can anyone point me to a how to on how to get the pcm out on my 95 atx ? wont start getting code 511, i reckon a bad pcm, i think i found it but it looks awfully tight in there, pita? it does come out from under the hood correct? i appreciate any help, posting from texas hill country
pcm replacement 95 atx
- Thread starter luke
- Start date
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luigisho
SHO Member
NO. The main wiring harness has an integrated bolt at the middle of the plug which mates to a threaded hole in the pcm. You have to turn the bolt until it is threaded all the way out, unplug the wiring harness, and then on the other side of the firewall-open glove box, push on the sides so the 2 rounded things can be pushed inward and removed from the grooves it slides in. Allow the glove box to hang all the way down and then remove the pcm. It should/may still have a small plastic bracket that has to be removed. I forget if it is a small s crew or hex head holding it. Some people do not have it any longer but that is the stock config. and helps keep it from flexing around. Replace is reverse. PCM pins protrude into the engine side of firewall. Good luck.
thanks for the reply, i figured it out after a closer look, just hope it fixes the no start , hate just throwing parts at it especially a $200 part but what are you gonna do aye? at least its plug and play! think im gonna try the cid sensor first $35 , even though i didnt get a code for it lotta oil down there, thanks again luigi
BaySHO Performance
SHO Member
511 is EEC Read Only Memory (ROM) test failure or Lifetime Performance Module (LPM) detected.
If you had an LPM it would be plugged into the back of the computer. Highly unlikely you have one on an ATX.
But be aware that the ROM test failure would have been triggered by disconnecting the battery. If you did that, it's highly unlikely that there's anything wrong with the PCM.
As you now can't start the car, you can't get it to throw any codes. Now best to check for fuel and spark. Turn the ignition on and blip the valve on the fuel rail to see if fuel comes out. And check for spark while turning the engine over. These work great if you don't have one:
Let us know what you find.
If you had an LPM it would be plugged into the back of the computer. Highly unlikely you have one on an ATX.
But be aware that the ROM test failure would have been triggered by disconnecting the battery. If you did that, it's highly unlikely that there's anything wrong with the PCM.
As you now can't start the car, you can't get it to throw any codes. Now best to check for fuel and spark. Turn the ignition on and blip the valve on the fuel rail to see if fuel comes out. And check for spark while turning the engine over. These work great if you don't have one:
Let us know what you find.
thanks Chrimes , should have included this in the 1st post(full picture) i had to borrow the battery out of it, so it sat for about a month with no batt, when i put the batt back and tried to start it is when the trouble began. it actually started but sounded terrible like it was running on 3 cylinders, i kept feathering the throttle to keep it from dyeing,hoping it would clear out, the next thing i know the oil that had accumulated on the cats(ps leak i think)Ignited!! Now ive got a fire under my car ***?,embarrassing and scary. i was going to let it burn itself out before i got too nervous and sprayed some water on it. no damage done i dont think. im thinking the exhaust got extra hot due to a lean fuel condition or timing out of whack? ive checked the pcm ground at the battery, seems ok, has original cables, tach is working when cranking. i can use a timing light to ck. the spark correct? gonna try a new cid sensor next, guess i cant rule out the cps yet. thanks again i'll let you know what i find. i was going to make a comment on SF but i dont want to offend. hope everything is good for you there
forgot to say that when i try to start it now, it sounds like it wants to start but it just stumbles and pops through the intake at times other times it will stop cranking like its locking up? thanks
Try pulling a couple of your spark plug wires and see if there is oil in the plug wells
my car would sometime lock up when trying to crank and I found a bunch of oil in the plugs wells. it would also take longer to crank and start up
my car would sometime lock up when trying to crank and I found a bunch of oil in the plugs wells. it would also take longer to crank and start up
BaySHO Performance
SHO Member
ok thanks i will let you know
PaulTAutoX
SHO Member
The cats would get extra hot if there was a cylinder or more than one failing to ignite. The unburned fuel gets to the cats and the reaction attempts to oxidize the fuel, but there is so much of it that it's essentially a fire inside the cats. This if maintained for long will destroy the cats (and gets the shell hot enough to ignite the oil deposits as you found). Probably better to have put the external fire out as you did, this will prevent damage to the car and perhaps limit the damage to the cats by cooling them back off.
missfiring it was, note to self and anyone else, dont leave your hood open if there is rain in the forecast, yeah it wasnt oil ,water ,rain water. pulled bank 2 plug boots and all 3 wells were full, dried them out and it started , still missfiring , going to ck bank 1 and replace plugs , thanks for the help.
