$$100 dollars if you fix it....
IMHO, what it seems to me that you need the most is someone with a diagnostic cable and DataMaster. You can hook the cable up to the diagnostic port under the dash, plug it into the laptop via USB, and then turn on the data logging. Then turn the key to the "ON" position (don't crank it or start it) and see what codes are being thrown as well as what the PCM is seeing as your water temp. I bet that would give us the best information.
Check the positive side too, make sure the PCM is even getting power.
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Last edited by stevo9389; Nov 4, 2009 at 11:30 PM.
With all the malfunctions you're engine's experiencing I suspect an incompatability between the harness in your 94 and the 95 setup you bought.
If GM changed the pin-outs, even though the PCM and sensors would plug in, it could be that all your problems are due to the harness itself.
I'd call one of the companies that make custom wring harnesses for swaps, like you've done, and ask. Start off by calling F.A.S.T. 1-662-224-3495 to see if they can help. If not ask them for a reference to another company.
I'm sure someone has come across this issue before and knows the "fix".
Jake
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Start with the obvious, dumping fuel. Are you sure the injectors are good?
Next, the VIN difference should be the aigbag codes. Several 98 cars who swapped to the +99 PCM had similar problems as do 3rd gen SBCs running LS1 PCMs (mostly isues with the CTS reading)
Next, some issues come up with the CTS (two pin in the water pump). When CTS' go bad, they either go full open, full closed, or stuck on one value. I cant remember which gives what resistance, but they can register a temp of -60*C. If the PCM reads this faulty measure it will adjust and dump fuel as if the car was in the arctic circle. This problem is common on LO5 trucks. Easy way to rule it out is to unplug the CTS. Unplugged CTS will throw a code and reset to default temp. If richness is still present, CTS is not your issue
Next the HO2s. Ive heard alot of people blame all sorts of problems on O2 sensors. Simply put, if your problem is present at startup and/or warmup IT IS NOT O2 SENSOR RELATED. O2s are not even used until the engine switches to closed loop operation
The biggest issue so far is the PCM grounds not changing how the car runs. With a multimeter, check continuity from pins A2, C32, A18, D1 to the PCM ground ring. Next check continuity from each ground ring to the others. They should all be connected. Broken continuity and high resistance values mean poor connections



