I have a 94 Z-28 with 150,000 miles on it. About 6 months ago, it started to run rough. I had replaced the fuel filter, but it did not fix the problem. I was then advised to replace the injectors. After replacing the injectors, the car ran much better, but bogged a bit when accellerating hard.

A few days later, the car became hard to start, and would stall on and off while driving. The problem became worse, and I was left stranded. I had the car taken to a mechanic who told me the problem was due to the fuel pump. They said they tested it and the fuel pressure was low. They wanted to charge me $800 for the job. I had the car towed back to my house and replaced the pump my self. I started the engine, the car ran great for 5 miles, and then started to stall again.

I believe that it could be the fuel pressure regulator, but want to be sure before I put more money into new parts that may not fix the problem. Any advice would be greatly appreciated.


Thank you,


Joel Bondorowsky

 

The process of elimination would make me agree. It's a pretty easy swap. Do you know what PSI you're running at?

 

Thank you for your input. I do not have a fuel pressure gage, but I believe the mechanic said that I was running at 8psi. When I try to start the car it does at times sputter and I smell raw gas.


Thanks,


Joel

 

8 PSI is very low. Are you sure he didn't say 38 PSI (which is normal). Do you smell any gas under your hood or anywhere for that matter? What makes you think it's fuel related at all? Generally, what you describe may very well be ignition related. Has the opti-spark ever been replaced? Has it been raining or is it possible your engine got wet recently?

 

I had replaced the optispark about a year and a half ago. The smell of fuel comes from under the hood and into the car. The mechanic said the fuel pressure was low which is why I had replaced the fuel pump. Unfortunately, that didn't fix much of anything, however replacing the injectors, which I did a few weeks ago did help a lot.

Joel

 

Did you ever pull the vacuum line off the fuel pressure regulator and check for raw fuel? If its there, your regulator is shot.

Other than that, you need to measure you fuel pressure at all operating conditions, including WOT. That's the only way you will know if you have a fuel pressure problem.