That's not what I have found in my experience or what I was told by the GM engineers at the training facility.Originally Posted by Buzz
That's not what I have found in my experience or what I was told by the GM engineers at the training facility.
1999 GMC Sierra 1500 standard cab long bed 4.8 V8 2WD - A work in progress.
2000 Grand Prix GT sedan 3800 - My new daily driver inherited from the wife via the insurance company totaling it out after a minor collision.
2006 Grand Prix GT sedan 3800 Supercharged - The wife's new grocery getter.
How many standalone Gen IV wiring harnesses have you built ?
Last edited by Buzz; 04-25-2014 at 11:48 PM.
This is my first experience with a Gen IV anything!
I decided to post my experience, to help others who might want to know what is involved. I greatly appreciate all the awesome support I've received!
I will soon learn what is required to get this Gen IV project up and running. There could be conflicting information in this tread, which causes me concern. I will post back what I did to resolve the conflicting information.
The attached pics show Accessory Wakeup circuit 5985. I am in hopes once everything is hooked up, I'll be able to read the E38 computer thru the ALDL connector. It's my thinking if I am successful with reading the E38 without the BCM, the engine / trans will work. If more work is required, I'll post back with questions / solutions.
I have a good track record of success doing new and challenging things, I will accept nothing less than success with this project.
I could have wimped out / gone the easy route and purchased a harness / computer from Current Performance http://www.currentperformance.com/LS2.html I don't think the people at Current Performance are any smarter than me, they just know things I don't know YET!
dave w
Dave, I have no doubt that you will come up with what works for you, and that it will work well for your customer.
This is a commercial venture for you, and I am aware that you are the type of person who likes to know everything about how things function - very admirable.
I run a commercial operation and therefore don't give out "how to" instructions for the products that I sell. Kind of like asking Howell or SpearTech how to build a wiring harness.
That said, I really like the environment yourself, EagleMark, and others have going on this Forum. To this end, I will never knowingly let you make an error on a commercial product. I have attempted to provide helpful hints in this thread, as well as more specific assistance off the Forum.
I know you will get it sorted out to your satisfaction.
I could ask you how much training you received from General Motors pertaining to their High Speed GMLAN network and how many GM engineers you have consulted with, but this is supposed to be an informational thread not a pissing contest. Your earlier post stating that you need 120 ohms resistance to communicate indicates the answer to my question. The proper resistance between the high and low GMLAN wires is supposed to be 60 ohms because the wires are terminated at either end with 120 ohm resistors in parallel. You may be able to communicate with the ECM and TCM with 120 ohms resistance in the wiring using a programming interface such as efi live and you may be able to get a vehicle to run and drive with that configuration as well. But that doesn't mean that the system is configured properly and the modules will function as they are designed to. MY advice wasn't based on what he can "get by" with, it was based on how it SHOULD be configured.
1999 GMC Sierra 1500 standard cab long bed 4.8 V8 2WD - A work in progress.
2000 Grand Prix GT sedan 3800 - My new daily driver inherited from the wife via the insurance company totaling it out after a minor collision.
2006 Grand Prix GT sedan 3800 Supercharged - The wife's new grocery getter.
I am only here to help ... I don't like, nor seek conflict. Your posts are informative, and no doubt based on a lifetime with GM products. That said, GM does not provide its Techs with training in how to build Hot Rods, nor how to run the systems in a non-OEM configuration.
You are trying to help Dave, but are making an educated guess a lot of the time - no problem, just indicate when these are guesses or logical inferences.
To getting things back on track to assisting Dave ...
The diode discussion stopped short of where it should have gone. The diode part number discussion took things in a non-productive direction. The answer as you guessed, was that these are integrated in the under-hood electrical centre - so therefore, there is no part number for these. Where the discussion should have gone, was to why these are used, when these are used, and is there a pattern per use versus controller. Yes - there is.
On CAN Bus comms issue - the wiring harness in a Hot Rod does not need a second 120 ohm resistor, if only an ECM and TCM are on the bus. Lots of threads on the internet regarding this topic - with arguments on both sides - the smart people have tried it both ways, and realized it doesn't really matter - the comms function either way.
