CM871 poor power and fuel econ

[Grounded Pilot]

(07-19-2022 )Rawze Wrote:  ...
Welcome to the bad delete club!.

This is the typical hack-n-slash garbage-can delete where some complete moron thinks that if they do as little as possible and only block codes, then jack with the turbo to try to make it run better.. and hope there is magic fairy-dust leprechauns inside the the ecm that will make everything all better. -- What a damn mess this one is.. is all I can say.

Thank you Rawze, that gives me a point to start and to pitch to the truck owner. That is pretty much what I expected to hear, not that I knew what the issues would be but that is was done improperly. With the lack of traceable history and the way this thing has been cobbled up in other places, I didn’t expect the Ecm work to be any better. Im open to suggestions on how to right the ship?? I’m working through the Cal/Insite programs and learning, but it’s a heck of a steep learning curve! Lol!

[Rawze]

(07-20-2022 )Grounded Pilot Wrote:  

(07-19-2022 )Rawze Wrote:  ...
Welcome to the bad delete club!.

This is the typical hack-n-slash garbage-can delete where some complete moron thinks that if they do as little as possible and only block codes, then jack with the turbo to try to make it run better.. and hope there is magic fairy-dust leprechauns inside the the ecm that will make everything all better. -- What a damn mess this one is.. is all I can say.

Thank you Rawze, that gives me a point to start and to pitch to the truck owner. That is pretty much what I expected to hear, not that I knew what the issues would be but that is was done improperly. With the lack of traceable history and the way this thing has been cobbled up in other places, I didn’t expect the Ecm work to be any better. Im open to suggestions on how to right the ship?? I’m working through the Cal/Insite programs and learning, but it’s a heck of a steep learning curve! Lol!

if you can copy the program out.. you can put it back in. - Meaning you can fix it yourself...
here is what it takes in detail: http://rawze.com/forums/showthread.php?t...5#pid58675

[Grounded Pilot]

Man, my hats off to you guys here on the forum and Mr Rawze!! Finally got it headed in the right direction I believe. This thing runs so different! Everything is more smooth, acceleration feels much better and shifts seem easier(maybe in my head, maybe because the motor is less erratic). I did 6.7mpg (paper figures) from fill to fill on a 110 mile leg running north on I35 through Witchita, KS at about 59k lbs and 73/76 mph!! This thing has never averaged over 6mpg with any sort of load on it. Was getting 7.3mpg on the dash after getting up to speed up until I was exiting to hit the TS.

Thank you all for the help!!

[Rawze]

(07-31-2022 )Grounded Pilot Wrote:  Man, my hats off to you guys here on the forum and Mr Rawze!! Finally got it headed in the right direction I believe. This thing runs so different! Everything is more smooth, acceleration feels much better and shifts seem easier(maybe in my head, maybe because the motor is less erratic). I did 6.7mpg (paper figures) from fill to fill on a 110 mile leg running north on I35 through Witchita, KS at about 59k lbs and 73/76 mph!! This thing has never averaged over 6mpg with any sort of load on it. Was getting 7.3mpg on the dash after getting up to speed up until I was exiting to hit the TS.

Thank you all for the help!!

Now all you have to do is learn to slow down and keep your foot out of it. 70+ mph with a class-8 truck is dangerous and wastes fuel like mad. It also beats the h$ell out of the truck over time, increasing all operating costs.

-- Learn to drive it and deliver your loads at 63 mph + limit boost to about 20-psi up the hills, and you will get into the mid-to-high 7's.. That is where the real money is at.

[Grounded Pilot]

(08-01-2022 )Rawze Wrote:  Now all you have to do is learn to slow down and keep your foot out of it. 70+ mph with a class-8 truck is dangerous and wastes fuel like mad. It also beats the h$ell out of the truck over time, increasing all operating costs.

-- Learn to drive it and deliver your loads at 63 mph + limit boost to about 20-psi up the hills, and you will get into the mid-to-high 7's.. That is where the real money is at.

Hey now!! Let’s not go talkin crazy!! Lol!! My name is grounded pilot because I was a crop duster pilot until I had heart surgery. I used to dodge trees, towers, wind turbines, power lines (most of those anyway….), and whatever else could be in my way at 10-15ft above ground level while running 150mph!! :) Also, I drove modified dirt track cars, have a ‘71 Chevy pickup drag racer, and just for good measure I have had a couple derby cars!! LOL!!

All that being said, I do normally run closer to 65 mph. This thing used to like 67 and 71.5mph best for fuel Econ. Needed to save some time yesterday so I was running the speed limits.

[Rawze]

I have always bneen a heavy advocate on slowing down and keeping more money .. rather than "keeping up with the rest of the idiots" in the roadways ...

you need to throw all that in the garbage can. trucking is all about taking home the bacon.. not the glory. Don't be the fool that funds these guys private islands for fun...

[Grounded Pilot]

I need advise on a new but recurring issue. With a couple of you guys guiding me along, the programming has been rectified and the truck has run a ton better!! Like almost 2mpg average better!! Thank you to all for that!! But it has went back to rough idle and starts up hard and has a very bad idle rhythm when it fires. Checked injectors 2 weekends ago and had one fail the “bubble” leak test on the rear bank. All 6 injectors were replaced in the last 9 months. The oldest being #6. Thought maybe I got a bad injector or maybe the ongoing problems had hurt it. Ordered a new injector and was going to change it this weekend. Got home this evening and got the truck in the shop and started checking to see exactly which injector was bad. But figured I’d recheck both banks. Now I have injectors blowing bubbles on both banks. The oldest injector in the front bank is 6 months and I run roughly 8,000 miles a month.

My questions are:
Is it possible I damaged injectors in both banks that quick?

Or got 2+ defective injectors from the factory?

Or do I have a head issue?

[Rawze]

(09-17-2022 )Grounded Pilot Wrote:  ...
My questions are:
Is it possible I damaged injectors in both banks that quick?

Or got 2+ defective injectors from the factory?

Or do I have a head issue?

on a Cm570, 870, or 871, always adjust the overhead valves + set the proper torque on the injectors before doing an injector leak test to prevent false positives.

[Grounded Pilot]

(09-17-2022 )Rawze Wrote:  

(09-17-2022 )Grounded Pilot Wrote:  ...
My questions are:
Is it possible I damaged injectors in both banks that quick?

Or got 2+ defective injectors from the factory?

Or do I have a head issue?

on a Cm570, 870, or 871, always adjust the overhead valves + set the proper torque on the injectors before doing an injector leak test to prevent false positives.

I re ran the overhead and everything was within tolerances. Re ran the leak test and still getting bubbles. #1 & 2 on the front bank. Haven’t switched to the rear bank again but will in a bit, had to run in town and take care of some things quick. I’m assuming I’ll get bubbles there as well. So back to square one as to why I have 3+ injectors bad in under 9 months?