no check engine light
Thread Starter
4th Gear
Joined: Aug 2004
Posts: 4
Likes: 0
no check engine light
I have an '84 corvette. The current problem is that I keep blowing the fuse to the electronic control unit. Also, the check engine light never comes on, including trying to use on-board diagnostics.
The fuse is connected to the ECU and the electronic spark control. The ESC only connects to ground, fuse, knock sensor, and ECU.
Fairly certain that this indicates I have a bad ECU, but wanted to get confirmation on this before I shelled out the money (poor college student).
I assume if the problem was the ESC or it's sensor the check engine light would come one.
How do I tell if it is the ECU or the PROM in the ECU?
Any answers to any related question that I didn't think to ask are welcome also.
Thanx
The fuse is connected to the ECU and the electronic spark control. The ESC only connects to ground, fuse, knock sensor, and ECU.
Fairly certain that this indicates I have a bad ECU, but wanted to get confirmation on this before I shelled out the money (poor college student).
I assume if the problem was the ESC or it's sensor the check engine light would come one.
How do I tell if it is the ECU or the PROM in the ECU?
Any answers to any related question that I didn't think to ask are welcome also.
Thanx
Heel & Toe
Joined: Aug 2004
Posts: 18
Likes: 0
From: Amarillo Texas
You may want to check the back of the information console. I wasn't getting the check engine lite when performing diagnostics. Got curious and removed the center information console and found out there was no bulb/socket installed.
Racer
Joined: Jun 2004
Posts: 271
Likes: 0
From: Sacramento CA
Originally Posted by Chris9
You may want to check the back of the information console. I wasn't getting the check engine lite when performing diagnostics. Got curious and removed the center information console and found out there was no bulb/socket installed.
Thread Starter
4th Gear
Joined: Aug 2004
Posts: 4
Likes: 0
I checked the bulb and even though it looked ok I changed it with one I knew was working.
I have found one source that says when the check engine light doesn't come on to check the service manual. I have looked in two repair manuals. The Haynes manual I have doesn't mention any way to check or know when the ecu/prom is bad (though it does tell you how to replace it :-/). I know a mechanic in town who let me look through his Mitchell repair manuals. I, still, couldn't find anything discussing what could be wrong if the check engine light doesn't come on.
Something, somewhere should say what to do if the diagnostic system can't give output, but I haven't found it.
I have found one source that says when the check engine light doesn't come on to check the service manual. I have looked in two repair manuals. The Haynes manual I have doesn't mention any way to check or know when the ecu/prom is bad (though it does tell you how to replace it :-/). I know a mechanic in town who let me look through his Mitchell repair manuals. I, still, couldn't find anything discussing what could be wrong if the check engine light doesn't come on.
Something, somewhere should say what to do if the diagnostic system can't give output, but I haven't found it.
