I have a 90 IROC Z-28 conv....305 stock. Last year I had issues with the car running, but would then die after X period of time, and would be very difficult to restart. After receiving great advice here on the forum, I ended up replacing the injectors (South Bay replacements), the Distributor (whole assembly) and the EGR. The car started immediately after, and ran like a champ.

I do not drive the car everyday....as the top still needs to be replaced. But, I do start it periodically. Well, now I notice that it is very hard to start. The car will turn over, so battery and starter are ok....but it is like car is not getting fuel. After a prolonged period, it will finally start up.

I read some threads here on fuel pressure...and still had my fuel pressure gage from the prior problem. I attached the gage today via the Schrader valve, and noted the reading was 0 initially. I turned the ignition on, and still 0. I tried to turn on the engine...and finally it started at which point I noted around 38/39 on the gage. I shut the engine off, and the pressure jumped to 41 or so and remained. I returned to the car in 2 hours, and pressure was around 30....and the car started right away with just the turn of the key. I cycled the engine from on/off a few times while watching the fuel pressure gage, and noticed that sometimes the gage would drop to around 0. During those periods, the car would not start.....but after a couple of cycles of the ignition switch the pressure would jump to 40 and the car would start. During my testing....I also noticed once when the engine was actually running the fuel gage dropped to just above 0....but the engine remained on but ran rough until the gage returned to a 40 reading.

So I am guessing that I have an intermittent fuel pump....but before I go tearing into the gas tank for this....just wanted to see if there was anything else I should look at or check. I have had the car for over 10 years....third owner...and to my knowledge the fuel pump has never been replaced. The car only has around 132k miles original.

Thanks for the advice....and Merry Christmas / Happy New Year to all.

 

I've haven't had a TPI fuel pump failure (yet), but I have had a TBI fuel pump fail in a very similar manner to what you describe. If you have a voltmeter, I suppose you could check for voltage, but that is going to be easier said than done at the tank. And never assume the ground connection is good. Do you have a good electrical schematic?
But sure sounds like a bad pump to me. I've heard that in some cases you can beat on the tank (I don't like the sound of that either) and the pump may start up. If that 'works' in your case, its time for a new pump.

 

Thanks for the reply. Just strange that sometimes the gage will read almost 0....even when the engine is running. Then it pops up to around 40 which is normal. One thing I noticed is that when I see good fuel pressure in the rail prior to starting the engine, I do not need to pump the gas pedal to get the engine to start. The engine turns over and fires up right away, even in cold weather.