'97 Grand prix takes long to start, P0441 DTC and bubbling brake pedal

[olopezm]

Originally Posted by tblake

Looks good. Do you have any more issues?

Hello there, I tested my car today and the gas smell seems to be gone, however the hissing noise coming from the back is still present altough isn't as loud as before and I still have a low fuel economy (1/2 of a tank in one day under moderate use).

Besides, my Service Engine Soon light came on again, I had it scanned and it turns out I have a P0102 code, as i read it is related to the air sensors so I checked the MAF, VAF and MAP sensors as Autozone suggested and I found out my MAP sensor is broken so I will replace it tomorrow.

What symptons can a broken MAP sensor cause?

And finally i found a small leak in the brake fluid reservoir. I already bought it and will replace it tomorrow.

Will this cause a vacuum leak also? Or it will only result in brake power loss?.

I really appreciate your help. Best regards...

Oscar

P.S. I forgot to mention that the brake pedal bubbling seems to be gone, maybe this is just coincidence since there is a leak in the brake fluid reservoir.

[tblake]

Check the MAP sensor's rubber grommit to make sure that it is in good shape and not sucked into the intake.

[olopezm]

Originally Posted by tblake

Check the MAP sensor's rubber grommit to make sure that it is in good shape and not sucked into the intake.

Hi tblake thanks for you help buddy, I replaced the MAP sensor since the old one was literally broken, that solved the P0102 code.

Some of the old symptoms (brake pedal bubbling, fuel smell from the back of the car, RPM's dropping or going to high, having to crank the engine for 10 seconds to start and P0441 code) seem to be gone.

The only remaining symptoms are:
- Hissing sound coming from the rear (doesn't seem to be as loud as before).
- My transmission slipped while I was driving uphill and waiting for green light, I had to change to (N)eutral and back to (D)rive to make it work, again the fluid level is OK, right at the top circle on the stick.
- Rougher driving as the car warms up.

Here is a list of what I've done so far:
- Replaced 'T' shaped vacuum line going from the engine (at the top of the thermostat housing) to the fuel pressure regulator and the transmission also.
- Replaced fuel tank cap
- Replaced brake fluid reservoir
- Replaced MAP sensor

Best regards,

Oscar

[olopezm]

Hello guys, any other advise someone could provide? All of the symptoms that seemed to be gone are back again. I guess I will take apart the whole fuel tank to check everything again.
Also my car has a P0102 wich is related to the MAF sensor and has erratic idling while waiting at a street light. Is there any way to clean the MAF sensor or will I have to replace it?

Thanks in advance.

[tblake]

You could try cleaning the MAF with Maf sensor cleaner, but often times that is a wast of a 14.00 can of cleaner. You could unplug your MAF and see if your symptoms go away. If they do, then you may want to look into replacing the MAF.

[olopezm]

Hi tblake thanks for your help. I unplugged the sensor on monday before hitting the highway and the result was a slightly better driving but if I took my foot off the pedal the RPM's would fluctuate on a weird way for example:

Running at 2000 RPM's and then taking my foot off, the car would remain on 2000, then go down to 1500, then back to 2000, then back to about 1300, then back to 2000 and so on...

Could this be caused by the lack of the MAF reading and the car relaying on the other sensors?.

Also I disconnected the vacuum hose on the fuel pressure regulator and turned the ignition key on, no fuel came out so I guess the diaphragm is ok, but is there any other simple way to diagnose the FPR? I read that if the FRP is bad it may cause excesive or low pressure causing the fuel pump to make a squealing noise.

Thanks in advance.

Added: I forgot to mention that I took down the gas tank for the second time and found no leaks or problems with the fuel lines.

[richtazz]

To test the FPR, take fuel pressure reading key on/engine off (should be 48-55psi). Start the car, at idle fuel pressure should drop 3-7 psi from the KOEO reading. Then disconnect the vacuum from the FPR and readings should spike up to or near KOEO readings again.

