treefingers

iTrader: (2)

I have a few questions I was hoping someone could answer. I'm under the impression that I'm going to have to use the Lingenfelter signal conversion box, since I have a 58x motor and a 24x PCM, but what about my harness?

I was told that the older PCM can't read the signal from the newer knock sensor. Is this true? What other differences are there in terms of my older wiring harness and this newer motor?

I would just buy a GEN IV PCM/Harness, but I'd like to stay DBC.

4wheels

The PCM won't read the Gen IV knock sensors, at least not with a standard PCM calibration. The PCM can understand that type of knock sensor but the tables aren't populated with the correct data from them. Some people have tried to convert the calibration to read the newer type of knock sensor with varying degrees of success.

The easier thing to do is just relocate the Gen III knock sensors that are normally in the valley to the sides of the block.

Racetronix makes a harness for this and you should be able to find pictures of how it is done/where on this forum and others.

Make sure you do NOT use a cam sensor extension/conversion harness if you are using the Lingenfelter 58x to 24x conversion module.The harness in that module already converts the camshaft sensor wiring so running the adapter harness swaps the pins again and it won't read the camshaft signal correctly.

Some other things on your harness that may need to change depending on what parts from he 58x engine you are using and what engine it is. Other things that may need rewired or adapters include:

• Injectors (Gen III car engines use the Minitimer/Sumitomo style connectors while Gen IV car engines use the USCar connectors).
• MAP sensor
• MAF sensor

Calibration changes to your PCM may be required for the following:

• Injector size
• Engine size
• Cylinder head type/ignition advance requirements
• MAF sensor type
• MAP sensor

Another option is to go to a MEFI5 or an aftermarket ECU that will support 58x and mechanical throttle. Not as cost effective as the OEM parts though.

treefingers

iTrader: (2)

This was way more comprehensive and informative than I ever could have hoped for. Thanks so much!

JimMueller

iTrader: (9)

I did my swap 5 years ago, so perhaps there are additional options. The crank I used already had the Gen3 reluctor wheel installed, so I just used extension/conversion harnesses for the knock, cam & MAP sensors. I think I originally used the stock MAF, MAP (RTV'ed into front LS3 MAP port), prior 4-bolt TB, and relocated knock sensors to side of block. Had a challenge finding a throttle/cruise bracket which didn't interfere with the manifold vanity cover. Gen3 PCM doesn't play nice with later style map and knock sensors. Use LS3 injectors so you have known good injector data to put in the PCM injector tables; you'll need adapters between the injectors and the stock harness. That's all I can think of of the top of my head. I did later upgrade the TB and MAF due to tuning challenges though.