Maf sensor maxing out even with FCD?

[azian6er]

Hey all, quick Q for the guru's that I am kinda clueless about.

I am getting spark/fuel cut at low temps at like 13 psi when it is kinda chilly out here... only thing is, i am running an fcd as well so I dont really know what is going on.

I cant decide wether:

A.) the maf is just like "**** this s***" i dont care if you have a defender, im still gonna max out,

or

B.) Something else is happening...

I am assuming the FCD just clamps the maf voltage to a certain amount of air flow, so say a stock maf msp woulf hit cut at 10 psi on a chilly day, then add the fcd, and then wouldnt hit it unless you ran like 18 psi or something...

What i am wondering is, is my maf just maxxing out even with the fcd? Are there ANY other ways to be able to flow more air through it without getting a piggy/ems?

My car is doing just fine with the extra injector setup, the last hurdle i need to conquer is this pesky maf cut at like 13-14 psi for me.

ANy body have suggestions? Is there any other maf we can use in place of ours, like a gm maf and translator? or is this just really not an option for our cars?

Thanks all

-Bryan

 

[BlkZoomZoom]

You are pushing enough air through the Maf that even with the resistor in line the pcm is seeing 5v's. Find out what size resistor is built in the fcd and replace it with a bigger one (small increments) until it stops. I had to do the same thing before I got the mpi.

 

[CWiLL]

why not try to do a set up like the dsm's (gm blow through mass air and maf translator to tune it)?

 

[azian6er]

You are pushing enough air through the Maf that even with the resistor in line the pcm is seeing 5v's. Find out what size resistor is built in the fcd and replace it with a bigger one (small increments) until it stops. I had to do the same thing before I got the mpi.

is there a way to check the resistance with an ohm meter fom wire to wire? or do i need to contsact Joe P., aka the man?

How would i test the resistance of the unit? (sorry i am not to keen with electronics )

Also, what size resistor did you find necessary before you went mpi?



CWill--- about the maf translator... i think they have to be pre calibrated for your specific MAF sensor, so they were only produced for the mitsubishi crowd (they get everything easy...)

Bryan

 

[Bigg Tim]

Blkzoom hit it, the ECU is still probably seeing 5v. See if you can get someone to ride with you and meter pin#88 to see what the highest voltage is. If you are getting 5v, then you need a larger resistor.

 

[wicked]

Blkzoom hit it, the ECU is still probably seeing 5v. See if you can get someone to ride with you and meter pin#88 to see what the highest voltage is. If you are getting 5v, then you need a larger resistor.

yup.

I always see this s*** to late,atleast you guys are on top of it.

 

[azian6er]

i received this answer from joe p:


"Honestly, when I designed the FCD I figured it would be good for the "stock" guys and
even said then once you get past that, you should have some kind of engine management and
would not need an FCD. Adding more resistance will throw a CEL if you have it inline and
will make it hesitate badly if you use a switch (like the one on the FCD). You really
should go with some type of engine management at this point to keep the CEL off and such.
With OBD2 cars, there is only so much "tricking" you can do before it throws a CEL
unfortunately. I'll dig up my paperwork though and see what resistance I used- I really
can't remember off the top of my head.
Joe
Joe P. Manual Boost Controllers"

SO ... what do you guys think? What type of resistor would i need to splice into the maf wire? Any ideas? I really have no clue but would like to investigate this a bit further. How do i test the resistance of the resistor in the fcd?

thanks again

-Bryan

 

[Bigg Tim]

i received this answer from joe p:


"Honestly, when I designed the FCD I figured it would be good for the "stock" guys and
even said then once you get past that, you should have some kind of engine management and
would not need an FCD. Adding more resistance will throw a CEL if you have it inline and
will make it hesitate badly if you use a switch (like the one on the FCD). You really
should go with some type of engine management at this point to keep the CEL off and such.
With OBD2 cars, there is only so much "tricking" you can do before it throws a CEL
unfortunately. I'll dig up my paperwork though and see what resistance I used- I really
can't remember off the top of my head.
Joe
Joe P. Manual Boost Controllers"

SO ... what do you guys think? What type of resistor would i need to splice into the maf wire? Any ideas? I really have no clue but would like to investigate this a bit further. How do i test the resistance of the resistor in the fcd?

thanks again

-Bryan

Look at the colors of the stripes on the resistor and go here: http://www.ealnet.com/m-eal/resistor/resistor.htm and put in the colors and it will tell you what resistance the resistor is.

