blurat

Hi, I changed a noisy fuel pump 2 mos ago, no problems. Last week the engine died several miles from home. The coil had grey along the outside rail indicating a spark jumping due to worn ign parts. Changed the coil and it fired right up. Went ahead and changed the wires, plugs, cap, rotor, and all seemed well.
This week it died again. Driving along, then dead motor. Cranks fine but wont start. It is an X motor.
I changed the fuel filter to no avail. Cranked it a bit then took the line off the front of the filter to make sure it was pumping fuel. There seemed to be plenty of pressure and fuel present.
If I poured a little fuel in the air throttle it will start and burn till the fuel is gone from the manifold.
My book says maybe the computer. I dont know how to check this stuff. Am I to get married to a chevy mechanic for the first ime in 50 years? As I am LOST under the hood on this computerized concoction.
Thanks
ps.. no check engine light

RacerX

I m not sure what you did. Did you check for spark? you replaced the coil, ok worked for a while and now no? did you check for spark again? no spark= bad coil, bad coil ground, but probably bad ignition control module.

do you check fuel pressure? do you have fuel pressure? if you have fuel pressure then pump works. no fuel pressure then no fuel pumping.

if you pour fuel down the butterfly and it runs til its gone, then you have spark. suspect fuel pump? Here s an idea....CHECK the connections in the fuel sending unit. You used an aftermarket pump I am sure so you probably cut and crimped the connections. When the car is stationary NO PROBLEM but when you are driving, the movement and vibration makes one of the contacts loosen and the car stalls.

oldchevy

If it ran when you poured gas down the throttle body then it means you have a fuel problem. Do a fuel pressure check. If that checks out it could be the fuel pressure regulator or some real dirty injectors. Just because the fuel pump is fairly new doesn't mean that it is good. Some of the aftermarket ones aren't real good.

blurat

Thanks for the input. I thought the fuel pump was working because when I pulled the line after the filter off I got a large spray of fuel. Well........went and got a fuel pressure gauge and tested. 38 lbs. My system requires 58 to 61. You would not think, or I wouldnt, that it would cause a no run condition.
Bought another fuel pump and it runs like a top now.
Thanks again for the input.

RacerX

I dont think the pump was faulty but more that you bought the wrong pump. 38psi is normal for the 80-90s era multi port fuel injection systems. but they were using different style injectors back then also. Your higher pressure system probably was designed specifically for the style injectors they use now. Which you didnt know when you bought the pump and neither did the guy who sold it to you.

blurat

It did run for a couple mos after I put the first one in. Same part number but consistant at the pressure, which like you say is good for the earlier system. I thought it would work on a lower pressure vehicle but dont want to give someone else a possible headache.