Incorrect ECM part numbers

[Kenneth P.]

With regards to the 1990-1991 JG I wonder where they got the part numbers that have listed on page 182 for the L98 & B2K ECM. They list the L98 as 16153993 & B2K as 16159798. I can not find anywhere either in the GM parts book or online those two part numbers they reference. For my 1990 the factory label would have the module #1227727 and the prom #16134302 along with its BCC ANHU. The prom part number and BCC will be different depending on whether it's a auto or manual and the gear ratio of the rear end.

[Joe L.]

Re: Incorrect ECM part numbers

With regards to the 1990-1991 JG I wonder where they got the part numbers that have listed on page 182 for the L98 & B2K ECM. They list the L98 as 16153993 & B2K as 16159798. I can not find anywhere either in the GM parts book or online those two part numbers they reference. For my 1990 the factory label would have the module #1227727 and the prom #16134302 along with its BCC ANHU. The prom part number and BCC will be different depending on whether it's a auto or manual and the gear ratio of the rear end.

Ken-------

There never was a GM #16153993 that I can find. However, there was a GM #16163993. It was the ECM for 1992-93 LT5.

GM #16159798 was the E-Prom used for 1991 L98 with 6 speed manual transmission

[Kenneth P.]

Re: Incorrect ECM part numbers

I like to know who decided that these were the correct part numbers for judges to follow. I have a spread sheet that list all the ECM by part number, BCC and year and neither of these number can be found for the 90 & 91 year models. I could see if they we're off by a one or two numbers but they don't even come close.

[David H.]

Re: Incorrect ECM part numbers

Ken,

I'm going to PM a note to Pat Fullam to check out this thread. Pat compiles a lot of C4 information for later inclusion/correction of the Judging Guides and your spread sheet looks like useful information.

Dave

[Pat F.]

Re: Incorrect ECM part numbers

Folks, I am going to try and help out with this ECM question. First I must state that most of my research concerns the 1994-96 ECM as the LT1 ECM Number for 1996 was incorrectly stated in the 1994-96 Judging Manual as 1618133. It should have been 16214399. This ECM Number was also correct for the 1996 LT4.
When this question was first raised the Judging Manual was thought to be correct but after examining a number of 1996 LT1's it was determined that the Judging Manual had incorrectly stated the ECM Number for the 1996 LT1. This information was passed onto the National Team Leader for correction in the revised 1994-96 Judging Manual.
Also the 94-96 Judging Manual stated that the ECM Number for the 1996 LT4 was 16230041. This statement was also incorrect. That number appears in part on the second lower number of the ECM Label.


As far as the 1990 ECM I have a photo of a 1991 ECM and it has Service # 01227727 and a lower number of 16159831. I do not have a 1990-91 Judging Manual so I can not comment on the ECM listed in the Judging Manual. We have to rely on the information provided by Ken. I know that this does not help much with the initial question, but I would suggest that this question be present to the National Team Leader to determine if this has been encountered in the past and that his Master Judging Manual may contain the correct ECM. I know this function of updating the Master Judging Manual exists as I have done it many times at Regionals and Nationals by taking the Master judging Guide and following the Judging Teams and recored and differences.
I have photos of the 1991, 1995,1996 ECM's would be willing share them with anyone.

[Patrick H.]

Re: Incorrect ECM part numbers

I like to know who decided that these were the correct part numbers for judges to follow. I have a spread sheet that list all the ECM by part number, BCC and year and neither of these number can be found for the 90 & 91 year models. I could see if they we're off by a one or two numbers but they don't even come close.

On the thankfully rare occasion I've had to judge late C4s, I've found that the part numbers quoted for more items than just the ECMs are not at all correct. You're judging an original car with an obviously original and dated part and... the benefit of the doubt always went to the owner. I could only shake my head at how the numbers arrived in the JG when they were so obviously incorrect.

I also hope that someone is compiling correct numbers for a future edition of the JG.

[Pat F.]

Re: Incorrect ECM part numbers

As a follow up here are some photos which differ than what the 1994-96 Judging Manual calls for these ECM's.
Also I am attaching a photo of a 1991 ECM.

[Kenneth P.]

Re: Incorrect ECM part numbers

Pat

I've been researching this for the last few months since a friend of mine almost lost points over this when he had his 90 judge. I have found, with regards to the 90-91 ECM, is that the only characters on the label that are consistent is the Service No. 1227727 top left and the BCC letters top right. The lower part number, you refer to, from what I have found is not consistently a good part number. In your first pic that ECM would be for a 1991 L98 with a RPO of GM1 (2.59 rear gear). The part number 16159831 on that label, which I assume in the past was the prom part #, is not listed in my parts book which covers 84 to 96. The prom part number for that car should be 16159800.

