Changed OS Can't Enable PE

[Steve Bryant]

I've switched back from a custom OS and moved to the most modern standard OS that my truck can use (12212156). Here's what I've done so far:

1. Calibrated the VE table for Stoic (trucks are set @ 14.68 vs. 14.63 for cars BTW)
2. Calibrated the MAF (with {B0120} change over to go exclusively to MAF for 400 RPMs)
3. reset the MAF (with {B0120} change over to go exclusively to MAF for 4000 RPMs) & verified that setup will track stoic nicely to about 5,600 RPMs (here's where the problem starts)
4. Attempted to enable PE (see attached tune)
5. Commanded VE obediently goes to 12.0 (set as test value initially, see attached file) and WB02 (using PLX analog on Aux Voltalge input 1) gets worse rather than better when PE is commanded.

Please take a look at the image of the problem, the tune and the logged data. I realize that I also have a spark/KR issue that needs to be addressed. Note: this is for a 2000 Yukon XL with an LQ4, a 200/206 cam running 87 Octane. Everything about the stock truck tunes are set up to not use PE. Also, when PE was disabled, the MAF calibration was at least maintaining about 14.6:1 AFR.

Thanks to all,

Steve

PS: this boy needs help!

[WeathermanShawn]

Steve..

Excuse my ignorance on this one, but is the normal PE TPS Enabler B3616 supposed to be 90%?

I take it you are wanting to enable PE, but it does not? I am just wondering if that high of a TPS setting along with the fuel step size is a concern.

Just a thought..

[Steve Bryant]

Shawn,
Thanks for your response. I first started with steps set at 0.020 (stock setting for this OS for a truck). That seemed to migrate the commanded AFR at a slow rate, so I found a 2002 Z06 Corvette tune (HoldenCrazy) and I copied and pasted all of the values from the Mixture Parameters from the Corvette tune into mine. On {B3616} 90% may be a little high. My thought was that I wouldn't want to have a rich mixture for pulling long mountain grades towing my 8,600 pound trailer. I did just now find one of my older OS tunes where I was able to successfully enable PE and that tune had {B3616} set at 65%. That tune included a Back Up VE table and did not have a step size parameter.

[joecar]

Steve, I would try doing a full flash again.

[Steve Bryant]

Joe, I'll try a full flash again. As an aside, my turck has two fuel tanks that each have a float type fuel level sensor. The PCM is picking up the level/percentage of each, but the PCM is not summing the two, only the primary tank . . . so maybe all of the bits are not in their proper 0/1 status. Another thing that I could try is to go back to my older OS tunes where PE did work properly and see if PE still works there, then do a full flash with this tune.

Thanks very much for your suggestion.
Steve

[joecar]

Steve, what was the original OS and what COS did it have prior to this OS...? Yes, give the older OS a try.

It may be possible that your PCM might not be compatible with this particular 12212156... having said that, look at tables G1206/G1207, I don't see any mention of fuel tanks in G1207, but maybe the value G1206 is significant beyond the values in G1207 (i.e. there may other features not mentioned in G1207)... this is just a guess on my part.

[Steve Bryant]

Joe, my original OS was 09381344. I thought that any of the other standard or custom operating systems for the 512 kb PCM's would work. I have flashed COS 01270002 and 01270003 in this PCM. I experienced some problems with the maintenance of stoicimetric AFR using 01270003, so I switched to the latest 512 kb standard OS that had been used on the 3/4 ton GMT800 series vehicles (among other things) which is why I choose 12212156. I'm also attaching my original factory tune.

Thanks again for your willingness to help!

Note, I could also have some sort of unmonitored failure of my PCM (self test checks of RAM & checksum come back OK). Also, reflashing the PCM (full flash) with the same tune has not borne any fruit yet. I'll try a full reflash with one of the older tunes where PE was successfully enabled (back about in 2005/6).

[wait4me]

B3644 needs to be moved to 1. That will make it add fuel faster

[Tordne]

Hi Steve,

The B3644 parameters Jesse mentions is in the 2002 OS (12212156) in case you're wondering why you can;t find it in the tune you attached.

One thing I noticed in the attached tune (Post #7) is that the B3608 (delay before entering PE Mode) value is set at 60 seconds. Have you tried setting that to 0?

[Steve Bryant]

Thanks everyone for the additional comments. The tune in post 7 was just to show what the original factory tune and OS were when I bought the truck (posted in relation to Joecar's comments). I have not used that tune for about five years.

I'll make two more posts to show some more details.