Hopefully that is enough of an olive branch to get things back on track ...
As a matter of fact yes it is. I don't take issue with being corrected. It is the manner in which it is done. That being said, I would like to get back on track as well.
I actually thought that I did address the "why" in the diode issue or at least why they were necessary with that particular configuration. I knew that I had nothing to contribute as far as a part # which is why I left that unanswered. I figured that the information that I gave regarding the two possibilities of where they were placed would lead Dave to the answer he needed. I did have a part # for the diode that I took pics of, but didn't post it on purpose because I knew that it was not the correct part.
1999 GMC Sierra 1500 standard cab long bed 4.8 V8 2WD - A work in progress.
2000 Grand Prix GT sedan 3800 - My new daily driver inherited from the wife via the insurance company totaling it out after a minor collision.
2006 Grand Prix GT sedan 3800 Supercharged - The wife's new grocery getter.
My apologies in advance to Dave. I know you want to keep this on track so if this reply results in significant off topic discussion it can be broken into a separate thread.
Buzz said:
It may well be that there are no guesses being made, rather we're seeing the endeavor of an alert student to teach what was taught. Having spent a few years as a GM tech, I know full well that what GM teaches is not always correct for what GM produces.You are trying to help Dave, but are making an educated guess a lot of the time - no problem, just indicate when these are guesses or logical inferences.
I became a GM tech, and went to GM schools, to build hot rods with computers when few believed an EFI hot rod was even possible. Most of GM's training was an excellent basis for building safe, fun, and reliable weekend cruisers. But in terms of servicing electronics, the most successful techs are usually the most conservative with customer vehicles. Keep the OEM configuration OEM. But you imply that you have built enough harnesses to gain confidence in your approach. So I think the interesting question is why you don't include the 120 Ohm resistance. Not intended as an accusation, this question gets at the reasoning and motivation behind making the system work without what is described as proper termination. Why do you have confidence that it doesn't matter if the resistor is included or not? Was it truly trial and error? With my GM background and desire not to be interrupted by an angry customer stuck at a car show on Saturday night, I would tend to include it even if the system worked without unless I really understood the potential repercussions of omitting it.That said, GM does not provide its Techs with training in how to build Hot Rods, nor how to run the systems in a non-OEM configuration.
BTW, you read like someone I know from an old mailing list. Did you attend any of the meets at Bruce's place?
PMKLS1 said:
To put it bluntly, some people aren't interested in giving out trophies for wrong answers. Wrong is wrong, and that's all they feel needs to be said. It's hard to weed out the person who's like this from the trolls and wannabees since the reply by itself feels like an affront to your skill, training, and pride. Kudos for your reply and for continuing the discussion despite the heat it created.I don't take issue with being corrected. It is the manner in which it is done.
I thought things were back on track ... guess not. As I have stated repeatedly, I only come here to help - I have never asked a question, and it is doubtful that I ever will. My intentions therefore are altruistic.
To your point to "keep the OEM configuration OEM" - then why not also include a BCM, EBCM, FPCM, IPC, HVAC, and all other modules that were originally on the CAN Bus system ? The obvious answer is that these are not needed in a custom / stand alone application. Same goes for the second 120 ohm resistor. You can you use any or all of these if you wish, but they are not strictly required.
What modules get used or not used is up to Dave, it is his build, but stating that a particular item is mandatory (when it is not) does not provide Dave with the totality of information needed to make informed choices.
I respond to a single post with a "true" and "false" comment, nothing derogatory, no argument, and that constitutes "heat" ? I then take the time, and make the effort, to get things back on track when this has been perceived as offensive (was not intended as such), and you are commending the other gentlemen for putting up with me ?
No offense intended, but your response comes across as more than a little one sided.
The easy thing for me to do is that my bat and ball and go home - I don't receive any direct benefit from participating in this Forum - but I have developed a great respect for Dave and EagleMark - despite having never met either them.
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