We've all chased a ghost, haven't we? (ECM/PromID in truck vs. BCC lookup)

[87ChevyR10]

Well, I've been tinkering around the truck trying to see all what I'm in need of replacing the most. I yanked the ECM out recently after spending hours reading all 3 of my manuals and across the net about PROM programming, ecm/prom ids, etc. So with a little more knowledge on it, I yanked mine to eliminate what I've read as a possibility.

A little over a year ago when my truck laid down in Savannah, I came to the only place I knew for help.... HERE, thanks to bd, capt, irisha and several others, I got a handle on most of it and got her back running. But if yall remember, I posted I believe 5 codes the ecm threw. After ordering parts online and in-person I replaced everything on the code list. NOW..... this brings me to the ecm and the yanking of it out the truck.

In each manual it says if you've replaced the item in question, its likely a faulty ecm. EACH code says this if its been replaced. So I yank the ECM and as they say, men lie, women lie, #'s dont lie. And the #'s just aren't adding up. Long story short, I'm thinking maybe the ECM/prom/or related is wrong, so below is what we have based off researching the codes on Service-ID/BCC lookup, etc......


BCC      Year   Release Date    Eprom         ECM         PromID      ScanID      Platform    Engine     Disp.
ABHL    1987   31517    16067485   1227747       7486         6771            r1          L03           5.0   

Trans       Trans Type    Gear Ratio
MD8           AUTO              
*** Gear Ratio not marked under BCC Lookup, all info is correct to knowledge, but Service ID in my glovebox specifically lists RPO code GU2, which is a gear ratio of 2.73 ***

ECM Info from MY TRUCK: 7-7747 / Code: 0802CD
With the ECM's plugin facing me, the small chip I'm assuming is the eprom chip based of the code ID, it says 16060837(eprom id?) on the top line of the chip and 28635 (release date? / 2 is circled). The Larger chip to the right has the 4 letter/4 digit ABHL 7486 code on it.

Some googling of the 7-7747 bounced back not much. I've read here that any designation on the ECM of 7747 is correct, its simply an aftermarket. But also the search on google came back several links attributed to the 5.7/350. Referencing ECM/BCC lookup, we've got several issues of items not matching up. Coupled with the manuals pointing to a faulty ecm if item throwing trouble code has been replaced, I'd say the ecm isn't faulty rather I'm leaning towards the wrong ecm period, or wrong chips in here somehow someway. My dad bought this ECM from a local mom n pop shop years ago when I 1st got the truck, so I can't go back and ask, the shop has long been closed.

Got a job this week finally, been droppin apps like hotcakes since moving back from Savannah, so I'll be updating yall regularly now on the 87's progress. It's sitting in the backyard at the moment with the tbi pulled(began rebuilding process, just picked up the gp sorensen full rebuild kit but dang no new spring!)
         
                                                                                                           - Josh
pics are of both chips inside ecm and the label on the outside of the ecm with part #

[87ChevyR10]

the other 2 pics, outside label on ecm and another code id inside ecm

[87ChevyR10]

I may have just answered my own question. After much research before/since post, I believe I've uncovered what I suspected. Correct me if wrong of course. The computer in question is infact the right computer, the eprom is not. The 350s/305s in many applications use the same computer, either the ACD #1227747 or many other 7747 incarnates thru aftermarket reproducers. However, based on specific application on your vehicle, the proms are different so on and so forth. The prom ID on this shoots back to a 350/5.7, which my motor infact is not. Which could/would/should explain blowing thru 3 fuel pumps, on the 4th now(ACDelco in it now, those who responded back then when it happened may recall) as well as the truck's computer throwing all those codes when infact those items were not infact faulty, per the manual if those items have been fixed, the ecm is faulty. Again, it appears while the ECM nor the prom chip faulty, the long sought after culprit is a prom chip for a 350 motor. If I'm offbase, please let me know.

I'm going to wait until someone can verify before I jump up and down and hoot and holler, but, at this point, I'm willing to go all in that this has been the issue. NOW, assuming this is the issue, I'm not really getting too much in return on google for the correct prom chip. I've got numerous sites saved dealing with EFI and chipping, but anybody give me a hot lead on this? I swear ive got a brain cramp from this.

Look forward to hearing back. This quite possibly marks the greatest day for me and my 87 assuming of course, THIS IS THE CASE.

[VileZambonie]

What is the symptom and what codes are you getting? You have an 87 R10 with a 5.0L?

[87ChevyR10]

Yep. 305/5.0 L03 engine.

I'm not getting any codes since i changed all that stuff last year, but since the truck came back from Savannah, its been sitting. What prompted this post was trying to verify that this indeed is the right ecm, but wrong chips in the ecm since this ECM is used for many GM trucks and F-Body cars, the chips always vary. But, the chip # appears to be wrong in this ECM, for this engine/truck, as its not a 350/5.7L.

