J-bodies and MAP vs MAF

[TBK]

The Mass problem existed for a short period time. The thick (thin?) film
mass got used long into the future. It certainly was easier than replacing
all of the mass sensors. However that problem was in 86-87 I think and the J
cars had the mass well into the 90's.

I prefer mass over map any day of the week.......when it works.....If you
are altering the system, the mass is tons more forgiving.

An example is my X-11. With the mass and a very hot aftermarket cam, the
mass flow is correct at about 6 gm/S at idle and 135 gm/S at 6000 RPM. With
the SD system, it reads the ECM "calculated" 20 gm/s at idle and 255 gm/s
(pegged) at 6000 RPM. I don't think so. A lot of correction to the rom is
needed to get it back into reality. Something not a lot of people can do.

That same SD system on the stock 2.8L/3.1L reads correct. Just the cam alone
throws the system off.

On the other hand, SD is simpler to deal with. I do get your point.

TK
-----Original Message-----
From: Clare Snyder <snyder at huron.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Friday, April 17, 1998 6:20 PM
Subject: Re: J-bodies and MAP vs MAF


>TBK wrote:
>>
>> Mass systems had map too. Therefore on the Mass needs to be added. The
EGR
>> (digital or linear) may be different. HEI or DIS is slightly different.
>>
>> -----Original Message-----
>> From: ABTSZ <ABTSZ at aol.com>
>> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
>> Date: Thursday, April 16, 1998 6:05 PM
>> Subject: J-bodies and MAP vs MAF
>>
>> >  Hi,
>> > I've been told different things by different people about whether
J-body
>> V6s
>> >are MAF or MAP.  According to the schematics I've seen, some are MAF and
>> some
>> >are MAP based on different years and\or models.  The manuals I have only
go
>> up
>> >to '90, however.
>> > Does anyone know if any J-bodies are MAP based, and what years or
models?
>> I
>> >don't know if I should trust the Chilton manuals I've been lookin at or
>> not.
>> > Also, If all I can find is a MAF based system with a 7730 ECM, is this
>> >difficult to convert to MAP?  I realize I'd have to get a prom for a MAP
>> based
>> >care (F-body V6).  What about the wiring to the MAP?  Is there "vestual"
>> >wiring in the harness?
>> >
>> >Adam
>> >
>There were so many problems with the MASS sensors that GM developed the
>speed-density prom rather than replace the mass sensors. Many vehicles
>with the mass installed don't use it at all. Eventually they stopped
>installing it.
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