Originally Posted by Tygen1
Thanks, especially for the details!
I thought those were lock-up torque converters?
The "all new programming for the chip to deal with the new injectors" did you get that done on a dyno or just a mail order tune?
Why is it that Excursions tend to get better MPG after tuning than the F250's? I thought the motors were identicle?
Yep, they're lock-up torque converters... However, the added wear (previous owner never serviced it properly) plus increased torque from tuning can cause the TC to cheese out internally (various things can fail, e.g. clutch, turbine, impeller, etc (actually, malfunctioning TCs can result it massive fuel consumption issues...), which will result in slippage or catastrophic failure. If memory serves me correctly, my old transmission was also having trouble shifting out of (or into?) 3rd (per the codes). Overheating the trans fluid will cause the ..peller fins to warp and eventually frag out.
Fortunately, I'm only a few miles from DI's headquarters here in Houston and they simply pulled the module and re-flashed it with a program that covered my mod combination. Had I mail ordered it from them; I would have had to arrange either a cross-ship or else be down for a few days. It would probably run on the stock ECM, but would have been very rough - I assume it may have perhaps gone into "limp mode". Since the injectors are all mechanical expect for the firing mechanism, timing is a key factor.
Yes, same engine, but slightly different function/logic in the wiring harness. One example that I'm painfully aware of is the Excursions like to fire the glow plugs during normal operation, whereas the pickups only fire them to aid in start. (Twice) in my case, this resulted in my under valve cover harness all the way back to the glow plug control module frying itself out - thanks to Ford for having engineered the glow plug wire using a light gauge wire. (on my list of things to do is to mod the harness with a heavier wire (have heard of a mythical repair kit, but haven’t found it yet)) This alone isn't enough to make that much of a difference... “The Wizard” at DI told me that his customers tend to report higher numbers on Excursions, but the reasons aren’t exactly clear (most of his clientele aren’t exactly looking for economy). After all, Excursions are quite a bit heavier than their pay-loading cousins.
My F250 has slightly more mods than the Excursion (I have the aFe stage II intake, the regulated fuel system, and more aggressive programming) and I'm only seeing 14/26 at best. My wife has mastered the driving habit, whereas my lead foot gets in the way.
We’ll see how it fairs after I upgrade the tranny and injectors – have to wait for the current one(s) to fail. And this will have to wait until after I get my Austin Cooper up and running, hopefully with a TDI under the hood.
I added the URL
to my project page - its work in progress and I've got a real job to attend to.