Fuel Pump

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#46
Huh....I would have guessed that bumps would have affected that loose connector more than heat..........but maybe the heat was from the heater and not the engine?
 

Boomer

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#47
Huh....I would have guessed that bumps would have affected that loose connector more than heat..........but maybe the heat was from the heater and not the engine?
I'm surprised too. I figured the truck would have quit while driving. Like I said, I can't be sure that it's solved but, it was definitely loose enough that other things started acting up. That screw was all the way loose. I simply forgot to tighten it. I hope it's fixed
 

nickb2

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#48
Bill...the "one second fuel pump buzz".....you don't need a good crank sensor to make that happen. When Boomer's truck won't start, the "one second fuel pump buzz" isn't happening.
Second that comment large.

The more I am reading this thread, the more this is sounding like a PCM driver issue.

I really like Dan's idea of cooling it down with an ice pack, may get you home.

And pin point down the fact that a internal fp driver in the PCM is shot.

So, like I said before, if all wiring is ok, might be time to check the underneath of the power distribution, make sure no melted contacts there.

Just as an example, I had a buick rendez vous in the shop with a 3.9l I think, who cares what size engine, same circuit. Anyway, 3 fuel pumps later, I fell on this problem. Suv would run fine for weeks on end, female client back on towing time after time and at her wits end.

It ended up just being a bad/melted contact under the PDC relay center. Nver underestimate the fact of a loose/melted connection. Always take apart any thing FP related and look closely.

Most likely, the first tech that look at this buick was right in assuming the pump was bad, drawing to many amps, melted relay 86pin pcm control relay signal to activate but he missed that. Second tech said it was a faulty new pump, third tech said f it and went home. Thats when I fell on this. That is where I went through this thing with a fine tooth comb. All it was, just a melted relay signal pin from PCM @ PDC.
 

nickb2

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#49
Anyways Boomer, kudos on being assiduous, posting back a photo and what you think is a fixed thread. If all were like you, we would have an easier lifer here at BAT auto.
 

nickb2

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#50
It took me a few minutes to read to whole replies and the fact that you talked to a co worker and he put you on a logical thinking. You owe him a beer.

These types of threads are a paycheck for me. If at first you don't succeed, try and try again. GF is snoring like a peterbuilt mixed in with a MAC/ I sicked my cat on her. I think I am going to be stuck on the couch.

No sleep for the wicked apparently.

 

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#51
After testing for 3 days, I think I can say this problem is now :fixed: I've driven to work, shut if off, and restarted with no issue. Even stopped at the store yesterday briefly. Started right back up fine.

I'm guessing the loose connection was causing a high resistance connection to the coil side of the fuel pump relay. As we know, resistance in an electrical circuit produces heat.

At least tightening that connector was much easier than changing a fuel pump.

Thank you very much to everyone who replied. :beer:
 

Boomer

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#52
Anyways Boomer, kudos on being assiduous, posting back a photo and what you think is a fixed thread. If all were like you, we would have an easier lifer here at BAT auto.
I think it's important to properly close out a thread with the fix. It can certainly help someone else.
 
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#53
Kev2, haven't seen him lately always use to ask did you do any vehicle modifications or recent work lately? Maybe should be a standard question.
 

Boomer

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#54
Kev2, haven't seen him lately always use to ask did you do any vehicle modifications or recent work lately? Maybe should be a standard question.
I agree Nick. Since it started and ran fine immediately after the heater core, I thought it was all good.

In the future if I’m going to take an electrical connection apart, I need to take it all the way apart.
 
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#55
I use a magic marker and use a 1-1, 2-2 sequence on each connector housing, memorize the last number and reverse the procedure. On some vehicles found three identical connectors, others, an unused connector for some option that I don't have, put a red X on that.

Have no problems reconnecting them with one hand but need both hands to disconnect them and the release tabs are all different.

Ha, think about the days when we only had six wires going from the dash to the engine. On this new stuff, really finding a lot of 28AWG wire, really have to be careful with these things, very easy to break a wire.

On that 93 Bravada, fuel economy was terrible, still had a distributor that had to be timed, but have to disconnect a connector first before timing it. If I didn't have a shop manual, would have never have found it, was located in the lower dash under the glove box. Was set at zero, suppose to be an -10, man, that made a difference.

Have to remove the front seats first, but on some vehicles, find that center console to be really literally a PITA.

Other concerns are disarming airbags first so you don't blow your head off.
 
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#56
Boomer said...
In the future if I’m going to take an electrical connection apart, I need to take it all the way apart.
Sometimes I cause a problem when I am putting things back together and I put a connector only half-way into a sensor, (because I am afraid that I will have to remove it to access something else during reassembly, and if I "click it", I will have to fight the awkward lock again). But then I don't need to remove it after all, and I forget that I still need to "click it" and visually (if it is even visible) it looks OK during a once-over. A minor annoyance if vehicle won't start or a warning light comes on....a much bigger deal if the connector separates later when far from home or in the possession of a customer.
 
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#57
Ha, never had formal training on how to disconnect an auto connector, but sure would help if you could see what you are doing.
 

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#58
Sometimes I cause a problem when I am putting things back together and I put a connector only half-way into a sensor, (because I am afraid that I will have to remove it to access something else during reassembly, and if I "click it", I will have to fight the awkward lock again). But then I don't need to remove it after all, and I forget that I still need to "click it" and visually (if it is even visible) it looks OK during a once-over. A minor annoyance if vehicle won't start or a warning light comes on....a much bigger deal if the connector separates later when far from home or in the possession of a customer.
Yes, you really don't want to hand it back to a customer and, then have a problem. I'm pretty happy with the way I did everything except for that on a big job like the heater core. It is a pain that those connectors all seem to be different. I remember mumbling some choice words about that when I was tearing this apart. It was really nice up in the 4x4 switch area. When you are looking down from the top of the bezel and the clip is on bottom, you can't see how it comes apart. It would have made too much sense to orient it on top where you could easily see it.

I like Nick D's idea of numbering connectors. That would help make sure you don't leave one that's buried unhooked. I'm going to keep that in mind.
 
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#59
Once marked, stay that way, have to pull the IP off my Supra again to lubricate the speedometer cable, when that needle starts to bounce, knocks it out of cruise. Have no idea why you can't pull from the transmission end, so much easier, but like to do everything the hard way.