Here we go again - no fuel

[OldChrome]

Thought I had it all fixed.

My '93 Explorer XLT once again did the dry spell... the fuel pump did not activate upon turning the key.

Previously, I had replaced the filter and the Fuel Pump Relay. It ran fine... perfectly until about 2pm when sitting in the exact same spot where it happened before, she refused to get gas.

I went under the hood, swapped the plugs around, twisted the ignition switch back & forth until I finally heard the pump kick in and she got me home but... now I am back to square one.

Here's the link to my first passage:
http://www.explorerforum.com/forums/showthread.php?t=431879

One guy who stopped to help suggested it could be the ignition switch in the steering column. The key-over-fitter thing is loose and can be flopped around with the key inserted or not. He also said that there is a wire coming directly from my battery that powers the fuel pump and so the post may need changing.

And, of course, it's coming back around again that it could be the fuel pump. But... when she runs, she runs like a dream. And, after twiddling the key and swapping some relay switches, she did start.

So, next step should be taking it to a shop... but before I do, depositing my wallet, thought I'd stop by and ask this...

-> Could the ignition switch be the problem?
-> Could it be battery wiring?

If it were your beloved Explorer XLT... what would you do next?

Thanks for any suggestions...

Mike

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[FR-425]

Have a look at the bottom of the power distribution block.

Corrosion on the underside is common. Corrosion of the sockets and heat stress can cause intermittent problems.

You can remove the entire block, use battery terminal cleaner and then reassemble with Dielectric grease (light bulb grease).

Examine the relay sockets with a magnifying glass.

Start with the Ignition switch, it is far more likely to be the culprit.

Just in case you don't know this: The ignition switch is not where the key tumbler is. It is on top of the steering column about half way to the fire-wall.

literally a 5 minute job and about $15 You do not need to disassemble any part of the steering column to replace this part.

Youtube vid: it's a bronco but same steps. AND same symptoms! https://www.youtube.com/watch?v=KK2uO_xaDKA

 

[mekelly]

Make sure your EEC relay isn't flaky. If it doesn't energize, you won't get spark or fuel.

A quick test is to turn the key on (engine off) and see if you 'Check Engine' light comes on (assuming your bulb isn't burned out). If it doesn't, your EEC isn't getting power and the truck will never start.

 

[MrShorty]

Accidentally posted this in the old thread:

I once had an interemittent fault in the fuel pump circuit. It was kind of frustrating (as most intermittents are). I was finally able to trace the fault to a break somewhere in between the fuel pump fuse and the fuel pump relay. Cut that wire out and spliced in a new wire and that problem was solved.

How good are you with DC circuits? I know we talk about "all the electronics" in cars, but the fuel pump circuit (outside of the PCM) is a fairly straightforward DC circuit. I found mine by 1) getting a wiring diagram out of Chiltons (even that one was good enough) and a voltmeter. 2) Then, starting at the battery, measure the voltage at key points in the fuel pump circuit (battery, fuse, relay, inertia switch, tank). 3) To test points downstream from the relay, you will need to manually close the relay using the "fuel pump test lead" in the self-test connector.

Your fault lies between the last point where you have 12 V and the first point where you don't (The PCM generates a 6-7 V "ghost" voltage that shows up in the fuel pump circuit. Don't let that confuse you).

The frustrating part -- being intermittent, you have to wait until the fault manifests before you can do this. If it fixes itself while you are testing, you have to wait again.

 

[OldChrome]

Thanks for the checkpoints!
Gonna dive in tomorrow morning and chase each of these down.

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[OldChrome]

The bottom and inside of the Power Distribution Box is clean however, the plug slots for the Fuel Pump Relay switch and EEC, etc. look a little weathered.

I have a can of spray used to clean the Air Intake Sensor... you basically spray it on the element and it cleans before evaporating. Would this be an acceptable solution for those plug slots?

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[FR-425]

Sure, it's basically electronics cleaner.

 

[OldChrome]

Sure, it's basically electronics cleaner.

That was my view as well. Just wanted to be sure.

Thanks.

 

[OldChrome]

Cleaned each plug socket and the plugs/relays. Replaced them (they went in far more smoothly) and she's running like a champ. I did accidentally displace a vacuum hose and panicked for a moment but got that back in order, lol.

Thanks again for the help

Mike