 

[BlkZoomZoom]

i received this answer from joe p:


"Honestly, when I designed the FCD I figured it would be good for the "stock" guys and
even said then once you get past that, you should have some kind of engine management and
would not need an FCD. Adding more resistance will throw a CEL if you have it inline and
will make it hesitate badly if you use a switch (like the one on the FCD). You really
should go with some type of engine management at this point to keep the CEL off and such.
With OBD2 cars, there is only so much "tricking" you can do before it throws a CEL
unfortunately. I'll dig up my paperwork though and see what resistance I used- I really
can't remember off the top of my head.
Joe
Joe P. Manual Boost Controllers"

SO ... what do you guys think? What type of resistor would i need to splice into the maf wire? Any ideas? I really have no clue but would like to investigate this a bit further. How do i test the resistance of the resistor in the fcd?

thanks again

-Bryan

I still have mine with the other resistor in it. I will look around for it. I didn't have to go up much, but I did need to activate when it came on. I had to set it to come on at a higher boost pressure.

 

[azian6er]

i did the resistor change to no avail. The stock resistor in the fcd was 62K ohms and i added a 10K ohm resistor in parallel and the cut still happened.

Im gonna try a fm voltage clamp and see if that works. If my understanding of the clamp is correct, it will

-Bryan

 

[MazdaSpeedTurbo]

wouldnt getting EMS finish one of the greatest MSP's? why not go for it all and get EMS everyone on these boards have probably followed the story behind your car i am surprised you havent got a EMS to this point and have been running a FCD.

 

[azian6er]

wouldnt getting EMS finish one of the greatest MSP's? why not go for it all and get EMS everyone on these boards have probably followed the story behind your car i am surprised you havent got a EMS to this point and have been running a FCD.

yes it would BUT who says this wont work? I am a pioneer and I love to experiment with things. I really think this will be fine. Everyone worries sooo much about timing but hey, look at the dsm's. They can run a larger maf/translator, afc and larger injectors and bigger turbo and not even think about timing. Our stock ecu is good and I am attempting to show people this.

The voltage clamp will work fine, and anyways, if it doesnt, i will be picking up an mpi and finishing it that way.

Have faith all.

I have been teling people that gtting a new turbo and a fuel pump is ALL that the msp needed from the factory to run good. Eveyone is like blak blah you NEED management. NOT TRUE period. Gt28 and a fuel pump/fmic and the car runs stoich.

-Bryan

 

[Dexter]

bryan,
add the resistor in series. parellel resistance adds up differently.

 

[never Ender]

I have been teling people that gtting a new turbo and a fuel pump is ALL that the msp needed from the factory to run good. Eveyone is like blak blah you NEED management. NOT TRUE period. Gt28 and a fuel pump/fmic and the car runs stoich.

-Bryan

this coming from someone who used to say the opposite back then? (encourage

-discreetspeed

 

[Dexter]

62+10ohm in parallel = 8.6 ohms.

 

[azian6er]

62+10ohm in parallel = 8.6 ohms.

but fuel cut was at the same point as before. If I lowered the resistance then the fuel cut should have been earlier than before.

Parallel is in a line correct like: ----O---- -----O---- ?

and series: -----O-----
..............|...............|
...............-----O-----
?
-Bryan

 

[azian6er]

i just looked it up, and yes i meant that i did it is series with the 10K ohm resistor in place. Still didnt work. Gonna use the fm clamp

-Bryan

 

[Dexter]

series is ine line , one after another. parallel is ...well...parallel...

   -----|---/\/\/----|--------
	|	     |
	|---/\/\/----|

 

[BlkZoomZoom]

I agree with the stock ecu doing a good job. However I do not agree with that on your application. If you didn't have to trick the pcm to see a different airflow value than I don't think it would matter too much. But you do. On top of that you don't know what voltage in the end your pcm is seeing.
While with alittle more diagnoising you could easily still use the fcd w/ more resistance, I think something like the clamp would work better for you. I assume the "clamp" goes inline of the Maf signal and once a certain voltage level is achieved it "clamps" it there so it won't go any higher, no matter how high the inlet voltage goes. If this is the case go for it.
I would check what the timing is though. You may find that you could get some power out of the motor.

 

[wicked]

can he just find a clamping diode that would work?