Won't Start

[mekelly]

1994 cranked right up this morning as usual. Never had a problem starting it.

Drove 4 miles to the bank. Parked the car for 4 minutes, went back out and it cranks but won't start.

I can hear relay click when I turn the key but don't hear the pump whine. It's a little difficult to hear by myself in a buy parking lot!

From what I've read could be inertia switch, fuel pump relay, fuel pump. Anything else?

I have a strong hunch it's the fuel pump as I believe it's original. I am going to check the inertia switch to make sure it's not tripped and switch relays to see if that works.

If not, I'll get a fuel pressure gauge and see how much pressure (if any) is on the rail.

Anything else I should troubleshoot or look at?

It's just weird that the pump would die like that. Never had any problems with it before.

 

[natenkiki2004]

Once you've checked the inertia switch, disconnect the battery, lift off the power distribution box and swap relays around.

 

[mekelly]

I checked the inertia switch, it wasn't tripped. I switched the A/C WOT and Fuel Pump Relay's and it started.

I shut it off and tried to start it again about 2 minutes later and it wouldn't start (cranks but no start). Tried switching the relays back again and still wouldn't start.

I am going to try a known good relay from my Expedition and see what happens.

I think it's either the relay or the pump itself (hopefully the relay)!

 

[mekelly]

Replaced the original Explorer fuel pump relay with a known good relay from my 1999 Expedition.

The Explorer fired right up. Got home, turned it off, and then attempted to start it again and it fired right up.

Cautiously optimistic it was the 21 year old relay. Makes me question whether I should replace the fuel pump though just as a preventative maintenance item. Not something I want to do at all (had to do it for my Expedition last year), but don't want anyone to get stranded in the Explorer!

 

[mekelly]

Well, it appears not so lucky. I tried to start the explorer again with the new relay and no love.

Unfortunately, it looks like I need a new fuel pump.

 

[BearHug]

After turning the key in your car -- before firing up -- try popping your hood, opening the fuse box and lightly shutting it. Or give fuse box a tap. I have this issue on my 1994 Ford XLT -- same thing, sometimes fuel pump won't whine when I turn key. However, every-time I do the above procedure it comes right on. I replaced the fuel pump relay, but still sporadically have this issue. I believe there is some loose or exposed wiring running under the fuse box in my case. Worth a shot.

 

[mekelly]

Wanted to close the loop on this one.

I replaced the fuel pump (it was still intermittent on hot starts but ran fine when the car started).

The strainer was dark orange (I assume from rust) and the pump had some rust stains on it. There clearly was (or had been) water in the tank.

So, a new pump was definitely in order to prevent being stranded somewhere! The car has fired up every time now, no problems.

 

[mekelly]

The gremlins are back! After replacing the fuel pump and hanger assembly with a new Bosch unit the car started fine for several days.

Took it out this morning, drove 4-5 miles, stopped at the Post Office for 5 minutes, came out, and it cranked but wouldn't start. Same exact symptom as before.

Let it sit for 30 minutes and it started. I think the crank sensor is OK because I could see it go up a little when cranking, it didn't stay buried (could be wrong on that).

I am thinking it's got to be electrical somewhere. It's almost like it's loosing Ground when hot sometimes. I removed the power distribution box and looked underneath it. Didn't see any obvious loose or charred wires.

So, I have replaced the fuel pump relay and the whole fuel pump assembly.

Any other thoughts on troubleshooting? When it happens again, I want to try jumping rightmost connection on the diagnostic port to ground to see if it starts (found that tip on this forum!). I guess I'll climb back under there and see if there's any obvious loose or corroded wires.

I don't want to just throw parts at it, but these intermittent problems are a royal pain to troubleshoot.

 

[natenkiki2004]

Not starting when warm is a whole other issue. I had a similar issue but not as drastic as you or some other forum users have had. Mine was more... drive it a mile or two, stop for a few minutes, get in and crank, it would take longer than usual and run really rough until you let it idle for 10-15 seconds or gave it a pinch of throttle. Either way, it would clear up.

It's been talked about that it's an injector issue. I'd have to agree. I haven't seen this issue since I replaced my injectors, FPR, put in new lower intake gaskets and rockers & pushrods. For what it's worth, my FPR looked fine. I know with the new injectors, it starts quicker.

I don't know what the answer is for you but I'd personally shy away from electrical issues and go towards something with sensors or injectors.

 

[mekelly]

Seems to me injectors wouldn't cause a no start condition and then run perfectly once started.

Once the truck starts, it idles and runs great. No stalling, hesitating, surging, etc. Very smooth.

I have a jumper wire in the truck now so when it won't start, I can force the fuel pump to energize. Will be interesting to see if it works.

In the meantime, I won't drive the truck (and stop it) more than a mile or so from the house in case I can't get it started.

Of course since the key is so worn I can remove it when the engines running, I can always park somewhere, pull the key out of the running truck and lock it while it's still running!

 

[mekelly]

I connected an ODB-1 scanner to the truck.

I got no KOER codes (111)

I got the following KOEO codes:

542 - Fuel Pump Secondary Circuit open PCM/Fuel Pump Ground
543 - Fuel Pump Secondary Circuit open PCM to Batt

I have begun my research but has any one experienced these codes before? What did you do to resolve the problem?

It clearly sounds like a ground problem. I am going to get under there to trace the fuel pump connection back but does anyone know specifically where the ground wire for the pump is connected? Specifically where should I check?

Does anyone have a fuel pump circuit diagram for a 1994?

Again, when the truck starts, it runs really well. Would a bad ground only affect starting the truck and not when it's running?

Thanks!

 

[mekelly]

I believe the 542 and 543 codes were from pulling the fuel pump relay and cranking the engine to drain pressure before installing the new fuel pump assembly.

I cleared the codes and they haven't reappeared even though the truck hasn't started on several occasions.

I hooked up a spark plug tester that lights up when there's spark as well as a fuel pressure gauge when the truck wouldn't start. When the truck wouldn't start there wasn't any spark or fuel pressure.

Swapped out the EEC relay with a new one. Got spark, fuel and the truck cranked right up.

Time will tell but after replacing the fuel pump relay and the fuel pump (which were both 21 years old so I don't mind replacing them), I believe it was the EEC relay all along.

When I would drive and then stop for 5-15 minutes to run an errand, the heat soak was killing that relay I think. After it would cool down, 10-45 minutes, it would start. There were a couple of occasions where it wouldn't start cold, but that was pretty rare.

So, hopefully that was it and the truck will become reliable again!!! I'll update once I've driven it for a week or so.

 

[mekelly]

Buried treasure

Hopefully, one final note on my crank-no start situation.

After replacing the EEC relay, I have had no starting problems (although it's only been several days, I've started it 8-9 times and it definitely would have not started before on some of those occasions).

This forum has some buried treasure in it. In searching for a solution to my problem, I came across a one sentence comment from several years ago that would have saved me hours of troubleshooting. It went something like this:

'If your CEL light doesn't come on when you turn the key, you're not getting power to the EEC.' (this obviously assumes your CEL light isn't burned out).

If I would have caught that early when the truck wouldn't start, I would have replaced the EEC relay first.

A very simple test for a lot of things, but certainly for a (my) crank-no start condition.

If you're getting a crank-no start situation, check this first. Don't just swap your fuel pump relay, swap the EEC relay. With no EEC power, the engine will crank, but you'll get no spark and no fuel pump!

Now that I've asked around and spoken to people about this issue, I've come across 3 separate occasions where people said their crank-no start condition was due to a bad/intermittent EEC relay!

Just a tip to help others in the future that may experience this problem!