2.5 turbo build

[Jezza]

I had mine running pretty well on HP before I switched over to stand alone. I was running the GM 12615136 2 bar sensor and had the fuel trims completely disabled. I would recommend leaving the trims turned on while you are dialing in the fuel map. That is one of the huge advantages of HP is being able to tune the fuel using trims and histograms. When you key on with the engine not running what is your MAP voltage and what is the displayed value for MAP in Kpa? Mine is a 4.0 so it is a bit different, but I can send you a copy of what I was running if that helps.

 

[Terrrs01]

I had mine running pretty well on HP before I switched over to stand alone. I was running the GM 12615136 2 bar sensor and had the fuel trims completely disabled. I would recommend leaving the trims turned on while you are dialing in the fuel map. That is one of the huge advantages of HP is being able to tune the fuel using trims and histograms. When you key on with the engine not running what is your MAP voltage and what is the displayed value for MAP in Kpa? Mine is a 4.0 so it is a bit different, but I can send you a copy of what I was running if that helps.

So KOEO with my GM 2 bar sensor I get 2.25V and (depending on what map scaling I put in) I get anywhere from 50-70.

It’s so odd. My Initial tune worked great for 2-3 hours of driving time and then through it’s first (low map sensor) code and switch to limp mode where the KPA stays at 40 no matter what and revs limit at 3k. During this turn I never messed with any high/low map volt limits or and baro adjustments. HOWEVER ever since then I’ve adjusted the tune 30+ times messing with baro and low/high map volt limit and a few other things and it will enter limp within 5sec every time. The only thing that will get it out of limp mode is using the stock 1 bar sensor.

if you don’t mind sending that tune that would help out a ton! I’d love to be able to compare what I have just to make sure I have missed anything. You can email to: terrrs01@gmail.com (3 r’s) lol.
Thanks for you help man

 

[BigKID]

If I am understanding the events correctly, sounds like a faulty 2bar MAP sensor. I would try a known good 2bar map and see if that works. You could also test the map with a multimeter and vac/pressure pump. I am sure there are pressure/ohms tables on the net for your particular sensor.

 

[Terrrs01]

If I am understanding the events correctly, sounds like a faulty 2bar MAP sensor. I would try a known good 2bar map and see if that works. You could also test the map with a multimeter and vac/pressure pump. I am sure there are pressure/ohms tables on the net for your particular sensor.

I went ahead and bought another just to be safe. The new one read the same as the old one, and oddly enough when I put the old one back in it stopped working completely :/

The whole tuning thing is starting to bug me. The bad side of all this is I have a decent 1 bar stock tune that does “ok” (pretty rich in the highway tho). This is unfortunate because it doesn’t really motivate me too much to get around to the 2 bar tune problem. (Hence why this is 2 months old lol)

 

[Terrrs01]

Update #??????
So I finally got around to working in this 2 bar map tune again. I ditched the GM 2 bar just for $hits and giggles and went to a 2.25bar SRT4 map sensor. The stock map scale was set at 244 and with the GM I had to down scale to 190-210 ish. With this new one for some odd reason I have to UP scale. My map scaling is around 290 with a KOEO kpa60, 7lbs of boost its at 85 ish.
BIG NEWS! No limp mode!

not really sure why, I was getting a limp mode when rescaling and then randomly at map scale 290 it went away. My guess is it isn’t related to the map scale but more of something else I have messed and by changing the map I crossed over some weird Kpa threshold. I still need to tinker on a few things and wait for my new wideband sensor to get here but I should have a decent trail and streets me tune before our Moab trip in late June!

 

[SvtLdr]

Have you considered if/ how the elevation in Moab (4,000 ft) will affect your tune as compared to the elevation you're at now (800 ft)?

 

[Terrrs01]

Have you considered if/ how the elevation in Moab (4,000 ft) will affect your tune as compared to the elevation you're at now (800 ft)?

A little but it’s a bit confusing, and to be honest I’m kind of interested in seeing what happens.

