LS1 PCM Choices - Help please

[GeoffP]

I'm astounded at the myriad of choices for GM PCM's for LS1 engines. I wasn't expecting there to be so many different options or those options to have so many variances. Can someone point me to some online reference for GM PCM's for LS1 engines or help describe the differences? This will be going in to my 68 Camaro with the planned engine and transmission being an iron block LS1 and T56 transmission. I won't need a custom harness as I plan to use an OE harness and adapt it to the car as I have with all the LT1's I've installed over the years. The engine has a 24x reluctor so I understand that limits me to all PCM's produced up to the E40 that went in the early LS2 GTO's. I know I want to use a drive by wire throttle and I would like to get the cruise working (properly!). Any gotcha's or suggestions will be GREATLY appreciated. I plan to go with a mail order tune initially to take care of VATS (or otherwise) and then drive it someplace to have the engine tuned if needed.

BTW I have already used the SEARCH feature both here and LS1Tech and have not found the info I'm looking for.

Thanks in advance!

[absintheisfun]

I'll be watching this as well. I know there are aftermarket controllers available, but if it can be done cheaper with a factory, then why not?

[GeoffP]

That's exactly what I'm thinking in asking this - hopefully someone will chime in!

[CarlC]

Have you looked into using a GM ECM from a C5 or, I believe, a '04-'05 truck? I'm considering doing a DBW changeover from an 0411 ECM (no DBW) at some point and believe that it can be done without too much difficulty.

[garys 68]

I've got a 411 pcm on my 6.0 corvette, it's probably the most popular and supports DBW or DBC. That ecu also works with auto or manual trans. Check with whoever is doing your tune.
I've got the 05 truck ecu in my 5.3 442. It works too but have heard some oddities with the tac/pedals. No problems for me though.

[GeoffP]

I'm "watching" an eBay add right now for an 01 or 02 Corvette PCM and wiring (no tac module but the connector is intact)...hoping it doesn't disappear on me before payday!

[12sec ss]

411 PCM is very common and easy to work with.

[EFI69Cam]

Before making an ECM choice you need to know how tooth count on your crank reluctor. The 12200411 PCM will only work with 24 tooth wheels.

There is another PCM 0243 I think that was used on O4-05 LS1s. It does not have the discreet inputs and outputs needed to support tachometers, speedometers and AC request as the cars and trucks that used these used the data bus to transfer that info to the cluster and HVAC controller.

DBW conversions are simple, but the base calibration in the PCM, the TAC module and pedal all need to match or you can brick your PCM.

[Mike Norris]

You mention you have an engine and T56 already, but to get the proper ECM it would help to know a few things such as:

1) What is the engine out of and does it have the intake manifold, injectors, coolant temp sensor, MAP sensor, MAF sensor, throttle body with it.
2) If you already have a DBW TB, do you have the matching throttle pedal and TAC module?

What I am getting at is, especially when going DBW, it is best to have everything from the same vehicle for best compatibility to make sure everything works together instead of fighting each other.

Hopefully that makes sense.

Mike Norris

[GeoffP]

Mike,

The engine is a pieced together LS1 from a 5.3 truck block bored to the LS1 stock bore. The crank is a stock LS1 crank with a 24x reluctor. Crank, rods, heads, and intake are all stock LS1 as well. I do have a DBW throttle body from a 5.3 truck, but I don't have any other sensors, the tac module, or a pedal. I'd really like to make sure I have all my facts straight since I want to buy everything to work together the first time rather than fighting stuff that isn't designed to work together.

It does make sense - I appreciate the input.

Thanks!

[John@Texas-Speed]

If you are going to use the 5.3l DBW throttle body you need to try and find a truck PCM. The car and truck electric throttle bodies do not operate the same and a car computer would not be able to operate a truck throttle body. If you have an early style truck throttle body it should fit on the LS1 intake no problem, but you will want to make sure as many of those sensors are from the truck.

[GeoffP]

Thanks John - this is the kind of info I'm looking for. I figured I'd either try to find a PCM, harness, throttle body, TCM, and pedal all from the same car if I found the combo at a decent price or get an 03 or 04 truck setup to work with the DBW throttle body I already have. You're correct that the truck DBW throttle body bolts right up to the LS1 intake. It fits like a glove.

[John@Texas-Speed]

Yes sir that would be the best. When all the sensors come from the same vehicle it makes it much easier to tune correctly.

[GeoffP]

I'll have to go visit the local pull a part in a couple weeks to see what I can find.