Maxing out Maf sensor
 

Just curious when I have to worry about maxing out my MAF? What do I do to fix it? Thanks

Re: Maxing out Maf sensor
 

Mine is maxing it shortly before shiftpoint now at the current power level.

Rog

Re: Maxing out Maf sensor
 

Most supercharged cars will max out the MAF pretty easy, the best way I have found to fix the problem is to tune the PE tables with a wideband. They sell something that is called a MAF Massager that is supposed to keep the MAF from maxing out but I dont have much experience on it nor have I researched it. Rich Krause told me about the PE tables and I took his word for it, he's a pretty knowledgable guy.

Re: Maxing out Maf sensor
 

The MAF massager doesnt prevent the MAF from maxing out, all it does is keep the code from being triggered so you dont get a SES light.

Re: Maxing out Maf sensor
 

If you have the OBDI, which you both have for 94 and 95, all you do is tune for it in the PE. You will still max out the MAF and it may throw a code, but nothing else will happen as long as you tune for it. Then just turned off the MAF code with your program. OBDII will be a different issue.

cheers

Re: Maxing out Maf sensor
 

Is there an aftermarket MAF that doesnt max out? Is tuning the PE tables more of a band-aid than a fix. I would think if you are maxing out the MAF and still pushing more air it wont add the additional fuel past the max reading on the MAF

Re: Maxing out Maf sensor
 

You will not max out the MAF at part throttle cruising, the only time you will max out the MAF is during full throttle high RPM driving. At WOT the PCM adds fuel according to the PE tables, during part throttle cruising and idle fuel is still added as required by the MAF and O2 sensors.

Re: Maxing out Maf sensor
 

That is absolutely incorrect for WOT, The PCM uses the MAF at all times. The PE table is just a % of fuel added per RPM cell. If the PE tables were the only thing used at WOT then we wouldn't be having this problem with the MAF maxing, the PCM wouldn't care.

After the MAF maxes the PE table is the only thing left for fuel enrichment, and should be used exclusively at this point.

Re: Maxing out Maf sensor
 

Did anyone ever get the pro-m maf to work? The pro-m was supposed to read over 900 gps.

Re: Maxing out Maf sensor
 

You can get the stock MAF to do the same, just need a frequency divider circuit. My friend and I have designed a circuit from readily available sources on the internet (just search for freq divider) but that is as far as we have went. My friend is just thinking of going MegaSquirt and doing away with the MAF.

Dividing the MAF freq in half or a third would require some retuning, possibly just a change in the injector constant to give the car more fuel for the less air it thinks it's getting. The circuit is not real complicated, If I remember right it just uses a 555 chip and a few resistors.

Re: Maxing out Maf sensor
 

We have a communication error, I didn't mean that the MAF was not used, only that once it is maxed it no longer has useful input and the PE tables must be used to compensate.

Re: Maxing out Maf sensor
 

That is absolutely correct ;)

Re: Maxing out Maf sensor
 

Interesting. Let me know how it turns out.

You know of anyone else thats tried this?

Later

Re: Maxing out Maf sensor
 

You will have an issue with the 555 being stable in an under the hood environment (freq shift with temperature gradients).


Another issue is that the hot wire can only sense so much so even with freq division it is still capped. (Both in terms of freq output and accurate range) If the snsor only puts out 11.6khz max at 500something gms, you will still be limited to maxfreq/2

The best approach is to do kinda like we have to do on the Mustangs. Have a much larger sensor calibrated for the stock lookup of freq vs airflow but halve the airflow. Now double the physical size of the injectors. This is all in an effort to reduce calculation accuracy issues in the PCM

Re: Maxing out Maf sensor
 

or take two mafs run them in parallel.. add the frequencies together then divide by two.

As stated, just dividing the signal by 2 on a single maf wont work, because the actual maf is not accurate above a certain level.