electric tranny effect engine?

[big83chevy4x4]

im ran into some problems, here in this post
engine swap problems

im think about just using the original harness and just tieing the tranny plug up out of the way if i can't find a harness that will work.

my question is does the tranny effect how the engine runs, acts, or anything else?

 

[big83chevy4x4]

anyone? /forums/images/graemlins/dunno.gif

 

[dyeager535]

If it's electrically controlled (the "E" variants) then I would expect a check engine light to come on (perhaps going into a limp home mode of some sort) without the tranny hooked up correctly.

 

[big83chevy4x4]

yes it is a 4L60E tranny, and i know about the engine light on, i forgot about the limp home mode. /forums/images/graemlins/thinking.gif

think it will effect the engine much?

 

[dyeager535]

Well, apparently there are actually other modes besides limp home.

But in some cases, limp mode means fixed timing to keep the engine from hurting itself. That alone will really hurt performance. Again, this depends on how "bad" the ECM interprets missing tranny information.

I can't be more specific, because I just don't think anyone but GM engineers know what kind of differences are made with each ECM, when certain failures or codes are triggered. Checking out the DIY PROM section on thirdgen.org I started reading about "limp home", and I'm still not sure if there was ever an actual consensus on what triggered what. If that all makes any sense.

Obviously a manual trans PROM would somewhat cure the problem, but not entirely. I suspect if the wiring plugs are different, the PROM is too, but I don't know that as a fact...perhaps the PROM itself is interchangeable?

 

[jac6695]

I would find a pinout of all of the terminals on the ECM for both vehicles (finding someone with a Factory Service Manual best) and modify the harness at each end (ECM and Transmission) to control the lockup. That way you can still use the 94 4L60E harness with the 700R4 end. You might need to cut and splice a few wires at the ECM end, but a little solder and heat shrink goes a long way.

 

[jac6695]

I **might** be able to help you out with the wiring diagrams. I was just given a 6 disk set of domestic wiring diagrams on CD, but haven't loaded it yet. I will let you know if I come up with something for you.

 

[big83chevy4x4]

the PROM from the van and the blazer are interchangable, even snapped it in to see if it would fit.

i never thought that the PROM would say that it has to control the tranny also /forums/images/graemlins/thinking.gif ill have to read the article on thirdgen.org. one thing is the axle ratio in the blazer is 3.08 and the van is 3.42, of all things working correctly, the main one is the speedo. im preaty sure the PROM contains that.

i have the haynes manual that shows the scematic for the engine/tranny harness, and i have the service manual for the 4L60E (not to mention a few others /forums/images/graemlins/whistling.gif) so i THINK im covered on the wiring. let me know if you can help cause i may need some more in case the haynes is off (like they are sometimes)

tomorrow im going to a junkyard hopefully finding the correct harness that i need.