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'93 EJ22T: What tells the fuel pump to pump??


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My car died last night. Left me stranded 75miles from home.

 

I pull the fuel line leading to the filter, crank the motor, nothing comes out....

 

 

What tells the pump to start pumping?? Is it the ECU? Does it use the crank angle or cam sensor? I pulled codes and im getting 11, 23, 49... there is one other, it was 2am on the side of the road so the codes could be wrong. I'll check again tonight for the codes... i know there were four.

 

Not sure where to check first.

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The ECU controls the pump but if it doesn't see a proper response from the ignition system it will disable the pump. The code 11 is for the crank angle sensor or circuit so it is causing the ECU to shut down the pump. You probably aren't getting any spark either due to that. The other codes have to do with the airflow meter or circuit to it. There may be a common power source to both of these areas and a fuse has blown for some reason. Without looking at some prints that sounds like the most likely scenario here. So if you haven't checked the fuses yet, do that. The problem may also be a broken power wire also to those areas so having something to check for power with is a must.

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McDave, there is no distributor on a legacy... but if it were a EA82 that would be the first thing I would have checked.

 

I did check my timing belt, and there is tension, so thats okay. It does have spark, i got the car to fire up on brake cleaner that i had with me.

 

I didnt have my multimeter with me, but I will bring it home with me tonight and check for power leading to the pump. Also use it to check fuses. I did a visual inspection of all fuses last night, but didn't see any that were obviously blown.

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I just thought of something else. Connect your green D-link connectors to have the ecu cycle the fp continuously. Listen for the fp running, check for voltage at the pump and relay if it's not. I believe the control wire between relay and pump is blue/yellow trace, but I'm not sure about that.

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Don't go too nuts chasing down circuitry (after checking fuses, of course) until you have verified that the pump actually works. Legacy pumps fail, sometimes "softly", seemingly more often than the pumps on the EA's did. I chased a problem on my 90 Leg for 2 calendar weeks before I tried swapping in a known working pump. RE: soft failures - the pump had temporarily quit 3 times on me, mysteriously coming to life before I had chased down the problem.

 

If you don't have a spare pump, just run power and ground directly to the pump; a spare connector would make this nice, but can be done with insulated aligator clips, or female mini-spade connectors, vampire splices, etc.

The connector's power and ground are fairly obvious.

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Well im almost positive its the fuel pump.

 

I put the car into d-test mode, and unplugged the fuel pump. I verified its getting 12v. If i plug it in, it doesnt do anything. I tapped on it and it came to life for a split second... but only did that twice, then went silent.

 

Guess tomorrow I buy a new pump.

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Well im almost positive its the fuel pump.

 

I put the car into d-test mode, and unplugged the fuel pump. I verified its getting 12v. If i plug it in, it doesnt do anything. I tapped on it and it came to life for a split second... but only did that twice, then went silent.

 

Guess tomorrow I buy a new pump.

Most likely. Did you happen to check the ground side of the pump too? Someone mentioned there's a connector under the seat that goes bad. You could be getting good power, but not good ground through that connector.

 

Buy yeah, tapping on the pump and getting it to run is pretty much a sure bet it's the pump.

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