MaxxForce 7 MODs

[Big Dreamer]

Originally Posted by jacob11379

You will have multiple issues. Pressure and temperature issues.

So how do you know? Have you tried it?
Normal operating both the temp and pressure sensors will read pretty much the same with a clean dpf. Difference in pressure or clogged dpf is what signals a regen. Temps should be a little higher on outlet side if cat is working properly and I would leave that alone. If you have no restriction it shouldn't trigger a regen.

[jacob11379]

Originally Posted by Big Dreamer

So how do you know? Have you tried it?
Normal operating both the temp and pressure sensors will read pretty much the same with a clean dpf. Difference in pressure or clogged dpf is what signals a regen. Temps should be a little higher on outlet side if cat is working properly and I would leave that alone. If you have no restriction it shouldn't trigger a regen.

I took coach in and they said it had a plugged DPF based on what their reader was saying from my sensors. But it also through the regen right when i pulled into their lot and they didnt drive it.

I took it and went on a 3 hour trip, regen went away as soon as I left their shop and didnt come back.

But I just pulled it, and the cat and pressure washed them. with them out I started the coach and DAMN does it sound so much better. not like an exhaust noise but I can hear the turbo and everything sounds free. No codes thrown so i took it around the block.

engine light came on as soon as I got to higher RPM in first or second. I cleared it numerous times to get back home as I have a steep driveway.

Throwing a code 3251 everytime.

Now I left all the sensors attached to plugs, just hung them up. pressure sensor just disconnected from DPF.

SO now im gonna try to put in cat and see what happens when I drive after that. Or maybe ill do that tomorrow....

[jacob11379]

I put the cat back and hooked up all the sensors but left the DPF out. Got the same code as soon as I got some RPM in first gear 3251

[Dennis_K]

The code list I found lists the following for 3251.

SPN FMI
3251 0 DPF Pressure Out of Range Very High
3251 20 DOC Inlet Pressure Sensor - Not Plausible
3251 21 DOC Inlet / Outlet Pressure Not Plausible

Without the sensors connected the last two faults seem logical.

[jacob11379]

Originally Posted by Dennis_K

The code list I found lists the following for 3251.

SPN FMI
3251 0 DPF Pressure Out of Range Very High
3251 20 DOC Inlet Pressure Sensor - Not Plausible
3251 21 DOC Inlet / Outlet Pressure Not Plausible

Without the sensors connected the last two faults seem logical.

It was showing a 3251 1....I didnt think the extra 1 was part of the code.

But regardless, the 3251 is clearing leading to a pressure sensor code issue. There does not appear to be a way around the DPF removal.

I took it to a mechanic shop I do a lot of business with. They put it in a degreaser "helm" of sorts and tried to further clean it. Then we blow it out for ever trying to get out the water.

I'll be putting it back today and see what happens. Cant say I'm confident itll make much difference but I'm hopeful. With the DPF out and everytime I would clear the code the coach would jump forward with power for about 5 seconds then code and limit power. So I know the coach has the ability, just being held back.

Thank you for your efforts on code...

[CampDaven]

Well, something ain’t right and the motor ain’t happy.
Best of luck

[jacob11379]

Put it all back together. Cant say I could tell much of a difference.

Guess well find out next trip or when I take it back to the shop which is coming up.

[Big Dreamer]

Hi, I don't know if you have seen this before so I thought I would pass it along. Better than most instructions I have seen.
https://www.tallmangroup.ca/--how-to...d-regeneration

i think most posts I have read regarding regen said you need to start at operating temp. They say stay below 170 F.

[Big Dreamer]

Not sure if completely applicable however looks like some pretty good information.
http://help.dieselsolutions.com/inde...achment/14/360

And I think I posted this one before... not sure
http://navistar.kmsihosting.com/ihtm...load/12423.pdf

And some codes, remove first or last number?
http://hnctruckparts.com/service-inf...ble-code-index

[Dennis_K]

On my DIESEL PARTICULATE FILTER for 2010 & LATER MAXXFORCE ENGINES flyer it states the following:

• The DPF lamp must be on.
• Engine is running.
• Engine temp 170º F. or greater.
• Transmission in neutral.
• Park brake is applied.
• Throttle in idle position.
• Foot brake pedal is not applied.

[Big Dreamer]

More info

http://www.navistarlearning.com/dotn...ntent_id=15129

[markulmer]

Originally Posted by Big Dreamer

More info



http://www.navistarlearning.com/dotn...ntent_id=15129

Thanks for posting these.

[Big Dreamer]

I can't do it while I'm traveling and I want a scanner I know works before I try anything, ( I think my previous employer has software in that year as they were to cheap to update it after however I digress).
I would like to find a couple v band flanges the correct size and build a pipe to put in place of the dpf, or acquire a core for a way more affordable price than $1500. I have seen medium duty truck and school bus forums where guys claim they have pounded out holes in the dpf and reinstalled with no ill effects. I just can't see myself destroying something worth $2500
Removing it and running it without a pipe I can see front pressure sensor reading something and rear one reading nothing and ecm not agreeing. Also it looks like 3 EGT sensors and without at least a pipe in there the last one will read ambient temperature and I'm sure that would mess the ECM up.
My theory is if pressure and temperature sensors are still in the loop it shouldn't call for regen. You might not get the extra hp and torque the ecm programmers claim but... and I haven't studied egr in depth yet to have a theory on that.

[Big Dreamer]

Stumbled onto this..
https://www.ebay.com/itm/DPF-emulato...EAAOSwrslaWCZw