I do have a question , Table 44216(stopped Idle VSS) , have you ever increased it from OEM 1MPH ? did you ever "play with it" my kids got a 08 3.8 JK coming in to the shop next week that 's getting a 505performance Stage3 cam , Normally I bump 44216 bump up to 5MPH(most V8s is 3mph) with any performance cam install , was just wondering if you ever changed your and if it responded to the change.
62 Biscayne 425/409 SS/D stock class car 10.60s
66 Dart 426CIG3 8.60@171 2750lbs Naturally asperated
04 Ram All Alum , 468Ci G3 10.50s @4800 lbs Naturally asperated
04 Rumble Bee, built 6.1 ,4000lbs 10.48 @ 129s MPH. Naturally asperated
05 Rumble Stock 5.7, 3.92s TUNE ONLY 13.94@98mph
Yep, I have tried changing the Stopped Idle VSS (table 44216). Wish I could remember what the downside was, but I ended up liking changes to the Idle VSS (table 12983 on the Fuel>Oxygen Sensors tab) from 5 to 7 MPH. If I remember right, this made it easier (more time) for the PCM to update the idle fuel trims to better numbers after some temporary heat-soak.Originally Posted by rays04gtx
Very interested in your 3.8L project, stay in touch!
Hey Mr T... V558 is your latest tune right? (I think I have one of your older ones saved). I just read the little womans 2010 Rubicon and am going to start working on a tune for her jeep.
If I recall correctly, isnt your jeep a manual trans jeep?
I need to re-read this thread and understand what you did to shorten my learning curve (HPT experience = dodge diesel, this is my 1st gasser).
Yep, V558 is the latest and it's a manual trans.
hey any reason this shouldnt work on a 6 speed 2007?Yep, V558 is the latest and it's a manual trans.
Should be the same, or very similar. Compare, copy and paste to your stock tune file as desired.
3.8L Jeep tune update
Latest update added to post #1, and I'm pretty happy with this change! Essentially it's a three part'er to get smooth and precise torque when slipping the clutch from a dead stop, especially on inclines or obstacles. The newest change is to make the part throttle spark table more gradual as it increases the advance beyond idle. Note that it actually idles with about 5.5 deg despite the 20 something degrees in the table, which makes the transition from idle to just above a balancing act that's not directly adjustable. The second change is getting rid of the large bump in pedal to throttle blade just off-idle, and the third is a tighter proportional band for idle speed control.
The result is quite an improvement, it even sounds better just off idle slipping the clutch from a dead stop. Before, it's always tended to have a rough and shaky spot there, like spark advance and combustion were erratic. Maybe this engine has some tolerance stacking and the actual real timing is running advanced, or maybe it's the higher alcohol in fuel these days. Here's part throttle spark graphs, top is stock, crawl tune is at the bottom.
PTspark 1.jpg
PTspark 2.jpg
@Mr.T I have yet to drop in the 1st tune on the wifes JK, bandwidth is not allowing for it if it goes down for any reason. But... I did pop on a 2008+ 4.7L TB on it and was quite surprised by the performance change. She has seen an approx 1.5 mpg bump, seemingly reduced if not eliminated throttle lag and easier pulls up hill where it no longer sounds like the engine is going to start crying at any time... much easier to pull the hills. The next step there is to fab up an appropriate intake hose from the air box, will be going 3" end to end.
Did you do this mod on your jeep?
Also, I did a mod to my 2002 Dakota 4wd 4.7 where I added capacity for the intake manifold. This gave the Dak a very SOTP noticeable bump in power from approx 1500-3k rpms, right where I wanted it. Was shocked by it so I experimented further and found that the higher the vacuum in the IM the better the power was. I am believing that it is coming from advanced timing with the higher vacuum signal. I originally set out to smooth out the MAP sensor signal from previous mods and discovered this.
I want to do that mod to the wifes JK but I believe it is responsible for a large evap leak code on the Dak. Do you know if there is a way to change the trip point for the large evap leak detection?
I am looking at late july before I can do some tuning on her jeep (Ram should be back on-line by then so 3 vehicles between us).
I haven't changed the TB (Throttle Body); the logging I've done is showing very little pressure drop at WOT with the original TB, especially using an AFE intake with the large 7-layer filter. A larger TB would flow more at lower opening, and that would give more power with less accelerator pedal -- But I'm suspecting nearly the same when fully open??? A larger TB would also change the expected airflow for a given TB opening, which has an associated table that would be interesting to change with data to match a calibration that used that larger TB.
On a related note, there is also a table to change the pedal to throttle blade relationship so that there is more opening with less pedal. I've actually been going down the opposite path, making the initial TB opening less when the pedal is initially pressed -- Going for fine control rather than quick power.
