Check engine light is on but when i cross terminal A and B on the ALDL it doesnt flash a code. It starts up but only runs at like half power. Iv replaced the ecm and prom but still the same problem. 87 2.5l auto
Just to cover the obvious - you have the key ON, but the engine is NOT running, correct? Make sure you're using the right pins. The ALDL plug may be upside down from what you're expecting, so you may be in the wrong location.
Just to cover the obvious - you have the key ON, but the engine is NOT running, correct? Make sure you're using the right pins. The ALDL plug may be upside down from what you're expecting, so you may be in the wrong location.
ya I was thinking that as well, I have never had one not flash anything.
Steve
------------------ Technology is great when it works, and one big pain in the ass when it doesn't
Pin B of the ALDL connector is the White/Black wire. At the ECM try grounding that wire (Key on) Does the light now flash? If so your wiring to the ALDL connector is bad.
Did you try two PROMs or did you swap the prom from one ECM to the other? Since the power is way down the ECM might be running on limp mode because the PROM is bad.
Since this really sounds like either a bad ECM or bad PROM, that is the way I would lean. Perhaps two bad ECMs. $40.00 for a working used 7748 ECM if you are interested email me. I have three so most likely I can supply you one with the correct PROM.
gofast@reddevilriver.com - email
[This message has been edited by phonedawgz (edited 04-04-2014).]
Iv only had two proms the originally wich if you were to push on it it would run fine and the one i had someone burn but when you push on the one the guy burned it doesnt do anything so idk if its just that or what. He said he did it corrextly and checked so.
Now how do you go about testing this ground wire caus even if it was a bad prom it should still flash a code for that
if you just want to test the ground wire in the plug you just need a test light and a live + power supply. take your cigarette lighter out, its always live and put the point of the test light into the center of the lighter all the way to the back, make sure you don't touch the side of the lighter casing. then put the alligator clip on the ground wire. the light should light as soon as you make contact, if not you ether have a bad lighter socket or the ground is bad, or you didn't get a good connection on one of the places.
