12587811 PE Issue

[SkinnyPedal]

I'm just wondering if anyone has figured out how to make these go into Power Enrichment? I have searched and found a few threads. I do have everything set correctly and I have tried many variations. I also have used na LC1 on it, so no PE has been verified. Anyone found a parameter combo that works on this stubborn SOB? I have done a few other 12587811s and not had an issue.

[joecar]

Post your tune file here.

[SkinnyPedal]

I'll post the stock tune modified for PE only for abvious reasons. I have tuned this service number before with no issues. This one is the only one giving issues.

14289

[ScarabEpic22]

I understand why you only posted a stock tune with your PE params, but honestly you're only giving part of the puzzle. Could be something else in another part of the tune thats not letting it go into PE even if all the PE settings are correct.

Im taking a look at it now, will report back.

[ScarabEpic22]

Ok here are my thoughts based off a quick look through the PE settings:

B3618- Why do you have this set to 11.89:1? That’s WAY too rich, you'll be choking the motor. Should be more like 12.5-12.6:1. Whats are the stock values for this table?
B3605- See its modified to the same AFR as B3618, should change it based on what you do with B3618.

B3616- Look at it and try changing the TPS setting to like 50% to see if it will activate then. Log the proper TP PID while doing this and make sure the TPS is actually going above the values in this table.
B3610 – I like to set this a little lower, try 3000rpms to see if it will go into PE.

What kind of MAP values are you pulling under WOT runs?

Hope that helps, Ive heard of some issues with fullsize trucks not activating PE mode before but never seen it.

[SkinnyPedal]

I have run just that tune and it still does the same thing. No PE. I got tired of chasing my tail and returned everything to stock and only modified the PE portion to see what was going on.

[ScarabEpic22]

Ok, can you post a log of it not going into PE? Also try changing the tables I mentioned above, for a test just leave B3618 and B3605 alone for now but change B3616 and B3610.

[SkinnyPedal]

To answer your questions I have the engine running that rich to verify it is coming into PE. So I would saturate the O2s and feel it.

I have taken the TPS all the way down to 25% and nothing, I have tried every 10% from there on up.

I have set the rpms as low as 1500 and about every 500 rpm from there up.

I have logged everything possible to try and chase this down. MAP is 91-95 KPA wide open. TP is 99%.

I have tried multiple MAP values as well.

[SkinnyPedal]

I'm willing to try anything at this point problem is I have tried just about everything I can think of and everything I have found searching. Short of swapping PCMs or trying a different OS I really don't know what is going on.

[SkinnyPedal]

To make things worse. Here is another pickup exactly the same, year and service number that works just fine. Again I have the AFR so low to verify everthing is working and to hold the O2s contant.

[ScarabEpic22]

Same OS number in that last log? Or different OS?

I think its time to try another OS, seems like you've done the research.

[SkinnyPedal]

Its the same OS. I've tuned a few with the same OS and never had this issue. I may send him to the dealer for a full reflash. Worst come to worst I'll try a new OS and or new PCM.

Thanks for all the input!! It is appreciated. If anyone has run into this as well let me know. I will keep everyone updated with what I find.

[ScarabEpic22]

Interesting, have you tried full flashing it for kicks? I dont know what other year OSs interchange, could you try an 05 OS?

[SkinnyPedal]

I have tried a full flash, with the stock OS and a download from tune file depot. I'll check with a friend that works for GM and see if there is an upgrade to the OS. If there isn't ill try another PCM or even a previous year PCM.

[SkinnyPedal]

So I thought I would update this thread. I finally got this fixed and working.

Here is a few things we did that did not work. We tried reflashing with same OS. We had the dealer flash from a tech 2 and it ended up being the same OS, still did not work.

I then used a 2005 OS and bingo, power enrichment but now I had a TAC module issue. I called a friend that had a 2005 TAC module and we swapped it for the 2006. Now everything is working great and the truck runs awsome.

Short version we used a 2005 OS and a 2005 TAC module.

[joecar]

Thanks for posting back.

[SkinnyPedal]

Have anoher 7811 at my shop and no PE.

Does anyone know if there is a min torque enable/reqest setting or anything that has to be met like the TPS and MAP? I wonder is there is something else in this OS that has to be changed to be able and activte PE.