Looks like I bricked my PCM

[cholmes729]

I installed a Generic tune I found on the internet to see how it performs, I think the battery in my car is junk, it completed the tune(so I thought), I tried to start it, and it ran and idled, but would not rev up, and the fan was on.

I put the battery on the charger, try to talk to the PCM again, no communication, fan stays on all the time, car will start on occasion, but will not rev up, and dies. The service engine soon light is flashing very dim.

I think the PCM is junk. Anybody here repair these?

Its an OBD1, 94 Z28 Auto.

[popo8]

I installed a Generic tune I found on the internet to see how it performs, I think the battery in my car is junk, it completed the tune(so I thought), I tried to start it, and it ran and idled, but would not rev up, and the fan was on.

I put the battery on the charger, try to talk to the PCM again, no communication, fan stays on all the time, car will start on occasion, but will not rev up, and dies. The service engine soon light is flashing very dim.

I think the PCM is junk. Anybody here repair these?

Its an OBD1, 94 Z28 Auto.

Damn... when we would cook mine during tuning the fans would kick on... but the car would crank...no fire.

Im sure someone still sockets these.... but you can pick them up used pretty cheap.... just sold my last one for $40.00 shipped.

[firebird_1995]

If it ran and idled its probably not junk. Just a bad tune. Ses light could be on due to emissions equipment being on the tune that you don't have. Let it charge overnight or try another battery.

[cholmes729]

If it ran and idled its probably not junk. Just a bad tune. Ses light could be on due to emissions equipment being on the tune that you don't have. Let it charge overnight or try another battery.

The service engine soon light is not on, it just dimly flashes. It does not cycle when you turn the key on either. Removed the PCM bat fuse, fan goes off, reinstall fuse, fan comes on, same with the ignition fuse. Car will crank fine, you can hear the engine hit every once in awhile. Now it will not communicate.

[MEAN LT1]

Your PCM isnt junk. I would charge the battery or get another and reload your stock tune and try again.

[cholmes729]

I will try it again, but the engine cranks over fine.

[MEAN LT1]

update.....

[Mystery Bird]

I agree it does just sound like a bad tune. If for some reason it does turn out to be a dead PCM you can have it repaired by Madtuner.

[95ImpySS]

Every time I've killed a PCM, they do nothing. No fire or fuel at all.

Good luck

[cholmes729]

I disconnected the batteries for like an hour, recharged the battery, tried to connect to the ECM, still nothing, same thing. Any ideas here, Im sure its a bad tune, how do I get it out if I cannot communicate with it?

[popo8]

... how do I get it out if I cannot communicate with it?

You cant....

Isnt it still in your laptop?

[cholmes729]

I do have the original tune(stock), but I cannot communicate to the PCM now(through the car). I am pretty sure my cables are fine, when it tried to connect, it says PCM not found.

[popo8]

I do have the original tune(stock), but I cannot communicate to the PCM now(through the car). I am pretty sure my cables are fine, when it tried to connect, it says PCM not found.

Then maybe you really did kill the computer. Do you have the ability to borrow another one, just to see if the car will start?

[cholmes729]

I got another ecm, car tried to start but would not run. I could smell raw fuel like the injectors are pumping fuel. I tried to flash it using my stock 94 tune, this was a 95 PCM, now the fans come on low again, check engine light is not flashing this time, and now when I tried to flash it, the progress bar gets about 50 percent then says Error: Cannot communicate with PCM. Disconnected the batteries for an hour, reconnected, batteries are fully charged, engine cranks with plenty of RPM. This is ECM number 2. This is pissing me off.

[firebird_1995]

What was the original problem? Was it running fine before you tried tuning it?

[cholmes729]

What was the original problem? Was it running fine before you tried tuning it?

It was running, driveable, just needed tuned.

