95 GT PCM issue?

[RatFink]

I'm hoping this piggyback tuner (Bama 4-bank) that was previously on the car will work. If it somehow got messed up with all the previous issues listed I'll call and order a new one. This has been a head-scratching deal from day one.

 

[ttocs]

did the old car have the same general parameters as far as injectors, maf, ect? If not I am not sure I would slap a blind tune on it and hope it fixes it.

 

[RatFink]

The only thing that was changed was the computer and distributor. Everything else, including the piggyback tuner was previously on the car when it originally quit me.

 

[ttocs]

honestly even if I knew what the parameters were for the tune, if I knew bama did it I would not put it on my car. I did bama one time and all the options I had were in their pull down menus so I figured a simple trickflow top end would be easy to tune for. The tune they sent was horrible, I limped it to a dyno and was happy from then on.

 

[RatFink]

I'm honestly not even sure where the nearest dyno would be in my area (southern Missouri, Arkansas line). Is tuning something this old still even a possibility without a MS or something similar?

Took the car out this evening with the tuner back on. The trip was a little rocky for the first few miles and then it began running great. Put 30 or so miles on it in total.... It's the strangest thing I've ever dealt with.

 

[duh09]

It would be possible to find someone to tune it with the older chip, but it'd probably have to be someone who's been tuning this stuff for 20+ years to still have the bits to burn the chip.

Swapping to something modern ECU wise is still the route I would go. Even if it isn't the root of your current problem, it will help tracking it down significantly. And with a modern ECU, remote tuning becomes a real possibility. My buddy and former OG here Steven did remote tuning on my car and got it running pretty swell over a few phone calls and some datalogs. He'll be doing it again once I get the motor put together and then get the blower tossed on.

 

[RatFink]

That's definitely the route I'd like to go when budget allows. With mine being an auto, I'll have buy an additional unit to communicate with the AOD.

 

[RatFink]

Drove the car again today and it acted crazy. At one point, it throttled itself up pulling onto the road and got sideways. Other times it acted like it didn't know what gear it was in. In one last post of desperation I'll rehash the whole ordeal.

Was originally driving and the car quit. Ended up being the MSD distributor. Swapped it for an OEM from O'Reilly. The car ran after that, but surged like crazy. Threw a new TPS on but got no change. While messing with the piggyback tuner I could see some leaky capacitors inside the ECU. Bought a new one from Flagship One. Swapped it out and didn't put the piggyback tuner on. The car would barely idle. Plugged the tuner back in and the car sounded great. With the tuner plugged in, sometimes the car runs great, and other times it has a mind of its own (high revving and trans issues).

My question is this - Does the MSD distributor have something the OEM doesn't that could be causing the issues? Or could the tuner have somehow become corrupted and is causing sporadic issues? Until this point, the car had always been very reliable. The only parts Swapped during this process was the ECU, distributor and TPS.

Minor mods include smog delete, TF upper and lower, TF heads, e303, BBK 70mm throttle body, larger MAF, cat delete. Previously I wrote 02 delete, but this was an error on my part.

Again, the car has been historical dependable until the distributor went out. Since then it has been a nightmare.

 

[RatFink]

I want to add one more thing to the above post. Right before the high idle issue, it's like the engine drops out for a split-second, catches itself, high idles for a sec and goes back to a nice choppy idle.... any input is greatly appreciated.

 

[95opal]

Drove the car again today and it acted crazy. At one point, it throttled itself up pulling onto the road and got sideways. Other times it acted like it didn't know what gear it was in. In one last post of desperation I'll rehash the whole ordeal.

Was originally driving and the car quit. Ended up being the MSD distributor. Swapped it for an OEM from O'Reilly. The car ran after that, but surged like crazy. Threw a new TPS on but got no change. While messing with the piggyback tuner I could see some leaky capacitors inside the ECU. Bought a new one from Flagship One. Swapped it out and didn't put the piggyback tuner on. The car would barely idle. Plugged the tuner back in and the car sounded great. With the tuner plugged in, sometimes the car runs great, and other times it has a mind of its own (high revving and trans issues).

My question is this - Does the MSD distributor have something the OEM doesn't that could be causing the issues? Or could the tuner have somehow become corrupted and is causing sporadic issues? Until this point, the car had always been very reliable. The only parts Swapped during this process was the ECU, distributor and TPS.

Minor mods include smog delete, TF upper and lower, TF heads, e303, BBK 70mm throttle body, larger MAF, cat delete. Previously I wrote 02 delete, but this was an error on my part.

Again, the car has been historical dependable until the distributor went out. Since then it has been a nightmare.

A few things the msd dizzy should not make any difference over stock in regards to it running correctly, just as long as you re-timed it to 10*BTDC.
High idle jumps can be caused by a sticking throttle body. Many of the cheaper brands have been known for this issue.
If everything is mechanically correct I would think a crappy tune is your culprit. I would not use BAMA for a new tune. Use a reputable dump shop who knows how to tune the sn95 PCM. This will be your hardest hurdle as this knowledge is getting to the point of extinction. As someone also stated moving to a stand alone ECU may be the smarter move.