'88 IROC 5.7 Mass AirFlow Sensor...

[Bill Childers]

I've owned my 88 5.7 IROC for a year now, and I love it!!

EXCEPT...

My car has the mass airflow sensor (MAF) equipped TPI unit. I had the
sensor go out about 2 months ago, and replaced it with a new one from GM
($200!!).
Now, my car is exhibiting the same problem AGAIN... If I thump the MAF with
my hand I can get it to work for about a week... then driveability problems
start to show up. I've checked the leads going to the sensor, and they are
in good shape (no loose connections, etc).
I have heard of a way to swap out the PROM in the car so as to disable the
MAF... but I can't seem to find any info on it. Anyone know how to do
this???

Thanx,
Bill Childers

[IROCZ 1987]

Instead of that had you considered purchasing an exchange unit from TPIS
in California $79 exchange. Screens are removed and heat synch is
machined to maximize flow potential - The ECM does too many good things to
nuke it over one bad sensor.

*************************** 1987 IROC-Z
*********************************
5.7 L98, A4, 3.27:1 Borg Warner, 52mm TPIS Throttle Body,
Accel Adjustable Fuel Pressure Regulator, Enlarged Tuned Port
Runners, Accel 300+ MSD Ignition System, Hypertech Thermo-master
Chip, 160 degree Thermostat, Flowmaster, Air Flow Research Heads,
TCI Reverse Manual Valve Body, B&M Ratchet Shifter, Crane Gold
1.6:1 Roller Rockers

**************************************************************************
*****

[ho...@ballistic.com]

chil...@garlic.com (Bill Childers) wrote:

>I've owned my 88 5.7 IROC for a year now, and I love it!!

Bill,

I have an '89 Pontiac Trans Am. My MAF (Mass Air Flow) Sensor went out
a while back. I don't know if you are aware or not, but the MAF sensor
is part of the Emmission Control System. This means that, by law, it
carries a 50,000 mile warranty. The place where you bought it has to
replace it, even if it's a rebuild. I'm not sure if anyone else will
replace it. The place you bought it from should have put the mileage
down on it.

I dont know where you can find a prom chip that will bypass your MAF
sensor, but if you find one I'd appreciate an email. I've been
looking for one so I can go with a K&N air filter that will fit on the
TPI. Thanks,

Mark

[Andris Skulte]

>I dont know where you can find a prom chip that will bypass your MAF
>sensor, but if you find one I'd appreciate an email. I've been
>looking for one so I can go with a K&N air filter that will fit on the
>TPI. Thanks,
>
>Mark

The MAF measures the amount of air going into the engine, so it can measure
the right amount of fuel (kinda oversimplified) If you don't have the MAF, the
fuel milage will be terrible, and you'll make no power either. The only way
the car can run w/o one is to go to te 91/92 way and use a MAP sensor
instead. This means a new computer too, with the speed density measuring.. Go
aftermarket and buy a new MAF for $250 instead of $500 for GM's...

[Preacher]

ho...@ballistic.com wrote:
>
> chil...@garlic.com (Bill Childers) wrote:
>
> >I've owned my 88 5.7 IROC for a year now, and I love it!!
>
> Bill,
>
> I have an '89 Pontiac Trans Am. My MAF (Mass Air Flow) Sensor went out
> a while back. I don't know if you are aware or not, but the MAF sensor
> is part of the Emmission Control System. This means that, by law, it
> carries a 50,000 mile warranty. The place where you bought it has to
> replace it, even if it's a rebuild. I'm not sure if anyone else will
> replace it. The place you bought it from should have put the mileage
> down on it.
>

> I dont know where you can find a prom chip that will bypass your MAF
> sensor, but if you find one I'd appreciate an email. I've been
> looking for one so I can go with a K&N air filter that will fit on the
> TPI. Thanks,
>
> Mark

Mark, Bill or anyone else,

This may be what you are looking for:

TSB # 90-132-6E, Switching from a MAF to Speed Density.
This "kit" includes a speed density (MAP) sensor and a PROM

Applies to:
1987 J car 2.8 (VIN W)
1987-1988 A & L cars 2.8 (VIN W)
Codes 33 or 34 (MAF) NOT 23 or 25 (MAT)

I got this from my old notes when I went through GM training in 1989, I believe that it
later covered more then the 2.8's. I know that it went on to cover some V-8's but may
have been under a different TSB #. I will see if I can dig up some more data on it.

Mark is correct when he says that the part is covered under warranty, but it is the
dealer that has to make the repair. Federal law states that it must first "fail" a smog
check, so I don't know if this will apply to your situation or not. It is usually a
5 yr/50,000 mile or a 7 yr/70,000 mile warranty, you may be out of luck. If you bought
the part from an aftermarket source you may have some recourse there. Ask your local
dealer, it can't hurt. The worst that could happen is he might say no.

Preacher