downshift???

I have a 1993 Chevy 1500 4wd and it had a V6 in it. I just put a 350 in and it will not start off in 1st gear. It was fine before I took out the 4.3. Could this possibly be the Downshift Relay? Or what?? Please Help

I have a 1993 Chevy 1500 4wd and it had a V6 in it. I just put a 350 in and it will not start off in 1st gear. It was fine before I took out the 4.3. Could this possibly be the Downshift Relay? Or what?? Please Help

Welcome to AF on your first post.
We need a lot more info or discription of problem.
Is it stuck in a higher gear or just will not start off or take off?
What all did you change like wiring and pcm and transmission?
What kind of transmission does it have?
You may have to undo some of the things that you have done.:grinyes:
MT

It seems to be in a higher gear. The trany I think is a 4L60. I did not change the wiring or the transmision, but I did change the ECM. I did some checking this eavening on my plugs on the trans. and found one wire pinched behind a bracket to where it was striped to the bare wire so I fixed that. Do you think that could have done something to my ECM or Downshift Relay or something else? It was a green wire that appears to go to a plug connection near where the linkage comes through the floor. I don't know what else you might need. Thanks, Tim

It seems to be in a higher gear. The trany I think is a 4L60. I did not change the wiring or the transmision, but I did change the ECM. I did some checking this eavening on my plugs on the trans. and found one wire pinched behind a bracket to where it was striped to the bare wire so I fixed that. Do you think that could have done something to my ECM or Downshift Relay or something else? It was a green wire that appears to go to a plug connection near where the linkage comes through the floor. I don't know what else you might need. Thanks, Tim

Did you also change the transmission or engine wiring?
Did it work after you fixed the wires.More than likley the ecm you put on it.
What no ecm and what year and what prom id did you stick on there and what was your old ECm and prom ID?
Get a scanner on it and see what is is doing or not doing.
Unplug the transmissin and see what it does.
Mt

When you say unplug the trans. what do you mean? where do I unplug it?

When you say unplug the trans. what do you mean? where do I unplug it?

Unplug all big electrical wiring going to it?

Ok new question....If I take the prom out of the ECM from the 4.3 and put it in the ECM from the 350 will in ruin the ECM? Someone else suggested I try that.

Ok new question....If I take the prom out of the ECM from the 4.3 and put it in the ECM from the 350 will in ruin the ECM? Someone else suggested I try that.


Hard to say.
You have not answered the questions I asked about it yet.
Or done what I told you to try.
MT

Did you also change the transmission or engine wiring?
Did it work after you fixed the wires.More than likley the ecm you put on it.
What no ecm and what year and what prom id did you stick on there and what was your old ECm and prom ID?
Get a scanner on it and see what is is doing or not doing.
Unplug the transmissin and see what it does.
Mt

Like these questions.
MT

Did not change the trans. or wiring
did not work after fixing wire
ECM # 16168625 year 93-95
not sure what the prom ID is. (written on the outside of the ECM is BJDR)
Do not know the old prom ID
Do not have a scanner
Have not unpluged the transmission

Did not change the trans. or wiring
did not work after fixing wire
ECM # 16168625 year 93-95
not sure what the prom ID is. (written on the outside of the ECM is BJDR)
Do not know the old prom ID
Do not have a scanner
Have not unpluged the transmission

The emc no is about right.
You will need to find a prom to match your trans and engine.
Good luck
Mt

so would the prom out of the ECM that was in the truck when I had the 4.3 in it work? When I called the dealership to try to get a prom they said there was 11 pages of proms for that engine and transmision. How do I narrow it down for them? Or did that parts counter guy just not really know what he was talking about?

so would the prom out of the ECM that was in the truck when I had the 4.3 in it work? When I called the dealership to try to get a prom they said there was 11 pages of proms for that engine and transmision. How do I narrow it down for them? Or did that parts counter guy just not really know what he was talking about?


What transmission do you have and what year engine and engine code did you put in it?
You will need a prom that matches your transmission and engine.
Your old prom for the 4.3 will match your transmission but not the new engine.
But try it in there and see if the transmission problem goes away.
Yes the parts man knows stuff. And a good one could match somthing up for you.
Good luck

4L60 transmision
a 1992 350 engine
I do not know what engine code. where do I find that?
So do you think I ought too talk to a different parts man and see if he is more helpful?

4L60 transmision
a 1992 350 engine
I do not know what engine code. where do I find that?
So do you think I ought too talk to a different parts man and see if he is more helpful?


Did you try your old prom and see if transmission problem goes away?
Have you put a scanner on it to see what is going on?

First make sure it is the prom giving you the problem.
Then take all of your information to the dealer.
Like VIN no and pcm no. and get or tell them what engine you put in it with the vin no. from the truck the engine came out of.
Actually you may have to go threw the service department to get the right no prom ID for it.
My dealer the service department has a prom machine that tells what prom you need and after you find thsat it may need a updated prom.
I know it is a pain going from one engie to another but that is all i can tell you on it.
Good luck
MT

I am trying the old prom when I get off work today. I do not have a scanner to scan it with so I am trying everything else first. I bought the engine from the salvage yard so I will have to get the vin #v from the van it came out of.
Thanks for all of your help!