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1991 Oldsmobile 98 Regincy Elite 3.8L
08-04-2011, 07:43 PM
Post: #1
1991 Oldsmobile 98 Regincy Elite 3.8L
I have replaced the fuel pump,fuel regulator and the fuel filter. I have checked the power to the coils and the injector all to be found good. I can spray gas into the intake and the car will start and run as long as i keep spraying. I have also replaced the EFI sensor. I don't know what else to do. I have fuel going threw the rail. Somebody PLEASE HELP before i do something i may regret later SadSad
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08-04-2011, 09:05 PM
Post: #2
RE: 1991 Oldsmobile 98 Regincy Elite 3.8L
Sounds like a good start but power to the injectors is only part of the big picture. The power also needs a ground and that's what the ECM switches to pulse the injectors. (fuel spray) My first two guesses are either a poor ground somewhere, (cause the car is 20 years old) or a bad crank sensor.

If you check across both wires and you get a pulse (about 3 - 5 volts) then I would double check to be sure you have the proper fuel pressure. I have seen a wrong pump installed more than once and many look exactly the same.

Some may suggest a scan of the computer but that year is too early to get any codes for a no start condition.

Keep checking things and let us know what you find.
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08-04-2011, 09:34 PM
Post: #3
RE: 1991 Oldsmobile 98 Regincy Elite 3.8L
Thank you for your response. I will check the ground on the injectors. If the problem is the ground, what can i do to repair it? Will this be a bad ECM?
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08-04-2011, 09:54 PM
Post: #4
RE: 1991 Oldsmobile 98 Regincy Elite 3.8L
The ECM is my last guess as they seldom go bad. I would follow the harness and look for wires going to a ground point. The most common one is usually right on the stud for the thermostat. If that wire breaks or the connection gets cruddy it will not start. I know this from personal experience years ago.
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08-05-2011, 12:33 AM
Post: #5
RE: 1991 Oldsmobile 98 Regincy Elite 3.8L
Ok thanks. I checked the voltage to the injectors i got 13.5 volts with the key on. Thats using both wires hot side and ground side of the injector plug. This car as me so steamed. Do you know if the TPS would cause the car not to start. I have never seen one keep a car from starting, I have only seen them affect the idle of a car.
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08-05-2011, 10:51 AM
Post: #6
RE: 1991 Oldsmobile 98 Regincy Elite 3.8L
The TPS should not be an issue for starting. The 13.5 volts at the injectors has me wondering if you are checking the proper wires as there should be no completed circuit unless the engine is turning... and even then it would be a flicker. (injector pulse signal) The other thing that concerns me is why you have a voltage reading above 12.6 (nominal "resting" voltage of the battery) seeing as the engine is not running.
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08-05-2011, 01:36 PM
Post: #7
RE: 1991 Oldsmobile 98 Regincy Elite 3.8L
Ok i checked it with a test light, before i found this web-site. When i put the test light on the power lead it was solid, when i put it on the ground lead with the egine turning the light did flicker but dimly. I talked with a friend who is a machanic this morning and he said it is more than likely the cam sensor. Can this sensor be tested, if so do you know how. I didn't think to ask him.
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08-05-2011, 08:43 PM
Post: #8
RE: 1991 Oldsmobile 98 Regincy Elite 3.8L
If it has a cam sensor it's in the hole that looks like where a distributor might go in the old days and it's got a plug on it going to the ECM. (weather pack connector) You might get a variation of readings using an ohm meter across the terminals (while cranking) but a full function scanner is probably a better bet.

If it's got a distributor then the cam sensor *IS* the distributor.

That said, the fact that you have a flicker at the injector plug is an indication that the injector is probably sending fuel to the cylinder... but only if you tested across both wires on the same injector plug. The next questions is about fuel pressure. If it's way low for some reason then there's your problem. For most injected GM cars it should be 55 - 60 psi.
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08-06-2011, 10:24 AM
Post: #9
RE: 1991 Oldsmobile 98 Regincy Elite 3.8L
Thank you very much you have been a great help. I'm glad i found this web-site. Thanks Again and may you have a Blessed weekend.
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