BaySHO Performance
SHO Member
I suggest that, once it has stopped misfiring, you check your cats. I had the same case years ago, and it destroyed a cat.
how do you ck. them ? where is the best place to purchase? $? thanks
BaySHO Performance
SHO Member
Separate the Cat back from the Y Pipe. Stick a long probe into each arm of the back of the Y pipe to see where it stops. That should be right where the cat reaches its widest point. If it goes in further, at least the back half of the material has disintegrated. If you want to check from the front ends, you will have to remove the Y pipe. If you do that, you can also **** the Y Pipe against the ground to see if any black 'sand' comes out.
The other thing that might have happened is that a piece of the material has become clogged in the cat back. If so, you will have excessive back pressure and the car will be have a very noticeable loss of power. I've used a drain snake inserted into the front of the cat back to go all the way in to the muffler. Some times I've managed to break it up with the drain snake. One other time I wasn't able to do that, but was able to mark where the blockage was and have a muffler shop cut it open to remove it.
If one is bad, I suggest replacing them both as the other one will have been compromised:
Just so happens I am having the cats replaced in a '93 ATX tomorrow morning. It will be a challenge as the replacement cats are straight, whereas the front of the front cat has a bend in it, as does the rear of the rear cat. I'll let you know how it goes.
The other thing that might have happened is that a piece of the material has become clogged in the cat back. If so, you will have excessive back pressure and the car will be have a very noticeable loss of power. I've used a drain snake inserted into the front of the cat back to go all the way in to the muffler. Some times I've managed to break it up with the drain snake. One other time I wasn't able to do that, but was able to mark where the blockage was and have a muffler shop cut it open to remove it.
If one is bad, I suggest replacing them both as the other one will have been compromised:
Just so happens I am having the cats replaced in a '93 ATX tomorrow morning. It will be a challenge as the replacement cats are straight, whereas the front of the front cat has a bend in it, as does the rear of the rear cat. I'll let you know how it goes.
BaySHO Performance
SHO Member
Sheesh, the **** word was b a n g. Censorship on this site is crazy.
thanks for the info, i thought b a n g was just a sound , they must have their minds in the gutter *** ****
BaySHO Performance
SHO Member
Found out today that the cats from SHO Source won't fit. They and I are coming up with the right ones. I'll keep you posted.
BaySHO Performance
SHO Member
Yes, some custom bends will be needed. The cats we are looking at are the Walker 81126:
Overall length 13.25"
Body height 4.25"
Body width 6.125"
I am going to compare its dimensions with what's on the car today to see if they will work.
Most of my customers go with the Taylor wires from SHO Source.
Overall length 13.25"
Body height 4.25"
Body width 6.125"
I am going to compare its dimensions with what's on the car today to see if they will work.
Most of my customers go with the Taylor wires from SHO Source.
BaySHO Performance
SHO Member
So, stock cat dimensions for a '93 ATX:
Length 13"
Width 7"
Height 3 1/2"
Vertical gap between front cat and oil pan 3/4"
Walker and Magnaflow both give body dimensions WITHOUT the heat shield. You need to add 3/4" for the overall height. If that's 4 3/4", it will clear the oil pan by 1/8". But the recommended Walker 81126 (California compliant, your part numbers will be different) at 5" would hit the oil pan.
Trouble is here in California, the smog test station will look up the CARB code stamped on the cat to make sure it's the right one for the car. If not, it will fail the visual. Don't know what would be the case in Texas.
Length 13"
Width 7"
Height 3 1/2"
Vertical gap between front cat and oil pan 3/4"
Walker and Magnaflow both give body dimensions WITHOUT the heat shield. You need to add 3/4" for the overall height. If that's 4 3/4", it will clear the oil pan by 1/8". But the recommended Walker 81126 (California compliant, your part numbers will be different) at 5" would hit the oil pan.
Trouble is here in California, the smog test station will look up the CARB code stamped on the cat to make sure it's the right one for the car. If not, it will fail the visual. Don't know what would be the case in Texas.
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