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When
the Tuned
Port fuel-injection
system arrived in 1985, it was a significant improvement on the
throttle-body systems that came before. Much cooler looking and with
more power potential, the Tuned Port Injection (TPI) system used a
mass airflow sensor (MAF) to determine fuel/air mixture.
The
Tuned Port MAF sensor is a sensitive piece of equipment that
incorporates a thin piece of wire that reads air intake and reports
to the computer the current air conditions. If the wire is damaged in
any way, the engine will not run properly, hunting for a rich or lean
mixture to keep the engine operating. Regardless, the engine will not
meet performance or pollution requirements.
Our
'86 Corvette was running poorly. A
diagnostic check netted a Mass Airflow Meter error code (number 34).
In addition, several of the air-cleaner pieces were broken, including
the clips attaching the MAF sensor to the air intake, the air-cleaner
element box screw mounts, and the air snorkel from the MAF to the
throttle body had picked up a hole. Any or all of these problems can
cause the MAF sensor to misinterpret the data from the computer.
Parts
List
Zip
Products: Modified Mass Air Flow Sensor, part number EH-478; Air
Filter Housing, part number AC-134; Air Intake Duct, part number
EH-459
K&N: Air Filter
Element, part number 33-2014
One
call to Zip Products fixed all that. In addition, we improved the
flow of the system with a K&N air filter and a Modified Mass Air
Flow Sensor. The installation took about five minutes, and a recheck
of the system netted an all-clear by the computer. This is truly a
simple fix and one that any novice mechanic can complete. If you can
change an air-filter element, you can complete this operation.
The
Modified Mass Air Flow Sensor is an excellent changeover to any TPI
system. The Modified unit allows more air to flow through the sensor
into the engine. As any engine builder knows, the more air your
engine ingests, the more potential power you can generate. Knowing
that the intake system of these cars is already somewhat restricted
by the underhood configuration of the
engine compartment, anything that increases airflow is a good thing.
If you're already changing the MAF sensor, this swap is a good idea.
Follow
along as we repair and improve the intake system on our '86 Corvette.
It's easy.
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The basic layout of the intake system on our TPI '86
Corvette. Disconnect the battery when performing any engine work.
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A check of the diagnostic system on our Corvette
resulted in a faulty MAF-sensor readout.
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Our air-filter housing had broken tabs at the point
where it was to connect with the MAF sensor. The new housing was a
dramatic improvement.
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The air-intake duct had a hole, allowing air and
debris into the engine behind the MAF sensor and air-filter
element. Bad news.
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