picked up another lb8 intake system at the yard. I got maf, flex tube, dual snorkle, and bottom side and all. I want to test the maf to see if its good or not. If its junk, I'm going to gut the inside, smooth it out.

I have a steel pipe in place of the maf/flex tube, and it gets HOT as a ****.

So can you test a maf? If its good, anyone got a junk one we can trade?

Anyone need LB8 intake as well?

 

>So can you test a maf?

Good question. Can always be tested, but how easily. Lets say this is an '86-'89 MAF which as an analog output. There is also a burn off cycle.

As for the output, wire up ground (2 pins) and +12 volts. Then a DVM (or scope) on the output. With no airflow the output should be close to 0 volts. As the aiflow increases (will the missus miss the vacuum cleaner?) the output will increase.

When at a steady state gently tap on the MAF, output should stay the same. For the most part this will show whether it lives or not.

Then the burn off cycle. A short application of +12 volts should have the element glowing red. There is also a signal that is sent to the ECM to verify this. Not sure what it is. Although it is on the analog output line.

The diy-efi/gmecm site has '165 f-body wiring diagrams that will help out (under the ecm types).

If the MAF is from an '85 it is a frequency MAF and will need to be read with a scope or a DVM that can measure/display frequency.

RBob.

 

Rbob, the info I have states that all 2.8L MAFs are of the film frequency style.

 

Also, we use the '302 ecm... not the '165

 

I just need to test it. Does film frequency style matter? Can I still test it, just a different way?

Its already inline in the intake, so I can just start car n test it. No need to use the "mrs" (like I have one )vac. Anyways, got a HUGE wetdry vac, I can get some airflow

 

ill trade you a junk one for that mystery one.

 

Ack, yes, lb8, not lb9. What was I thinking (i was seeing lb9)?

With a frequency MAF it becomes a little more difficult. A scope would be best, but a freq counter or a DVM with a frequency counter function should also work.

Need +12 v on A, ground on C, and signal out on B. The signal out will probably be low frequency. In the range of 10Hz through 150Hz with a 5V amplitude. I can't guarantee this but is typical of the low freq MAFs of that period.

Lower freq at lower airflow. No burn off so that is easy. Yep, shop vac will work.

RBob.

 

Yep... it's calibrated from 32hz-150hz... not sure if that's hz or Khz, though... I think it's simple hz.