• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

Maxing out the MAF what are the symptoms

2barxr

2barxr

Member
Joined
Sep 3, 2015
Location
Fallbrook
Hi all I believe I am maxing out the MAF I just want to confirm that.

Car runs strong I get to around 12-15 PSI WOT and then it will fall on its face I believe fuel cut until the RPM drop then it will come back.

AFR go down to 9.8 at full song so I do not believe lack of fuel at this point

car is chipped and I am not close to the redline ported head Do 88 intercooler IPD turbo cam stock MAF and injectors 19/20T BB/STS turbo "may be the issues" 15G didn't do this as bad

any input would be appreciated.

Note. I do plan to get a stage 2 chip and run the larger MAF and injectors just want to bake sure there is not something else going on
 
Last edited:
Can't remember if LH2.4 has a max injector pulse width/duty cycle set. AFR is so rich that I wouldn't be surprised if fuel cut is because of that. Also that much fuel could and would cause ignition problems with a stock system.
 
You are probably just maxing the flow through the MAF, causing it to go over 5V, which causes a fuel cut. But you are way too rich, not good for your engine. Your oil probably stinks of gas and causing premature wear.
 
I had chips which removed the fuel cut. I always thought when it bogged down like yours it was due to too much fuel. The ECU seemed to just dump all the fuel in at a certain point.
Tried all the tricks on here to alleviate problem including a potentiometer which I think reduced the signal from the MAF to the ECU. This worked at WOT but gave equally unacceptable hunting at lower revs/idle.
Eventually cured it by getting a Speeduino, which I did not want to do but has proved to be way better in many ways.
From the mods you have already done I think you will not be satisfied with the stock ECU with whatever chips for much longer, probably better to put your money towards an a/m ecu (and possibly fuel pump!) sooner rather than later.
Tim
 
2turbotoys said:
You are probably just maxing the flow through the MAF, causing it to go over 5V, which causes a fuel cut. But you are way too rich, not good for your engine. Your oil probably stinks of gas and causing premature wear.
Click to expand...
14.5-7 normal AFR it only goes down at WOT and around 12 psi @ 9.8-10.2 AFR 15 psi 10.5 -10.8.

i didn't have the issue as much with the 15G as I do now
 
K9 240 said:
I had chips which removed the fuel cut. I always thought when it bogged down like yours it was due to too much fuel. The ECU seemed to just dump all the fuel in at a certain point.
Tried all the tricks on here to alleviate problem including a potentiometer which I think reduced the signal from the MAF to the ECU. This worked at WOT but gave equally unacceptable hunting at lower revs/idle.
Eventually cured it by getting a Speeduino, which I did not want to do but has proved to be way better in many ways.
From the mods you have already done I think you will not be satisfied with the stock ECU with whatever chips for much longer, probably better to put your money towards an a/m ecu (and possibly fuel pump!) sooner rather than later.
Tim
Click to expand...
I will go aftermarket ECU at some point to help run the 8HP transmission.

i want to swap in but need to be able to get the car to pass California emissions every 2 years so i would like to play with the chip set a bit more before going down that road. i plan to get an ostrich to help tune it.
 
sbabbs said:
Spark blow out or collapsing rubber hose the air in hose connected to the turbo from the AMM. Colder spark plugs tighter gap. NGK8's..
Click to expand...
Thanks for the info man!
The air intake from maf to turbo inlet is all brand new piping with 2 new couplers.
I thought that it was spark blowout to. I dropped the gap, no change. So installed a msd 6al, seemed to maybe help a little bit.. but still cuts out at WOT. I've replaced the maf, 2 actually. I've got 2 954 ecus that I've tried. And 2 ezks I've tried as well.
 
Falling on face effect usually is the intake hose collapsing, the spark blow out effect is more of a pop, pop, pop no power. Did you put in NGK BPRES8's? 6 is stock, 7 is one colder, 8 is two colder. Then gap about 22. If you using other plugs the numbers and colder is backwards number wise so what plugs you got?

Other thing is with LH 2.4 you could possibly have your distributor turned one way to far so as the computer adjusts timing it can't spark cause your distributor is too far one way. That is a pop, pop, pop effect also. Here is a video of that.

<iframe width="560" height="315" src="
" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>

Here is rev out fixed that problem see?

<iframe width="560" height="315" src="
" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowfullscreen></iframe>
 
Last edited:
Thanks for the videos!
Yes I have ngk bpr7es plugs gapped at 23
Msd 6al box.
The issue that I am having doesn't sound like the car in the video.
(Which sounds lovely btw!)
Mine is like you are turning the ignition of and on when it does it.
it doesnt pop, it just violently jurks.
i have installed a walboro 255 fuel pump. Still no chnage.
i have a brand ne microsquirt and harness built for a b230.
im not ready to go that far yet. (Im still collecting parts)
i have confirmed that my max mass air flow sensor voltage is 4.43 volts when it starts bucking.
i have confirmed that the ignition signal is not being cut out.
also confirmed the fuel pump power is also not being cut neither.
i have swapped ecus, and ezks..
all grounds are perfect.
I have cleaned and tightened all connecter pins that I could think would help.
Maf,tps,ect,crank sensor,knock sensor, injectors
unfortunately chasing this issue I have replaced almost everything on my car.
Luckily I have 3 volvos.
I really appreciate yalls help! This car is not going to beat me!
 
Man I sure wish that was the case with mine.
Mines hard piped from air filter to turbo with the exception of 3 silicone couplers to place the maf in there. The way I have it all joined up, everything is pulled up end to end (the pipe) so that there is 0 chance of any couplers being able to collapse.
I'm stumped.
 
What I would do is turn the boost down to 6lbs and see if it does it then. The turn it back up a little at a time and see when it starts doing it. My buddies 940 was doing it and it was a vacuum leak, I could hear the boost hissing when it boosted and it was loose bolts holding the tps to the intake. So it could be a hole somewhere else between the turbo and motor. I have blown out intake manifold gaskets also...
 
You must log in or register to reply here.
Back
Top