Fordnatics List Archive

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Mail From: Robert King <(email redacted)>

Date 6/3/94
Subject RE>Mustang MAF installation
>From Robert King
To Clifton Koch
CC Fordnatics

Subject:RE>Mustang MAF installation
Cliff,
Thanks for the GREAT article on replacing your injectors and speed
density system! I've been contemplating that same modification when I
re-build my '88 this next spring (my engine has 160k miles on it.) I
have a couple of questions though.

First, there are three mass air systems that readily come to mind: the
stock unit used on 1988 California and 1989 and later Mustangs, the unit
sold through the Ford Motorsport catalog, and the Cobra unit. Do you
know what the differences are?

Second, if the stock MAF sensor is replaced (apparently it is EXTREMELY
restrictive,) does the computer need to be re-calibrated?

+-----------------------------------------------------------------------+
| Robert A. King | |
| Systems Software Engineer | |
| Kodak Health Imaging Systems | "I drank WHAT?!?" -- Socrates |
| | |
| (email redacted) | |
+-----------------------------------------------------------------------+
| The opinions expressed here arn't even mine, much less my employer's! |
+-----------------------------------------------------------------------+

This read-only message was archived from a public mail list.
Mail From: chucko (Chuck Fry)

Date: Fri, 3 Jun 1994 10:00:22 +0000
From: Robert King <(email redacted)>

First, there are three mass air systems that readily come to mind: the
stock unit used on 1988 California and 1989 and later Mustangs, the unit
sold through the Ford Motorsport catalog, and the Cobra unit. Do you
know what the differences are?

I'll give this a shot, since I've recently been MAF shopping. The
primary differences between these units are the inner diameters, and the
intended fuel injector sizes.

The stock unit on '88-'93 Mustangs has an ID of something like 55 mm,
and is calibrated for 19 lb/hr injectors.

The Ford Motorsport unit is basically the Pro-M 77 mm ID part. Pro-M
supplies these calibrated for 19, 24, or 30 lb/hr injectors. I don't
recall which calibration is sold by Ford Motorsport.

The Cobra MAF has a 70 mm ID with a strut running right down the middle,
which some critics claim makes it as restrictive as the stock Mustang
MAF. It is calibrated for 24 lb/hr injectors, and should be used with
the Cobra EEC-IV computer.

Second, if the stock MAF sensor is replaced (apparently it is EXTREMELY
restrictive,) does the computer need to be re-calibrated?

The computer cannot be "calibrated". What's in the PROM is what you
get. It will automatically adapt somewhat to mismatches between the
injectors and MAF, but has a limited range. E.g. various sources say
the EEC-IV can adapt to 24 lb/hr injectors with a 19 lb/hr MAF.

-- Chuck

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Mail From: Peter Whales <(email redacted)>



>
> Second, if the stock MAF sensor is replaced (apparently it is EXTREMELY
> restrictive,) does the computer need to be re-calibrated?
>
> The computer cannot be "calibrated". What's in the PROM is what you
> get. It will automatically adapt somewhat to mismatches between the
> injectors and MAF, but has a limited range. E.g. various sources say
> the EEC-IV can adapt to 24 lb/hr injectors with a 19 lb/hr MAF.
>
> -- Chuck
>
If you change the mass air meter and it is not calibrated for the
injectors, then the ignition will be wrong. The fuelling will be also be
wrong but only when the computer goes open loop. ie at start up and on
full throttle. Otherwise the oxygen sensoe will tell the computer to
correct the fuelling and on part throttle the fuelling will be correct.

Peter