Tyler_Basham

I could be posting this in the wrong area but those that are posting here seem to have the most knowledge of the subject. I am looking to convert my s-10 4.3l with the 6395 ecm to a 7749 ecm. I have done many searches here and on google with no luck. Will my harness plug into the 7749. If not what vehicle can i get a harness from that will plug into the 7749. Im not so much worried about the repin or running wires i would just like to have the plug.

Also if i buy a reman 7749 ecm from an autoparts store how hard is it to find the memcal that is compatable?

This is a great board i dont know how i didnt come across it sooner.

tony_cogliandro

iTrader: (3)

its from a 91-93 4.3 turbo cyclone and typhoon.

Six_Shooter

iTrader: (2)

If you want a S-series specific harness. It will be difficult to find and likely expensive due to it's difficulty in finding.

I'm not familar with your ECM service number, is that similar to a '7747? Under dash with two connectors?

If it is I would just re-pin it, and adding the third connector. This third connector can be had from many, many vehicles, that use the '7730 and similar ECM. Cavailer from '87 to '94, Beretta from '88 to '93, F-body from '90 to '92 (IIRC), and many other vehicles that I can't think of right now. The Turbo Sunbird from '87 to '90 also used a '7749, though the pin out at the ECM is slightly different than what the Sy/Ty used, where it comes to injectors.

RBob

iTrader: (1)

The '6395 is a PCM, it also runs the electronic transmssion. Unless you are losing the 'E" trans the '6395 either needs to stay, or need to put in a separate trans controller.

You will need all three of the ECM harness connector shells for the '7749. The '6395 PCM shells won't work. The pins are compatible between the shells, so just need to R & R them to re-pin.

RBob.

Six_Shooter

iTrader: (2)

Ahh, so it's a gen2 S-series. That makes it more difficult. LOL

tony_cogliandro

iTrader: (3)

the turbo cyclone was on a suv - and i think it holds the world speed record for that engine - 175 or 180 mph on the turbo - test was run by gm - all stock engine but probably was lowered and gear changes.
it appears to be not a bad motor - if you like a 6.

Tyler_Basham

Thanks for the help. I transplanted the 2ndgen motor into my 93 firstgen truck. I removed the 4l60e and put a stick behind it. When i put the motor in i knew nothing about tuning(still know nothing but trying to learn) so i bought a chip and had the guy remove the transmission stuff and change it for 1.6 roller rockers and ported heads. Now that i know i can do it myself so im trying to learn before i get started on the fab work in the truck.

So the first thing i need to do is find my plugs and try to repin to the 7749 config. Im going to be running a fuel injected marine intake and my current setup is cpi which has only one injector. Will i need to run induvidual wires from the ecm to those injectors.

RBob

iTrader: (1)

For a harness it may be best to get one from a '7730 car. A '90-92 Camaro/Firebird TPI harness would be ideal. Second would be a '90-'92 Camaro/Firebird MPFI (V6) harness.

The V6 harness you would need to add two injector connectors.

Although the TPS and IAC may use different connectors. GM varied on these over the years & models.

Modifying your current harness is a bunch of work. Yes, need to install 8 injector connectors, and most likely change out the TPS, and IAC connectors. Let alone a major re-pin job. And strip out the tranny wires. But it is do-able.

RBob.