[firebird_1995]

Send one out to get repaired and have a stock tune flashed to it. Do not try to reflash it. There is more than likely an issue with the laptop causing the flashing errors with the ecms. I had an old dell that burned up an ecm during flash. They cannot be harmed while downloading the tune from them and its recommended you do that several times before trying to flash.

When you say it needed a "tune" is this because of recent upgrades?

[popo8]

Send one out to get repaired and have a stock tune flashed to it. Do not try to reflash it. There is more than likely an issue with the laptop causing the flashing errors with the ecms. I had an old dell that burned up an ecm during flash. They cannot be harmed while downloading the tune from them and its recommended you do that several times before trying to flash.

When you say it needed a "tune" is this because of recent upgrades?


I was going to say.. is there any chance your Lap top is corrupted.

I had a tuner once who would always fry my computers. He always blamed the old LT1 computer. He would say there was a power surge or whatever, till I started looking over his shoulder.

WHile flashing the car.. all of the sudden he would get virus pop ups....

I bought a used computer.... and I took it off line so it could not go wifi... cleared the entire thing off (no antivir) no nothing... and installed the LT1 edit.

never had a tuning issue of burning up my shit anymore.



THAT REMINDS ME... I HAVE LT1 EDIT!!!!

[bigtoyz]

I'm with Popo on this one......I have a tuning Lappy with nothing but windows updates and LT1 Edit, and scanner software. No other program can popup and run or it can toast the ECM computer.
What it does is interupes the tuning process and the interuption is what causes the software to stop talking to the ECM. It really doesnt fry the computer, but it is locked inbetween two programs is actually
what has happened.

Also having computer plugged in and a batt charger on can do a surge through the ground I think it is that I read.

I recommend to anyone who is gonna do tuning to send in the ECM and have it socketed and order a couple extra sets of chips on hand for just incase. And as they mention Madtuner (Ion is his name I think) is a good person to goto.

[Alex94TAGT]

the progress bar gets about 50 percent then says Error: Cannot communicate with PCM.

In that case, the PCM is most likely fried.

There are two flash chips within your PCM: a "T" side and an "E" side. My understanding is that the first 50% of the upload process erases the chips, and then the second 50% uploads the new bin file. Thus, if the programming fails at 50%, then the chips are left empty/blank. They will not communicate again, because there is literally nothing on them -- not even the basic code for i/o communication. Only way to get the chips communicating again is to get them on an external chip burner, which is where "socketing the PCM" comes into play -- you desolder the chips from the board, solder in a plcc socket in their place, and then the flash chips can be easily reprogrammed and replaced -- they simply pop in and out of the socket. I've done this to one of my old PCMs (click for big):

1http://i.imgur.com/xiVdenbs.jpg (http://imgur.com/xiVdenb.jpg) 2 http://i.imgur.com/lDjAiegs.jpg (http://imgur.com/lDjAieg.jpg) 3 http://i.imgur.com/WmY4q5Ns.jpg (http://imgur.com/WmY4q5N.jpg) 4 http://i.imgur.com/9U2xRa0s.jpg (http://imgur.com/9U2xRa0.jpg)

5http://i.imgur.com/Dh5mRHBs.jpg (http://imgur.com/Dh5mRHB.jpg)6 http://i.imgur.com/2aRKHbms.jpg (http://imgur.com/2aRKHbm.jpg) 7 http://i.imgur.com/63fuT3Is.jpg (http://imgur.com/63fuT3I.jpg) 8 http://i.imgur.com/8nX5ZdSs.jpg (http://imgur.com/8nX5ZdS.jpg)
(Getting the old chips out is the difficult part -- gotta be extremely careful not to lift the traces off the board. New parts were purchased from Ion/Madtuner).

