CM870 questions

[CandianJake]

I have a couple questions,

1: is CT the best option for viewing and sending ecm programming information? And can I upload new programming to my ecm with it?

2: ive identified a bad injector (as per the injector test video), is there a way to test a used injector before i install it on my engine, and can i use a CM871 injector on my CM870?

Cheers,

[Rawze]

* DO NOT change injector part#'s. If you put in different injectors, they require different ecm programming, and if you do not have matching injectors from one cylinder to the next cylinder, your engine will run unbalanced and that causes excessive wear somewhere internally. It sounds like your trying to jump over a dollar to save a few pennies. That or you have no knowledge that those different injectors ARE VERY DIFFERENT FROM EACH OTHER!. Different spray patterns, different chamber sizes, some require different pistons or cam profiles, .. all sorts of variations. Just because they fit in the hole, does not mean they are even close to being the same! - BAD BUSINESS DECISIONS WHEN PEOPLE DO THINGS LIKE THAT!


(CM870's only here)...
* CT can be use to UPLOAD/COPY a program out of a CM870 ecm .. but it absolutely SHOULD NOT BE USED to send that program back in. CT does not pull a completed image of the ecm 100% properly (a CM870/875 GTIS-3 issue), and a chunk/block of data is always partially missing. This means that if you copy the program out, then send it back,.. you have a HUGE CHANCE of corrupting the ecm and it may not run right. Sometimes you cannot see what happened right away, sometimes you may loose the gauges in the dash of the truck, them not working correctly, or you may even brick the entire ecm. CT can be used to pull the program out and inspect it, e-mail to to someone for review, checked for safety, etc.. but it should not be used to put the program back in unless you are willing to heavily hand edit the raw file data to re-construct the missing chunks (not easily done unless your a familiar with working on raw intel-hex data formats).

- Most people resort to editing factory files and flashing them in with insite on the CM870's as this presents the least chance of corruption. Even so, there is only one version of CT that I have seen that can edit factory original (incal) files without corrupting them. That is version 3.17 (made in 2017). Any other version, and your pissing up-wind and taking huge chances that any 870 file you touch with it can get damaged. CT has had an issue with this for many years, it is well known, and the version 4.x and above versions of CT are known to corrupt the 870 files too.

- Last, but not least,.. there are some settings in the CM870 in particular that are only located in the ram memory of the ecm. You can pull the files out of that ecm till you are blue in the face and flash it any way you like, but those ram memory settings will not get set properly, nor will their settings be in the file you copied out. - It takes editing the ecm live and being connected to it to set them and CT is the program to use, but you have to know which ones to edit to get it right if a 'delete', or re-doing one is the goal.

here is some related info:
http://rawze.com/forums/showthread.php?t...0#pid53580

[Rawze]

(06-10-2020 )CandianJake Wrote:  I have a couple questions,

1: is CT the best option for viewing and sending ecm programming information?
...

Well, CandianJake sent me a copy of the program running in his truck engine (CM870) today. All I can unfortunately say is ...

Welcome to the bad delete club.


* Program is set to report only 565HP with 1850 torque but the reality is that it is set to 619HP and 1981 torque.

* Injection timing AT 619HP .. is set to 9+ BTDC and this is severely harmful for this engine at this power level. - A person would be doing good to allow that at 420hp/low torque, would be risky for even low HP,.. but for it to be 9+ at 619hp?--- I guess someone wants it to fret liners out of it every couple years and engine destroy itself? -- Clearly someone not knowing what they are doing there. Looks like someone took the already advanced+ factory emmissions injection timing mappings and added about 6+ more degrees to them.

* No proper engine mode control. This is harmful and causes unstable ecm conditions, unpredictable run modes and all sorts of ill-effects.


* Engine brake is set so that the turbo chokes the exhaust at a full 100%... This is so high and hard on the engine and valve train at higher RPM's that it is a wonder this thing has not dropped a valve in it yet. This is seriously abusive and dangerous.

* Aux. emissiions is still active, not shut off properly and trying to derate the engine and screw with it.


- Those are the main issues with it that I see when glancing at it. There are other mistakes in the program, it is clear that someone did not know much about what they were doing. This is definitely a bad delete that is going to severely shorten the life of that engine all while the truck owner not knowing this thing is trying to actually make nearly 620HP in a way that is going to be very harmful.