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Turbo boost logic?

jeepin48

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Many of you have seen that my Jeep is struggling to do what other diesels are doing while towing a trailer. It does not overheat but instead faults other codes and goes into limp mode. In an attempt to figure this out myself, I have started looking at some OBD stats while I am driving. I have found that while doing just 55 mph, my turbo is boosting to 100% or about 22 PSI according to my OBD FUSION app.

Can anyone confirm what boost they are getting while cruising at 55 mph and 65 mph with a trailer?

Here are some screenshots from my app that show I reach 100% full boost while the calculated engine load is only 75%. I am not sure if this is standard or if this points toward an issue with my boost controller. My only explanation is that the way this turbo is controlled is done through the VGT to vary the volume of air going through, while maintaining full boost.

-screen shots where towing at 65mph on flat ground with light head wind.
-the OBD Fusion app I was using was the setup for a Ram 3.0L so the number may off.

Jeep Gladiator Turbo boost logic? Screenshot_20221008-172305


Jeep Gladiator Turbo boost logic? Screenshot_20221008-164439
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@californiajeeping

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22psi is not full boost. It should make closer to 28-29 fully loaded 100% throttle going through the gears.

While cruising I usually see over 18-20psi quickly up a slight incline or at higher speed unloaded in 8th (I manually shift to 8 early and keep steady throttle to keep boost up) but with big tires. (similar to towing a trailer).

Sometimes at higher altitude 4-5000ft it struggles to make ~19-20psi unless full throttle running through the gears.

You want as much boost as possible even while cruising. This will keep your EGT's low and give you the most power. Your engine load is 75% that boost is about right. The extra 25% is probably going to get you up to 26-28psi.

I dont see a problem there. What issues are you experiencing exactly and what is your trailer weight and frontal area looking like?
 
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jeepin48

jeepin48

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@californiajeeping . Thanks for the detailed replied. Can you please tell me how you read your boost psi? I would think I can read it with my Tazer also but I would like to confirm apple to apples as my OBD Fusion app is likely doing calculations for a Dodge truck because I used the template from the Ram forum.

My truck keeps getting a lightening bolt and it derates to about 50% and says service electronic throttle. I have to restart it to get full power back and it typically comes back if I dont let it significantly cool down. Dealer says there are no component malfunctions and nothing to fix.
 

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I'm using the Banks iDash gauge. Cruising, it bounces around depending on grade. Full boost, I've seen 30.4 psi.
 

@californiajeeping

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@californiajeeping . Thanks for the detailed replied. Can you please tell me how you read your boost psi? I would think I can read it with my Tazer also but I would like to confirm apple to apples as my OBD Fusion app is likely doing calculations for a Dodge truck because I used the template from the Ram forum.

My truck keeps getting a lightening bolt and it derates to about 50% and says service electronic throttle. I have to restart it to get full power back and it typically comes back if I dont let it significantly cool down. Dealer says there are no component malfunctions and nothing to fix.
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DPF says 100%.. that can’t be right.
 
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jeepin48

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DPF says 100%.. that can’t be right.
I am new to this OBD stuff so it may be wrong. I am using a "program" from a dodge truck with the 3.0L so it is probably off.
 

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That EGT right, at cruise w a trailer, pretty high. If going up a hill I guess, but on flats even with a trailer should be in the 900 or less range
 

@californiajeeping

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That EGT right, at cruise w a trailer, pretty high. If going up a hill I guess, but on flats even with a trailer should be in the 900 or less range
I also notice that if EOT is above 230 the VGT seems to hold the turbo back. I need to datalog to confirm.
 

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Jeepin48,

The screenshots are showing you were in regen mode. It seems to be running normally. The EGT is getting hotter, looks like a warmup stage in the regen process to get exhaust up to 1200 F for about 20 minutes. The 100% soot is a good give away. It will show higher load during a regen as 30% of fuel is not useable for torque, since it is pushed out during exhaust stroke to make heat.
 

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@californiajeeping . Thanks for the detailed replied. Can you please tell me how you read your boost psi? I would think I can read it with my Tazer also but I would like to confirm apple to apples as my OBD Fusion app is likely doing calculations for a Dodge truck because I used the template from the Ram forum.

My truck keeps getting a lightening bolt and it derates to about 50% and says service electronic throttle. I have to restart it to get full power back and it typically comes back if I dont let it significantly cool down. Dealer says there are no component malfunctions and nothing to fix.
Your reluctor ring has lost a magnet. When this happens your truck switches from using the crank position sensor to the cam position sensor and effectively goes into limp mode. Take it to the dealer. Tell them you want the reluctor wheel and crank position sensor replaced. There isca recall for the ecodiesel on this exact issue. Search the forums on the ram and gladiator ecodiesel. This is well documented. If they won't fix it then take it elsewhere or get jeep cares involved. With the recall the replace the reluctor ring with an upgraded part. But only if it fails. Yours has failed. My truck was exactly like yours. Dealer had it replaced and fixed in a week.
 
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jeepin48

jeepin48

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I also notice that if EOT is above 230 the VGT seems to hold the turbo back. I need to datalog to confirm.
Is this a real known thing? If so that could explain a lot. I was only aware that if engine oil temp EOT was over like 260 than it would derate.
 
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jeepin48

jeepin48

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Jeepin48,

The screenshots are showing you were in regen mode. It seems to be running normally. The EGT is getting hotter, looks like a warmup stage in the regen process to get exhaust up to 1200 F for about 20 minutes. The 100% soot is a good give away. It will show higher load during a regen as 30% of fuel is not useable for torque, since it is pushed out during exhaust stroke to make heat.
I am confident that this was not in "Active Regen" but was in a lighter " Passive Regen". The green light comes on for Passive Regen almost anytime the DPF is above say 650 or so. My DPF typically says 100" for the second half of the DPF fill limit. EX I may get 500 miles untill 100% then I can drive another 500 before it actually "Active Regens" and goes to 0%
 
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jeepin48

jeepin48

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I am confident that this was not in "Active Regen" but was in a lighter " Passive Regen". The green light comes on for Passive Regen almost anytime the DPF is above say 650 or so. My DPF typically says 100" for the second half of the DPF fill limit. EX I may get 500 miles untill 100% then I can drive another 500 before it actually "Active Regens" and goes to 0%

Your note that you can loose power during regen does make sense with my occasional check engine light. I found that after my CEL was on and derated me, it would later show DPF 30% or so that would indicate that it was trying to regen and then tripped a error. I wonder if I have an accurate DPF % (mine is clearly off) then I could voluntarily slow down and allow it to process. :idea:
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