At any rate, your problem is caused by your programming hardware, not the car. I fried my stock PCM because I was using an unreliable USB-to-DB9 serial adapter, which was really buggy when operating at the PCMs unusual baud rate. Since I switched to a PCMCIA adapter (arguably the most reliable adapter, albeit the most expensive), I haven't had a single programming failure in nearly 100 uploads. Reliable hardware is absolutely vital. You may also have to go into Device Manager and fiddle with the port settings. And as already stated by popo/bigtoyz et.al., disable all screen savers and energy-saving shutdown settings, disable wifi, disable anti-virus, disable windows update, exit all other programs, etc. I created a seperate startup mode on my tuning laptop that has everything disabled but the bare essentials.

Above all else, heed firebird_1995's advice. Always, always, always "read"/download the PCM file immediately before uploading a new tune. Always. Make it a habit, each and every single time you upload a new file. If there's a problem with your hardware, then you'll experience the same form of communication error, but it wont fry your PCM during a read-only operation. Once the file has been successfully read from the PCM, then you are usually safe to select and upload a new tune immediately after. Alternatively, I think I also have a program called ALDL Test, which checks whether the cable is communicating properly without having to wait 5 minutes.

To reiterate, your options now are to either find a replacement PCM, or have your current one repaired.

[cholmes729]

I read online that some adapters can cause tuning probs, I did have the adapter plugged into the cigarette lighter. I had an extra pcm, so I removed the two flash chips, and I ordered some sockets, I am also putting my order for two chips from madtuner. I did have WiFi turned on, no virus programs are installed, according to the task bar, nothing else was running. My current mods are.Cc503 cam, 1.6 roller rockers,58mm throttle body, long tube headers, off-road y pipe, Cai. That is all.

[Alex94TAGT]

so I removed the two flash chips

Uh, you did? What did you use to desolder the chips? Have you done electronics work before?

My last post was not a write-up explaining how to do it, so I trust you found directions elsewhere online. I only generally explained that you must desolder the chips before soldering in the plcc sockets, but I did not explain how to do either one. Most people choose not to do it themselves, because it is not easy for someone without experience or proper equipment, though it is fairly easy for someone who does. I sincerely hope you didn't go in there and just tear the chips off the board without desoldering them, ignoring what I said. If chips were so easily removed, there would be little purpose to installing a socket. If you ripped the contact pads off along with the chips, then it would be nearly impossible to solder in the new plcc socket -- you'd have truly reduced the PCM to an inconvenient paperweight at that point.

From the factory, the entire PCM boards are covered in a protective silicone coating. I gently scraped this silicone layer away from the contacts on the flash chips using a small exacto knife. I then desoldered the chips using a two-step process: using a Hakko FX-888 + desoldering braid to remove as much excess tin/solder as I could from the contacts, before covering the board with aluminum foil and using an electronic temperature-controlled heat gun to melt all 32 solder joints simultaneously while very gently lifting the chips off the board with forceps / a tiny flat-blade screwdriver. The aluminum foil shown in the photos was to protect the other components and connections from the heat of the heat gun. This requires a skilled hand, as you want to heat the contacts just enough to melt the solder to be able to remove the chips without pulling up the contacts, without overheating the board and causing any unwanted damage to the surrounding components.

With the chips removed, I then cleaned up the boards' contacts with the desoldering braid, then fluxed and "tinned" the contact pads on the board using good electronics-grade solder (I use Kester 44 leaded "eutectic" solder (63% tin / 37% lead / 0.031" diameter -- though thinner would be better). Then it's just a matter of positioning the plcc sockets and soldering the new pins down, being very careful not to jumper consecutive pins. This is the second process that requires a skilled hand -- people new to soldering use way too much solder, making an absolute mess. Very little solder is needed. Crappy $5 soldering irons from Walmart really aren't good enough for this kind of work, though I could do it with one in conjunction with mild cursing. If you jumper two terminals, then you must desolder them using desoldering braid and try again, but doing this repeatedly can also make a mess. Sometimes little hair-like strings of solder can jumper between terminals -- these are pretty easily removed using a small/sharp exacto knife. Use a voltmeter set on "continuity test" to ensure no pins are jumpered together.