[olopezm]

Originally Posted by richtazz

To test the FPR, take fuel pressure reading key on/engine off (should be 48-55psi). Start the car, at idle fuel pressure should drop 3-7 psi from the KOEO reading. Then disconnect the vacuum from the FPR and readings should spike up to or near KOEO readings again.

Hi richtazz thanks for your help, I checked the pressure at the schrader valve and the results were as follows:

KOEO: 60 PSI when pump is working, after that it will constantly decrease at a moderate speed.
Idling: It will quickly oscilate between 54 and 52 PSI.
Idling with FPR vacuum hose off: It will go up to 58 PSI.

Acording to this values I think the sound coming from the fuel pump is due to a high pressure. As I mentioned before I already checked the fuel lines and everything is fine, I guess the only remaining cause is a bad FPR. Am I right?.

Best Regards.

[richtazz]

The change in pressures would indicate that the FPR is functioning, but your readings are on the high side. Do you have access to another fuel pressure gauge just to see if your's reads a bit on the high side? I'd hate to have you replace the FPR, only to find that it wasn't bad and it was your gauge.

[olopezm]

Originally Posted by richtazz

The change in pressures would indicate that the FPR is functioning, but your readings are on the high side. Do you have access to another fuel pressure gauge just to see if your's reads a bit on the high side? I'd hate to have you replace the FPR, only to find that it wasn't bad and it was your gauge.

Hello again and thanks for your help, I don't have access to another gauge, the one I got is a brand new "actron" from autozone I wish I could have borrowed one, but they don't rent that kind of stuff here so I had to buy it (it may sound desperate, but to be honset that is the way I feel right now about my GP, everytime I fix something, two or three months later something else will brake...). Any other way to check the FPR condition?.

Thanks again for your help.

[tblake]

How fast will your fuel pressure drop to 0 after you turn the key on and the pump primes?

[olopezm]

Originally Posted by tblake

How fast will your fuel pressure drop to 0 after you turn the key on and the pump primes?

Hi tblake, thanks for helping.

I checked the reading again, after I removed the FPS just to see if there was any visuble damage and I putted it back in; and teh reading of the pressure gauge was 62 PSI, while the car was idling: 52-54PSI, without vacuum hose 62PSI.

It took 10 minutes and 30 seconds to drop down to 0 PSI. Finally I would like to add that the bubbling sensation on the brake pedal inmediatly after starting the engine is back, and now it will bubble 3 out of 4 times.

Best regards...

[olopezm]

Hello again, my GP is driving me crazy !!! Today I went to "Home Depot" with 1/2 of a gas tank, after 20 minutes I was about to start the engine and saw my fuel needle was between 1/2 and 1/4, aso I noticed that the fuel gauge will change it's reading depending on how many times I I turn the key on, I have uploaded some pictures so you can see: Each picture is a different KOEO cycle and were taken in order.

Finally the hissing sound will sometimes start from a cold start, it no longer matters if the engine has warmed or not, and now I can hear the fuel pump making a whining sound (sometimes is pretty loud).

Would all these problems mean that my fuel pump is definitely going bad?, Will it be OK if I only get the fuel pump replacement parts (motor, filter, seals) or am I gonna have to replace the whole sending unit too?

Best regards...

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[olopezm]

Hello again people, after a few days without a DTC, today the SES light came on again, I had the car scanned at autozone and the result is P0441 again, when I drove back home I noticed a kind of "deep breathing" noise if I rev up to 2000 RPM's and take the foot off the gas pedal. As a last resource I will change the fuel pump, maybe the vacuum leak is coming from it.

My last question is: how high does the temperature needle needs to go to say that my car is overheating? Does the temperature reading on the following picture is still a normal reading for this season of the year?

Thank you very much for your help to everyone, best regards...

[tblake]

That is getting up there, but mine has gone that high a couple times in stop and go traffic on a hot day with the AC on. Usually turning the AC off will help keep my temp down.