No Start + Engine Bay REALLY hot???

[YW84U]

Ok, I'm stumped -

This is the second time the Ex has failed to start in last two weeks- identical symptoms:

After driving, well within operating temps, I will stop somewhere for a minute, get back in, and find that it will not start, and the engine compartment is really hot all way around - pwr dist box, air box, fenderwells, hoses you name it all feel to me to be 'too warm'.... There is no sound from the Fuel Pump charging up ....if I leave it sit for 20+ minutes, away I go - fuel pump starts and everything is alright again. Outside temps around 30 celsius.....

Since March 2002, I replaced the fuel filter, fuel pump, fuel pump relay, both new sets of battery cables, 130 amp alternator, new battery, new starter, crank angle sensor, new thermostat, brand new rad, new neg ground to battery.....and probably other stuff (put in Reflexes earlier today!). I do note that the temp guage was rock steady after the rad, but now goes cold while driving - have yet to figure that one out, but do not know if it's related.

If a fuel pump goes bad, don't they just die and stay dead? The thing is just over one year old (Carter, I think..). Two relay changes have not helped either. I don't have a fuel pressure guage, so I cannot check the rail. Would the FPR failing result in such symptoms?

Or is it because I just put new shocks on

Any help is greatly appreciated!!!!

 

[93xltnewb]

check coil pack wires plugs
go with the easy stuff first

 

[YW84U]

Would those affect the fuel pump? Sorry, I should add that when the no-start happens, the engine will crank and attempt to run, but only until the fuel in the rail fizzles out on the first start attempt. Then, the apparent lack-o-fuel continues on (no pump sounds, unable to tell if relay clicking with all of the others) for the 20+ minute cycle.

I would tend to believe it is fuel delivery related, but I guess I'm trying to aviod dropping the tank again in under one year......

I just went out to cycle the key on and off 8 times, and each time you could hear the pump spin up and then click off after priming - followed by a small 'gurgle' from the gas tank area. No fuel smells at all....

Thanks

 

[YW84U]

Starts up fine this morning - fuel pump primes as its supposed to. I took the distribution box apart and cleaned everything, and will throw in a new EEC relay - maybe it's flaky when it heats up...

I've checked the inertia switch - all is fine, plus all of the plugs on the wiring harness to the fuel pump are ok. Definitely a mystery!

Thanks in Advance!

 

[YW84U]

I thought I would resurrect this thread, as my truck was just towed home (from the dump, of all places ) - the same problem as I noted last year. Again, it was near 30 celsius was driven and turned off for about 10 minutes. Upon restart, no fuel pump prime - of course, no start condition. having gone through this before, I whipped out my spare FP relay, but it made no difference....

Can anyone think of any heat-related issue as to why a fuel pump would not run? Does the ECM have the ability to cut off the fuel pump based on some sensor input? The truck died at 2pm, but I just cranked it over at 10pm (cooler outside), and she started without a hitch, FP priming as normal. I had planned to start tracing wiring in the morning, but now everything works. BTW, I replaced my FPR 2-3 months ago.

Thanks in Advance!

 

[MrShorty]

The computer does control the fuel pump, but the pump should be on anytime the engine is running. There is a lead in the self-test connector that will allow you to ground the fuel pump relay. That would take control of the fuel pump away from the computer. Do you have a wiring diagram? Have you been through the circuit with a voltmeter in an attempt to find where the fuel pump loses power? And don't forget the ground side of the circuit, either. The fuel pump ground is under the hood as well.

 

[YW84U]

I had great plans of taking the meter out the following morning to start tracing, but the pump is working now... chasing ghosts I guess! I have the Hayes manual, but are you able to describe where I may find the test connector to manually ground the pump? I think what I'll do is keep my meter and some jumper wire with me on the road so if I am able to duplicate the symptoms, I can do some triage at roadside. This one is tough as it seems so infrequent (once or twice a year so far). I'm going to inspect the wiring as best I can this morning to see if I can locate anything obvious. I'm really at a loss about the heat aspect of the problem; perhaps some portion of the circuit gains resistance with increased heat?

I really appreciate your reply!

Tom

 

[Opera House]

I would make a jumper from a couple inches of wire with two 1/4" male spade connectors and take it with you. When you pull the fuel pump relay, the two opposite sockets with pins facing in opposite directions are the two you want to jumper. This should cause the pump to run regardless of key position and ally you to diagnose with a meter.

If this causes the pump to run, the problem could be in the control wire from the computer to this relay or the ECM relay is not turning on. The same jumper can be used on the ECM relay and it will turn on the computer regardless of key position.

These two tests will provide an indication of where the problem is and might get you home.

You can insert a meter in the 10A range to get a general test of the pump motor. It should draw about 5A. Under 4A indicates some fuel problem.

 

[MrShorty]

Don't you just love diagnosing intermittent electrical faults ?
Your Haynes manual may have a description of the self-test connector. Check in the fuel pump testing article. My best description in words: Self-test connector is trapezoidal with a long end and a short end. fuel pump test lead is the outermost lead on the short end of the trapezoid. FYI, this test lead is just "tee-ed" off of the circuit used by the PCM to control the fuel pump relay. Grounding this lead to run the fuel pump assumes that the fuel pump relay (and, by nature of the circuit, the EEC relay) is functional. If you ground this lead and the fuel pump doesn't come on (key needs to be on), then there is a fault in the power supply to the fuel pump relay.

 

[YW84U]

Thank you ever so much! So far, everything is running fine (its cloudy), but I will put my meter on it this morning and see what comes of it. I was poking around yesterday, and realized also that there is a seperate 'relay' if you will that was put in by the previous owner to isolate the battery from a towed trailer (relay and some dual junction block of sorts). When the truck was dead, I do not recall hearing that unit click over on key on - I'm not 100% if that may disrupt the fuel system electricals, but I think I will change those items out also just to be on the safe side and double check the wiring as well.

I really hope I don't have to drop that tank again! Thank you for the tip on the amps draw to look for also - man, where would I be without the fine people of this board?

Tom