Well a while back I had an issue where the truck just died. Ended up being corroded wires on the top of the tank for the fuel pump. Fixed the splice and all was well.

Today I got halfway to work and she just died. She was a bit rough starting this morning (really unusual) and yesterday on the way to work she cut out 3 times but kept on going. Never happened on the way home though.

I'm thinking I have another wiring issue with the pump. Where to the wires go? From the pump do they just run to the cab and into the ECU? As of now she is sitting in a parking lot and I'm not sure when I can get her to a garage (well my parents, I don't have on yet).

Any other thought? It does run on starting fluid and I have jumped the pump at diag box and still nada.

I'm assuming it's an electrical issue and I think I'm just going to run wires to the pump but I don't know where they start at. Sooooo anyone knows where they go that would be great. Thank folks.

 

Anyone??? Come on, someone's gotta have an idea?

Could it be the relay going bad? I was looking at C7 in the FSM on page 68. Is the relay between the pump and the Diag jumper? Meaning if the relay is bad it does not matter if you jump the circuit?

I know you folks here are all smart and nat so fix my truck!!!
At least give some insight here.

Thanks...

Before ya ask it's the 92 in my sig.

 

Not even one other thought???

Well I now have it at my folks and I'm heading over there shortly to mess with it a bit more. The garage is only slightly above freezing and it's about 15 now outside now.

 

Give us time man...this is a forum not AAA.

First thing to do is check for power at the fuel pump. If you have power there you can assume your fuel pump is faulty. If you don't have power at the pump then check the relay...When you jump B+ (12V) and Fp (fuel pump) this relay should engage. If you do not have 12V on the output terminal (going to the fuel pump) you can assume the relay is bad, or there are loose connections at the relay. If you do have power at the output of the relay you have a loose connection/broken wires somewhere between the relay and the fuel pump.

If it works when jumped but doesn't without then you probably have an issue with the VAFM

 

LUMPY...I just found this thread, next time send me a PM or something.

Listen, it's damn cold out.......few years back(same weather) my truck started bucking and not accelerating and finally had to park it on the side of the road on my way to work and get a ride from the cops (cuz I'm cool like that)...... had the wifey pick me up the next morning and threw a bottle of drygas in, went to get breakfast, came back, started it up and drove it home like nothing happened.

Start simple, throw some drygas in...1 or 2 bottles and top off the tank...see how that does. If that doesn't help then maybe you have an actual mechanical problem. Funny crap happens when it's so cold......I remember, when I used to work with te Fire Department, we had a city garbage truck temporarily parked in the garage to "thaw out". I'm not quite sure how to tell you to thaw out your truck other than get it runnin and leave it running and maybe some ambient heat wil find it's way to the tank .

God luck, keep me / us posted.

 

Had it towed to the folks last night...I'll tell ya it was cold and a pain to get on a car dolly but we did it. Later last night I headed back over and tossed a charger on it and started messing around a bit.

So Milehigheric, am I right in assuming that the Fp and B+ trick is before the relay and the pump does not run on the jumper? I did swap relays (Fp and Starter) and it still turned over with no starty. So I guess I can rule out the relay. Does the wiring run from the engine compartment through the cab, out again, and to the pump with out hitting the ECU?

Sunday I'll pull the bed and check the connections at the pump and start tracing back from there. I did have a bad splice there in the spring but "I thought" I fixed it. Maybe that's the issue again.

92 I don't think it's from the cold or freeze up...but it very well could be. I dumped some stuff in the take shortly after it died yesterday. Last month we were close to 0 and she started fine, still doesn't mean that water didn't get in the tank (It's all but full as well).

Right now she's sittin in my folks semi-heated garage. I gotta go to Pittsburgh today so tomorrow I'll get on it again.

Thanks for all the input!!!

 

LUMPY....is it a funeral for the Steelers....should be.......BAH!! Maybe next year.....but until then I'll be cheering AGAINST the Eagles...I root for the Steelers and anybody playing the Eagles.

Yes, well, I'm just basing what I said on my own experience...sounds like you've been down that road before with you fuel supply issue....so good luck.

 

Well I do hope it's something much simpler than the wiring...like you suggested. -sigh-

 

OK now......go get your cholesterol elevated.......maybe it will right itself.

 

Bit of background might first help....The fuel pump is independent from the ECM, not directly controlled. It is controlled by a relay known as the Circuit open relay (COR). This relay is a duel coil and initially activates (the first coil) when the key is on start. During this time your starter is cranking and the engine begins to suck air opening the VAFM. This open flap grounds the second coil keeping the fuel pump running untill the time that the engine stops sucking air ( a safety feature in the event of a crash).

The B+ and Fp jumper simply bypasses this whole VAFM and COR and sends 12V directly to the fuel pump. When jumped it should run constantly regardless if the engine is on or off. If it is not running when jumped, first I would make sure that the b+ terminal in the diagnostic panel is actually 12V (weird things happen with old wiring) and if it is you know that there is a severe or a loose connection in the wiring between the COR and the fuel pump.

The fuel pump is the best place to start...If you can't find any issues with the wiring there you should get a voltage reading just before the fuel pump. If you have 12V there, but the pump doesn't work still then you have a bad ground or a faulty pump...On the flip side if you don't have 12V there, trace the wire back to the front and look for the issue.

 

This is true.


Not quite. Jumping +B and FP does bypass the COR and send power directly to the pump but +B is the lead from the EFI Main Relay that feeds power to the ecu - and it is triggered by the ignition switch. So the jumper only sends power to the pump when ignition is on.

FP is connected to the wire that goes from the COR to the pump - and so it should be hot when a helper is cranking the motor. If not, then either the COR is bad, or there's a bad connection - either in the wire from the ST1 term of the ignition switch or a bad ground, or possibly in the wire from the COR to FP.

If FP is hot when motor is being cranked, but the pump is not receiving power, then the COR is fine and it's a bad connection between the COR and pump.

http://personal.utulsa.edu/~nathan-b...28fuelpump.pdf

 

Ok Thanks guys!!! This will help me out greatly!!! That is what I really need to know is how the jumping (B+ & Fp) actually did what they did. I'll be able to test faster tomorrow. Starting about noonish, the boy has a soccer game in the morning.



.

 

what is your status

 

I was not able to mess with it today. I'll be on it tomorrow.
Gotta test a few things then probably pull the bed and start working backwards from there.

 

Ok just got back from the folks and I drove the truck!!! Yeah for me!!! After some testing I found I was getting power towards the pump. So we pulled the bed (well took out most of the bolts and jacket it up) and found that the plug on the end of the pump was shot. One of the prongs broke off and that's what it was. It broke just past the splice I fixed in the spring. So I cut it all out (plug and splice) and soldered a new piece in and were in business!

Thanks everyone for your help!!!


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good deal..

 

I was lost without my baby...I was stuck drivin the lil lady's Jeep.

 

Good Job LUMPY!!!!!

 

nice.

 

i bet you dont feel like a woman anymore driving that jeep