Then it's just a matter of plugging everything in and crossing your fingers. If the PCM fails to communicate at that point, then the real fun begins.

For a novice, I would recommend that you pay someone else to do the socketing (Ion/Madtuner does it), else just get a new stock PCM and figure out the problems with your programming hardware/software.

[cholmes729]

Uh, you did? What did you use to desolder the chips? Have you done electronics work before?

My last post was not a write-up explaining how to do it, so I trust you found directions elsewhere online. I only generally explained that you must desolder the chips before soldering in the plcc sockets, but I did not explain how to do either one. Most people choose not to do it themselves, because it is not easy for someone without experience or proper equipment, though it is fairly easy for someone who does. I sincerely hope you didn't go in there and just tear the chips off the board without desoldering them, ignoring what I said. If chips were so easily removed, there would be little purpose to installing a socket. If you ripped the contact pads off along with the chips, then it would be nearly impossible to solder in the new plcc socket -- you'd have truly reduced the PCM to an inconvenient paperweight at that point.

From the factory, the entire PCM boards are covered in a protective silicone coating. I gently scraped this silicone layer away from the contacts on the flash chips using a small exacto knife. I then desoldered the chips using a two-step process: using a Hakko FX-888 + desoldering braid to remove as much excess tin/solder as I could from the contacts, before covering the board with aluminum foil and using an electronic temperature-controlled heat gun to melt all 32 solder joints simultaneously while very gently lifting the chips off the board with forceps / a tiny flat-blade screwdriver. The aluminum foil shown in the photos was to protect the other components and connections from the heat of the heat gun. This requires a skilled hand, as you want to heat the contacts just enough to melt the solder to be able to remove the chips without pulling up the contacts, without overheating the board and causing any unwanted damage to the surrounding components.

With the chips removed, I then cleaned up the boards' contacts with the desoldering braid, then fluxed and "tinned" the contact pads on the board using good electronics-grade solder (I use Kester 44 leaded "eutectic" solder (63% tin / 37% lead / 0.031" diameter -- though thinner would be better). Then it's just a matter of positioning the plcc sockets and soldering the new pins down, being very careful not to jumper consecutive pins. This is the second process that requires a skilled hand -- people new to soldering use way too much solder, making an absolute mess. Very little solder is needed. Crappy $5 soldering irons from Walmart really aren't good enough for this kind of work, though I could do it with one in conjunction with mild cursing. If you jumper two terminals, then you must desolder them using desoldering braid and try again, but doing this repeatedly can also make a mess. Sometimes little hair-like strings of solder can jumper between terminals -- these are pretty easily removed using a small/sharp exacto knife. Use a voltmeter set on "continuity test" to ensure no pins are jumpered together.

Then it's just a matter of plugging everything in and crossing your fingers. If the PCM fails to communicate at that point, then the real fun begins.

For a novice, I would recommend that you pay someone else to do the socketing (Ion/Madtuner does it), else just get a new stock PCM and figure out the problems with your programming hardware/software.

Thanks for your concern, you are correct, your last write up did not explain how to do it. Have I desoldered chips before?, The answer is no, so I took a pry bar from out in the shop, about 24 inches long and my wifes hairdryer and pryed up on the chips and they came right off. When my chips come in from Mad tuner, I have a special tool, Kent moore part number 8390312 that I will install the chips with. I have mild case of parkinsons disease, so my hand is not as steady as it was when I was in my teens. All I have is a cheap $5 walmart soldering iron. The silicone was tuff to remove, so I took some sand paper and my palm sander and it came right off.

You mentioned pads and traces?, what are those?. When the chip finally came up off the board, there were these hair like strands dangling from the legs of the chip. I figured the chip was no good because of the bad flash, I just left them on it.

[firebird_1995]

:eek:

[firebird_1995]

Can you double check that Kent Moore tool part number? I came up with a "input shaft bearing driver"





:p

[cholmes729]

Can you double check that Kent Moore tool part number? I came up with a "input shaft bearing driver"





:p

Ya, its used for both.