The codes thrown last year when it kilt over were:
13 - Oxygen Sensor Circuit/Code 22 - Open Throttle Position Sensor Circuit, Code 32 - Exhaust Gas Recirculation System, Code 33 - Manifold Absolute Pressure/Mass Air Flow Sensor Malfunction, Code 34  - Manifold Absolute Pressure Sensor Malfunction, Code 43 - Electronic Spark Timing Malfunction

But again, all the manuals shoot back to the ECM being faulty if those have been replaced, which they have. So, thats why after much debate and looking around I decided to pull the ecm and pop the cover off and see what the #'s were on the chips.

[VileZambonie]

So the truck is not currently running then. Just pick up a used ECM which will already have the prom installed.

www.car-part.com

[87ChevyR10]

And btw, my apologies for not directly naming you as well. It was more than a few of you who jumped to the rescue on here when I posted last year about all the codes.

You get what I'm saying though right? At this point, its about the only thing that makes sense as to why the issue persisted. Even after believing the problem was fixed with the dist. rotating slightly due to the bolt in the bracket being loose, that apparently isn't the reason its getting garbage fuel mileage either.

I admittedly dont know anywhere in the same galaxy as much as some of yall do, so im not claiming im airtight 100% correct here, but it does lend a great deal of probability that its ecm/prom related does it not? If that prom(16060837) is indeed for a 350, it was making the engine send more fuel thus flooding the pumps out, ultimately causing the multiple failures, no? Not to mention the multiple false codes even after replacement of items in the codes given.

Distributor was "fixed" by shop by way of replacing a bushing or so said the service order, later on the timing manually reset even though the ECM will reset it properly on its own after a certain amount of time on the road, the bolt on the bracket near the dist. tightened down and loctite applied = Truck still ran poorly, stalling out from time to time, piss poor fuel mileage. All kind of pointing back to the wrong prom in there for the 350.

Or nah?

[87ChevyR10]

So the truck is not currently running then. Just pick up a used ECM which will already have the prom installed.

www.car-part.com

If the ecm was in it and i wasn't rebuilding the tbi unit it would be, but at the moment, no.
But easier said than done on purchasing another ecm as each are application specific. There's umpteen GM vehicles with the 1227747 in em. The modules can be programmed of course if I go to one of the many only prom programmers or if I DIY, but unless im lucky, theres no guarantee buying a completely different ecm will have correct modules. So far, the 350 prom mods are all over the net and all over ebay, but not 1 single prom module available from what ive seen for the 16067485

I'm going to attach the BCC info, so we can look at the same thing. you get what im saying right?

Edit: I could roll with summit, jegs or JCW but they all appear to be for performance applications, which my truck is not. So I'ma take a shot in the dark and say i buy one, i could not only potentially be wasting my money as my truck has no aftermarket cams, no performance headers or heads on it, but i throw a Jet chip in there and blow not only 200 dollars, but blow my motor up because its not the right chip for it.

[roboticjunky]

BCC      Year   Release Date    Eprom         ECM         PromID      ScanID      Platform    Engine     Disp.
ABHL    1987   31517    16067485   1227747       7486         6771            r1          L03           5.0   

Trans       Trans Type    Gear Ratio
MD8           AUTO              
*** Gear Ratio not marked under BCC Lookup, all info is correct to knowledge, but Service ID in my glovebox specifically lists RPO code GU2, which is a gear ratio of 2.73 ***

ECM Info from MY TRUCK: 7-7747 / Code: 0802CD
With the ECM's plugin facing me, the small chip I'm assuming is the eprom chip based of the code ID, it says 16060837(eprom id?) on the top line of the chip and 28635 (release date? / 2 is circled). The Larger chip to the right has the 4 letter/4 digit ABHL 7486 code on it.

Your truck is suppose to have a PROM chip in it that says ABHL with the PROM ID. 7486.

Right now, it has a PROM chip that says ABHL 7486. That's sounds like you have to right PROM chip.

7747 ECM is the right ECM for TBI in trucks and vans without electrically controlled transmissions (1987-1992).  If you think there is a problem, then get a different 7747 ECM and put your PROM chip in it.

[zieg85]

I tried to respond to your PM 87ChevyR10 but your mailbox is ***FULL***.  I am currently on vacation and won't be back to see my manual for a couple of weeks.  I do have a ECM module from a parted out 87 with a 305 which I can look to see what numbers are on it but it will have to wait till I return and find it in the shed

[roboticjunky]

There's more than one PROM chip out there for your truck. If you do and get another PROM chip here is a list of PROM chip based on their BCC. Like example, your BCC is ABHL.

Here's 3 spreadsheets with a lot of PROM chips, if you need help finding another one. www.v6z24.com/jbodyforum/download,id,52601.html