Replaced Dead Fuel Pump and now it won't start.

[Randy88FJ62]

Ok: I'm going back to the beginning. I want to test the new fuel pump again. I want to elaborate on number 14 in my first post (14. Wired diagnostic box +B to Fp and I can hear fuel pump.) Just because I hear the fuel pump when i connect these wires doesn't mean it is functioning correctly right? What else do i have to do to check it 100%? I am trying to avoid draining the gas tank and lowering it again but I might do it.

Does the sound I hear when connecting those two diagnostic terminals mean that fuel is being pumped to the engine?

 

[sandcrawler]

I'm not sure if anyone posted this here or not, but after my fuel pump adventure, my Rig wouldn't start either - I checked the wiring harness in the rear driver's side quarter panel and the connector had corroded to the point where one of the wires actually broke loose from the connector. Once I sorted that out, it fired right up.

It's worth checking.

 

[Randy88FJ62]

I'm not sure if anyone posted this here or not, but after my fuel pump adventure, my Rig wouldn't start either - I checked the wiring harness in the rear driver's side quarter panel and the connector had corroded to the point where one of the wires actually broke loose from the connector. Once I sorted that out, it fired right up.

It's worth checking.

Yes, that was mentioned above and I checked all wires and grounds. I'm looking at specific fuel pump testing right now without taking the tank out.

I need a little help deciphering the FSM and taking the FSM fuel pump testing one step further past shorting the +B to Fp diagnistics terminals.

 

[Randy88FJ62]

bump. Need help with fuel pump diagnostics.

 

[Front Range 4x4]

Have you disconnected a fuel line in the engine compartment to see if fuel is being pumped?

 

[Randy88FJ62]

I have disconnected a fuel line and I get gas coming out; meaning that there is fuel pressure. I have not tried this while starting the car to see if it "pumps" fuel out. Do I need to see it pumping out or is pressure in the line enough to assume that it works?

 

[Front Range 4x4]

Sounds to me like you're getting fuel w/o problem so you can rule out a bad fuel pump. You can reassure yourself by leaving it disconnected and turning the key, just make sure there's nobody standing by with a cigarette.

I had a fuel supply failure that was apparently a combination of FPR and MAF, replaced the FPR and things improved, replaced the MAF and things improved remarkably.

 

[John McVicker]

I have disconnected a fuel line and I get gas coming out; meaning that there is fuel pressure. I have not tried this while starting the car to see if it "pumps" fuel out. Do I need to see it pumping out or is pressure in the line enough to assume that it works?

Randy, I am not certain on an EFI....but on a carbed engine I would want to see fuel pumping out. So if it were me I would crank the engine ....unless someone knows of a reason not to.

John

 

[Randy88FJ62]

I'm going to guess right now that it's spark. I haven't been able to fire it up at all. All it does is turn over. I'll check spark first and then if that checks out I will check for fuel being pumped.
Thanks for the responses.

 

[Randy88FJ62]

I finally checked spark and that is not the problem which leads back to the fuel pump or fuel pressure. I was pissed at having to drop the fuel tank again so I said screw it and got out the angle grinder.

Here's a few more pics of my angry trimming.

Be careful of the wires when you cut:

I had to cut another piece to allow the hard fuel lines to move up so I could remove the fuel pump. You can see it here lifted up.

So, I shorted +B and Fp to bypass the relay and the pump does not get power. Is my next step to directly give power to the fuel pump at the two wires in the picture above? How do I make sure the fuel pump is not a dud?

 

[Front Range 4x4]

Direct wires to the FP will tell you whether the pump is working or not.

 

[Randy88FJ62]

Direct wires to the FP will tell you whether the pump is working or not.

I assumed it was that simple. I'll do that and check back in.
THX.

 

[Randy88FJ62]

I need help: here is the update.

I have spark. It turns over but won't start so that means no fuel...

Here's what has been replaced and or checked:
EFI Main Relay
EFI ECU
Circuit Opening Relay
Ignitor / Coil
Distributor
Fuel Pressure Regulator
Fuel Filter
Fusible Link
Spark Plugs
Basic Fuses

Gas is in tank
Oil level in engine is full
*Fuel Pump runs when i run direct wires to it but not otherwise

I have not checked fuel pressure to see if the pump is working properly
I see no kinks in the fuel lines so that looks ok.
I shouldn't need to check Neutral start switch because it turns over when trany is in park.
maybe I need to check start injector time switch?
maybe Check air flow meter?

Who has any guesses. I'm all ears.

 

[Front Range 4x4]

Have you manually disconnected the fuel line under the hood to see if it's flowing? Might do that - quick & easy. I had a similar problem that turned out to be the MAF and FPR to a lesser extent so I'll guess the MAF.

 

[Randy88FJ62]

It's alive! I just manually connected the fuel pump wires directly to the battery and it runs!

What is stopping the fuel pump from turning on normally? Why do I have to bypass the whole electrical system to get it going?!

 

[Front Range 4x4]

*Fuel Pump runs when i run direct wires to it but not otherwise

It's alive! I just manually connected the fuel pump wires directly to the battery and it runs!

I'm a bit confused by what appear contradictory statements but it's all good since it's running. Trace the wires you bypassed with the direct wire. There's probably a bad connection in the left rear below the rear window washer bag.

Nice to be getting near the end of this issue!

 

[Randy88FJ62]

The above two statements are not contradictory, i just didn't explain properly. When doing diagnostics I ran a 12V power source to the fuel pump and it turned on. I did not however try to start the car when I did that. I was checking other things.

Today I did the same thing by giving the fuel pump power directly and it started. So now I'm thinking it's a wire issue.

My wiring is all intact as this car was originally from new mexico and now it's a california car. All wiring was fine until I replaced the fuel pump. I bet I pulled something when I pulled the fuel tank out to replace it. hmm.

Drivers side quarter panel wires seem to look ok...

I'm gonna be checking wiring. If anyone has any other ideas please let me know.
-Randy

 

[Front Range 4x4]

I bet I pulled something when I pulled the fuel tank out to replace it. hmm.

Yeah, sounds likely, glad it's running

 

[Randy88FJ62]

While I had the truck running I disconnected the direct power to the fuel pump and it still runs. Now it runs normally without direct wires to the fuel pump...

Sigh.. It runs but I don't feel like I've solved the problem.

 

[Front Range 4x4]

MAF