Help with a beater.....

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Oct 12, 2007 | 04:49 PM

GDaina

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Joined: Feb 1999

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From: In Dreams There Is Truth Ohio

Help with a beater.....

92 Buick 3.3 liter v-6. Took the motor out, in Dec 04, bought another junkyard motor, complete, as the motor I had, the block was cracked, and the cam and roller lifters were shot. Used the junkyard heads, cam, lifters, block...new rings, bearings. Assembled and dropped it in this past summer....

Problem....ECM will not engage the fuel pump...

Have power to the pump, relay and fuse are new
Put new fuel pump, in fact exchanged three pumps
Replaced the oil pressure switch, and have oil in the pump
Have ignition
Fuel lines are clear and new fuel filter

Car will not fire as the lines are empty and ECM will not engage the pump. I am at wits end on this, I have no clue why this is happening.

I know it's not a vette tech thing, but I need help

Oct 12, 2007 | 05:02 PM

silver 76

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Joined: Nov 2004

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From: Somerville NJ

Are you checking only the hot side + at the pump? You may not have a complete circuit ( no ground ). Worth a shot.

Oct 12, 2007 | 05:06 PM

...Roger...

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From: Dayton, Ohio

Maybe you have to prime the fuel pump.I think the pump only turns on for a few seconds without oil pressure.
edit-do you know if your getting that initial 2 seconds of pumping before lack of oil pressure shuts it off ? The fuel pump doesnt pump "air" very well.
If the lines and the pump are full of air-I would remove the connector from pump and run 12 volts to the pump and let it run the air out of the system.Then put the connector back on the pump and cycle the key on and off a few times and then try to start.Good Luck

Last edited by ...Roger...; Oct 13, 2007 at 09:05 AM.

Oct 12, 2007 | 05:08 PM

texbeasr3

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Joined: Jun 2006

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From: Missouri City Texas

There should be relay that is activated when turn the key to ON.
It should activiate for a short time to prime the system, then turn off.
Do you know if the relay it is working?

Oct 12, 2007 | 05:09 PM

rihwoods

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Could be a ECM glitch by itself...there may be a way to test the ECM...I'm not familar with them,but repairs/replacements are avaliable...

Rich

Oct 12, 2007 | 06:30 PM

crazywelder

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From: Yooperville MI

Have you run a jumper from the relay feed connection (at the relay) to battery power? This should start the pump letting you know that the problem lies in the fuel pump circuit. Also, you can check the crank sensor. If the ECM does not detect engine cranking rpm's, it won't send a signal to start the pump.

See if you can find a factory service manual, beacause this can really get in depth. Even a factory manual for a similar GM vehicle will have a good diagnosis flow. Once I get home I can scan some basic circuits if you need them.

Oct 13, 2007 | 12:29 AM

ss4ever

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Joined: Jul 2007

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From: Shelbina Missouri

I have had to replace several ECMs on these types of cars. Check your injectors with a Multimeter, check for the resistance between the two prongs. All of the injectors must read similar readings(very close) if you have one that is WAY off leave it unplugged and try starting the car again.

Have you checked all the fuses?

You might also try a Noid light in the plug in for the injector/injectors and see if they are getting "fire", if so the light will flash while cranking over.

As for priming the pump, no need it should prime itself. As for air in the line that should be no problem because the return line would let the air that is in the fuel lines recirculate back to the tank.

Good luck finding the problem.

Randy