CM870 tuning

[DCtruckin]

I am looking for some input on having my cm870 tuned. I own a 2005 Peterbilt, I de mandated the egr when I put on a new vgt P/N 2881994RX, but egr still all in tact, I put the block off plate right behind it. CPL 8520 its a recon long block with about 80k miles on it. I am not looking for a "high power" tune, maybe bump it up to a safe level? looking for better driveability I do a lot of local in town stop and go driving, never loaded more than 90k. And most definately looking for longevity. Seams to be kind of sluggish going through the gears stop light to stop light, but still manages to get up and go to highway speeds just fine. It feels "jerky" through the gears if your not really smooth about acceleration. Not sure whatsoever if it has ever been tuned or not. The truck never gets above 850-860 on the pyro, boost is 30psi. CEL is always on since I blocked off the egr. Has an intake manifold and {garbage} fuel pressure harness. Working on getting a laptop, nexiq 2, and team viewer. any info i can get about this is appreciated, thanks.

[Pigpen 2869]

Get with Running Rough. He does the 870’s. Throw the fuel harness in the trash

[DCtruckin]

(01-13-2024 )Pigpen 2869 Wrote:  Get with Running Rough. He does the 870’s. Throw the fuel harness in the trash

Ok will do. I’ve heard mixed reviews on the harness. I’ve left it on 0 the last several months.

[Rawze]

(01-13-2024 )DCtruckin Wrote:  

(01-13-2024 )Pigpen 2869 Wrote:  Get with Running Rough. He does the 870’s. Throw the fuel harness in the trash

Ok will do. I’ve heard mixed reviews on the harness. I’ve left it on 0 the last several months.

STOP READING THE CRAP YOU SEE ... MOST PEOPLE ARE COMPLETELY BEYOND DAMN CLUELESS!.. AND WOULD BUY THE MOST STUPID THINGS OUT THERE!!> AND FOR EVERY GARBAGE PRODUCT.. THERE WILL ALWAYS BE BUNCH OF COMPLETELY CLUELESS IDIOTS OUT THERE SWEARING AND RAVING ABOUT THAT CRAP!!>


Those things are beyond horrible and absolutely cause progressive engine damage. THAT CM870 ENGINE IS NOT An old 1980'S BIG-CAM!!!, WHERE YOU CAN THROW FUEL INTO IT AND IT NOT CAUSE DAMAGE!

Also, the fuel pressure is mechanically regulated in the CM870. so those 'fuel pressure harness' garbage devices are NOT going to actually change the fuel pressure itself. They fool the fuel pressure sensor into reading low .. effectively making the ecm not only give up fuel that it does not know about (bad enough), .. but it also throws off the injection timing quite badly at the same time, causing harm and damage over time to the cylinders due to loss of friction control by the ecm. It also destroys engine cylinder balancing as well, because the damn ecm thinks the injector are all leaking fuel (and over-fuelling) all the time and slams the cylinder balancing data against its lower limits to try to correct this, . rendering it useless.

Not only that,.. but since the ecm cannot account for the fuel qty into the cylinders any more properly, it also makes the fuel mileage readings in the dash read higher than normal... fooling the driver into thinking they have gained something.. when in fact it is causing harm instead.

The result is an eventual dropped liner or perhaps a cracked valve seat, and/or all the other problems associated with bad injection timing and over fueling on a modern ISX engine. It is no better than a really bad delete program!.

Like others have said.. throw it in the trash and chok it up as stupidity for even trying it.

=============

Also.. there is no need for a block plate on a CM870. The valve closes against the exhaust flow unlike newer model engines. Simply unplugging the EGR temperature sensor on the intake will put the engine into its proper non-egr engine operating mode, and closes this in turn closes the valve for you.

and yeah.. for a CM870 .. forum member 'running rough' is 100% trustworthy with CM870's specifically. I have seen his work plenty of times. He knows all of their quirks inside and out + knows how to edit all the ram memory settings properly.. unlike most of these other garbage delete clowns out there.

[DCtruckin]

(01-13-2024 )Rawze Wrote:  ...
and yeah.. for a CM870 .. forum member 'running rough' is 100% trustworthy with CM870's specifically. I have seen his work plenty of times. He knows all of their quirks inside and out + knows how to edit all the ram memory settings properly.. unlike most of these other garbage delete clowns out there.

I do appreciate the cold hard truth on this! I will remove that harness asap. I’m still learning these motors… and that’s why I came here! I will pm running rough and see if he is able to help me out.

[DCtruckin]

Also forgot to mention along with my good EGT temps and boost, the truck consistently averages 5.7-5.8 mpg also

[tree98]

Your boost and pyro are both too low. While low boost isn't really harmful, it's just a waste of fuel. The low EGT's could point to trapped heat and higher than normal coolant/oil temp. You need to get this straightened out properly and then you can brag about fuel mileage lol.

[DCtruckin]

(01-15-2024 )tree98 Wrote:  Your boost and pyro are both too low. While low boost isn't really harmful, it's just a waste of fuel. The low EGT's could point to trapped heat and higher than normal coolant/oil temp. You need to get this straightened out properly and then you can brag about fuel mileage lol.

Copy that, good to know. Put in a call to Running Rough today, he’s going to help me get sorted through this and get the truck dialed in!

[DCtruckin]

I’m having a hard time finding a genuine NexIQ 2. Im finding the 3 pretty easy but looking for a 2. Anyone point me to one?