[twelve03]

I have a 99 s-10 2WD. It had a 4.3liter in it; I've put in a 1997 5.7L engine. Does anyone know if my orginal computer will work or do I need a computer out of 5.7? And also, what do I need to do to make it (the computer) run? I have left my 5speed transmission in. I've been told I need the old computer to run the accessories and a new computer to run the motor. Help! I've had my truck down since January 2003!! Thanks for any help. Email me at [email protected]

 

[Alucard_1995]

Ummm does the bolt pattern on the 4.3 5-speed even match up to the 5.7?? And one more question, if you dont know about the computer how did you have the knowledge to do that kind of swap?

 

[Alucard_1995]

BUt no a 4.3v6 ECM is not going to work on a 5.7, you need a custom wiring harness too genius... but you'd figure that out if you really had a 5.7 in there

 

[GoofyGuy]

you can use the 4.3 comp but it needs custom harness for the two more cylinders and injectors.

 

[LaidoutS10]

you can use the 4.3 tranny cause its the same tranny(700R4) that is used in silverado's.

 

[MPETESS10]

UMM WOULDNT THERE ONLY BE ONE PLUG FOR THE INJECTORS
since its a center sequential unit just like the ones we have for the 4.3
therefore he wouldnt need a custom harness
yes a 4.3 has the the same bellhousing bolt pattern as a 5.7
maybe he has a 5.7
maybe he dont
but
he is here asking for advice
try helping him instead of slamming him
if you dont know an answer
dont say anything


and to answer your question you can use the 4.3 comp
but
not the way you think
you will need to have the comp sent out and reflashed up to 5.7 standards
I dunno if the fuel and timing curves and tables and such will run the 5.7 accurately and effieciently and you will probably end up damaging the 5.7
it will probably end up ebing easier and cheaper to just get a comp from a 5.7
but remember the computer has the vin burned into it for diagnostic purposes



and by the way for you haters from what I understand the vortec V6 to vortec V8 is almost as simple as a carbed V8 swap because the V6 harness needs almost no modification to work with the V8
there are a few minor sensors that need the wiring lengthened to work but I think thats about it

 

[CPWire]

The ECM will work, it just needs to be reprogrammed. You can take it to a dealership and have that done. They will need a VIN number for a full size truck with a manual transmission though in order to do the programming.
If you are not running the emissions controls though, you will need to have the computer program customized or else you will get a check engine light.
Also, you will most likely need to have the program modified for tire size and gear ratio in order for your speedo to read properly.
As for the "cusom harness" that someone said is required, the 4.3 harness is very easily modified to work on the 5.7L.

 

[pkoerbitz]

As for the "cusom harness" that someone said is required, the 4.3 harness is very easily modified to work on the 5.7L.

I had someone do that, but i can't quite remember who it was.............. :racing:

 

[pkoerbitz]

you can use the 4.3 tranny cause its the same tranny(700R4) that is used in silverado's.

700R4 huh? boy i thought they used 4l60-e's now, man, i hope my PCM dosen't find out. lol

 

[[N8]]

I have left my 5speed transmission in.

What's 700R4 & 4L60-E have to do w/ his 5-spd

Can't help w/ the harness tho, sry.

 

[Joedirt3]

y not just get a computer and add too injecters to the harness? isn't that about it?i mean all the sensors should be about the same. because all the 4.3 really is is a 350 with 2 cylinders cut off.

 

[350*s-blazer]

BUt no a 4.3v6 ECM is not going to work on a 5.7, you need a custom wiring harness too genius... but you'd figure that out if you really had a 5.7 in there

just cause you can bolt somthing in doesn't mean you know anything about electronic engine controls. he obviuosly isn't done or he would know. thats why he is asking people who have completed it.