1986 4 cylinder 5-speed. I was going to pick up my son and ended up going through some deep puddles (streets are flooded), when all of a sudden the check engine light starts flashing quickly then after a bit it stayed on steady. The car kept running fine so I went the 5 blocks home and shut it off. Hoping that it was just because of some water on the engine I went out later and it started up fine but still had the check engine light on. SO I checked the codes and got a code 51. PROM. Could this just be from the rain (crossing my fingers), or when I go and clear all the codes am I going to find that I have to go in search of a new PROM chip? Any guesses?
1986 4 cylinder 5-speed. I was going to pick up my son and ended up going through some deep puddles (streets are flooded), when all of a sudden the check engine light starts flashing quickly then after a bit it stayed on steady. The car kept running fine so I went the 5 blocks home and shut it off. Hoping that it was just because of some water on the engine I went out later and it started up fine but still had the check engine light on. SO I checked the codes and got a code 51. PROM. Could this just be from the rain (crossing my fingers), or when I go and clear all the codes am I going to find that I have to go in search of a new PROM chip? Any guesses?
The good thing is eproms are relatively cheap. It may be easier than that though. I would try resetting the code by disconnecting the battery for a bit. If that does not clear it, open the cover on the ECM and see if the eprom is seated all the way down. While you have the center back cover off, check the ECM ground. It is the little screw holding a black wire to the metal frame below the ECM area, a little forward of the ECM and on the pax side.
Anyone else had this?
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07:10 PM
Trekker Member
Posts: 830 From: San Bernardino,CA. U.S.A. Registered: Mar 2004
I disconnected the battery for a bit, re connected it but the code is still there. It's still pouring rain out but I will check to see if the PROM is seated correctly and grounded when it clears up a bit. It still seems to run fine though other than the check engine light and code, is this normal? Does it go into a 'limp home' mode or something?
Darth Fiero at Sinister Performance can make a copy easy enough. Several members in the mall section would have the whole ECM too from parts cars. Post a want to buy ad. I show the ECM is 1226864 and the eprom is FAU2975. http://www.cruzers.com/~ludis/fieroprom.html
I hate spending money if I don't have to so make sure its just not damp or something. Computers hate moisture. You could even bring the whole ECM inside the house to check it.
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08:45 PM
Apr 21st, 2007
Trekker Member
Posts: 830 From: San Bernardino,CA. U.S.A. Registered: Mar 2004
HEY! The Fiero Gods have finished playing with me! I checked for codes again this morning and it still gave a code 51. So as you suggested Hudini, I checked the PROM and it DID go in a little when I pushed on it! Started it up and no codes! I still have to take it on a test run yet but hopefully...........PROBLEM SOLVED!
Darth Fiero at Sinister Performance can make a copy easy enough. Several members in the mall section would have the whole ECM too from parts cars. Post a want to buy ad. I show the ECM is 1226864 and the eprom is FAU2975. http://www.cruzers.com/~ludis/fieroprom.html
I hate spending money if I don't have to so make sure its just not damp or something. Computers hate moisture. You could even bring the whole ECM inside the house to check it.
At risk of hijacking this.. but speaking of eproms and ecms:
My PO swapped chips and tossed the original. Would an aftermarket chip ( one of those hypertechs from the fierostore ) prevent a ALDL cable from reading from the ECM?
But aside from that, Im wanting to swap back to a regular prom due to the poor gas milage it got, and now having major problems wtih the car after an engine swap and want it back to OEM, just in case that is part of my problem. The car is a 87 5speed, but the engine is a 85... ( 2.8 original and swap ) so how do i figure out what eprom i actually want ?
EDIT: looking at that chart, it appears that since i have 15" wheels, i go with the 87 eprom as my best bet.. APN0154
[This message has been edited by User00013170 (edited 04-21-2007).]
Hey Dodgerunner! Nope, the chip you sent is still working fine, just took a stab at escaping LOL! Had me scared there for a bit but it was just gremlins. I see in another thread that you may be working on a belt tensioner for the 4 cylinders. Keep me posted as the belts are my next project! Didn't really miss the Mid West winter at all this year, we did get up to the mountains an hour away to do some sledding though. I see on the weather channel you are having some storms, what's funny is around here they don't have storm warnings, they have a chance of thunder!
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12:58 AM
PFF
System Bot
USFiero Member
Posts: 4877 From: Everywhere and Middle of Nowhere Registered: Mar 2002
