My MPG gain is fenominal with a Pre F37 TCM

racertracer · **Posted:** Sat Oct 15, 2011 7:02 pm

Installed a pre F37 TCM and the mileage gain is fenominal.

The EVIC is showing MPG gain thru the roof.

Installed the pre F37 TCM yesterday, drove the CRD all day today and put on a total of 175 highway and city miles mostly highway and the evic is sitting at 30.5 MPG. I took advantage of the cruise control when I could and kept the speed at 65 mph.

Before the timing belt and new head gasket work, the best i ever got was 26.5 MPG.

I will be hand calculating MPG's in the near future to confirm what the EVIC is showing and report back.

I don't believe I'm dreaming .....But as for todays trip, I filled up the tank and used 5 + gallons to go 175 miles.

arengant · **Posted:** Sat Oct 15, 2011 10:35 pm

how does this compare to the GDE tcm you had?

racertracer · **Posted:** Sat Oct 15, 2011 10:45 pm

The GDE TCM was great for towing, I no longer needed it for that ... the camper is sold.

arengant · **Posted:** Sat Oct 15, 2011 11:35 pm

but what wast the MPG you were getting? I thought you would have been getting euqally great MPG up to 55 (not towing your camper) with the GDE as you are now getting with the pre f-37.

But then again I am still confused which GDE tune you had lol :banghead:

DOC4444 · **Posted:** Sun Oct 16, 2011 11:22 am

He had the "original" TCM tune. The "tow tune" expands the use of fifth gear. However, the greatest fuel economy gains occur between 35 mph and 60 mph. If you spend little time in that range, you won't see a big improvement.

DOC

ATXKJ · **Posted:** Sun Oct 16, 2011 3:57 pm

At 65mph - there should be no difference in Mileage Pre/Post F37 or GDE - all are locked up in 5th.

even in the original Pre/Post F37 - it really mattered how you drove on whether in improved or killed your mileage - (mine wasn't a huge change - F37 just killed the fun to drive factor)

yrkcrd · **Posted:** Sun Oct 16, 2011 4:22 pm

What did you do with the gde tcm tune?

I'm interested if your selling it.

arengant · **Posted:** Sun Oct 16, 2011 4:50 pm

i know racetracer had a lot of work done, so not sure what we can credit for the good MPG, but if he had the original GDE TCM tune that gave better MPG through 55-60 MPH, and now he has a Pre-f37 TCM and is impressed by the current MPG, this leads me to believe the pre-F37 would be better than what he had...

His title, "MPG gain is fenominal with Pre F37 TCM" MPG gain over what??

I guess I should just PM him

racertracer · **Posted:** Tue Oct 18, 2011 6:46 am

The Credit goes to the pre F37 TCM, because soon after the TCM swap, the mileage on the EVIC began to climb.

So far, I get 24 to 25 MPG in town.

Highway mileage continues to climb and to date I have reached 30.5 MPG.

I wavered between 60 -70 MPH maneuvering around slow moving vehicles but I mostly traveled on the right lane cruising at 65MPH with the cruise control on.

I say continues to climb, because the more miles I travel on the highway the more the EVIC climbs.

I want to test the CRD on long trips (350 miles or more) to see where the MPG on the EVIC levels out and then compare the mileage with hand calculated figures.

I'll be doing this in the near future and report back.

As far as what has been done to the engine recently (2 weeks ago), here is the list:

1. Replaced all of the required Timing Belt parts with OEM parts.
2. Replaced cylinder head and cylinder head gasket and bolts.
3. Replaced ceramic glow plugs with the new revised OEM metal glow plugs.
4. The ECU was reflashed by the dealer as required for the glow plug update, wiping out the GDE Hot tune. (I’ll be sending the ECU out to GDE for the reflash)
5. MAP sensor is unplugged and no CEL light on the dash (don't know if it will ever come on).
6. Elephant hose modification is done.
7. Coolant flush was done.
8. Oil change with Mobil 1 - 5w-40 TBD-Truck and Mobil 1 filter.

The engine sounds and runs great, but there was no noticeable mileage increase on the EVIC after this work was done.

The pre F37 TCM was installed 4 days later and an immediate noticeable mileage gain began to show up on the EVIC.

I couldn't believe my eyes and had to test it on the highway last weekend.

