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Fuel pump probs--89 RX......FIXED w/update


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Yup, finally at that point. But the fuel pump isnt working properly. I have power to it with the green connector hooked up, it supposed to cycle on off but the pump wont run. I removed the FP and hooked 12v to it and it works fine. I didnt have time to go thru the codes or troubleshoot it today, but is there a common problem and remedy when it does this? If I really have to, I can temp wire it, but I'd rather fix it right.

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Problem solved!

Added a ground wire to the FP, it works fine now.

The engine was still having problems. It seemed like it was fuel starved and running on2/3 cylinders. I could barley get it up to 3K and hold it. I tried just about everything until I was adjusting the disty for the umpteenth time, when I turned it I bumped the main wiring harness and it sputtered and died.

Doh! I checked the plugs (I could swear I pushed them suckers together tight) and they were both loose. I had to use the frame rail to push against but they are tight now!

After that she fired right up :headbang:

After I did some quick fine tuning, I jumped in (after rearranging stuff inside :rolleyes: ) and actually drove it down the street and back.

I've had the car for over a year now, gone thru 3 engines trying to get one that was decent enough to put together. Not much luck with ones that had blown HG, they pit the cylinder walls bad when they arent drained of water.

Thanks to Qman for providing the running engine and parts car.

My RX is finally running! W00T! :drunk: Its going to be ready for WCSS7, I hope I can get the body work done by then too.

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The ground connection for the fuel pump is most likely controlled by the ECU. I had the problem with a couple of ECUs for my '88 GL-10. It turned out, the same driver transistor in both of the units had failed.

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That is an extremely common problem with every EA82T I've ever seen.

 

It's so common that most Oz people I know, convert the earthing system from the ECU to the car body even before it becomes a problem.

Funny how Subaru changed the fuel pumps in the Legacy & later to simply earth out.....

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I think that if I removed the ground wire on the FP, it would still operate. I'm sure the major problem was the wiring harness plugs. I am aware that the grounds are a common problem and I did clean all of the ones in the engine compartment during the install. We now know that the plugs are also a item that needs special attention when doing engine swaps.

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Is your GL an EFI?

 

On the EFI models, the positive side of the fuel pump is controlled by the fuel pump relay, which is controlled by the ECU, while the negative side goes back to the ECU as well. Why? Who knows.

 

The problem is with whatever controls the negative side in the ECU, so you simply earth the negative wire from the fuel pump to the body instead.

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