I have a 96 Chevy Lumina with over 100,000 miles. While driving I shut the engine off only to find it backfired and wouldn’t start. I replaced all three ignition coil packs and it ran for a few moments. Checked fuel pump fuse and replaced relay and it will turn over but not start. Do I need to replace the fuel pump?
“While driving I shut the engine off only to to find it backfired.” Care to expand on that?
Tester
You may or may not have to replace the fuel pump, but by all means you should stop just replacing things based on guesses. It is really expensive. Did you even check the coils before replacing them?
Clarify this: “While driving I shut the engine off only to find it backfired and wouldn’t start” - are you saying that you were driving along and turned the car off? Why?
Anyway, to quickly find out whether or not your fuel pump is working (at least some), turn the key to start w/out cranking and listen for a little 2-3 second hum. That is the fuel pump. You should then investigate the fuel supply further by checking the fuel pressure. If you don’t have a gauge, borrow one, or you can pick one up for $40 or so. If hear nothing from the pump and/or get no pressure, check for voltage at the pump - for this you just need a multimeter - also cheap. But if you invest small amounts in some diag tools, you’ll quickly save it by not throwing unneeded parts at the car.
It backfired a little and wouldn’t crank. In prior periods it would do that and the CEL would flash momentarily, stop, and everything is okay. My CEL light stays on anyway. My mechanic said he couldn’t find anything wrong and run some fuel stabilizer through it.
You need to find another mechanic. The Check Engine light is the first place to start as it might be a clue. And with the backfire, don’t overlook a jumped timing chain.
Tester
I’m still really wondering about the turning off the car while driving thing. You haven’t clarified anything about that.
And I’ll second the fact that you need a new mechanic. Go to an auto parts store and ask them if they have loaner OBD-2 readers (since the car isn’t running). Take it home, follow the destructions, pull the codes and post them - exact codes (like P0301 or something).
The codes were posted by the mechanic at an earlier time. Some, he could repair and others he couldn’t. They didn’t affect the car’s driveability and I didn’t worry about them. That was several months ago. This problem is recent and the jumped timing chain sounds like a possiblity. I will have him look at that and test the fuel pump among other possibilities.
The engine codes, set when the check engine light came on, is a DIAGNOSTIC aid. Engine codes point fingers at the problem area. They are most useful.
It doesn’t help us ANY that the mechanic posted them somewhere months ago. Why don’t YOU post them here?
Would the statement, “While driving, the engine shut off, and would not restart”, be what you meant to say?
When it backfired while cranking, was there a pop in the exhaust, or was it in the intake?
This diagram shows all the parts involve in making spark: http://www.autozone.com/autozone/catalog/search/searchResults.jsp?searchText=ignition+coil&_requestid=1503190 Click on Coil-Ignition, then click on VIEW JOB DIAGRAM. Your mechanic needs to check the cam (or, crank) position sensor. The instructions on how to do that are in the Haynes, of Chilton’s repair manual.
Thank you all for your help. But, it turned out to be the fuel pump after all. Mysteriously, CEL went out. I don’t know if it was because of all the parts I installed, disconnecting the battery or maybe a combination of all of them. If it relights I’ll pass the codes on for deciphering.