A couple of question about a '99 GMC 7.2l diesel

[canucker]

Hello everyone, been canoodling an issue for a while and I'm hopeful I've finally found the place to help me fix this.

So a friend of mine who builds hot rod is making himself a goofy project, and I'm the young electronics nerd car enthusiast who helps on electronics projects sometimes.

He got his hands on the abovementioned engine for cheap, and he has a GMC chassis that has been sitting for years that the diesel will bolt right on top of.

Then someone gave him a rusted out 70's mach one mustang, and he want's to massage the mustang outer skin onto the chassis with the big diesel engine.

Now, as ridiculous as this seems, it's easily within his skillset so aside from a little intro, this thread isn't about this.

This thread is he asked me to figure out how to hack the GMC computer so that it doesn't require any inputs to run. It has a big ass complicated wiring harness and he want's it gone. Some sort of very simple engine management program running and ignition control and that's it.

So basically, I have 2 questions:

1. Can I buy a particular programmer that hooks up to the wireharness and lets me start screwing with it. (Basically any tools I can just order to make things easy.)
2. Where does one learn more about hacking car computers to delete all the bits of code that look for inputs from sensors and anti theft garbage that we are not interested in.

Thanks so much guys

I've simplified everything quite a bit, please don't think I'm an idiot I was just hoping maybe someone could just help me in the right direction so I could do a ton of research into exactly how I can accomplish this goal.

I'll be lurking through the forums here over the next couple weeks trying to see if I can find the info I need but if someone feels like giving me some pointers I'd be right into it.

Thanks guys.

[antus]

I think stripping sensors is going to be the wrong approach. The engine should run in factory configuration with anti-theft disabled, but the more you remove the more problems your going to create and the worse its going to run. I'd say you need to know what car the engine is from and find a tuning tool that supports it (hptuners?). Also find a wiring diagram for it (and post up here if you like). Then power it up just sitting wherever it is (even without starting it). Learn to the use logger (scanner) and see if there are any errors reported before you start. It will need to be running to check some things, but its still a good baseline. You should see sensible readings from coolant temperature, intake air temperature, voltage and the like. Assuming thats OK, remove unneeded wiring (eg air conditioner or anything like that - body loom stuff), disable anti theft, then install the engine in the project with the aim of hiding the wiring. The work is then mostly physical and the engine should just work as intended. Trying to remove sensors is going to be a world of pain and trouble, and they are there for a reason. The scanner will be useful for fault finding incase any wiring is damaged during the install - it should be able to identify and problems and point you straight to the circuit you need to physically inspect.

[Gareth]

I thought HPtuners as well, but isn't listed on their supported vehicle list

[antus]

Hmm indeed your right. EFI Live doesnt seem to have it either. If there is no good tuning option then that might be the reason it was cheap

In that case you might need to find any aftermarket place that can disable security, and check that OBD2 is supported (it should be) then use a generic scan tool app for diagnostics. It wont be as good as say hp tuners, but it should still provide basic sensor information for troubleshooting.