-Our jeeps do have a barometric gauge that reads right when we turn out engine on before it starts. The odd part is it reads this baro reading through our MAP sensor so even if everything was perfectly tuned, since I rescaled the MAP sensor I’m not sure how accurate the baro reading/adjustment would be. The baro reading is then used as a multipler for higher altitude=lowers pressure.I added a pic for reference. My current tune I have all of those changed to 1 so it doesn’t mess with my tune.

-baro adjusted seems I be one of the biggest issues with tuning out JTEC PCM’s. Most guys seem to tune their jeep at theirs level/ with rescaling their MAP and then tell the baro to fly a kite. My problem is I won’t be able to really “tune” for 4,000 feet without really being there. After rescaling my MAP, my Kpa is no longer a real Kpa reference but essentially a small algorithm. An example is (rough numbers) we are semi close to see level.
-I get 99kpa with stock tune, stock map which is right around 14psi of ambient barometric pressure.
-After my map rescaling my jeep now recognizes its ambient baro pressure at 69kpa at the same exact location.

-could I guess a tune??? Sure. But the right thing to do would be to check what my jeep recognized before it starts at west. Maybe there is some math I could do but ehhh. Who has time for that.

Back to math...
I did some calculations and the 3,200ft difference only came out to about 13kpa off. I would hate to have any weird problems with no Internet to be able to reflash every so I think I might just chance it and see. 13kpa difference isn’t too much anyways. More fuel and less air is typically better than more air and less fuel lol.

 

[Jezza]

That's one of the reasons I don't care for HP. When you put 1s in all the boxes for the altitude correction it kills the PCMs ability to change the fueling for different barometric conditions. The PCM uses the MAP sensor at key on to determine the current barometric pressure, but I think it also updates the baro at WOT as well. In my experience every time you hit a higher boost level it moves you higher up the altitude table making it useless for actual altitude correction.

 

[Terrrs01]

That's one of the reasons I don't care for HP. When you put 1s in all the boxes for the altitude correction it kills the PCMs ability to change the fueling for different barometric conditions. The PCM uses the MAP sensor at key on to determine the current barometric pressure, but I think it also updates the baro at WOT as well. In my experience every time you hit a higher boost level it moves you higher up the altitude table making it useless for actual altitude correction.

So I’m pretty close on my current tune and I see exactly what you were talking about earlier. Very hard to get a constant AFR. It varies more than I expected it to be, so it’s making tuning a little tough. I almost have to tune everything a tad rich to account for variable change and still be safe.
Good news tho is your tune helped out and so far (about 2 hours of driving) no limp mode.

 

[Terrrs01]

Update:
Went Dow to dirty turtle off road in KY for the first time. I currently had the jeep on a 1 bar tune, which honestly worked very well for wheeling (just not highway cruising).

This was the first time I really got to climb some rocks, climb some steep sketchy hills, and breaks some parts with the newly added horse power.

The problem I did find with having a turbo while wheeling is I always want to hear it! This makes me drive a little more on the skinny petal. And ended up snapping an axle shaft and scoring my locker pretty good.

 

[Wildman]

Update:
Went Dow to dirty turtle off road in KY for the first time. I currently had the jeep on a 1 bar tune, which honestly worked very well for wheeling (just not highway cruising).

This was the first time I really got to climb some rocks, climb some steep sketchy hills, and breaks some parts with the newly added horse power.

The problem I did find with having a turbo while wheeling is I always want to hear it! This makes me drive a little more on the skinny petal. And ended up snapping an axle shaft and scoring my locker pretty good. View attachment 255279
View attachment 255280

That power is addicting or the sound of it is... Bummer about the axle shaft. Hope it didn't do any serious damage to your locker.

 

[Terrrs01]

That power is addicting or the sound of it is... Bummer about the axle shaft. Hope it didn't do any serious damage to your locker.

It sure is! I started with 5lbs thinking I’ll stay at 5. Then I moved to 7lb where I’m at currently and could really tell the difference. Now I’m itching to sneak to 8-9, but I think I might be pushing my luck :/

-I ended up saving the locker. A few hours with the dremil and was able to clean it up and press a new bearing on. Scared to screw up my locker again, I went ahead and ordered some 4340 chromo from axles shafts. We shall see how they hold up

 

[Wildman]

It sure is! I started with 5lbs thinking I’ll stay at 5. Then I moved to 7lb where I’m at currently and could really tell the difference. Now I’m itching to sneak to 8-9, but I think I might be pushing my luck :/

-I ended up saving the locker. A few hours with the dremil and was able to clean it up and press a new bearing on. Scared to screw up my locker again, I went ahead and ordered some 4340 chromo from axles shafts. We shall see how they hold up

Is this the front or rear axle? If it's a rear Dana 35 you should get the 1541 shafts and not 4340 as the way the bearings ride on the shaft can cause issues.

