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87 G20 SportVan fuel pump not running, and trans rebulding...


denisond3
01-22-2011, 04:30 PM
My 87 G20 sport van has no fuel pressure and I dont hear the pump when I first turn on the ign. key - so I want to find & check out the fuel pump relay. I bought a wiring diagram from ebay today, so when that arrives it might tell me where to look. Or someone on this forum may know. It has the 350 engine with throttle body & (I think) the 700R4 transmission. I replaced the fuel pump 2000 miles ago, so I hope its not that. What I then thought was a bad fuel pump might have been a failing pump relay.
If I dump a little gas down into the throttle plate, the enigne will fire up and run nicely for a couple of seconds.

Its transmission is the 4 speed where 4th is an overdrive ratio. Is that the 700R4? I think it should have a lock-up torque converter, but it doesnt lock up. Is there any reason I shouldnt drop the trans and 'rebuild' it myself, & put in a rebuilt torq. conv.? The vehicle has 260k miles on it, but the trans is marked 'Rebuilt for General Motors" atop the bell housing. Since the trans works fine except for 'no-lockup', I would hope I could just replace the bands and clutches, the seals, "O" rings & gaskets, clean up the valve body, and put it back together; with a rebuilt torque converter. Im a hobbyist, and have successfully rebuilt a couple of the little Mazda/Ford F4EAT transmissions & one A727 torqueflite trans. Being retired I have the time.

We use this van for driving between our winter home in TX & our summer home in N. VA - and I dont want to have it fail me in between. So Im thinking I might want to pre-emptively replace the main & rod bearings. The oil pressure is good though & hasnt changed in the 8 years and 60,000 miles we have had the van, so I dont know if its worth doing.

MT-2500
01-25-2011, 10:09 AM
My 87 G20 sport van has no fuel pressure and I dont hear the pump when I first turn on the ign. key - so I want to find & check out the fuel pump relay. I bought a wiring diagram from ebay today, so when that arrives it might tell me where to look. Or someone on this forum may know. It has the 350 engine with throttle body & (I think) the 700R4 transmission. I replaced the fuel pump 2000 miles ago, so I hope its not that. What I then thought was a bad fuel pump might have been a failing pump relay.
If I dump a little gas down into the throttle plate, the enigne will fire up and run nicely for a couple of seconds.

Its transmission is the 4 speed where 4th is an overdrive ratio. Is that the 700R4? I think it should have a lock-up torque converter, but it doesnt lock up. Is there any reason I shouldnt drop the trans and 'rebuild' it myself, & put in a rebuilt torq. conv.? The vehicle has 260k miles on it, but the trans is marked 'Rebuilt for General Motors" atop the bell housing. Since the trans works fine except for 'no-lockup', I would hope I could just replace the bands and clutches, the seals, "O" rings & gaskets, clean up the valve body, and put it back together; with a rebuilt torque converter. Im a hobbyist, and have successfully rebuilt a couple of the little Mazda/Ford F4EAT transmissions & one A727 torqueflite trans. Being retired I have the time.

We use this van for driving between our winter home in TX & our summer home in N. VA - and I dont want to have it fail me in between. So Im thinking I might want to pre-emptively replace the main & rod bearings. The oil pressure is good though & hasnt changed in the 8 years and 60,000 miles we have had the van, so I dont know if its worth doing.

Relay under hood.

Check fuse CHK/FP first.

And check for any power to fuel pump.
May be tan/white wire to fuel pump.
But on some it goes threw a hot fuel module.

It is equiped with a oil pressure switch for fuel pump incase relay fails.

Cranking enough to bring up oil pressure should turn on fuel pump if relay is bad.

denisond3
02-09-2011, 08:08 AM
I found & fixed the fuel pump 'not running' problem. Having dropped the tank, I found a bad connection where the wires from the pump connect to a fitting on the 'lid' of the sender and pump support. I soldered the connection, put it back together, re-installed the tank. All is well.

MT-2500
02-09-2011, 09:14 AM
I found & fixed the fuel pump 'not running' problem. Having dropped the tank, I found a bad connection where the wires from the pump connect to a fitting on the 'lid' of the sender and pump support. I soldered the connection, put it back together, re-installed the tank. All is well.

Good find.
Thanks for posting back how it went.
Good luck

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