93 Explorer Rough Engine Problem
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Joined: Jul 2004
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From: Winnipeg, Mb. Canada
Here's another thread where the PCM turned out to be the culprit.
https://www.ford-trucks.com/forums/s....php?&t=412608
https://www.ford-trucks.com/forums/s....php?&t=412608
Senior User
Joined: Jul 2004
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From: Winnipeg, Mb. Canada
Originally Posted by Jharger
Oh sure! Point out my learnig experience then...I see how you are 
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From: Phoenix
You know this is an interesting point you bring up dblee50 - I had always thought that a limp home mode of operation meant the open loop operation - no O2's used but run on a set fixed, A/F table. Then when playing with my new SCT chip, I switched to the disable engine position on the switch and the engine kept running. Ran like crap but did not die. Felt like I was on 3 of 6 cylinders. So I checked with SCT and they said no, my car is too old for the "kill the engine" technology so they set this chip switch position to go to the "limp home" mode. They explained that if a PCM was somehow damaged, but not so bad that it knew it was damaged, it would give minimum amount of engine controls output to enable you to limp off the highway and to a shop. So if your PCM is sensing the end of it's life, it may have put itseldf on a resporator. So maybe the limp me home mode keep the fuel pump on all the time? How I wish I had a copy of the design notes for an EEC-IV.
Any luck finding either of those 2 PCM's on eBay?
Any luck finding either of those 2 PCM's on eBay?
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Only found a Ranger pcm with those numbers, the cma. But other characters like the large four letters in upper right hand corner didn't match. Mine was ANY1 and on ebay it was HAG0. The 63ENG46 number on mine ended with A14 and on ebay it was A25 and the others were off too. Think I'll order from RockAuto which has a pretty easy to navigate web site.
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From: Phoenix
OK - if they have it and you are willing to spend the money vs wait for eBay. I was lucky that I didn't need one and was only looking for a spare. With all the PCM failures lately, I'm glad I found one.
But hey - if you are going to buy a new one, get the upgraded one - the 1994 number I gave you. The truck will have less propoensity to stall when cold when you let out the clutch - this is what the TSB was for. Made the cold start/cold run tables a little richer.
But hey - if you are going to buy a new one, get the upgraded one - the 1994 number I gave you. The truck will have less propoensity to stall when cold when you let out the clutch - this is what the TSB was for. Made the cold start/cold run tables a little richer.
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Final update, maybe.
Car had gotten where fuel pump ran continously with key on, and it would crank but not start. Got new CMA pcm in and installed. When I turned on key, fuel pump came on for a second and shut off, as it should. Car then cranked and started. I took out for a 30 minute drive, and it performed great with no sign of problem. However, when I first had problem it wouldn't show up for a couple of weeks and then go away, so time will ultimately tell.
I believe the pcm has fixed the problem. Jharger, thanks for all the advise and troubleshooting direction. Hope this one's put to bed.
dbl
Car had gotten where fuel pump ran continously with key on, and it would crank but not start. Got new CMA pcm in and installed. When I turned on key, fuel pump came on for a second and shut off, as it should. Car then cranked and started. I took out for a 30 minute drive, and it performed great with no sign of problem. However, when I first had problem it wouldn't show up for a couple of weeks and then go away, so time will ultimately tell.
I believe the pcm has fixed the problem. Jharger, thanks for all the advise and troubleshooting direction. Hope this one's put to bed.
dbl
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Joined: Jul 2004
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From: Winnipeg, Mb. Canada
Didn't the problem deteriorate to the point where it was happening all the time? I think your PCM was intermittent to start with and then finally gave up, as mine did. Good luck, I think you solved your problem.
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From: Phoenix
Hey guys - just back in town after a few days.
Woo Hoo! Sounds like we got one huh!
It's wierd. When Intel chips start to go what happens is they loose memory locations. Everyone blames the software. But the software says - I left the data here, where is it?
EEC-IV computers have Intel PCU chips. Just because I work there doesn't mean I have loyalty does it?
For the Ford EEC-IV PCM's, we have seen the most extreme reliability - more than any regular desk top PC for sure! But I sense we are now getting to a real where computer reliability can now be a regular component to reliability in the EFI system.
DBLee50 - looks like you found a 1994 PCM - that is the same PCM I have in my 93 Explorer. You should have a better starting and cold running car now too - better than your original truck. Whoever had it new, nerver got the upgraded PCM.
Do get back to this post so that we all know if you are good to go or still need help. Gotta love the internet!
Woo Hoo! Sounds like we got one huh!
It's wierd. When Intel chips start to go what happens is they loose memory locations. Everyone blames the software. But the software says - I left the data here, where is it?
EEC-IV computers have Intel PCU chips. Just because I work there doesn't mean I have loyalty does it?
For the Ford EEC-IV PCM's, we have seen the most extreme reliability - more than any regular desk top PC for sure! But I sense we are now getting to a real where computer reliability can now be a regular component to reliability in the EFI system.
DBLee50 - looks like you found a 1994 PCM - that is the same PCM I have in my 93 Explorer. You should have a better starting and cold running car now too - better than your original truck. Whoever had it new, nerver got the upgraded PCM.
Do get back to this post so that we all know if you are good to go or still need help. Gotta love the internet!
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I got it at www.rockauto.com for $113 with a $75 core charge. About $8 to ship and I got it in four days with regular shipping. Pretty good experience so far with this company. The yb was a little cheaper but I went with your recommendation and believe the car definitely runs better.
I'm not sure if my crank sensor was bad or not, but when I tapped on it and things started clicking, fuel pump cycling, etc thought I had it until the new sensor went in. That must have been the end of the road for the pcm. Anyway, I'll stick with the new crank sensor and pcm.
Now I'm back to just oil leaks to contend with, but that's managable.
I'm not sure if my crank sensor was bad or not, but when I tapped on it and things started clicking, fuel pump cycling, etc thought I had it until the new sensor went in. That must have been the end of the road for the pcm. Anyway, I'll stick with the new crank sensor and pcm.
Now I'm back to just oil leaks to contend with, but that's managable.
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From: Phoenix
If you have a oil filter adapter to the motor block leak, look for a thread i posted in here or find it on this web site http://draco.acs.uci.edu/explorer/
I had the site owner post it as it was a bit humerous but does lend some good info that the chilton's book does not cover.
I had the site owner post it as it was a bit humerous but does lend some good info that the chilton's book does not cover.