I really do think that the JG should reference the Service No. and the 4 letter BCC which can be found on the build sheet in block 58 (ECM). I'll put together everything I got and email you the files over the weekend.

Ken

[Kenneth P.]

Re: Incorrect ECM part numbers

Here is 3 pages from the parts book that list the proms and computer modules for the 90-91.

Ken

[Joe L.]

Re: Incorrect ECM part numbers

Here is 3 pages from the parts book that list the proms and computer modules for the 90-91.

Ken

Ken------


These are not necessarily the original part numbers and/or the numbers appearing on the original PRODUCTION-installed ECM's. These represent the SERVICE part numbers as of the date of the catalog which, in this case, is March, 2000.

[Kenneth P.]

Re: Incorrect ECM part numbers

Ken------


These are not necessarily the original part numbers and/or the numbers appearing on the original PRODUCTION-installed ECM's. These represent the SERVICE part numbers as of the date of the catalog which, in this case, is March, 2000.

The part numbers that are reference in the 90-91 JG don't exist at least I can't find them anywhere. My point is for judging purpose the service number and BCC on the label should be the deciding factor if you have the correct ECM. If you look close at the listings for the module they do have a part number but as it states the computer is label with a service number that is related to that part number. Also the prom corresponds to the engine and transmission type as well as the rear end gear which will be listed on you RPO label.

Also I have a parts catalog dated 1989 that covers 84 to 90 and it shows the same part numbers and I have found no history of changes in part number from GM for any of these parts.

[Kenneth P.]

Re: Incorrect ECM part numbers

Here are two labels one is from a 1990 and the other is the 1991 that Pat uploaded. Only the top line has any true meaning as far as I can find. The Service No. 1227727, on the left, is the main computer and has a corresponding part number 16198260 and the BCC Alpha code, on the right, is the program chip which is also called the prom, memcal and eprom. Don't forget that the computer 1227727 (the black box) is also used in a variety of other GM cars around that time period and is not corvette specific. The BCC is however is specific to the car and provides most of the information that can be cross check with the build sheet and RPO codes under the center console lid.

So to begin with these are what the factory label will look like and here is what you can tell from the BCC on the label on from each label.

ANHU is 1990 Corvette, L98, Auto, 2.59 gear ratio (GM1).
AXCR is 1991 Corvette, L98, Auto, 2.59 gear ratio (GM1).

1990.jpg 1991-.jpg

[Pat F.]

Re: Incorrect ECM part numbers

Ken, thanks for all your time and effort in this matter. Again, we agree that the build sheet should be made a part of judging process. For not only would it resolve this problem with the ECM, but in latter years it would resolve a number of problems for instance the radiator hoses and the seat belt identifiers. There are more that we could go on and on with.

The Build Sheet or Forecast Sheet is readily available for all the C4's from the National Corvette Museum.

[Kenneth P.]

Re: Incorrect ECM part numbers

First of all Dave take a deep breath and relax. My post was to bring attention to the 90-91 JG for not having actuate part numbers listed for the L98 ECM. According to the JG for the 90-91 it is either you have the part numbers listed, which are not correct, or you stand to loose all points for the ECM even though you may have the correct one.

Apparently the build sheet has been a topic of discussion long before I got involved. That said I did bring up the fact that the build sheet for this particular year of corvettes could be used to cross check with the ECM label. Whether or not it would become part of the judging process is well above my pay grade. I just want for the NCRS to correct the mistakes in the JG for this particular item so to prevent any future misunderstandings. I do agree with you that the judging sheets are long winded and nitpicking. Also reading some of the things in the JG are just as confusing as an IRS book.

I appreciate your input.

Ken

[David H.]

Re: Incorrect ECM part numbers

... According to the JG for the 90-91 it is either you have the part numbers listed, which are not correct, or you stand to loose all points for the ECM even though you may have the correct one. ...

Ken,

Go back and READ Dave Perry's post on how the ECM is actually judged. You do not "...stand to loose all points..." because the part number may not match the JG. At most, a minor issue at a Chapter meet, at Regional/National the Team Leader is available as an information source - that "different" part number most likely has turned up before on the judging field. Even a 40% deduction for an obviously remanufactured unit would be 4 points. Out of 4500 points, not much of an issue.

Never change what you know to be an original part, to make it match a Judging Guide. You don't want to destroy the originality of the car. Original part numbers that don't match the JG serve to expand our knowledge base.

Dave