[Alex94TAGT]

Thanks for your concern, you are correct, your last write up did not explain how to do it. Have I desoldered chips before?, The answer is no, so I took a pry bar from out in the shop, about 24 inches long and my wifes hairdryer and pryed up on the chips and they came right off. When my chips come in from Mad tuner, I have a special tool, Kent moore part number 8390312 that I will install the chips with. I have mild case of parkinsons disease, so my hand is not as steady as it was when I was in my teens. All I have is a cheap $5 walmart soldering iron. The silicone was tuff to remove, so I took some sand paper and my palm sander and it came right off.

You mentioned pads and traces?, what are those?. When the chip finally came up off the board, there were these hair like strands dangling from the legs of the chip. I figured the chip was no good because of the bad flash, I just left them on it.

I'm not as active on the LT1 forums as I used to be, but it is posts like yours that assure me that I should stop altogether. I continually regret trying to help.

I'll put you on my ignore list, cholmes -- feel free to do the same.

[cholmes729]

You assumed that I did not know how to remove a eprom. Your post was full of assumptions that led you believe I did not know how to remove a flash chip. So you decided that you would fill my thread full of information that can be obtained from Madtuners website, that I previously visited before I posted about the chip removal. The type of tools I used was a butane soldering iron, with aluminum foil covering the surrounding processors, used a pick to lift up on the chip till it came off. Now soldering the socket will be a little harder. I will then buy a better soldering iron, smaller solder and some solder wick and go to town.

Sorry you were butt hurt about my post, but I did not ask how to remove the flash chip, I took it upon myself to educate my self via GOOGLE and you tube. Feel free to ignore me, I cant tell you anything you don't already know anyways. I am new to LT1s, I just did all the mods to my car 2 months ago all at the same time, and used this forum for information.

[cholmes729]

UPDATE: I went ahead and got another pcm from a salvage yard out of a cadillac, same ecm part number. Installed it, car started right up, has some hesitation, but expected with all the changes to the engine. Now I know a little more about flashing one, I will try not to blank this one. I have all my bases covered. Meanwhile, I have an extra one that I am going to socket.

[CamaroZGuy]

Awesome, glad u got up and running again

Sent from my DROID RAZR using Tapatalk 2

[cholmes729]

Well, I guess our batting average went down, we are now batting around 800, I drove mine. Now its time to clean up the interior a bit and give it a bath. There is a new LT1 that might join this site. Known him for awhile, he bought a nice 97 z-28 with a 392 or 396 stroker motor with AFR heads, cage. lots of work done to it. We had a local meet last nite(car meet, not LT1 specific meet), if my car was there, there would have been 3 LT1 cars there. There was going to be an LT1 powered 50 chevy pickup, but he decided to drive his 96 camaro instead. PM me if you want specifics. We meet in Choctaw every Wednesday.

[popo8]

... There is a new LT1 that might join this site. Known him for awhile, he bought a nice 97 z-28 with a 392 or 396 stroker motor with AFR heads, cage. lots of work done to it. We had a local meet last nite(car meet, not LT1 specific meet), if my car was there, there would have been 3 LT1 cars there. There was going to be an LT1 powered 50 chevy pickup, but he decided to drive his 96 camaro instead.... .

AWESOME!

Keep em coming!

[firebird_1995]

Glad to hear its running man!

[firebird_1995]

Did you ever remove that chip? I had an extra ecm I was using an a spare. I went to reflash it because I was selling it and as soon as I turned the ignition on the fans kicked on. So its bricked. Id like to take a shot at replacing the chips. I even have that Kent Moore bearing driver....

[FSTFBDY]

Did you ever remove that chip? I had an extra ecm I was using an a spare. I went to reflash it because I was selling it and as soon as I turned the ignition on the fans kicked on. So its bricked. Id like to take a shot at replacing the chips. I even have that Kent Moore bearing driver....

some good info on reading the pcm 1s. Glad I poked my head in here.

