Tuned Speedometer setting to limits an now PCM is corrupt

[Dominatorstang]

This is a 0411 PCM in a 94 Jeep Wrangler with 6.0 LQ9. I was trying to use the PCM ABS speed signal to run my speedometer but it made my speedometer read way high so on the tune I changed my tire size to 20 and gear ratio to 7 which is as far as it would let me go. I then wrote the tune.

Now the vehicle wont start and the fuel pump relay chatters at a high frequency. I then went to rewrite the tune but the sofware says it cant find the PCM.

I then contacted HP tuners support but have not got a response yet. Are they not 24/7?

I then on hooked everything from the PCM except Power to C1 pin 20,57,19,75 and serial bus for tuner to connect on C1 pin 58. Still acts the same as above.

[Dominatorstang]

It looks like this guy is having the same problem connecting to his PCM http://www.hptuners.com/forum/showthread.php?t=30163

Also I was tuning the speedo to try the easy way but really dont want to do it this way now anyway so will use the dakota digital converter box that I have. I really just need the PCM to work so I can drive it finish the last things on this setup. I just finished this build and I have only drove it twice now so i kinda sux not even being able to drive it more right now.

[Bill@HPTuners]

I am the only support person, I do sleep occasionally so no we aren't 24/7.

From the sounds of it changing the tables so drastically may have caused your pcm to become inoperable.

[Doubledip]

I had a customer of mine who is a tuning shop that ran EFILive do the exact thing as well.. the bad news was it happened to 3 ecu's till he realised what was causing it .. the good news is that i was able to recover them for him..

[Chris@HPTuners]

yeah we actually removed these params from the editor a few years ago for this reason, but people wanted them back so we added the warning and put them back.

[busta9876]

Is this a software issue someplace? I have HP Tuners & Tuner CAT OBD2. I've had ZERO problems setting ABS output to 8000 pulse/mile with TunerCAT stuff for jeep swaps. Works great.

I have also been able to setup PCM to accept a 8000 pulse/mile INPUT from the speed sensor, so you can use a dakota digital cable driven sensor, SEN-4160 as a speed signal input when using th350, th400 etc...again, no issues..however I have heard the same issue with PCM corruption from HP and EFI stuff???

[Chris@HPTuners]

yeah i've only killed a PCM by setting it to like 0 or a very low number, i never tried it with really big numbers. The problem is GM writes the value directly to the TPU with no bounds checking, so what the hardware can support is anyone's guess. Our range matches the GM acceptable ranges but obviously they are wrong.

[BJC]

This just happened to me. I altered the speedometer settings after making some calculations from it reading very low. Flash completed successfully. When I turned the ignition on the fuel pump relay was buzzin g at about 10-20hz. I spent hours troubleshooting the harness and even the engine sensors. I chalked it up to bad luck, bought a second ecu and bench tested/read entire before licensing and flashing with my sdtune file. Same thing happened. I spent more time going through the harness and even pulled it out of the car. This really sucks that I have two dead ECUs and wasted 4 credits over this crap. Not happy. Can anyone please help with recovery information on the ECUs?

[blownbluez06]

I've had great luck with http://www.pcmcalibrators.net/ on bricked PCMs.