89 w/ LS ECM, need assistance
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,408
Likes: 13
From: Dayton, Ohio
89 w/ LS ECM, need assistance
I have an 89, 6-speed .
the engine is a 383 first generation small block.
i have converted it to use an ECM from a 2000 Silverado, complete with crank trigger timing and 8 coil setup.
Everything is running and I’m getting the bugs worked out as far as tuning.
That’s not the problem I have.
I’m not having any luck getting my speedo to work.
all other gages work fine. Speedo doesn’t.
thanks in advance for any help offered!
the engine is a 383 first generation small block.
i have converted it to use an ECM from a 2000 Silverado, complete with crank trigger timing and 8 coil setup.
Everything is running and I’m getting the bugs worked out as far as tuning.
That’s not the problem I have.
I’m not having any luck getting my speedo to work.
all other gages work fine. Speedo doesn’t.
thanks in advance for any help offered!
Pro
Joined: May 2025
Posts: 613
Likes: 145
From: OK
Where is the stock speed sensor on an automatic car? You should be able to get a signal of some sort from the trans or ecu and feed it through one of dakota digitals converter boxes and turn it into a something the speedo will like.
Cool project btw.
Cool project btw.
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,408
Likes: 13
From: Dayton, Ohio
I’ll check out their website! Thanks for the idea.
Drifting
Joined: Jan 2005
Posts: 1,354
Likes: 325
From: San Antonio Tx
Unlike the later c4's The 89 speed sensor goes directly to the instrument panel. Speedometer works without the ecm. The input to the ecm comes from the speedometer. You might need a converter box to get the correct pulse per mile to the ecm but not for the speedometer to work.
Thread Starter
Drifting
Joined: Jan 2001
Posts: 1,408
Likes: 13
From: Dayton, Ohio
That’s a good tip. I’m going to need to bury my nose in the FSM this weekend. Then take a look at how I’ve currently got it wired. It’s been a few months but I’m sure it’ll come back when I get under it and compare it to the FSM and the new ecm.
Thank you for the advice.
Thank you for the advice.
