PCM programming on a 4 door.

[gchemist]

I installed the GM original Jimmy ECM sent to wait4meperformance.com on Thursday. WOW!! I noticed the idle change right way! The updated spider loves the changes. Engine revs past 5000 RPMs. Tranny shifts are awsome. The 4 door Jimmy jumps out of first gear. Accelleration is great! Downshift and jumping on to the freeway are no problems at all. No hesistation when I stomp the throttle. I have to feather touch the throttle because it's sensitive. The corrected speedo is nice too. Best $85 spent on the Jimmy!! The tank was 1/4 gone so I can't report on milage improvements. I'll report back later.

If you own a 4 door, get the PCM updated!! You won't be disappointed!!

[lesterl]

bump

[gchemist]

I can report milage at 80 MPH. I took a round trip to El Paso. 1200+ miles. At 80 MPH, the Jimmy pulled 20.5 miles per gallon. Wow!! I wonder what it will do at 70! A little slower and it goes up. I 'm running 255/60R17 (29") tires. The 4.3 had no problem turning the large tires. The extra power and fuel map sure does help.

Now, I'll be running in the city. As soon as I can go through a full city tank, I'll post milage.

[lesterl]

thats good mileage for 80mph, keep up the updates.

[j894]

any updates? Im about to get the same thing

[immexicansostfu]

so all u do is send yours in and wait for it to come back then just put it back in?

[gchemist]

Yup, I sent my original PCM. You end up saving money. The trade off, you can't drive your vehicle for at least a week. Here is everthing I included printed and sent with the PCM.
1. VIN Number: 1GKCS13W7T2xxxxxxx

2. Any Mods: updated MPFI spider with poppets removed, K&N filter, rebuilt transmission (rebuilt before I bough it), NGK spark plugs, external transmission cooler,

3. Tire Size: 255/60R17

4. Rear End Gear Ratios (if changed from stock): stock 3.42 gears

5. What you would like to see out of the tune: Better MPG, firmer transmission shifts, better torque converter lockup (45+ MPH lockup), corrected speedometer, better tune,
Please add anything I may miss to improve overall performance and MPG.

Internet users state you remove part of the torque drive programming. Removing up to 75% is fine. Internet users seem pleased with the change.

6. Phone number and return address:


7. Fuel: 87 octane

I'll be filling up soon. I can definately tell city MPG has improved. I'll post as soon as I fill up.

[gchemist]

Alright!! Went through the first full tank after having the PCM reprogrammed. Normally MPG were 16-17. The first tank put out 18.5! Or about 1+ MPG more. Even with being stuck in dead stop traffic for 1 hour. At that rate, the $85 will pay for it self quickly. Not bad for a 4 door and simple modifications done to the Jimmy.

[gchemist]

Update: The Jimmy has a solid 22+ MPG with PCM programming. It was close to 21-21.5 prior to reprogramming. It pulled 335.4 miles on 15 gallons. The gain is close to OD expected gains from the 4L60E.

I don't know how much the ram air will affect results. I'll post more results after running the ram air setup.

[immexicansostfu]

thats really good. i get about 20-21 in mine

[nate98blazer]

now im guessing this is highway mileage cuz i get about 20 highway in my 4 door, about 15 city, and city is mostly what i drive, thats the one im really curious about. i may have to try to snag me a pcm from u-pull it next time i go out there

[gchemist]

Note the 22+ is about 95% highway. I parked it unless I needed to drive a long trip. I wanted to get a feel for a long trip haul. I'm a happy with programming.

So at 18.5 MPG city driving ($3.89 per gallon), after 409 miles the PCM programming has paid for itself. 409 miles is easy for me in one month.

[4UH8Rs]

i would send mines in but the downside is i need my blazer everyday

[Yogi]

You can buy one from them for $159, including programming.

[pack of q tips]

can they solve check engine lights?
mine is on because i removed my evap system can they trick it into thinking its working?

[Yogi]

Quote: Originally Posted by pack of q tips

can they solve check engine lights?
mine is on because i removed my evap system can they trick it into thinking its working?

Sure. Piece of cake! And EGR delete also.

[usmc_noma]

what's the specs on your jimmy? is it lowered, lifted, etc?

what all did you do to your spider and don't the blazer/jimmys come with an external tranny cooler? not sure on the cooler.

[gchemist]

No major mods. It is lifted 3" because of the tires. 255/60R17 or about 29". Stock were 235/60R15s or 26.1". Updated FI spider, NGK spark plugs, tune up, K&N filter, 10-30 WT Castrol oil, a little Marvel Mystery oil in fuel tank added recenty, a little in the crank case too. Dexcool gone, running straight water right now. Flushing all the Dexcool stuff out. Will go to green coolant at the of summer. 195 thermostat with two small holes drilled into it. Check my pictures for details. I cut off the throttle body restrictor plate. Installed new U-joints.

Now it has a ram air or cold air setup too. I'll update any gains after running a tank or so.

The external transmission cooler is add on. Simple installation. You only cut the return line from radiator. Route it to the external cooler. Route the cooler back to the transmission return line.

The Jimmy is basically stock with minor changes. I am thinking about adding an electric fan. An electrical fan may make the gains solid and possibly ain a little more.

[immexicansostfu]

Quote: Originally Posted by nate98blazer

now im guessing this is highway mileage cuz i get about 20 highway in my 4 door, about 15 city, and city is mostly what i drive, thats the one im really curious about. i may have to try to snag me a pcm from u-pull it next time i go out there

no i get this in city. i know this for a fact cuz i deliver pizza everyday and fill up before work and after and do a lil math on how many miles / how many gallons. and thats wut i get. hwy prob about the same if not a lil more.