93 explorer sport starting issues

[2stroke]

Up north 15-20 years is when the sending unit rusts out and leaks gas. It could cause this exact problem, but I doubt it in California. By the way, dropping the tank is harder than the transmission. Cut an access panel.

 

[FR-425]

You know that raises a question. Since we have plastic tanks, I'm assuming they should be good even after 20+ years.

I'm assuming ethanol etc. etc. won't destroy the plastic, as surely by 91-94 auto manufacturers were using tanks suitable for ethanol, right? If that were not the case, my tank would have failed long ago. Am I right on that?

So, what other reasons would there be to replace a tank? Varnish buildup?

I can't think of any reason to replace the tank other than puncture.. ..However the rust around the pump ring and seal can damage the tank to the point you can't get a new pump assy to seal.

 

[SFCRangerDoc]

I have this exact (I mean exact) problem with my 96 sport. I cleaned and tested all the sensors and still have the problem. It's intermittent and after about 10 seconds it starts idling normally. I talked to a mechanic/friend who said even though the IAC valve is cleaned/opens/closes and tested fine, it could still be bad. He said it's a huge problem with this year range of fords. Not sure if this is the problem, but I'll be ordering a new IAC valve soon.

So I think i can rule that one out....and here's my thought on that. I tested it good, and when im actually ABLE to get the car started if i pull the plug on the IAC the car starts running horribly rough and almost dies. Soon as I plug it back in it idles normally again.

 

[mattZ]

So I think i can rule that one out....and here's my thought on that. I tested it good, and when im actually ABLE to get the car started if i pull the plug on the IAC the car starts running horribly rough and almost dies. Soon as I plug it back in it idles normally again.

Well at least that is eliminated. I should try to unplug mine... Keep us updated if you find something!

 

[SFCRangerDoc]

Update!!!!!

Well gents, I can say with near 100% certainty that it is the computer. My tests this morning proved it.

Car had been sitting unstarted since 5pm yesterday. It was cold and damp last night so even better. I took the ECU and the ICM out of my sisters 93 4x4 4door and dropped them straight into my wifes sport w/out cranking or attempting to start. Turned the key it fired immeadiately...ran a little rough, but hey, its a different ECU with different programming. COOL ok so i took my wife's ECU and put it back in the sport but left my sister's ICM in just to be sure i didn't have two points of failure. Car wouldnt start...crank and crank. So i pulled out her ECU and put my sisters back in but this time put my WIFES ICM in and the car once again fired right back up...ok final test...put my wifes ECU back in with her ICM and once again the car struggled to start. I finally got it running though, so YES, it appears i do not need to drop the fuel tank after all!!!!!!

So now i guess I have a new problem...do I attempt the Capacitor repair on the ECU to see if its that? or do i junkyard it up to find a 93 sport ECU

 

[2stroke]

Junkyard computer. You have to be a certified technician with a special set of tools to diagnose and repair a circuit board, unless you see a burst capacitor, loose solder joint, or get lucky. I'm glad you got it figured out, most people would have quit long ago. Props to you. I don't know what ECU's go for at the junk yard, but with scrap at $30 a ton (the one near me told me they are only giving a flat rate of $50 for a whole car or truck until prices rise), I'm guessing they are cheap enough to get two just in case one doesn't work.

 

[SFCRangerDoc]

Junkyard computer. You have to be a certified technician with a special set of tools to diagnose and repair a circuit board, unless you see a burst capacitor, loose solder joint, or get lucky. I'm glad you got it figured out, most people would have quit long ago. Props to you. I don't know what ECU's go for at the junk yard, but with scrap at $30 a ton (the one near me told me they are only giving a flat rate of $50 for a whole car or truck until prices rise), I'm guessing they are cheap enough to get two just in case one doesn't work.

Actually I'm quite proficient with a soldering iron and electronics. I've repaired everything from high end amplifiers and audio gear to building circuitry for robotics to replacing blown capacitors on motherboards. I may try the caps anyway and if I screw it up I've at least given it a shot and I'm not out anything that's not already sorta broken. I did a quick ebay search and only turned up a small handful of ecus for the model expy we have. I guess I just need to match the part numbers and it should be ok. Does anybody know if there's a way to flash an ecu that doesn't involve taking to ford?

 

[2stroke]

In that case, if you have a logic probe, you should be able to quickly test the various capacitors and resistors. I don't have the slightest idea where you could find a diagram to check high and low at the chips. I also don't know how to re program these computers. Its kind of transition technology. TBI often you could just re program one chip, OBD II can be plug in with the right software, but OBD I is kind of off the map.

 

[natenkiki2004]

A different part number may be ok, it's mostly important to make sure that you get one for the same transmission and similar emissions items. Like, don't get a 1991 computer for a 1994. A 1994 computer may be fine for a 1993 model year though.

It'd be interesting to see if you can fix your current computer and post about it. Have you opened it to see if there's corrosion or broken solder joints?

 

[SFCRangerDoc]

A different part number may be ok, it's mostly important to make sure that you get one for the same transmission and similar emissions items. Like, don't get a 1991 computer for a 1994. A 1994 computer may be fine for a 1993 model year though.

It'd be interesting to see if you can fix your current computer and post about it. Have you opened it to see if there's corrosion or broken solder joints?

Yes, I cracked it open and there's nothing visible that I can see. Everything is nicely coated in the rubbery coating that they dip the boards in after soldering and unlike a lot of the stories that I've heard about the caps dying and leaking and black discoloration there's none of that in this ECU. However, capacitors are chemical devices and they can go bad internally w/out showing any sort of external bulging or leakage.

pic of the ECU for reference:

 

[SFCRangerDoc]

I wanted to put one final update to this 5 page saga.

I ordered an ECU with the same part number and codes and everything from ebay. I know I'm taking a risk as it was a pull and could have similar issues. The car has been sitting unstarted for almost a week and i put the new ECU in it and it fired right up w/out hesititaion. Its running a little rough but I think as the new ECU figures out the sensors it should settle down.

Thanks to all for their input. Now I guess I'll see if I can take the old ECU apart and replace the caps in it and all that just because I can.

 

[mr cribb]

Two weeks later, how's the explorer running?

 

[acschilling]

Curious too...possible ICM or ECM issues. How'd it turn out?