Hi all,

Late 99 f350 7.3 c/c dually w/6631 mod and Edge Evo

I thank the people here who tried to help me with my MAT Sensor issue.

After looking and finding the MAT Sensor on the Spyder, it appears fine and the wiring as far as I can tell is ok as well.

I removed the Evo Tune from my truck and ran it in stock mode. What A Drag!!! any way, the code P1119-Manifold Air Temp Sensor High Output was listed again.

The truck seems to run fine, no problems at all.

I would like to know what is the function of the MAT Sensor, what would cause this, If it'll hurt the truck if left untreated, and how to fix it.

I can't afford to go to the stealership or anywhere else for that matter.

Thanks in Advance

John M T

 

Sorry to hear that John. I was hoping it was just a code set by the tuner. You did clear all the codes when you set it back to stock right?

Here's a description and some tests you can do to help isolate if it's a wiring or sensor problem.

Nevermind. It won't let me attach it again. Here's a link to the attachment I was going to give you. It's a pdf file called MAT.

https://www.ford-trucks.com/forums/7...ml#post5986487

 

Hey Chris,

Thanks for the Link, and that's a great PDF file,

I just posted a reply to you in that thread, if you take a look at
my reply and get back to me I'd appreciate that.



thanks in advance

John M T

 

Let's do it here so we don't confuse too many folks in the other thread.

1st Curtis (Pocket) is correct in his post when he replied to you. That fuzzy insulation hidden under the foil is there to keep the noise down only. When a sensor fails the PCM uses a default or inferred reading for that sensor instead of plugging in some value that will make the truck run bad.

I can't comment on Parklands post because I don't know what that word means.

I had to take some spaces out to get the pdf file to fit as an attachment so it's a little confusing. If you look under the Yes No box that tells you to go to DI2, you will see the next thing listed is
DI2 Induce opposite failure.

After the DI2 steps you'll find DI3. Sorry for the poor formatting on the attachment.

 

Is your gas mileage suffering? My MAT was bad and defaulted to some factory setting. I think it's only $30 bucks or so. I swapped a in new one and my truck actually picked up a little mileage that I had lost. I also relocated the IAT to the end of the 6637 where it should be. I noticed mine didn't like it hanging behind the MC like everyone says to do.

As far as troubleshooting goes. I work with wires and computer based stuff all day long. You gotta start somehwere if the wire looks good. Mine was good and it was doubtful that the PCM was bad so the sensor got changed. Cheap fix too.

I did all of my scanning with a Predator if that helps any...

 

Hey Chris,

thanks for staying with me on this, don't worry too much about the PDF formatting, after glaring at it for some time, I figured it out.

Thanks to John as well, btw where did you pick up the sensor, just in case I need one.

So here's the latest. after I removed the evo tune and ran it in stock, the code came back. yesterday I had to take the truck, I checked the codes before leaving and there were none. I drove about 8 miles, came back rechecked the codes and there were none in stock mode. Put the Evo tuner back in, under the same previous program and went for a ride.
Rechecked the codes and guess what, none, not even the common P0603

Now the only code reader I have is in the Edge Evo, maybe the Edge was wrong? As I said previously, all the wiring seems good, I believe that John's wiring was fine as well, but he replaced the sensor.

as far as checking the sensor with an ohm meter I know I use pin 1 & 2, but how do I set up the ohm meter? on which scale? could this be an intermittent problem? I don't think logically a sensor would be intermittent like that being it's electrical, but I don't know. I'm also going to put the IAC? sensor back into the 6631 mod.

BTW the truck ran great with and without the P1119 code, and I have no idea as to how long the code may have been there. I really don't check that often, maybe @ 3 month intervals.

Thanks in advance

John M T

 

Sensor was a dealer only item.

 

Stoic ratio is how lean or rich a fuel air ratio is. Or better said, it is the "right" mix for combustion in an engine. I think on gas engines its somewhere around 52% air 48% fuel vapour.

A diesel just takes all the air it wants, but if 48% were diesel fuel vapour, it would smoke and burn holes in pistons.

I'm not 100% sure how you measure "vapour", aboviously a gasoline engine dosnt have half the cylinder full of gasoline, It must mean the amount of fuel + air burned?

....

 

John. What settings do you have to choose from on your ohm meter? Maybe a setting of 200 or auto select?

Parkland: Gotcha. Perhaps the percentages are for the amounts being injected into the cylinder, not the cylinder volume?

 

"Stoich" or "stoic" is the shortened version of the full word stoichiometric. What a mouthful!! Here's some Wikipedia info for those....errr....interested.

Parkland, have you been spending late nights reading Gene's posts?

 

I print Genes post out and leave them on the wall, when I have a couple tall ones, i start reading.