DIY PROMDo It Yourself PROM chip burning help. No PROM begging. No PROMs for sale. No commercial exchange. Not a referral service.
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Well, I may have figured out all the ALDL troubles I have been having...here's a rundown and the prognosis ain't good.
1.) Found some wires that the PO had put in the wrong place. He wired the Park/Neutral switch to the ALDL ground. I fixed that. Still got nothing.
2.) Started tracing more wires and found everything else to be intact and correct.
3.) Started the engine and got nothing but packet errors. GRRR...
4.) On a whim, I took the 27C256 chip out of the G2 adapter and tried to start the engine with no chip. It started just like it has been starting in the past. Looked at the ALDL screen and it stayed the same. PROM ID $00C6 (should be $0061) and a bunch or senseless data.
Looks like my 1228746 ECM is broken. Time to shell out some $$ for a new one.
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__________________ 1980 Jeep CJ-7 with a GM-fueled AMC V8, Accel 300+ ignition...GM 1-ton axles front and back...still sort of under construction
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Nothing. No lights...nada. That's why I didn't think to look at that as a potential trouble spot.
Ya know...I have a 1227747 ECM outside. How difficult would it be to convert the wiring to a 7747? The 7747 doesn't have any chips in it. Could I desolder the MEMCAL from the 8746 daughter board and put it on the 7747 daughter board? I have the wiring diagrams for a 7747. I may look into doing just that.
Last edited by jeepguy553; 02-14-2004 at 05:52 PM.
Originally posted by jeepguy553 Nothing. No lights...nada. That's why I didn't think to look at that as a potential trouble spot.
Ya know...I have a 1227747 ECM outside. How difficult would it be to convert the wiring to a 7747? The 7747 doesn't have any chips in it. Could I desolder the MEMCAL from the 8746 daughter board and put it on the 7747 daughter board? I have the wiring diagrams for a 7747. I may look into doing just that.
Ah yes, POS (previous owner syndrome). I have a truck like that myself.
The '7747 is a plug in, no wiring changes. Not sure what you mean about unsoldering/soldering the MEMCAL. Can't interchange the PROMs between them. The NETRES interchanges between the two.
The ALDL stream will operate w/o starting the engine (just an FYI to make it easier to troubleshoot).
At key on, no crank, SES should turn on, blink off (ca. 1/2 sec) then turn back on solid. If not, then something is wrong.
I guess I am using the wrong terminology here. Sorry. I am still kinda stupid at this point...but I learn fast.
I am referring to the small chip that is actually soldered to the 8746 daughterboard beside the PROM. The 7747 ECM I have has a socket similar to the PROM socket for the small chip. The PROM socket is identical to the 8746...at least it looks that way.
The POS comes from the fact that the harness I have was butchered when I got it. The Park/Neutral switch wiring was something I overlooked when I was going through the harness and fixing all the problems I found. After that, I think one small oversight is pretty good.
Thank heaven that I have the 7747 ECM and that I can use it. My tax return is already stretched pretty thin.
I just looked at the wiring diagrams for the 7747 and compared them to the 8746 diagrams. I only saw one difference and that was in the fuel pump relay wiring. I may plug it up and see what happens.
OK, the small chip is the NETRES (Network of Resistors). Can swap that over to the '747. Soldered on the '8746 as that ECM was only used on V8's. Socketed on '7747 as was used on V6's and V8's and the NETRES differ's between the two.
So as long as I take the NETRES from a V8 ECM (8746), I can swap it over to the 7747 board for use with a V8.
This looks like a job for my electrician buddy. I'll screw this one up royally. I didn't have a solder sucker when I put the G2 on the 8746, so I rigged one up in the lab with some lab-type vacuum tubing and a glass pipetter with the tip broken off. I plugged it into the lab vacuum manifold and went to work. It was ghetto and crude, but it worked.
Results tomorrow...I hope.
Where can I get a NETRES if this cockeyed scheme doesn't work?
The 747 was new in the box when I got it. It doesn't have any chipset on it at all. No PROM or NETRES. It only has 2 open sockets. I am going to install the Moates G2 adapter and the 8746 NETRES on it.
I think a bone yard trip for the chip or a trip to the dealer for $14 would be easier than desoldering and resoldering the netres.
JMO
Some yards around me only charge $20 for the whole ecm.
You might get a V8 7747 with the right chips.
I called around and couldn't find a 7747 in any junkyards. At least not that anyone would own up to.
I don't have the 7747 PROM. I have the G2 adapter and 29C256 with an AutoProm. I already have the G2 adapter on the 7747 daughterboard, but I am having a little trouble with the NETRES. I would like to try to finish this today so I can drive the Jeep to work tomorrow. It is RIGHT there on the verge of being ready...if I can get past this one little setback. If I can't, oh well. If I screw up this ECM (or if it is already screwed up) I am not out any $$ and I can go get another one later this week.
Last edited by jeepguy553; 02-15-2004 at 04:31 PM.
