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HP Tuners MPVI3 and a Jeep

TerryD

TerryD

Mildly demented...
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I ordered the MPVI3 this evening to start tweaking the ECM in my LJ. I'm going to download the software and start playing around with it this evening.

I need to start by correcting for my new 4 hole injectors. I've noticed LTFTs zero out on hard acceleration and climbing a hill on the interstate yesterday while completely alone, I could smell sour converter. I'm thinking my fuel tables being set for the smaller OE injectors are throwing it really rich during PE.

I also want to work on the transmission shifts. It behaves pretty terribly as most Chrysler automatics do.
 
I thought LTFT's of 0 was actually good. The farther from 0 they are the more they're trying to compensate..?
 
I don't know Chrysler PCMs, but there should be a setting that represents the flow of the injector. It's better to adjust there than try to scale your entire VE and MAF tables.
 
JoshHefnerX said:
I thought LTFT's of 0 was actually good. The farther from 0 they are the more they're trying to compensate..?
Click to expand...
Well, if my cruise LTFTs were 0%, yes. But when I go to PE (power enrichment) it just blanks them so it doesn't seem to be adjusting the base rates in PE for the larger injectors and seems to be running on a preset value based on the old OE injectors. That would be 7-10% too rich for my current injectors.
 
Blue85 said:
I don't know Chrysler PCMs, but there should be a setting that represents the flow of the injector. It's better to adjust there than try to scale your entire VE and MAF tables.
Click to expand...
I had meant to download the software last night and try to find a 2006 tune to explore but by the time I was done with chores and my shower, it was past my old man bedtime....

Also, this is a speed density setup. Last year of the TJ with the JK inbound so they made zero effort to update it.
 
TerryD said:
when I go to PE (power enrichment) it just blanks them so it doesn't seem to be adjusting the base rates in PE for the larger injectors and seems to be running on a preset value based on the old OE injectors. That would be 7-10% too rich for my current injectors.
Click to expand...
That's all it can do. WOT/PE is open loop. It's trying to run rich, like 13.5:1 or something. With a standard O2 sensor, the PCM has no idea if you're at 14.4:1 or 10:1. It only knows it's richer than 14.7.
 
Blue85 said:
That's all it can do. WOT/PE is open loop. It's trying to run rich, like 13.5:1 or something. With a standard O2 sensor, the PCM has no idea if you're at 14.4:1 or 10:1. It only knows it's richer than 14.7.
Click to expand...
That's what I was thinking but it's been a while since I dug in to the theory of it all.

Also looking for a WBO2 controller that will simulate a NBO2 signal and run one of my O2 sensors through that for tuning purposes. I can lock it in open loop if need be but I wouldn't mind being able to reference my LTFTs on one "bank" (front 3 VS rear 3 cylinders).
 
Well. The programmer arrived today. It will not read the ECM in the PCM. It will read the TCM though. Not sure what's going on yet.

It's never simple...
 
How many credits did you buy? Some take credits for both the ECM and the TCM.
 
Blue85 said:
How many credits did you buy? Some take credits for both the ECM and the TCM.
Click to expand...
2. Doesn't require credits to read from what I read online.

Possible battery voltage issue? Drove it to breakfast and was able to read both ECM and TCM afterwards.
 
I got it to read this morning after logging while driving it to breakfast. I'm thinking it is a Jeep battery or lap top battery issue? I've seen both reported with "timeout" issues.

Moving forward, I'm going to do some testing but I will probably have the Jeep on a charger when I try to read or write.
 
So twice today I've written tunes to the ECM successfully. I charged the battery while I did an oil change and that SEEMS to have been the holdup.

1st tune I bumped the entire timing table by 3 deg. I've seen guys say these 4.0Ls will take 9 deg without issue but I'm playing it safe for now. It made a noticeable difference though. Slid it out sideways from a dead stop off an interstate exit. Never done that on dry pavement before, especially with me not driving very hard.

2nd tune I adjusted the PWM tables for the injectors to account for higher flow from the Bosch 4 hole injectors that are in it. I don't have exact info on them so I went conservative again and raised the table by 3%. I'm was getting between 5% and 9% negative LTFTs across the board. Hopefully this will bring them closer to 0.

I need to drive it more so it can adjust and then I'll do some logging to see where to go from here.

My next focus will be shift points I think.
 
If you're not confident in that battery, don't do any writes.. Good way to brick it. Bricked one of my vehicles once. Thankfully I was able to send to someone to fix it.
 
JoshHefnerX said:
If you're not confident in that battery, don't do any writes.. Good way to brick it. Bricked one of my vehicles once. Thankfully I was able to send to someone to fix it.
Click to expand...
Good to know. The battery is good, I short trip to work and back plus I spent several hours with the doors open a lot cleaning it a few weekends ago.

I do a maintenance charge with a NOCO charger every oil change on all our vehicles these days for just that reason. But I will definitely stick it on charge before I do a bunch of tuning in the future.
 
It's general procedure to have a charger on the vehicle while writing.

Again, don't rescale an entire table to account for different injectors. Start by correcting the injector information and then see what else is needed.
 
Not sure if you dug into their pages or not - but this is the suggestions when writing.


I use a 'dumb' charger while I'm writing, as I figured any of the 'smart' ones have the chance to change up what they're doing in the middle of a write adding noise to the system. They also suggest making sure accessories arent changing/lights ect all for the same reason. Newer vehicles have gotten better about writes but..
 
Blue85 said:
It's general procedure to have a charger on the vehicle while writing.

Again, don't rescale an entire table to account for different injectors. Start by correcting the injector information and then see what else is needed.
Click to expand...
I corrected the PWM VS fuel tables for the injectors. Dropped them by roughly 3%. LTFTs are less negative than they were to start with. I need to find a more accurate flow chart for these injectors though. Right now I'm guessing but these were a rebuilt set I bought from Precision Auto Injectors. They might have a closer scale for me.
 
I've been doing a little cleanup on the tune. I missed the startup scalar and min pulse width. I also dropped the startup PW table as well to lean out the start back to OE-ish ranges.
 
I also have my 2006 LJ 4.0 licensed on my mpvi3. I haven’t done much tuning with mine yet. I have no mods to my engine. I just licensed mine cause I had the mpvi3 and wanted to be able to adjust it.

If your comfortable pulling a valve body this shift kit from transgo cleans up the 42rle shifts quite a bit.
transgo.com

TransGo - Chrysler 604 SHIFT KIT® Valve Body Repair Kit

This TransGo 604 SHIFT KIT® Valve Body Repair Kit fits 1989 and newer Chrysler, Plymouth, Dodge, Eagle, Ram, Jeep and Mitsubishi vehicles equipped with
transgo.com transgo.com
 
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