Fuel Pump stopped running

[LucyFord]

Hello,

I have a 91 Subaru legacy with a stage 2 revtronix chip, 550 injectors, and a walbro 255. I ran into a issue with the tips of the injectors falling off and had to pull apart the intake to get them out of the cyl head. I believe that issue was caused by a kink in the line of return line on the stock fuel pressure regulator.

So to make sure that this problem didnt occur again I wanted to run a test. So I place some paper underneath the intake (with it removed) and reconnected the fuel lines with the plan of putting the car in the accessory on mode (which should prime the fuel pump).

Well the fuel pump wouldn't turn on. I tried cranking the car, i reconnected all the injectors, i disconnected and reconnected the battery, i plugged in the maf, i phyisically traces all the wires to the dash and they seemed fine.

I have NO idea why the fuel pump will not run. My friend checked with a mulimeter and there was no power going to the pump so its not the pump.

Is there any "safe mode" in the ecu that would stop the pump?
Is there any common reason that the fuel pump won't turn on?
Is there a sensor that i might have not plugged back in?



I ended up "hot wiring" the pump the complete my test but i still dont know what it wouldnt turn on.

[LucyFord]

Well just for reference. The Haynes Manual say that if the crank angle sensor is disconnected that the fuel pump will be disabled.

To bad my crank angle sensor is connected.

[SILINC3R]

there is a fuse( 17 I believe) that is somehow connected with the radio. I had this problem a couple of times and did everything i could think of and that seems to work sometimes. There is a relay that you could check also to make sure it didn't get shorted out. you can use a multimeter to test it or just plug into the sunroof socket and push the open or close. if you hear it click it good, if nothing then it is bad unless your buttons don't work. It is a quick check on my car.

But again, check the fuse panel in the car. Just pull fuses out check for continuity and then plug back in. hope this helps

[Subiman91ss]

neutral safety switch... lol

sometimes I miss the small things when I get frustrated

[LucyFord]

I checked all the fuses with a mutimeter (but i will check again)
I also swapped the relays around to try to eliminate the chance that it was bad


Neutral safety switch seems legit BUT the car will crank over. I assume if it was the neutral safety switch the starter would be disabled also?

[Subiman91ss]

you have a good point... my only other idea is that you could check the fuse box with the relays.. I have seen boxes melt and short out, thus not turning on the pump..(never really seen it on a subaru, but it happens on land rovers all the time).

this is just a thought tho

[Legacy777]

Do you have power to the pump at the connector under the rear seat? If not, the next spot to check is the fuel pump relay and ignition relay. From there, if the relays are good, you've got the power supply and grounds to the relays and then the triggers that come from the ECU.

You can d/l the 92 engine & electrical factory manual from me, which should help in diagnosing the electrical issues. The wiring numbers/pins may not be 100% the same, but should be close enough to help in the diagnostic process.

http://www.main.experiencetherave.com/s ... lectrical)

I've also got some diagrams from the 90 model year on my swap write up
http://www.surrealmirage.com/subaru/swa ... ml#neutral

[LucyFord]

Thanks guys. I ended up having a poor connection the the cam position sensor (i must have bonked it removing the intake). Starts right up.

I should have checked for spark eariler. Once i did this and saw i wasnt getting any i knew it was something related to the ECU.

[Subiman91ss]

happy to hear it was simple.. thats always good