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observations of IP timing adjustment

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fastline

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Well I decided to just go ahead and move the pump even though I do not have a way to relearn the TDCO. I first went to the passenger side or CCW as you look at the front of the truck and that made it worse. I then looked on line a little more and OH, some people say go CW, so I did that, it seems a little better but I realize it needs timed now.


I am using my own brew of data logging but I have all the info the ECM can spit out. I just have not found any codes yet to prompt the learn and time modes yet.

What I noticed is when moving the pump to the passenger side, it seemed to move pretty easy. When I went to the driver to CW, it did not want to move. I seemed to spring back a bit. I had to hold it in position and tighten. I hope I did not damage anything there but need to get somewhere on this.

Are there other ways to induce the learn and or time modes?? pump pedal, hold brake, stand on one foot??

Hopefully my buddies at GM will come through with some prompt codes for these ECM tuning modes. Anyone else got access??
 
Welcome to the site, fastline.

Before anybody attempts to help you out here, we do need some information so we know what vehicle you be talking about.

I assume, for the sake of argument, we ain't talking about your wife's Volkswagon Rabbit?

Can you please fill out your signature in some detail and then somebody will be along shortly with some assistance.

Welcome aboard!
 
Well, I added it but not showing up yet.

1994, 6.5 TD, 4L80E, 3.73, S VIN

You're a familiar face.... Or should I say bear?
 
fastline said:
You're a familiar face.... Or should I say bear?
Click to expand...

Could be... you're a new member here; have you been on other forums, with the same name?

1994, eh? You have an OBD-I computer. The information you are looking for should be in post #2 here.

(I love the reference library we're building up. Thanks for the great post, gmctd!)

Hopefully this help you out... the process is fairly simple with a Tech-II or GMTDscan and a laptop; make sure your engine is at 180* minimum temp before trying to set timing, as PCM won't accept timing-set commands at lower temperatures, and when cold, the timing advance function inhibits your efforts.
 
I am working on the truck through my own software. I can pull any level of data I need from the ECM, but there are specific mode codes to put the ECM into time and learn modes. They are simple "words" or computer codes.

Also, the sticky does not clearly ID which way to turn what to get the desired advance. It bounces around from 8.5, 3.5, 0, -1.94, etc. Guess it should say more clearly that it should be set at 3.5* when ECM is set to timing mode which turns off all electronic advance so the 3.5* is purely mechanic. 8.5* would be target with the ECM in standard operation mode.

In the raw aldl data stream from the ECM, there is no TDC offset. There is only timing variability. I am still a little unclear as to what this offset really is. My understanding is the correction factor of timing that is commanded and what the ECM has to do to align the actual timing with it. They should align, but if not, the ECM corrects it.
 
really not sure what you just said.

KO KO???


I did read the sticky. Did I misinterpret something?
 
fastline said:
really not sure what you just said.

KO KO???
Click to expand...

This post just reminded me of something that needs to be fixed on this forum. Common abbreviations cannot be searched, and it can make things real difficult. Try searching for an ATA IC or an LP or an IP. Or how about trying to search for someone in AZ with a scan tool?:mad2:
 
Rhinopkc said:
This post just reminded me of something that needs to be fixed on this forum. Common abbreviations cannot be searched, and it can make things real difficult. Try searching for an ATA IC or an LP or an IP. Or how about trying to search for someone in AZ with a scan tool?:mad2:
Click to expand...

You can't search 3 digits or less on almost all forums; it's a limitation of the vbulletin software. Use google (advanced search), and delimit the search to only this domain, if you need to hunt down short abbreviations.
 
There are a few cheap good scanner software for OBD1 out that lets you do everything.

I think ENGH Motors is one of them??? I'm not sure cuz i'm obd2... but I'm jealous of obd1 for this reason. Look into it. Cheap.

Sounds like you want the code command to tell the PCM yourself via your methods... don't blame ya.... May be hard to find that info for free though. Let us know :)
 
Some can and some can't as far as the key and accelorator sequence goes. I personally did this with my 95(when it was still a 6.5) and it worked fine with the stock ECM and chip. The stock ECM failed so I got a replacement with an updated chip and the new one would not do it. So it's not a guarantee to be able to do it on OBD1.
 
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