i have a 96 buick regal thats been giving me problems for over a year now. it from time to time acted like it was out of gas even though it might have a half a tank. turns over fine but won’t start after it sits for a couple of days then it starts fine. last summer my son replaced the fuel pump after doing a pressure test and getting a low reading. no more problems until jan then it started doin it again. well about 3 months ago it wouldn’t start so i had my wife turn the key on and i stuck my ear in the fuel fill tube and i could not hear the fuel pump. i checked the fuel pump relay by puting my finger on top of it and i can feel it click when the key is turned on. also the air relay next to it is the same so i switched them no change so i replaced the fuel pump again and also the sending unit so every thing in the tank is new. car still won’t start can’t hear the pump runing and i checked for spark no spark now. my other son has been saying he thinks its the ecm so i just put a reflashed used ecm in. did the security relearn procedure still nothing. whats next? sombody told me check the cam and crank sensors and wiring. any ideas.? i also replaced all the ignition coils last summer. i need help
Your vehicle has an oil level switch that grounds the computer. This switch is intended to shut the fuel pump off if the oil level gets too low.
Unplug the oil level switch and install a jumper wire into the level switch electrical connector. If the engine starts the oil level switch is the problem. Either that, or there’s no oil in the engine.
Tester
A lot of cars , the ecm won’t turn on the fuel pump unless it detects the engine is turning. A faulty crank sensor, etc could cause this “cranks but doesn’t start” symptom. If there’s no spark during cranking, that would be a primary suspect. If the spark is ok, have you measured the fuel pump voltage at the pump connector (while connected)? That’s a possibility too. You could be getting some resistance voltage losses somewhere.
George,
The computer operates the fuel pump for a second or two to prime the fuel system before the ignition is turned to start.
Tester
yea the fuel pump isn’t coming on at all no prime and there was no spark when i checked it last week. checked oil dip stick oil level good.
No spark either? Hard for an engine to start with neither gas nor spark. If this were my car I’d work on the spark issue first. That will be easier to solve than the fuel problem probably. The oil switch as mentioned above is also possibility and should be pursued as described above as doing so won’t take much effort or time it appears. My first suspect would be the crank sensor. That’s what I’d check next (after the oil switch) if my car. The car’s shop manual should provide instructions on how to test the crank sensor. The ECM is always a possibility in these situation, but unless the car has been in a wreck, or been left in a very hot sunny place outside for a long time, enough to crack the ECM’s solder joints, the ECM rarely turns out to be the cause. A mechanic with the proper scan tool could test the ECM without much trouble to verify basic functionality. You’d probably need to visit a Buick dealer for a full test of the ECM.
That’s right.
If the fuel pump doesn’t run the computer see’s no reason to operate the ignition system and vise-versa.
The computer uses a binary code. That means 0 = NO and 1 = YES. So when starting the engine it has to see all 1’s or YES’s. If a 0 shows up the computer doesn’t allow the engine to start because it’s assigned 0’s to the other systems that allows the engine to start.
And the oil level switch/sensor can cause that 0 or NO to appear.
Tester