![]() |
Two different Hot Air MAFs?
I have a MAF of uncertain origin that was sold to me as "84/85". The problem is that, although they appear identical from the outside, there are two different part numbers for '84 and '85, and I've never been able to find out why.
This one is in the original-style case. It has a plastic sticker on it that reads: /-------- | 25007653 | SERVICE | | BP [rotated and large] | | 25007651 \-------- 25007653 is the '84 number. 25007699 is the '85 number. My ECM has the '85 PROM (CMM broadcast code). What difference could it possibly make, using one Hot Air MAF versus the other? This (apparently '84) MAF has a removable lid on the electronics box. Is there something in there I could learn something from? I've been banging my head on this for a while. I can't find any information to resolve it. And I know reman MAFs are a crap shoot, probably dicier than just using this one. |
Re: Two different Hot Air MAFs?
Here's a link to www.turbobuick.com where I just posted a pic of the MAF, with focus on the sticker:
http://www.turbobuick.com/forums/hot...nal-reman.html |
Re: Two different Hot Air MAFs?
You do realize you can post pictures here, right?
My guess is that whatever changes were made from 1984-1985 were minor, and either done to enhance tuning or to simplify the construction of the device. There is a very good chance that both are essentially interchangeable. On the 1984-1986 cars vs. 1987/1989 cars there was a change to the knock sensor filter. The change was to simply go from a four-pole filter to a two-pole filter. It was determined that a two pole filter performed well enough, and four were overkill. A good source for this answer might be Eric Fisher. Or possibly Eric Marshall. Actually, Tom Chou would probably be the best to answer this, but I doubt you'd be able to find him... |
Re: Two different Hot Air MAFs?
Quote:
Quote:
But if it was any kind of "backward compatible" improvement, you'd expect GM to specify the same service part for the '84. The various service MAFs all listed for exactly the same price. My concern at the moment appears to be "forward compatibility" of the '84 MAF to the "1st design" (non-ThermAC) '85. PROM-specific tuning might be an issue, however small. This is for a driver, I'm in California, and we do have smogcheck. Quote:
Overkill for '84-'86, or for '87/'89 as well? Would you expect the '84-'86 ESC to drop into an '87/'89 and work fine with no complaints? Quote:
|
Re: Two different Hot Air MAFs?
Quote:
Quote:
Quote:
Quote:
Quote:
|
Re: Two different Hot Air MAFs?
Quote:
Of course, that wouldn't rule out the possibility that GM developed a MAF to accommodate it and stuck with it anyway. Quote:
I would not be surprised if the '84 MAF was used in '85 production cars. I would not be surprised if the MAF and ECM in my photos came in the same '85 car from the factory. Not knowing is eating my brain.... Quote:
|
Re: Two different Hot Air MAFs?
....which in turn was a wry commentary on how difficult -- impossible -- GM made it to get this kind of information about these particular units.
|
Re: Two different Hot Air MAFs?
Quote:
|
Re: Two different Hot Air MAFs?
Um...not really.
Honestly, I'm not sure you know who Eric Fisher or Tom Chou are, what they do, or what they have done. While Eric Marshall sells aftermarket chips, I do think he has appreciation for the delicate (and antiquated) nature of the technology involved in making these cars run. I'm pretty confident at least one of those listed knows the answer to your question. |
Re: Two different Hot Air MAFs?
At the risk of getting an even angrier looking smiley....
You aren't showing much interest in the answer yourself, despite having been around these motors a lot longer than I have. I'm just amazed this is not a point of interest for people. As far as I can tell, I'm the only person who's ever expressed any interest. :dunno: I'm certainly not very enthused about bugging people who aren't interested enough to engage in this thread of their own volition. |
All times are GMT -4. The time now is 05:56 AM. |
Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.