay P.

Is this leading me to bad pcm/ecu?
I checked for any boodt leaks very carefully still nothing

Slowbalt2000

iTrader: (1)

What are the codes youre getting?

ECaulk

iTrader: (6)

Have you checked your maf? Miles on car and any mods?

Jay P.

For sure I am not mistaking multiple misfires have to go get check engine light check since it started to run fresh until I was out of the dealer

Jay P.

Yeah sensor has good resistance mod are hanh charge pipes catback exhust hahn exhuast tune

08SilverSurferBalt

Sounds like a Vacuum leak check your pcv lines on the valve cover intake and Turbo

Jay P.

Had the car smoked tested no leaks

Jay P.

Checked for fuel pressure key on it dropped like 7 psi and with engine running it was badly fluxuating from like 60 to 90psi

Slowbalt2000

iTrader: (1)

Key on engine off should be 60

Pressure should drop no more than 5 psi per minute i believe. How did you install the gauge?

Jay P.

Yeah pressure dropped from like 67 to 61 or 62 in about 30 to 45 seconds this would be with key on engine off

I installed the fuel pressure guage to the fuel rail released pressure into a bottle then started the whole process.
I first did the pressure test key on engine off which gave me the readings of 67 to around 61 psi en about 30 to 45 seconds.
Then when I started the engine psi was fluxuating like crazy badly from.like 60 to 90 psi..
I found on specs that fuel pressure with key on engine off should be between 57 to 67 psi..
What I did not find was the psi when engine was started

Slowbalt2000

iTrader: (1)

Try switching the relay with a different one and see if that does anything..

Might also be a good idea to test the amp draw to see if it is fluctuating as well or if its just the pump.

Another test you could do is hotwire the pump and check the volume. General spec is like a pint in 15 seconds i think

Jay P.

You mean the fuel pump relay?

Slowbalt2000

iTrader: (1)

Yes

Jay P.

Do you know if the fuel regulayor is in tankwith fuel pump?

Slowbalt2000

iTrader: (1)

Yes its in the fuel pump module(fuel pump bucket) with the pump. Its the assembly you pull out of the tank to change the pump.

Slowbalt2000

iTrader: (1)

if you end up getting a code, PM me and ill send you the flowcharts to hopefully fix your problem

Jay P.

I am thinking fuel regulator is bad, and yeah today after work I will get a scan of the codes

Wired

iTrader: (3)

For your engine (LNf turbo) wouldn't the most likely regulator be the one that is part of the high pressure fuel pump and not the in tank pump?

Slowbalt2000

iTrader: (1)

He said his fuel pressure was 60-90 so that would make it the in tank regulator.

Jay P.

I have like an extra quart of on my motor I did nothave 4 days ago, thinking it is gasoline

Slowbalt2000

iTrader: (1)

If youre spraying fuel and not burning it then its entirely possible

Jay P.

Made an oil change replaced the gasolined oiled with hd30