BTW I prefer to use this http://kalecoauto.com/index.php?main_page=product_info&cPath=13&products_id=51 to pry up on the chips 1st.
Then I reflash and install this to see how everything went.
http://kalecoauto.com/index.php?main_page=product_info&cPath=6&products_id=8

[meissen]

Thanks for your concern, you are correct, your last write up did not explain how to do it. Have I desoldered chips before?, The answer is no, so I took a pry bar from out in the shop, about 24 inches long and my wifes hairdryer and pryed up on the chips and they came right off. When my chips come in from Mad tuner, I have a special tool, Kent moore part number 8390312 that I will install the chips with. I have mild case of parkinsons disease, so my hand is not as steady as it was when I was in my teens. All I have is a cheap $5 walmart soldering iron. The silicone was tuff to remove, so I took some sand paper and my palm sander and it came right off.

You mentioned pads and traces?, what are those?. When the chip finally came up off the board, there were these hair like strands dangling from the legs of the chip. I figured the chip was no good because of the bad flash, I just left them on it.

I'm sorry but that was funny as hell. :lol: Hopefully Alex isn't too sore from the sarcasm - there was definitely a lot of assumptions being made about whether or not cholmes knew what he was doing so I can see where his sarcasm in the reply came from.

That said, though, Alex thanks for posting the more thorough explanation of how you did it so that others who view the thread can see some of the instructions. Definitely not for the feint of heart.

I also realized I must be extremely lucky that I haven't bricked my PCM yet -- when I flash I use my regular home laptop, connected to Wifi, Microsoft security essentials antivirus still running, AND I usually minimize WinFlash while I browse the internet in Google Chrome while I wait. 100% serious; not kidding. :lol:

[Alex94TAGT]

Hopefully Alex isn't too sore from the sarcasm - there was definitely a lot of assumptions being made about whether or not cholmes knew what he was doing so I can see where his sarcasm in the reply came from.

I'm fine, and you're of course welcome.

However, speaking as an electrical engineer, those assumptions were justified. The individual in question had just destroyed two PCMs and still sounded lost -- nobody in their right mind would have suddenly assumed he was an electronics expert. By his own admission, he was lost, so I took that at face value. Sounds like the PCM in question is still sitting on a shelf.

I just wish people would realize that what I posted was not made out of selfishness or condescension, but out of fear. I felt responsible for leading him in that direction, and was concerned that the information I omitted had led him astray and made matters worse. Any confusion would have cost him money out of his pocket if he made his PCM irreparable. That was my only concern.

Sorry to bring this back up, but you mentioned my name again, so I will respond to your statement. I'm fine, but it's not fun when people mouth off to you after you spend an hour typing up posts and linking images, trying to help. Waste of time.

[cholmes729]

I was not lost, I will admit the soldering of the chips were a little more difficult than I though. I succesfully removed them with no problems. I found a good deL on a used pcm locally for 30 bucks, I couldn't pass it up. I figured out that my laptop was blanking them out, I tried my other laptop and it has been working great. I researched before I did anything, but I was running out of time. I had to get it back running again. When I get time, I will continue working on it by using a better magnifieing glass and a smaller tip.

[firebird_1995]

Sorry to bring this back up, but you mentioned my name again, so I will respond to your statement. I'm fine, but it's not fun when people mouth off to you after you spend an hour typing up posts and linking images, trying to help. Waste of time.

I know what you mean. Regardless, your write up was great. It should definitely be archived or copy and pasted to the tuning sticky.





















But you have to admit, the Kent Moore bearing driver thing was pretty funny.

[cholmes729]

He did have a good write up. It was justified if I asked a question on how to replace the chips. He took it the wrong way and got a little butt hurt be ause he spent some of his time replying to my thread. All in all,it made people laugh and informed people at the same time.