enblethen
Moses Lake, WA
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Joined: 01/05/2005
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If the oil pressure sending unit contacts for the fuel pump are bad, the rig will not run.
The ECM only runs fuel pump for a few seconds then is out of the system.
I am still thinking no power to the pump via the oil pressure sending unit.
Bud
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1995brave
San Antonio, TX
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Daveinet, I thought the OP was DANDEAKINS, that is who i was giving the information to. I don't know what your problem is.
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rvrepairnut
bc
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the unit has fuel it has fuel pressure It runs when fuel is poured directly
into the TBI so it means the ECM is dead.Thats what controlls the Injecters
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1995brave
San Antonio, TX
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enblethen wrote:If the oil pressure sending unit contacts for the fuel pump are bad, the rig will not run.
The ECM only runs fuel pump for a few seconds then is out of the system.
I am still thinking no power to the pump via the oil pressure sending unit.
You are correct to a point. The OP came back and stated that he could hear the pump run for a few seconds when he turned the key on. The oil pressure unit closes when it has sufficient oil pressure to run the engine, i.e. puts 12volts to the pump. The first few seconds where the ECM turns on the pump is to build up the pressure of the fuel so when the ignition key is turned to start it can push the fuel through the injectors. Now i'm wondering if it isn't his pump after all. If you can't get fuel pressure in the line the injectors will not spray any fuel into the intake. Fuel pressure gauge is needed and connected to the fuel line at the throttle body.
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enblethen
Moses Lake, WA
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OP did get good flow when he supplied power directly to the pump at the rear of the rig.
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kdk
usa
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I agree with allot of what is being said here, however it has been my experience that even tho you can here the pump run if it's not putting out the correct pressure (around 21 psi for throttle body and 42 psi for multiport injection think) the injectors will not spray properly. An inexpensive in line fuel pressure gauge that is hooked right at the line going into the throttle body will tell allot here and end the guessing and let you know when and how much pressure you do have.
Another thought and I don't know if this applies in your case, but if your engine has a camshaft position sensor (tells the computer when to fire the injector) it could also be causing a problem. If my memory is correct the camshaft controls injection and crankshaft position sensor controls ignition.
Blessings; KDK
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rvrepairnut
bc
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Has the OP REALLY confirmed he has sufficient fuel pressure????????
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Daveinet
il
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1995brave wrote:Daveinet, I thought the OP was DANDEAKINS, that is who I was giving the information to. I don't know what your problem is. I was only talking about my system to make clear that it doesn't need the oil pump switch to run. Since I'm using the same ECM as he is using, I assumed it was worthwhile information.
The P30 manual states the the oil pump switch is only a backup system. Therefore the primary fuel pump control is the ECM.
Dave
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PaulJ2
Northwest Oregon
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enblethen wrote:OP did get good flow when he supplied power directly to the pump at the rear of the rig.
I read this also in one of his postings. As many on here know, the fuel pump runs for 2-3 seconds when key is turned on. This charges the lines for an easy start. While the engine cranks ignition pulses from the distrubutor module (after a certain number of pulses)will energize the fuel pump relay and supply power to the fuel pump.
After the engine starts the oil pressure switch will close and provide an additional 12V supply to the fuel pump. So--both supplys sending power to the pump at the same time. It is a back up system with either operating the pump by itself. The ignition pulse train from the distributor module also fires the injectors.
So even if the fuel pump relay failed the engine should still start after a long enough crank to build oil pressure.
Therefore I believe the injectors not firing looks like the problem to me. Check this out with a noid light. Suspect a bad distributor module or wiring problem.
BTW fuel pressure is 12 lbs not 21 on this system. Hope all this helps somehow.
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spacedoutbob
SF Bay Area
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Another thing I forgot to mention, Your distributor is okay? ECM is okay? Timing is correct? Just more things to check?
Bob In Calif.
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