I've never seen any settings for large evap leak detection, but it kind of sounds like an unrelated separate problem??? Regarding the intake manifold capacity, did you mean you changed the volume setting in the tune?
Last edited by Mr.T; 06-14-2023 at 11:29 AM.
The large EVAP leak came with the pipes off the IM.
On the IM capacity... adding a 1 1/2" by 9" pipe to the brake booster hose. I suspect the MAP is being monitored for its ramp rate as the engine pulls a vacuum in the manifold... Or it is monitoring a steady state value which is outside of its limits.
The biggest change with the TB was bottom end throttle response and performance. I will have a look for the table to change the pedal/TB blade relationship.
From the Jeep factory service manual...
The ESM switch mentioned above is essentially a vacuum switch that closes at a very slight vacuum, as in a few inches of water. The purge solenoid uses the relatively high vacuum in the intake manifold at part throttle to pull a slight vacuum on the fuel tank and evap canister which closes the ESM switch, then the PCM closes the purge solenoid with an expectation that it will hold vacuum (ESM switch staying closed) for some time period -- If not, there's a large leak. Can't quite see how adding a pipe to the brake booster hose would affect how this works.P0455 When Monitored:
With the engine running, during a cold start test with the fuel level above 12%, ambient temperature
between 4 degrees C and 32 degrees C (39 degrees F and 89 degrees F) and the fuel system in
closed loop. The test runs when the small leak test is maturing.
Set Condition:
The PCM activates the EVAP Purge Solenoid to pull the EVAP system into a vacuum to close the ESM switch. Once the ESM switch is closed, the PCM turns the EVAP Purge solenoid off to seal the EVAP system. If the ESM switch reopens before the calibrated amount of time, a large leak error is detected. Two Trip Fault. Three good trips to turn off the MIL.
Possible Causes
EVAP PURGE SYSTEM LEAK
EVAP PURGE SOLENOID
EVAP SYSTEM MONITOR SWITCH
Last edited by Mr.T; 06-14-2023 at 03:08 PM.
Thanks for posting up the process... Looks like it was coincidental to adding the tube, found the large leak yesterday while filling up, nice puddle of fuel under the tank when the tank is full. I will be dropping the tank to redo the lines under there and address the leak.From the Jeep factory service manual...
The ESM switch mentioned above is essentially a vacuum switch that closes at a very slight vacuum, as in a few inches of water. The purge solenoid uses the relatively high vacuum in the intake manifold at part throttle to pull a slight vacuum on the fuel tank and evap canister which closes the ESM switch, then the PCM closes the purge solenoid with an expectation that it will hold vacuum (ESM switch staying closed) for some time period -- If not, there's a large leak. Can't quite see how adding a pipe to the brake booster hose would affect how this works.
With that said, the Jeep will get the added tube this weekend as well.
It's nice when leaks like that show themselves! The tube sounds interesting, curious how it turns out on the 3.8L Jeep.
I will post up some feedback once its in.
I did the mod to the wifes Jeep Jk Wrangler over the weekend... did not feel anything close to what the Dakota showed. Installed a 12" section T'd off the brake booster line. She has been hand calculating her fuel and was un-aware her jeep had a LOM (Lie-o-Meter) for mpg's until recently. Her Jeep has historically been in the 12 mpg range with no long commutes to work (6 mi one way, most of it 35-45 mph backroads with 2 mi of freeway). Her jeep is a poster child for what not to do to get good mpg's... cut fenders, huge tires on heavy wheels powered by a tiny 3.8L mini van motor from dodge.
What I have done and what it did for mpg's...
1) Recalibrated the throttle body, this right away gave better throttle response and took mpg's from the 12's to the low 14's.
2) Installed a 4.7L throttle body, I believe it is 72mm and is referred to as the viper TB mod in the jeep world. This gave a noticeable bump in performance and the jeep no longer feels like its getting beat to death going up the taller grades that are local to us. 2 of them in particular you had to really get into the throttle just to keep the speed loss to 5 mph. RPMs were often in the 3000+ range. It seemed to me it was downshifting 2x a t times. Now there is just one downshift and it pulls the hills much better. I had to create a makeshift intake tube adapter to get this to work, the flow is pinched on the inside of the tube (has always been like that) and will be making a 3" setup from airbox to the throttle body. The 1st tank after this mod gave her a 15.1 mpg tank. At my request, she also reset the LOM when filling up on this tank. The LOM read 15.3 mpg so it was pretty close. She was so happy I was rewarded with slice of cheesecake on Fathers Day. Now that is a good motivator hahaha.
