Fuel pump goes out eliminates spark?

[gbrugger]

I bought a cheap 95 4Runner 3.0 motor not running of course. Guy said it needs a fuel pump and it was parked at his mom's house and he just needed to get rid off it. I am reading that if you have no fuel pressure the spark will be eliminated by the system? Is this true? Also if you remove the air intake tube near the throttle body you wont get fuel pressure or spark? Is all or part of this true.

I wanted to spray gas or starting fluid into it to get it to fire for just a few seconds before I drop the tank and replace fuel pump and fuel filter while I am down there. I did pull cap and distributor is turning. I checked spark plug with indicator light and get no spark. So hopefully if I get fuel pressure and spark it will run.

Any way for me to run a quick check and get it to fire before I drop the tank?

 

[KidVermicious]

I don't think lack of fuel pressure cuts out spark. I've never heard that anyway? Might be something else going on there.

Pulling the intake tube WILL cut fuel, because the Circuit Open Relay that powers the fuel pump relies on signal from the AFM in the intake tube. Without AFM signal, the pump will run for a second when you turn the key and then cut out.

Don't assume the fuel pump is bad, and don't drop the tank if it is. Lift up the passenger rear seat and gaze lovingly at the access hatch Toyota put there to give access to the fuel pump. Then crack that panel and listen for the fuel pump while somebody turns the key. If you don't hear the pump, probe the harness connector that's right there for 12v. If you've got power and don't hear the pump, THEN replace it. If you don't have power with the key turned to start, your next step is to bypass the Circuit Open relay - not sure how to do that on a 3.0 second gen, google should tell you. Good luck!

 

[mholme]

No fuel pump access panel on a 2nd gen. I saw a guy in a yard yesterday getting creative with a chisel in the passenger back seat area and I already knew what he was doing before I walked up on him. He was cutting a hole for access instead of dropping the tank.

 

[Bad_Vision]

MAF controls fuel flow might try testing that. As for spark I'm not sure but sounds like a separate issue.


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[KidVermicious]

No fuel pump access panel on a 2nd gen.

That's lame. Second gens are lame.

I have a new idea, gbrugger. Sell that junk on and get a real 4Runner. :laugh:

 

[gbrugger]

Well this weekend I will check the fuel pump to see if I can hear it. And I will hook up the air intake tube and any other loose hoses.

This is my second 95 4 runner I have owned. Toyota seems to complicate some simple things. Sounds like lack of spark may cost me more to fix and be harder to chase down.

That's lame. Second gens are lame.

I have a new idea, gbrugger. Sell that junk on and get a real 4Runner. :laugh:

 

[gbrugger]

Fuel pump replaced only runs with jumper

Ok replaced fuel pump and filter. It will start with starting fluid so I do have spark now. Pump can only be heard with test jumper in place? Think I will clean MAF and see if that clears it up. Also may take fuel line off at the fuel rail to check how much gas is getting up to engine. Good to hear it run, now if I can get it to run on its own.

 

[Hyde802]

A 3.0 needs 30ish fuel pressure to run well, with a peak of 38. Need to make sure your getting good pressure, not just pressure.

Have you tested for spark? What are you reading thats telling you the no spark/no fuel thinger? Assume nothing and test everything.