I cant figure out why I have low fuel pressure. I'm running lean and exhaust glows under moderate-hard acceleration but it has not thrown a check engine light. Fuel is at 38PSI with key on no start and drops to 30PSI at idle. I was told it should be 41-48 and drop 3-10PSI. Have replaced fuel pump, filter, regulator, air filter, O2 sensor(Bosch), Plugs&Wires, and cat convertor. Dealership scanned it and talked to GM and then told me they couldn't help me(HHHMMMM, can we say incompetant). Thought maybe it could MAF sensor, PCM, or fuel pump relay but they are all high$$$. Maybe I am looking in the wrong direction. Any help would get me further then I am now.

Thanx,

bigT

well, i have heard bad things about bosch 02 sensors. i'm sure other people will chime in on that one.

Is it possible you have a restriction somewhere in one of your fuel lines?

Maybe I have the wrong fuel pressure specs. Does anyone know what they are for a '95 Vin 1 3800. I was told 41-48 PSI, drop 3-10 PSI.

Thanks

Trevor

I know this is slightly off topic, but what is the fuel pressure for a 92 L67?

I had a friend scan my 95 today and he told me the the O2 sensor was pegged on the "rich side" at WOT. This kinda contradicts my whole lean theory. Does he know what he'* talking about? Will your exhaust man. get orange when running lean or rich both? When he started talking about millivolts and crap the whole operation flew over my head.

Thanks,

bigT

Do you have a service manual? It might be in there, if no one has it tonight, when i get back i'll see if it'* in mine.

Hey jwikoff99, my service manual says you should have 41-47PSI drop 3-10 just like mine, but you might double check.

Hey jr's3800, I can't remember exactly how many mV the guy said but the reading was as high on the rich side as the scanner would go I think.

Has anyone had trouble with an EGR that would cause my problem?

Thanks for your help,

bigt

P.*. If the '95 Vin 1 3800 SC doesn't have a MAP sensor, what tells the computer what the pressure is?

I gotta run but I thought I'd throw this in before I go. The PCM ignores the O2 sensor until it hits about 600deg. That would mean that if your having problems on initial startup it couldn't be your o2 because its being ignored. Make sense or no? I'll bbl

So what would happen if I unplugged the O2 sensor and ran it to see if the problem is still there, will that damage anything? Wouldn't it adjust using the MAF sensor?

Thanks,

bigt