Advertisement
If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Home Who's Online Today's Posts HP Calculator CompD Gift Shop Mark Forums Read
Go Back   Competition Diesel.Com - Bringing The BEST Together > Tech- General Diesel > General Diesel Tech
Register Members List Timeslips EFI Live Library Invite Your Friends FAQ Calendar Mark Forums Read

General Diesel Tech Farm equipment, Medium Duty, Big Rigs, and other General discussion can be found in here.

Closed Thread
 
Thread Tools
Old 02-09-2018, 10:19 PM   #21
Rig Wrench
 
Rig Wrench's Avatar

Name: Rig Wrench
Title: Wannabe Tech
Status: Not Here
Join Date: Jan 2016
Location: In the ditch
Member`s Gallery
Posts: 1,045
I almost guarantee his low boost hi egt is the cal. Almost every 870 that I see using the stock turbo does this woth the egr delete. When the tune is done it locks it in non egr mode. If you have a stock one and unplug the egr valve. It will do the same things. Often the tuner will put more fuel to it to try and overcome the lose pf power from the low boost, but it just runs hot then. Theres only a few people ive seen that can actually do the 870 right.could you havr the stock calibration put back in to try and see if it runs better?

Last edited by Rig Wrench; 02-09-2018 at 10:28 PM.
 
Old 02-09-2018, 11:00 PM   #22
Leiffi
 
Leiffi's Avatar

Name: Leiffi
Title: Too Much Time
Status: Not Here
Join Date: Jan 2013
Member`s Gallery
Posts: 1,381
Quote:
Originally Posted by allan5oh View Post
Does anyone know the max sustained get for the holset cm870 turbo?
EGT ? 760 celsius pre-turbo like any other turbo.
 
Old 02-09-2018, 11:04 PM   #23
Leiffi
 
Leiffi's Avatar

Name: Leiffi
Title: Too Much Time
Status: Not Here
Join Date: Jan 2013
Member`s Gallery
Posts: 1,381
High EGT at low load is actually good for fuel economy if it is because of VGT setting not pumping excess air to the engine. It might also be retarded timing to compensate lack of EGR which is not good.
 
Old 02-09-2018, 11:11 PM   #24
Ram12vcummins

Name: Ram12vcummins
Title: Too Much Time
Status: Not Here
Join Date: Mar 2015
Member`s Gallery
Posts: 1,659
Quote:
Originally Posted by Rig Wrench View Post
I almost guarantee his low boost hi egt is the cal. Almost every 870 that I see using the stock turbo does this woth the egr delete. When the tune is done it locks it in non egr mode. If you have a stock one and unplug the egr valve. It will do the same things. Often the tuner will put more fuel to it to try and overcome the lose pf power from the low boost, but it just runs hot then. Theres only a few people ive seen that can actually do the 870 right.could you havr the stock calibration put back in to try and see if it runs better?
I read this was a big issue. Was assured by the guy who removed diesel spec tune that his was a proper one and a few people vouched....not that it means they are right. The mechanic took the egr plug apart and ground out the contacts for some stupid reason instaead of just taping up the ends. I guess to look stock. The tuner assured he can tune it either way. I can try and see if we can go about trying out the factory tune. But how would that act with the egr deleted? I would also have to rejoin the wires which isn’t that big of a deal.

Quote:
Originally Posted by T-MAN View Post
This is why i asked about the boost, I had a cm870 after a head install that had crazy egts, narrow powerband and low boost. pressure tested cooler, tested boots vice grips on turbo actuator, timing on cams...ect drove me nuts. turns out the guys who put the head on used the ecm shoulder bolts in the ecm cooling plate and it was tight but wouldnt hold more them 25# of boost. The bolts topped out before sealing the plate to the head. Honest mistake but they walked away from it.... worth a look
I don’t understand how an ecm being bolted to a head causes this issue? Does the ecm seal off the intake?

Quote:
Originally Posted by Leiffi View Post
High EGT at low load is actually good for fuel economy if it is because of VGT setting not pumping excess air to the engine. It might also be retarded timing to compensate lack of EGR which is not good.


As I understand the guys who tune these improperly advance the timing to hide lose of power?


Sent from my iPad using Tapatalk Pro
 
Old 02-10-2018, 03:09 AM   #25
Leiffi
 
Leiffi's Avatar

Name: Leiffi
Title: Too Much Time
Status: Not Here
Join Date: Jan 2013
Member`s Gallery
Posts: 1,381
Quote:
Originally Posted by Ram12vcummins View Post
I read this was a big issue. Was assured by the guy who removed diesel spec tune that his was a proper one and a few people vouched....not that it means they are right. The mechanic took the egr plug apart and ground out the contacts for some stupid reason instaead of just taping up the ends. I guess to look stock. The tuner assured he can tune it either way. I can try and see if we can go about trying out the factory tune. But how would that act with the egr deleted? I would also have to rejoin the wires which isn’t that big of a deal.



I don’t understand how an ecm being bolted to a head causes this issue? Does the ecm seal off the intake?





As I understand the guys who tune these improperly advance the timing to hide lose of power?


Sent from my iPad using Tapatalk Pro
if they did it right, there would be no need to unplug the EGR, it should be done inside the software, just set EGR solenoid PWM to zero. I have heard many problems eith EGR deletes, one is that VGT control will close VGT completely and cause very high turbo speed and backpressure, turbo rpm control will limit overspeed. That is what PDI did and their solution was to raise turbo RPM limit which resulted in turbo explosion. They told customers that those VGT Holsets are just crap and they must buy their VGT delete kit.

Another problem after EGR delete is that ECM still tries to control NOx by retarding timing, that causes high EGT and high fuel consumption and possibly low power.

Needs a good tuner to realize and solve these problems but those tuners are very hard to find, most just wants your money and most get away with it because their customers dont understand engines.

I am not sure but I also believe that Cummins HPI system is not understood by tuners, it's like old PT system that most of the "gurus" dont understand even if they write articles about it for some magazines. Scania used same system in some of their engines and many of them failed after ECM tuning. I believe timing is overadvanced without them knowing when they add fuel to it.
 
Old 02-10-2018, 06:40 AM   #26
T-MAN
 
T-MAN's Avatar

Name: T-MAN
Title: misunderstood
Status: Not Here
Join Date: Sep 2008
Member`s Gallery
Posts: 352
Yes behind the ecm there is a huge window for a different style intake, only a rubber oring gasket and 4 bolts hold the plate in place, so even one of the incorrect bolts would cause a leak but only under boost.
__________________
2001.5 ppump allison 11.399@ 117.90 6850#
1997 rcsb 12v 6.7 9.38 @ 146.54
 
Old 02-10-2018, 11:54 AM   #27
Ram12vcummins

Name: Ram12vcummins
Title: Too Much Time
Status: Not Here
Join Date: Mar 2015
Member`s Gallery
Posts: 1,659
The unplugged egr was done by diesel spec mechanic. The guy who said he could fix it said it didn’t matter he could do it with it hooked up or not hooked up. Does someone know if it can be programmed either way?

T-man
We will replace turbo boots and pressurize whole intake to check any other clamps or possible leak spots.
 
Closed Thread

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 06:56 PM.

 


Powered by vBulletin
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2006 - 2024, CompetitionDiesel.com
all information found on this site is property of www.competitiondiesel.com