starting problems. i'm lost!

[mad hatter]

94 XLT 4wd. here's the issue:

Had very low fuel pressure. Thought the pump was bad but changed the filter to be sure. Now the fuel pressure is fine. The problem is spurattically when you turn the key the pump doesn't prime. I've tested the relay and inertia switch, both are fine. So here's where i'm lost. Last night it wouldn't start. No prime from the pump. So I had my friend crank it while i sprayed carb cleaner in the plenum, still nothing. So now i've established it has no fuel or spark. Great! I get back in it and start fidgeting with the key. Still nothing. I grab the shifter and shake it around a bit, turn the key and the pump primes. She fires right up. So now the question... WTF!?!?! Could it be the ignition switch? Ignition module? Nuetral safety switch? Anybody have any ideas? Info on how to test? I'm frustrated beyond belief.

 

[doonze]

My "guess" was going to be the neutral switch at first... but I'm pretty sure the pump still primes even when not in neutral, just that the starter won't engage. Otherwise you'd never be able to pop start em.

So yeah, no help am I? :scratch:

What could moving the stick have anything to do with the pump priming and you getting spark all of a sudden..... I can't come up with anything. Since you can pop start M5's then you get both spark and fuel when not in neutral, just no juice to the starter.

And since you can crank it, the clutch and neutral switches seem fine. Maybe just replace the relay, not just test it. It might be iffy. Course that wouldn't explain lack of spark.... but then again, I'm not sure these will run on carb cleaner...Starting fluid yes, but I know when I used throttle body cleaner mine wouldn't run until I "burned" through a bit of the cleaner..... was killing it NOT making it run.

So maybe you DID have spark, just no fuel....

 

[motopsycho650]

The neutral safety switch should throw a check engine light. I know I had one of those before. I got it during the key on engine off test.

Also, the neutral safety switch wouldn't disable the fuel pump. I had fuel pump noise, but no cranking.

With the key on, jump the starter relay next to the battery with a screw driver, and see if it cranks. (touch a screwdriver to the 2 large wire posts) If you still get nothing, I would go straight to the ignition.

Also, on the starter relay, there is a small wire with a 90 degree pink/red connector that simply pushes onto a small wire post on the relay. Mechanics used to play tricks on each other by un-plugging that wire. That is a reference wire that tells the starter relay to engage. If it is not plugged in, or it is loose, you will not get cranking.

 

[mad hatter]

It cranks just fine, just won't start. It only does this intermittantly. For example its ran fine all day today. No issues. But i guarantee by the end of the day it will do it to me again.

Again, it cranks, just doesn't start. The fuel pump doesn't prime. I have to mess with the ignition and shifter to get it to finally kick in so it will start. Thats why i'm lost.

 

[MrShorty]

Do you have a wiring diagram (even the one in Chilton's or Haynes would be a good start)?

Fuel pump power goes through the fuel pump relay (obviously).
PCM is responsible for closing the fuel pump relay.
PCM gets power from the EEC relay, which is closed by a circuit through the ignition switch. So, when it won't start does the PCM have power? Quick check of this: does the CEL come on when you turn the key on without starting (key on engine off or KOEO)? The CEL is supposed to come KOEO as a basic indicator that the computer is powered and ready. If it doesn't come on, then the PCM probably isn't getting power.

Can you get any codes out of the PCM? Sometimes, and intermittent no-start like this will leave clues in the PCM (especially if the problem isn't in the PCM power supply).

 

[TedJ]

Try a new relay even if it tests ok.

Is your CEL on with key on engine off (indicating power to the ECM)?. If key on engine off, CEL on, and no prime try replacing the fuel pump relay, if key on, engine off, cel off, replace ECM relay.

 

[mad hatter]

Next time it does it i'll look and see if the CEL is on. It did it earlier and i jiggled the shifter around and it fired right up again. I know that when it fires the CEL light is on but haven't paid that much attention the times it doesn't fire.

 

[EskimoEddie]

Had same problem

'94 EX Eddie Bauer auto

I had the exact same problem, never repeated itself, very intermittent. I found that if I swapped the heater blower relay with the fuel pump relay it would run ok, like for 4 months. I finally replaced the relay, the problem went away all together. But as a side note, I also had to replace the battery, and OEM battery cables (pos and neg) due to heavy corrosion. So if your battery/charging system is sub-par, then an intermittent "power-delivery" to critical systems in your ex, like fuel pumps, you could have problems. My .02 ¢

Greg

 

[nitro71]

And quit spraying starting fluid or carb cleaner in the intake, this isn't a lawnmower engine..

 

[doonze]

And quit spraying starting fluid or carb cleaner in the intake, this isn't a lawnmower engine..

No, just lawnmower tranny's...

I was thinking you had a M5, now I'm thinking your talking about moving around the auto shifter. But I would think same things would apply.

I vote for swapping some relays around and seeing if the problem follows the relay...

 

[mad hatter]

And quit spraying starting fluid or carb cleaner in the intake, this isn't a lawnmower engine..

You're right, if it was a lawnmower engine the damn thing would start every time. Maybe Ford should take some lessons from Brigg's & Stratton.

Both this explorer and my 95 have had nothing but problems. I just fixed mine again, and after fixing this one i'm done. Any more trouble with them and thier getting traded in on a Dodge. Yeah, prolly a bad word on here but its how i feel.