A couple of weeks ago I posted about a suspected bad fuel pump relay.

http://www.peachparts.com/shopforum/tech-help/418715-crank-but-no-start-88-190e-2-6-a.html

The issue is resolved, but it raised other questions. I mentioned in the post that the relay was original, but a search of my records proved otherwise.

In the spring of 1990 when I left my office the engine cranked, but at first would not start. After several tries I finally got it going, but had to keep it at 5000 revs for about a minute to keep it from stalling.

I drove to the dealer and left it with them overnight. I figured the OVP was bad because all the cold start enhancements are in the E part of the KE system.

The next day, 4-9-90 I picked up the car, and the RO said they replaced the FPR, part number 003-545-17-05, but the part I removed last week was 003 545 00 05.

The new part is URO (all that was available) equivalent to 003 545 24 05.

So I have two questions.

1. Why was the failed relay not the same part number as on the 1990 RO when it was replaced? Was the dealer playing some kind of game with the warranty work? ... any other ideas?

2. How does the MB part number system work? Since I've been involved with vintage Corvettes for 60 years I know the GM part number system pretty well. The former 9 digit numbers were issued chronologically. Minor changes in the design or manufacturing processes usually didn't warrant a new part number, but major changes do.

For example the first part number for the C2 cast iron half-shaft yoke that attaches to the spindle drive flange started with 37, which was '63 only. It was replaced by a forged design for '64, part number starting with 38 and again in the late sixties, part number starting with 39. Both replacements were backwards compatible, and the part number indicates the approximate year of release.

The first three digits of MB part appear to be the model for which is was designed, like 201, or perhaps a particular type of part like 003 for electrical system parts. And I assume the 7th and 8th digit are revisions, examples being the 00, 17, and 24 being revisions for the FPR. In fact the new one has 10 active pins, so later models must have some other function in the fuel pump electrical circuit.

Any insight is appreciated.

Duke