Hey I've broken 2 Dana 60 R&P's in my TJ & the V-8.

 

[SvtLdr]

That was his front HP Dana30. He was trying to climb out of a tank trap.

 

[Wildman]

That was his front HP Dana30. He was trying to climb out of a tank trap. View attachment 255333View attachment 255334

Yep that seems to do it. Great pictures.

 

[SvtLdr]

I gotta give him credit, I've been wheeling with him for alot of years. I've seen him dish out a number of rev-limiting beat downs on that 2.5Liter. He's never made enough power to break a shaft before, so he must be doing something right - even if it's not his driving. Lol

 

[Wildman]

I gotta give him credit, I've been wheeling with him for alot of years. I've seen him dish out a number of rev-limiting beat downs on that 2.5Liter. He's never made enough power to break a shaft before, so he must be doing something right - even if it's not his driving. Lol

Yep I never broke a front shaft even on 35" tires & my 4 cyl but I did break a u-joint & bust a Warn small hub in pretty much the same type of situation. I really enjoy reading about how he's coming along on this turbo install & tuning.

 

[SvtLdr]

He's learned alot in a short period of time, simply by reading, trying stuff and just figuring it out. I'm glad he's posting things here that might help others too.

 

[Terrrs01]

Update: I’m maybe 2 weeks into the tune and no problems! Not codes/limp mode. We went jeeping this past weekend and about half way through the day I noticed my AFR at idle went from 14.5ish to 10. You could smell the extra fuel, however once in boost the AFR went to what would be expected. A few hours later it actually through a cylinder2 misfire code, and could almost feel a small hesitation at idle but ran decide the rest of the day.

Got home that weekend and swapped out plugs just incase it was from a fouled plug, no help... Then I figured it could maybe be a sticky fuel injector since I bought cheap eBay 30lb ones lol. So I ended up buy another 4 to swap in and turn mine into spares. HOWEVER none of that was needed.

The next day I went out cruising and did a little data logging and noticed every now and then my MAP voltage would hang up and pause. First I thought it was a bad MAP sensor but then I realized a cheap vacume hose I had to the MAP got very hot and under a vacume it was actually sucking it’s self close. Swapped in a new hose and we are back in business!

 

[Terrrs01]

So been having a problem getting past 5psi lately. I current have a 5psi spring in my internal Wastegate but installed a mechanical boost controller awhile ago (which essentially bleeds a small amount of air right before the wastegate) and thought I had it set to 6psi, however over the past week I noticed I haven’t been much over 5psi.

Recently I put a new tune in the jeep to run 7/8 psi. I went to adjust the controller, which is very time consuming. You pretty much turn a screw, drop the pedal and create some boost, and repeat until your max boost where you like it. I spent a good 3 hours doing this and could not get over 5psi.

I then started to diagnose the problem. First I decided to closed the wastegate with a large spring I had. Went for a cruise, still 5psi. Next I went to check for boost leaks and ended up making my homemade boost leak tester. It’s just some simple PVC a rubber coupler and a valve stem.

I ended up have 4-5 very small leaks. I had to tighten almost every coupler. What I initially thought was tight was not lol. Fixed up all the leaks and and went for a test ride and nothing... no change.

confused, I decided to remove the controller, remove the hose to the wastegate and plug it with a screw. Went for a cruise and bam went to 17psi. Sketchy for sure! Got back to my shop and started thinking. I then was blowing through the boost controller and found the problem. Turns out the controller is directional and I had it in BACKWARDS and it was just bleed off the same amount of boost no matter what setting it was at. Lol

After feeling dumb, I put it on the correct way, tuned a few things and now boosting around 7/8psi. We live we learn.