3) Next (Saturday) I installed the "potato launcher" mod as I call it... Felt nothing SOTP that really stood out. Having a full tank with just 3 miles on it and the LOM having been reset, we used the Jeep for all activities this weekend, 80~90 miles I'm guessing and the LOM is indicating a 16.7 mpg. Knowing the thing is not that accurate until miles pile up we are not getting excited by it.
This week she is ditching me for a getaway with her kids so the Jeep will be parked at the airport for several days. Will report back what the tank ended up at when I know.
Last edited by steve05ram360; 06-21-2023 at 11:16 AM.
and to followup...mpg's came in at 15.3 mpg, as expected power jumps with cold fuel in the tank. Going to take a step back with the mod, wrap the fuel rail and lower manifold if possible w/o removing it and change the upper gaskets. They appear to be leaking from egr gasses.
200K miles tune update
I've updated the tune file in the first post with small changes in the spark tables for warm/hot temperatures and higher altitudes, plus some minor VE improvement at the high-end resulting from replacing the cats.
Bobble Torque is back to the stock setting. Lots of comparisons made, and throttle in the coast-acceleration zone is mostly smoother with it, especially when combined with a throttle curve (Pedal Percent Power Request 35060) that does not have the bump at initial opening.
Also fixed a minor bug in the idle speed control that caused a slight hunt under some conditions -- For reference, fine control of idle speed is with spark advance, and throttle control must be such that it doesn't move the throttle until there's a substantial RPM change.
Running better than ever after 200K miles...
Last edited by Mr.T; 07-16-2023 at 01:59 PM.
@Mr.T Did more work on the intake manifold mod with the tube on the vacuum booster line, what I have learned... the 12" tube gave great mpg's on the hiway but horrible in town (most of her driving). There was no SOTP bump in power with the 12", just mpg's on the hiway. Dropped down to a 9" tube and had similar results. Yesterday dropped down to a 5" tube and now I can feel SOTP change in power. Drove the jeep back to back days to work and on the hills, there is definitely a bump in low~mid range power with the 5" tube. Not driving her jeep daily I cant say what it will do for mpg's until she runs another 200ish miles on a fresh tank. I suspect that the engines ability to create a vacuum at part throttle makes a difference when picking a tube length.
Had no CE lights on her Jeep with this mod, the Dak & its large evap leak is a gross leak on the top of the tank which I believe is the seal for the pump (getting it swapped today).
Your tune (modified for her AT) will be going in 2 weeks from now (have a 3rd ride now in case something goes wrong)
@steve05ram360 Can you explain what you did to recalibrate the 4.7 TB on the JK 3.8 engine. I am looking for any mods for my JK that can help with low to mid range power. I have a bunch of long hills on the way to the beach and my jeep really struggles with them. I have an auto trans and on 37s with 5.38 gears and it cant keep 70 mph without downshifting and the rpms going way up. Also if you could post your tune with the TB calibration once you get it working it would be appreciated. Thanks
I followed the instructions outlined on one of the forums for TB cal... iirc it was as simple as turn key on, wait unti lights go off on dash, then slowly depress and release the throttle, then its either start the engine or cycle power and start the engine.
Other things I have done to the jeep for more power (still not tuned, waiting for my list of mods to be done 1st now...)
1) Dodge 4.7 2008 & up Throttle body aka viper TB mod - use an intake hose from an old jeep grand cherokee with a V8 & the separate TB hat, fits excellent but you will need to drill a hole to relocate the IAT sensor into it. This mod cost me under $50 for TB, hose & clamps at pick & pull.
2) 1-9" piece of 1.5" abs tube tapped into the brake booster line, still working on this mod.
3) 180* t-stat
4) Installed a custom piece under the air filter to make the airflow into the filter less turbulent, I just did this mod yesterday and the only feedback so far from the wife (her jeep) is it is an improvement over just the throttle body. I put 30ish miles on it yesterday and power was coming up towards the end of the drive, presumably the fuel trims were normalizing.
5) Soon to be installed fuel rail wrap to insulate the fuel rail from engine heat soak (I use exhaust wrap, simple install on most engines. Need to pull the upper intake maniifold on this one to get access to the fuel rail) This mod gives better low & mid range power, power that is not lost to heat soak. A fuel cooler is better but these days I dont risk it as it needs to be mounted in the air flow.
6) Soon to be installed lower intake manifold wrap to prevent heat soak.
MPG's have gone from 12's to 15's with the TB swap, hose was just added recently from a patched together setup that used the OEM hose, did not like that setup but I made it work.
From yesterdays air box mod... I noted that in the local back roads around home, cruising rpms are in high gear now vs 3rd. The wife also commented that same observation.
HTH.
FWIW, I have done these mods (and a few others) to the 2002 dakota I have and the thing rips pretty decently for being the heaviest dak on the worst gears... (3.55's) running a taller E rated tire.
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