I plan to hollow out a high-mileage DPF once my '08 rebuild is finished and use that as a stealth delete pipe. No inspections where I'm at, but I want to be able to pass a visual inspection if it ever happens.

 

The ECM will not perform a regen if the filter is not clogged, unless it has some kind of time period function that the ECM uses to force a regen regardless of the filter differential pressure.

But, aside from something such as a time based regen, the ECM will not perform a regen if the filter is bypassed becasue there is not pressure differential across the filter. No pressure differential means the filter is "clean".

Now the other issue, which is why tuners are needed, lies in that the ECM WANTS to see a pressure differential. If it reads 0 pressure differential all the time, it will throw some kind of filter inefficiency code, hence the tuner to tell the ECM that the DPF is always "clean", but still present.

Now whether the ECM only needs to see a constant differential or a variable differential, I don't know. There are may be of factors that take part for the ECM to monitor the filter.

If I was to "DIY" a delete, I would remove the differential pressure sensor and add some sort of electrical component to show a constant acceptable pressure that the ECM wants to see. You really have to know how the system works before tampering with it. It may be designed to be almost tamperproof.

 

They eventually will go into regen without a tuner and the regen won't stop because they won't be able to reach satisfactory EGTs to end the regen. So with a straight pipe and no tuner it can get stuck in regen mode.

 

I had heard that before, but wasn't positive.

It's weird, the commercial trucks I work on go by the differential pressure to determine when the regen is complete. It monitors temps along with pressure to adequately regen, but once the differential pressure is at a certain low pressure, it ends the regen.

You would think if the regen could not build heat, it would end the process and set a code, derate the engine or shut it down, and it would have to get repaired before putting back into service, not just keep on keepin on!

 

yeh, they put in a backup process in case the sensors fail..
if no pressure reading, it will FORCE a regen, and then they look for alternate completion signals as they can't trust the primaries.. and they throw a code as well (as I understand it, logical anyhow)

this regen is the one the tuner shuts off.. otherwise eventually the system will freak out and go to limp mode (as U suggest) cause it can't figure out what is wrong..

Sam

 

I'm also interested to know if anyone has tried a Spartan tuner leaving the exhaust stock and the DPF in place? I'm not willing to modify the hard parts that are still under warranty, and I can't afford to replace an engine myself. But if the Spartan operates the way they describe, it would be easy enough to restore the factory flash and remove the unit for maintenance. It would also be nice to have the extra temp gauges etc to monitor things.

Anyone installed a Spartan on a stock exhaust?

 

if you leave the DPF installed, you MUST regen to keep it clean, eventually
thus defeating the purpose of the Spartan to begin with..

sam

 

I am running the Spartan 150 DPF-on tune right now. The only reason I am running it is because I have not had the time to get my delete pipe installed. I wouldn't waste my time getting the Spartan if you are only going to run the DPF-on tunes, not that big of an improvement. Plus the shear cost of paying for 12 tunes when you can only use maybe 5 of them.

 

I'm sure that the fine folks at Spartan would argue the belief that the ONLY purpose of their tuner is to reprogram after the removal of the DPF.

If Ford thinks my truck needs a DPF to keep exhaust "clean" and for the motor run properly, fine I'll keep it for now, but that doesn't mean I don't think performance can't be improved even with stock parts. In the rest of the fuel injected world chips/tuners are often used to improve performance, provide more telemetry, improve mileage, changing shift points, etc on vehicles that are fully stock. Are you saying that this doesn't exist for a Ford F250?

 

in the older, pre-dpf days, lots of options were available. Unfortunately, in the DPF days we have now, things are different.

turn off regen, and eventually the DPF will fill and the exhaust will NOT FLOW..period..

and there are a LOT more interconnected parts, with finer margins than before.. replacing the air intake kits was cool before, and may cause problems now. more a delicate balance than before..

and at least on the 6.0, it appears there was less engine margin for the extra push these capabilities added (witness the number of head gasket failures)..

so, anyhow.. the risks seem higher, and the rewards seem lower than in the past. before 2005 I don't think I ever heard of a diesel not 'chipped'... chip is too primitive an approach now apparently, witness spartan et all that dump in new programs or program variables vs the plug in chip approach before..

I'm a newby diesel owner, but I see similar designs and design changes across my industry as well..

Sam

 

There's a user on another site who did just this, he was the first. His truck eventually went into constant regen and couldn't be driven. He worked with KEM for quite a while on the first tunes that eliminated the regen. Spartan and SCT came afterwords