Loses all power when uphill/overtaking

[Billnick]

I'll throw this in here because my ex brother-inlaw mechanic had a similar situation many years ago on a diesel. It turned out that the vent in the fuel tank was partially blocked allowing normal driving, but after a while a vacuum would build up in the tank as fuel was used. Come time to climb a hill the engine would starve of fuel. Stop for a bit, vacuum would decrease and normal driving is possible.

[Mattyjee]

I'm quite confident its not a fuel starve issue - even though that would seem an obvious answer. The fuel rail pressure stays nice and high the whole time - when it loses power it does it almost instantly. If it was fuel starve I would be able to replicate the issue when cold.

Also, I've managed to get transmission temp working via the torque pro app. It wasn't simple...

What is a normal/high temperature for auto trans temp? For the record, I've monitored coolant temp when it cuts out and everything is normal, not even slightly higher than normal running temps.

In my googling around on this issue (years ago) I found similar stories and people were accusing the turbo wastegate actuator. I can't find anything anymore when i search, and also don't see how this could relate. Anyone have any insight here?

And back to original question - does anyone know a good mechanic that would be able to work this out and not simply state "test drove, no issue found" as Jeep did both times I took it in to them back while still under warranty...

[MRGC]

Originally Posted by Mattyjee

I'm quite confident its not a fuel starve issue - even though that would seem an obvious answer. The fuel rail pressure stays nice and high the whole time - when it loses power it does it almost instantly. If it was fuel starve I would be able to replicate the issue when cold.

Also, I've managed to get transmission temp working via the torque pro app. It wasn't simple...

What is a normal/high temperature for auto trans temp? For the record, I've monitored coolant temp when it cuts out and everything is normal, not even slightly higher than normal running temps.

In my googling around on this issue (years ago) I found similar stories and people were accusing the turbo wastegate actuator. I can't find anything anymore when i search, and also don't see how this could relate. Anyone have any insight here?

And back to original question - does anyone know a good mechanic that would be able to work this out and not simply state "test drove, no issue found" as Jeep did both times I took it in to them back while still under warranty...

What was the trans temp at the time, it can overheat and not get hot oil light, it's happened to me.

If you do a search I have noted the formula you need to input for the tran temp.


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[samft]

try recreating the scenario but turn off overdrive before you hit the hill

I reckon its a combo of engine temps and transmission temps

OD-off should keep the torque converter locked up, reducing the heat

I'm not suggesting this as a fix, but see if you can get the jeep to perform better without the extra transmission heat...then you'll know the culprit

[Grahame]

The Hot Oil warning will go off at 135 deg C. It won't go into limp mode but the alarm will keep ringing and give you the shits until he temp drops below 135. The trans cooler is a dual unit with the aircon condenser between the intercooler and radiator. Under normal conditions the trans temp and engine temp will be approximately the same, at least that's how my old CRD used to run. I think limp mode is connected to the engine temp, I also believe that the thermo fan is connected to the engine temp and not the trans temp. I've had a hot trans and a relatively cool engine and the thermo fan remained off

[barnyard]

I tend to go along with what Billnick said. Had a diesel work ute a few years ago that suddenly started losing power and stopped completely, found that the breather part of the fuel cap was full of diesel-sodden dust and completely blocked, even sucked the walls of the tank in a little...and that was when fuel tanks where still steel! Cleaned it out and all good. Maybe take it for a drive and replicate the issue and see if the tank is deformed (sucked in). Hope you find an answer.

[Mattyjee]

I managed to get the Jeep to cut out today in the city. Been running for about 10 minutes in stop/start traffic. Got to the front of traffic lights with a big hill, so gunned it and got it to cut out. The trans temp was only 65 degC at the time, I had it up to 75 later on without cutting out so I don't think its the Trans.

I did notice this time as it was cutting out that I could hear a different noise in the engine - almost sounded like it was only running on 1 or 2 cylinders for a bit. I have previously gone done the fuel starve route and concluded it was not the issue but perhaps I was wrong...

I really need to replicate this on a dyno with a proper computer plugged in and an expert on the other end of it. Anyone know anywhere (WA)?