Tps

[RUSSH]

Originally Posted by bnaylor

To test it effectively and see if it is in GM specs I doubt it. It is important to see the minimum pressure the fuel pump is putting out. There should be a Schrader valve on the rear fuel injector rail passenger side of engine where you can connect the gauge. They are not expensive. Around $25 at places like Autozone.


Checking fuel pressure GM 3100/3400

Cool. Thanks man, I guess I'll go and get one from autozone this evening.

[BNaylor]

Originally Posted by RUSSH

Cool. Thanks man, I guess I'll go and get one from autozone this evening.

It may come in handy for the future and can be used on other cars too. Just another tool to add to the tool box. The one shown is the Actron brand which has a bleeder valve built in. So it can be used to relieve fuel pressure like for replacing a fuel filter. I got this one at AZ. Good luck.

[RUSSH]

Originally Posted by bnaylor

It may come in handy for the future and can be used on other cars too. Just another tool to add to the tool box. The one shown is the Actron brand which has a bleeder valve built in. So it can be used to relieve fuel pressure like for replacing a fuel filter. I got this one at AZ. Good luck.

My only concern now is, since the car only acts up after running for a little bit, won't the fuel pressure be inaccurate since I'm checking it cold?

[BNaylor]

Originally Posted by RUSSH

My only concern now is, since the car only acts up after running for a little bit, won't the fuel pressure be inaccurate since I'm checking it cold?

The fuel pressure will be fairly constant whether the engine is cold or hot. It changes depending on engine vacuum conditions. Initial readings are taken with engine to off, ignition to run (fuel pump prime) and then checked with engine running. The fuel pressure regulator (FPR) is vacuum operated. So the vacuum line to the FPR is removed and reconnected to see if there is a pressure difference. A difference around 4 - 6 psi would indicate a possible flaky FPR. Checking fuel pressure is just one step in the troubleshooting process. Until checked it is hard to rule it out. If fuel checks out then other areas would have to be looked at such as ignition. Components that are heat sensitive and can cause intermittent problems would be the two crank position sensors (24X and 3X), the camshaft position sensor and the ICM.

[RUSSH]

Originally Posted by bnaylor

The fuel pressure will be fairly constant whether the engine is cold or hot. It changes depending on engine vacuum conditions. Initial readings are taken with engine to off, ignition to run (fuel pump prime) and then checked with engine running. The fuel pressure regulator (FPR) is vacuum operated. So the vacuum line to the FPR is removed and reconnected to see if there is a pressure difference. A difference around 4 - 6 psi would indicate a possible flaky FPR. Checking fuel pressure is just one step in the troubleshooting process. Until checked it is hard to rule it out. If fuel checks out then other areas would have to be looked at such as ignition. Components that are heat sensitive and can cause intermittent problems would be the two crank position sensors (24X and 3X), the camshaft position sensor and the ICM.

Man...thanks a lot for your help. I'm gonna check the fuel pressure tonight and I'll let you know. Also if either of those sensors are bad, wouldn't it show an SES light?...and what do you think about the coolant temp sensor being bad?

[RUSSH]

Well I've been procrastinating the past couple of days and haven't checked the FP yet. I have concluded that the problem only occurs with about 8 gallons or less of fuel.

[RUSSH]

I thought I'd let you guys know. It ended up that the fuel tank walls are rusting and that's what was causing my problem all along. The guys that did all the repairs originally in June, went ahead and put a new fuel tank assy. in and noticed the contaminated fuel. I found a new tank for the car, so me and my brother in law are gonna tackle this job next weekend.

If you guys know of any tips or shortcuts, let me know and thanks for all your help.