I am currently experiencing low fuel pressure on my 1997 Saturn.

Pressure at key: 40 psi
Pressure at idle: 32 psi

Any suggestions or has anyone had similar problems? The nearest i can figure is it is a tired fuel pump, or a plugged fuel line.

My fuel pressure regulator checks out fine (i clamped it with a pair of pliars to see if that is where i was losing pressure).

Any suggestions?

 

Model of Saturn?

I believe normal key on range is 38-44 psi, and normal pressure at idle with engine at operating temp is 31-36 psi. So you are still within spec (someone please correct me if I am wrong)

Is there an underlying performance issue that is making you think these pressures are low?

Change fuel filter recently?

A good number of the 97 fuel pumps were defective and died before 70K or so and were replaced by Saturn at no cost. Don't remember details of extended warranty.

I have 214K on the original fuel pump of my 97SC2 and have similar pressure readings.

Is there more to this story?

 

Well it is a 1997 saturn SL2 with a 1999 engine in it.

The check engine light is on for a lean fuel mix, and the spark plugs are a nice white color instead of the more cream color that comes with the proper air:fuel ratio.

If i am within spec, and there are no real symptoms of a vac leak, unless the fuel pressure range is differant on the 99 than the 97.

 

Ever changed ECTS? If the original is still in there, it has likely failed by now. Although when the originals fail they usually result in an absurdly rich mixture, it's possible to fail in the other direction too (indicating to PCM that coolant is way hot, thus leaning out the mix.

Be sure to use brass OEM style replacement and replace connector at the same time.

Would also check for vac leaks at intake manifold and where throttle body attaches to intake -- spray with throttle body cleaner -- if RPMS change, you have found your leak.

Could be an 02 sensor issue but try the above first.

 

I have sprayed the throttle body and the intake manifold with, and had to replace my ECTS and the O2 sensor a couple of years ago, could the engine control mod be out of calibration?

 

did you replace the 02 with a Denso or a Bosch? In my experience, the Bosch sucks. Use the Denso. You replaced the front, yes?

The PCM does a comparison between the front 02 sensor and the one after the cat, and will adjust among other things fuel mix to control the emissions. Usually these sensors get poisoned by oil or coolant and become less responsive, resulting in a rich condition.....but anything is possible.

Maybe the post cat 02 sensor is registering too high....but that's a guess for now. See if you can get a real time display meter on the ODBII connector and watch the voltages as you drive.....

 

I did replace it with a bosch. I checked the spark plugs (I figured why not, they are there and easy to pull out) and they are white, which is a sign that it is running lean instead of just registering lean...

I had a brain fart, I checked for a vac leak shortly after a cold start...I guess I am going to re-check it after i have it running closed cycle.

Also my local mechanic came up with an idea of what it could be, if it fixes the problem its gonna cost me $40 including parts...if it doesnt no charge... Could a bad MAP sensor be the problem?

 

ECTS may have failed again...what is its resistance at operating temp?

 

I am not sure the resistance, however this has been a problem before and after i replaced the ECTS.

 

What I meant was the sensor thinks the car is running rich so it leans out the mix -- as you are observing.


MAP sensor -- maybe -- not alot of personal experience with MAP sensor issues....