Low MAF readings

[mjbrox]

My MAF is reading between 0.01 and 0.08 lb/min. Sometimes it will get as high as 1.0 but only for a moment


I have tried diffrent MAFs and i did have a tear in the boot but I replaced it and that has not changed anything.


What else can i check?

 

[mjbrox]

i am still getting low MAF readings and I think it could be contributing to my issue of not reving past 3K when hot.

 

[mjbrox]

I have confirmed that I have continuity from the MAF back to the Computer and a good ground

Also, when I put my hand on the intake and rev the motor it feels strong.

Finally, I have even run a back up computer.

 

[mjbrox]

apparently i have encountered something new

 

[discostew]

I've never seen mass air flow readings in lbs per min. What code are you getting? it's usually measured in grams per second.

 

[WaltNYC]

is the o-ring between the airbox outlet and the hose to the MAF in place?

 

[mjbrox]

is the o-ring between the airbox outlet and the hose to the MAF in place?

No, but i dont know how that would affect the MAF if its before the MAF. Or am i missing something?

 

[bgbrox]

No, but i dont know how that would affect the MAF if its before the MAF. Or am i missing something?

Swapping between my truck and yours, you ruled out air box/filter, o-ring, MAF and ECU.

The low voltage MAF reading happens on different MAFs.

 

[mjbrox]

The low voltage MAF reading happens on different MAFs.

Yes, I get the same readings

 

[mjbrox]

Okay, so update on this.....

I had the cats checked and the shop said they where clogged. So I ordered new cats and did my head gasket as well since it was due and I did not want to contaminate new cats. Before the HG job I did a compression test on all 8 cylinders that looked good.

Every plug was was inspected and treated with DEOXIT Gold.

I got it all back together and was initially running rich because did not hook the Fuel pressure regulator to vacuum. Once that was resolved the truck was running better than it did before I started but after driving for 20 mins, its back to not reving past 3k.

 

[WaltNYC]

Is there a difference in behavior between in gear travelling down the road and in park? Will it rev past 3k in park?

 

[mjbrox]

Is there a difference in behavior between in gear travelling down the road and in park? Will it rev past 3k in park?

Its revs are limited in park

 

[WaltNYC]

If it is the 1996 D1 I'd re-flash the ECU (even though you already ran a back up without a change), just to know you are starting from a 'clean' base tune.

How are you measuring low voltage from the MAF? Is it throwing a code? Check out the gems_obd document in the D1 section of the google drive to see the threshold voltage readings (at the ECU). Page 71

gems_obd: gems_obd document

all of RAVE: RAVE in pdf

Other things to look at...
EVAP system. Pre-AEL or AEL? Purge valve?

Fuel pump and fuel filter.

 

[mjbrox]

How are you measuring low voltage from the MAF? Is it throwing a code? Check out the gems_obd document in the D1 section of the google drive to see the threshold voltage readings (at the ECU). Page 71

I am reading it on my OBD2 reader.

I have checked fuel pressure when the truck is cold and Hot.