ok guys. i have an 87 camaro iroc-z, 305 tpi auto all stock. i got a fuel pressure tester kit from advance today. I got everything hooked up with the vacuum line hooked up. with the ignition ON, the fuel pressure went instantly to 40 then slowly went to 30 after like 20 seconds. then i started it and let it idle, and the psi was fluctuating between 36-38. then i revved it up at WOT, and it boosted all the way up to almost 60 psi. Is all this normal, cuz i need to know if anything in the fuel system needs to be changed. thx

 

When you frist key it on the ECM will trigger the fuel pump for 2 seconds to prime the fuel lines. A jump up to about 40 is normal, with pressure slowly creeping down after it shuts off again. 36-38 idling also sounds about normal. 60 at WOT is not right, though. 43PSI is the stock maxiumum fuel pressure (assuming a stock FP regulator).

You don't need to smack the throttle wide open to find out, though. Just unplug the vacuum line from the regulator (and plug the end of the vacuum line so you don't create a vacuum leak) and you'll get the same effect. It should read ~43PSI any time the fuel pump is running like that.

 

thx, so what would i have to look at that would cause this?

 

Given that it will drop down to a normal-ish 36-38 at idle, only going up to 60 at WOT (zero manifold vacuum) that would tend to rule out a restriction in the return line (which would give very high pressure while idling since that's the time when the highest volume of the fuel is being set back through the return line). Maybe a bad FP regulator is about all I can come up with.

 

I have a 1994 camaro lt1 and i had a problem about a month ago.My car wasn't starting right.I put a gauge on it and turned key to run position and it would go to 40 and slowly to 30 then all the way down to zero.But if i caught it in time i could start the car and pressure was about 30.My problem was the pump was almost gone.

 

well, i do have a brand new fp regulator. idk if its adjustable or not. My pressure doesnt go all the way to zero. it might if i let it sit, but idk what to do now.

 

If everything is operating properly on your '87 TPI, the fuel pressure at idle should be about 43 psi with the vacuum line connected between the fuel pressure regulator and the upper plenum. If you pull the vacuum line off of the plenum and plug the open ends, the fuel pressure should increase between 4 and 8 psi, so between 47 and 51 psi. That is normal. Disconnecting the vacuum line simulates what the FP is at WOT. I have no idea why the fuel pressure would jump to about 60 psi, as you stated above. When you state that you revved it up at WOT, are you driving the car or are you in the garage opening the TB?

 

today i went out and tried it again. Right away with the key on it went to 36 psi and slowly went down. then with the car idling, it was at 36-38 psi. i unhooked the fpr vacuum line and plugged the end and it fluctuated between 46-50 psi. also the car is harder to start, it cranks and like then starts like 5 seconds later and have to give it a little gas to keeping running when its first started, after that its fine.also today i went out and adjusted the tps. i have had no codes what so ever, i went and drove the car before i adjusted it and did the same crap (hesitating, backfiring, wierd clicking sounds). so i moved the tps down and drove it, the ses light came on and still did the same crap. so i moved it back to where it was and drove it. same stuff just no ses light. i have done so many tests on my car. vacuum line tests, they were positive. all the fuel system seems fine, good spark, idles good, new MAF sensor and still nothing. the only thing i have left to check is timing. what are the symptoms of bad timing, and how do i test/adjust the timing?

 

Do a search on adjusting the timing. Also, read the technical articles that you can get to from the home page here on thirdgen, lots of great info.
In order to adjust the timing, the first thing is to find the distributor EST wire. There is a large wire loom on the firewall on the passenger side of the engine bay. The EST wire is a single tan wire with a one wire connector. You got to find this wire. Then we can talk more. This EST wire connector must be pulled so that the ECM can not control the timing. 1) Warm up the engine, 2) shut engine off, 3) disconnect the EST wire, 4) restart engine, 5) set the timing to 6 to 8 degrees before TDC by adjusting the distributor. You will also have to get to the distributor hold down bolt to twist the distributor.