1985 ECM Repair???

Reply Subscribe

Thread Tools

Search this Thread

Dec 30, 2008 | 10:32 AM

#21

Muffin

Race Director

Joined: Jun 1999

Posts: 14,924

Likes: 9

From: Merritt Ils Fl

First there is no baro read on the 85. Second, cherokee did you get the No Code 12 diagnostic sheets? If so what were the results? A simple question: When you turn the ignition key to run do you get a steady Service Engine Soon light in the DIC?

Dec 30, 2008 | 10:49 AM

#22

BluRay

Pro

Joined: Dec 2008

Posts: 658

Likes: 0

From: Lubbock for now, headed for Oklahoma

Oh man don't leave us hanging here. Then what input did it offer? If it's not speed density and it's not used for BARO, what the hell does it do?

Dec 30, 2008 | 07:59 PM

#23

Muffin

Race Director

Joined: Jun 1999

Posts: 14,924

Likes: 9

From: Merritt Ils Fl

Quote:

Originally Posted by BluRay

Oh man don't leave us hanging here. Then what input did it offer? If it's not speed density and it's not used for BARO, what the hell does it do?

BluRay not sure I understand you post. The 85 is not speed density. Power loads are derived from MAF input to the ECM.

Dec 30, 2008 | 09:44 PM

#24

anesthes

Safety Car

Joined: May 2006

Posts: 4,290

Likes: 140

From: Salem NH

Quote:

Originally Posted by Muffin

BluRay not sure I understand you post. The 85 is not speed density. Power loads are derived from MAF input to the ECM.

He says there is a MAP sensor. He's not implying the '870 ECM is not a MAF based system, he's saying there is a MAP as well. I cannot verify, I know for certain on '870 fbody applications there is no baro or map sensor for any sort of calculation, but I have not had my hands on a corvette version of the '870.

I know some of the computer controlled carb's had a baro sensor for I think elevation but I wasn't aware of any MAF calibrations other than the LT1s using a map/baro sensor as well.

-- Joe

Dec 30, 2008 | 10:54 PM

#25

cherokeecorvette

Thread Starter

Advanced

Joined: Nov 2008

Posts: 59

Likes: 0

yes i get a steady light, I just got done troubleshooting the and it points to ECM being bad

Dec 30, 2008 | 10:55 PM

#26

cherokeecorvette

Thread Starter

Advanced

Joined: Nov 2008

Posts: 59

Likes: 0

I have voltage at ALDL and i ohmd the ground at ALDL

Dec 31, 2008 | 11:02 AM

#27

Muffin

Race Director

Joined: Jun 1999

Posts: 14,924

Likes: 9

From: Merritt Ils Fl

cherokee your ECM is available at most parts houses for $80-$90. That may be your best source. Yes they will be rebuilds but it may be the only game in town since the 870 was a one year application. Might try one of the salvage yards who are supporting vendors. Rebuilding yours may be a possibility, don't know.

MAF-MAP Application
82-84---L83---MAP
85-89---L98---MAF
90-91---L98---MAP
92-93---Lt1---MAP
94-96---Lt1---BOTH (MAF for flow/MAP back up) Includes Lt4

This table vadered from Corvette Fuel Injection by Charles D. Probst, page 70-71.