Joe Romas · **Posted:** Tue Oct 18, 2011 7:44 am

racertracer wrote:

As far as what has been done to the engine recently (2 weeks ago), here is the list:

The ECU was reflashed by the dealer as required for the glow plug update, wiping out the GDE Hot tune. (I’ll be sending the ECU out to GDE for the reflash)
.

So this is with the latest version of the OEM tune, I wonder what you'll see when you get the GDE tune restored. You had the HOT tune, I wonder if just the full torque ECO would give better MPG's:jester:
Any idea of what PRE F37 TCM tune you have? There were at least two.

I just checked mine. The Pre F37 version I have, PER VAG-COM, is 56044737AF and that agrees with the original tag. This TCM came from a salvage yard.
My January 06 build tcm tag says 56044737AI and that was also a pre f37. I'm not sure but I think it now, post F37, is AJ per VAG-COM but it's not in the jeep so I can't check.

racertracer · **Posted:** Tue Oct 18, 2011 7:50 am

Joe Romas wrote:

racertracer wrote:

As far as what has been done to the engine recently (2 weeks ago), here is the list:

The ECU was reflashed by the dealer as required for the glow plug update, wiping out the GDE Hot tune. (I’ll be sending the ECU out to GDE for the reflash)
.

So this is with the latest version of the OEM tune, I wonder what you'll see when you get the GDE tune restored. You had the HOT tune, I wonder if just the full torque ECO wopuld give better MPG's:jester:
Any idea of what PRE F37 TCM tune you have? There were at least two.

Not sure but I can look it up.

Squeeto · **Posted:** Tue Oct 18, 2011 12:11 pm

racertracer wrote:

4. The ECU was reflashed by the dealer as required for the glow plug update
.....
5. MAP sensor is unplugged and no CEL light on the dash (don't know if it will ever come on).

Odd.

Sir Sam · **Posted:** Tue Oct 18, 2011 12:24 pm

racertracer wrote:

5. MAP sensor is unplugged and no CEL light on the dash (don't know if it will ever come on).

Uh, wut?

racertracer · **Posted:** Tue Oct 18, 2011 12:32 pm

Sir Sam wrote:

racertracer wrote:

5. MAP sensor is unplugged and no CEL light on the dash (don't know if it will ever come on).

Uh, wut?

MAF oksw

Sir Sam · **Posted:** Tue Oct 18, 2011 12:34 pm

racertracer wrote:

Sir Sam wrote:

racertracer wrote:

5. MAP sensor is unplugged and no CEL light on the dash (don't know if it will ever come on).

Uh, wut?

MAF oksw

oh good, that makes much more sense.

boilermaker2 · **Posted:** Tue Oct 18, 2011 8:07 pm

I just did the ECM/7v-5v GP process and thought the same HS! what mileage gains! As I followed the gas gauge through its normal arc from F-E, I remember Jeep's stock tune of the Gas gauge and the accelerated fall from grace after the 1/2 mark (290 miles on the first half, 160 on the second half of the tank). I'm sure with the reflash from GDE it will go back to something a little more realistic.
B2

CRD Joe · **Posted:** Thu Oct 20, 2011 8:22 pm

Why cant I just take my rig to a dealership and have a PRE F37 flash done? My truck is out of warranty so no big deal right?

CATCRD · **Posted:** Thu Oct 20, 2011 8:31 pm

CRD Joe wrote:

Why cant I just take my rig to a dealership and have a PRE F37 flash done? My truck is out of warranty so no big deal right?

They will tell you that software is no longer available.

ATXKJ · **Posted:** Thu Oct 20, 2011 9:01 pm

Once it's connected to the mainframe - you get the latest/greatest - no options.
The dealership can't select versions.
(and if it's interrupted mid transfer - the Computer may be toast)

racertracer · **Posted:** Thu Oct 20, 2011 10:07 pm

MY Jeep is running better than ever before.

The pre F37 TCM coupled with the latest ECU update makes the CRD run smooth.

The MAF is still disconnected and no CEL light on the dash.

Smooth is the word of the day.

24 to 26 in city

30 to 31 HWY so far.

I am still planning a long distance trip to see how much further the MPG will climb on the EVIC, hand calculating the results.

The key is to lay off the pedal and let the ECU and TCM take over, sit back, drive and enjoy the view.

My MPG gain is fenominal with a Pre F37 TCM

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