jcs64

Im starting to finally understand more and more of this as I go through the options in tunerpro. I found my Wrangler w/ the 350 and a SD TPI setup that was "proffesionaly tuned" was actually set for a 305 engine! I fixed that and some other things and its running MUCH better now, but still under 11 mpg.!!!!!!
So as I keep coming accross settings for the TCC I finally gotta ask.......
What do I do since I dont have one?
The Jeeps running a T350 into the stock Jeep T-case (advanced adapters).
Im almost starting to think maybe I should set the chip as a standard tranny?
If thats the case, do I just check bit 2 at switch 18? Or do bit 0 and bit 1 also have something to do w/ it?

Thanks in advance Jeff

RBob

iTrader: (1)

It won't matter much if the option bit is set to TCC or stick. Best bet may be to swap in a TH350C.

RBob.

jcs64

I dont know anything about those. Would it be identical from the tail shaft flange forward? It would have to be able to mate to the advanced adapter exactly the way the T350 does, and also be the exact same leangth.

RBob

iTrader: (1)

Don't know if the tranny is the same. For mileage a lockup TCC helps. Being this is a thirdgen f-body board you may want to hit up a jeep board for the TH350/TH350C fit up.

RBob.

Beast407

A TH350 and TH350C are dimensionally the same from the tailshaft mounting flange forward.

TT 68

Any ideas what application a T350C came in? It sounds like the answer to a problem I am facing as well.

Beast407

I'm not entirely sure, but try 78-81 full size cars and pick ups. If memory serves they had a "universal" bellhousing pattern that would fit both Chevy and BOP blocks. They look like a TH350 but with the same 4-pin lockup connector as a TH200, 700R4, etc.

Make sure it isn't a TH250C however, which if I recall is basically a TH350C without an intermediate clutch that uses the band for 2nd gear.

My memory is a hazy on this, but hope it helps

Happy hunting.

Fast355

iTrader: (2)

I wouldn't even bother with the TH350C, you would do all that work to see MAYBE 1 MPG better. Just keep the current TH350 and maybe install a towing type torque converter, just the lowest stall unit you can find. The TPI likes staying pretty low on the RPM, but keep the RPMs low and it will WORK. Some of the fullsize Vans/Trucks had torque converter stall speeds as low as 1,200-1,300 rpm.

I am thinking that the gearing is going to be relatively low, the Jeep is going to be on LARGE off-road type tires, and the 350 is hopped up some. That is the makings for low fuel mileage, especially when you toss in the fact it is 4wd and lacks an overdrive transmission.

To get better fuel economy, I would use an automatic transmission bin so that the IAC parameters work right with the Park/Neutral switch (you have one installed right). I would also want a VSS so that the engine will idle correctly and the ECM can enter Decel Fuel Cut-Off mode. I would also tweak the timing, highway A/F mode, acceleration enrichment, deceleration enleanment, and throttle follower routines to my liking for best fuel economy. I also tune the idle for the highest vacuum at the lowest speed the engine will run smoothly at. On a stock small block that is about 500 RPM on a WARM engine. Too much time spent high idling will KILL your fuel mileage in the city.