Tuning for towing?

[RobertISaar]

well.... you could invest in something like the G3 adapter(and the EX switch) from Moates.... then if he experiences any pinging, he can switch to a different tune on the fly with one that has less advance to combat the detonation.

[dyeager535]

True, but I'd just prefer to have the tune be an "all in one deal". He's not the type of guy to want to deal with that sort of stuff if he doesn't have to.

If the timing is conservative enough as is, I don't think he'll have any issues. It must not be a huge issue, I didn't see any posts where people had said "when I tow my truck runs like garbage" in relation to the tune.

He's already got an adapter/ZIF, so on his past "trips" I've just given him a spare chip with a stock bin on it in case the bin I burned has a problem we didn't notice.

[EagleMark]

If you didn't do anything drastic to spark he'll be fine. I'm sure you have distrbutor and initial timing set correctly? You could post the bin for a look but really think he's fine. Can he hear ping? If his hearing is good and he here's ping then fill up with higher octane till he gets home.

[1project2many]

Where was it that I saw a cheap and small recorder to connect to the ALDL? Maybe it was so long ago that they don't make it any more. But it would work. Send Dad out for a drive with trailer and check the recording when he gets back.

[dyeager535]

Huh. Never heard of such a thing. Interesting idea, certainly simple. I've got an autoxray but pretty hard to drive and look at that thing. :)

[dyeager535]

So if I did this right, I've attached the bin he's running now.

Only difference I saw in spark timing was a couple of degrees added around idle, but that was mainly just playing around to see what difference I could get with closed loop at idle.

As I understand it the timing map should be relatively smooth, but I compared this against the stock ATPZ and the idle timing is all I changed.

[1project2many]

HAHA!!!! I found one of the old GM ones we used to use. This works, although it's almost old school enough to have been on Apollo 11. The only problem is that you will have to "play" the entire recording into the laptop before you can quickly scan through data to look for problems.
http://www.ebay.com/itm/GM-1150-OLD-...item53e85201f9

I've spent many hours with a Tech 1 and this tool looking for problems. But other than that it looks like the only thing available now is for OBDII stuff. There is a guy building a neat recorder that saves data on a CF card but it doesn't look like they're for sale yet:
http://www.delcohacking.net/forums/v...c2267&start=80

[EagleMark]

That's a very good towing bin file, reason I say this is PE is set kind of rich at 12.0 to 1 and no spark added, so when power is needed you get it, not all of it but it can be sustained for very long periods without building heat, like towing a load up a long mountain pass. The other thing that stands out that this is a heavy truck bin file is PE - Enable vs. TPS % is a flat 50%. Unlike smaller trucks which have a varied table. Simple yet effective, anything under half throttle is not in PE and getting better fuel mileage, anything above half throttle is putting out power to move load down the road. This type of bin was designed to run higher engine duty cycles for extended periods.

So to answer your question I think you can sleep at night with no worries. One thing I would suggest on this 5 speed is driving habits while towing. 5th gear is fine on flat lands or small short slopes, but when hitting a big long hill drop down to 4th which should be 1 to 1 ratio to pull hill. It will make it easier on motor and not build up heat in trans.

I'm not a fan of the bin switching as I can make a bin do it all. But in this case, even if it were my truck I would consider a bin switch. One for what you have while towing and one for driving with no load. You could easily pick up 50 HP at WOT with some PE work and add 10% to MPG with Highway Lean Cruise in the end a much better responsive and enjoyable ride.

Spark tables should be fairly smooth, actually all tables should be fairly smooth because the cell the ECM is reading is interpolated with the four surrounding cells to come up with amount used. Fuel is usually fairly smooth in these old ECM but spark is horrible up till newer ECMs, like look at an LT1 spark table. No wonder guys use it as a starting point for performance builds. I'm guessing the old spark tables that are horribly un-smooth are restricted to what the old slow ECM with a small bin file size could do while meeting EPA emissions, ie... it's OK here and EPA rule says it has to be here now.

The only issue I see with your bin is you added overall 19.54% fuel to VE. Now you said this helped overall and probably did with mods in certain areas. But $42 has an issue from factory which you just made worse. $42 has a main VE and a VE 2 adder. If you add some of the cells together you get over 100% stock! It will be truncated to 100% but it real world tuning should not exceed 95 with a better goal of 90. That said I have tuned these and saw results, but looking back it was probably do to PE adjustments. Dave W talked me into adding VE2 to VE1 and using only one table and it has had better results. But really the only way to add fuel is increasing fuel pressure. Dave is a great tuner and he increases BPW when running out of fuel and then adjusting VE tables so I believe this can be done to an extent as BPW is a calculated process including fuel pressure.

Someone had raised BPW very high with same pressure and was not having much luck getting VE in order so I went out and did some testing on my factory equipped, stock 7747 Suburban. First I checked and my VE with recording BLMs and was in order. SO I increased BPW same amount as other guy. He added like 25 to stock 135, so up to 160. My results were horrible. As expected it went pig rich at idle and as RPM increased it got better then it started leaning out to 140s. So there is a fine line of how much BPW can be added without throwing everthing out of wack... I did not test smaller changes like maybe 5 which may be doable... HTH!