Hi all!
I have a 2015 2.4 Patriot Sport with Automatic transmission (not CVT variator).
Near the top of each not small hill,
When Jeep loses speed inertia/momentum, it always happens exactly what at the end of video (not mine video) :

4wd is on.

Manual mode gear D = 1
ESP full off (5-7 second push)
Pedal is pushed to the metal.
No errors / lights on the panel.
Looks like engine revs are limited and cant go over 2000 rpms.

The same happens when you stuck BOTH front wheels 90° to a curb Forward or backward (See pics).

Patriot does not want to perform a burnout (I need it right now!) when feels hard obstacles....

What are possible reasons and how to deal with it?
1. Does TCS thinks that all wheels are spinning - so it blocks all wheels?

2. Rev/rpm limit does not allow to overcome TCS's brake pressure + hill angle gravity force ?

Tried to make all differentials free (brakes unlocked) by taking out ABS fuse #35.
It does not give a result - rpms are limited to 2000 with pedal to the metal = wheels dont slip/dont move...

I dont beleive that 2.4 cant overcome TCS brakes - it have to perform a burnout in this conditions, but it cant.....

Any suggestions how to remove this 2000rpm restriction at hard situations?

Thanks for any ideas!

Maybe to protect the transmission? It is pretty lame though, it should be able to drive up a curb with a 4x4 badge on the back.

 

It performs well 95% of middle-hard offroad but this 5% situations stress me up, having 4x4 Jeep badge

It can be a 'safe mode' by engineers not to brake transmission or engine, but in critical situation I have to accept this risks - just not to stuck and freeze somewhere far away...

 

Thats my video, its easy to explain lack of engine torque, no low range so you don't get the torque multiplication factor a vehicle with low range has, notice how it has no problem spinning 1 front and 1 rear wheel, its only the the brake lock differentials clamp down on the spinning wheels to send power to the wheels that aren't spinning. This is effective but takes twice as much torque to get meaningful movement out of the tires with traction.

It's not a safe mode I could recreate it many many times, FDII vehicles (which mine was) are affected to less of an extent due to the higher crawl ratio

 

But why ECU cant allow to increase rpms (by pedal) to increase torque?
Engine is not defenetly stalling, Im sure- i hear it and feel no vibrations !
just electronics do not allow to go higher than 2000rpms....

 

Any vehicle can run into the same problem. My Cherokee Trailhawk with the 3.2 gets bogged down in the exact same way if I don't use low range, even my 5.7 Grand Cherokee does the same, it's all about engine power and lack of low range.

 

That curve makes me sick at 2000rpms (((

 

You can't increase the rpms due to the torque converter, as such the stall speed is around 2000rpm. Its quite normal for small naturally aspirated engines to have very little torque a low RPMS. You will also notice in the very first video you posted, the vehicle had no problems spinning 1 front and 1 rear tire but again it didn't provide any useable traction, when forced (by the abs system) to transfer power to the wheels with traction it simply didn't have enough engine torque to do so.

 

You are also right.
But!
I had a talk with auto-mechanics today:
Inside Torque Convertor there are only
Oil & two turbines on the shafts:
One shaft is from Transmission
Another shaft is from Engine.

Even if shaft from transmission is blocked by standing wheels (curb/hill/etc)-
Shaft from Engine will be rotate-able anyway( turbine is inside liguid).

The worst case - engine shaft will slip against transmission shaft. But that mean that rpms are increasing when wheels are static.

In our case there is no torque convertor's slip - rpms are limited electronicaly!

 

Patriot does not want to perform a burnout (I need it right now!) when feels hard obstacles....

Any suggestions how to remove this 2000rpm restriction at hard situations?

Thanks for any ideas! View attachment 93988 View attachment 93989

On the trail here's some things to try:

When climbing a hill, try leaving it in Drive, and 2WD. Remember that it's a FWD vehicle first with most of the weight over the front wheels.
Send all the power to the front wheels and when the front wheels slip/spin, the RPM's will increase (higher up the torque curve) just before the computer kicks in the rear wheels.

Remember too, that adding a taller tire will change the final drive ratio. A significantly taller the tire will make it harder to climb a hill (increased radius / leverage against the engine). I noticed a decrease in acceleration / low end power going from a stock 215/65/17 (28") to a 30x9.5 (29.5"). I settled on a 235/75/15 (29") which gave extra clearance with no noticeable difference in acceleration over the stock tire.

Try airing down the tires. Airing down gives better traction with a longer contact patch, and will go over obstacles easier, "wraps around" the obstacle instead of climbing it.

Consider adding front sway bar disconnects. The sway bar tries to keep both wheels at the same level, which is good on the road but wastes torque/power out on the trail since engine power has to be used to overcome the resistance of the sway bar in addition to obstacle.

Disconnecting the sway bar takes the resistance of the bar out of the equation.

As always, YMMV.

Hope this helps / makes sense.

 

On the trail here's some things to try:

When climbing a hill, try leaving it in Drive, and 2WD. Remember that it's a FWD vehicle first with most of the weight over the front wheels.
Send all the power to the front wheels and when the front wheels slip/spin, the RPM's will increase (higher up the torque curve) just before the computer kicks in the rear wheels.

Remember too, that adding a taller tire will change the final drive ratio. A significantly taller the tire will make it harder to climb a hill (increased radius / leverage against the engine). I noticed a decrease in acceleration / low end power going from a stock 215/65/17 (28") to a 30x9.5 (29.5"). I settled on a 235/75/15 (29") which gave extra clearance with no noticeable difference in acceleration over the stock tire.

Try airing down the tires. Airing down gives better traction with a longer contact patch, and will go over obstacles easier, "wraps around" the obstacle instead of climbing it.

Consider adding front sway bar disconnects. The sway bar tries to keep both wheels at the same level, which is good on the road but wastes torque/power out on the trail since engine power has to be used to overcome the resistance of the sway bar in addition to obstacle.

Disconnecting the sway bar takes the resistance of the bar out of the equation.

As always, YMMV.

Hope this helps / makes sense.

Nice idea to leave in 2wd ) sounds reasonable for the first kick/slip )
Tires and traction are out of discussion here because

Jeep do not deliver all torque it has above 2000rpms to wheels

 

It delivers whatever torque it does @ 2000 rpm, which isn't much, and because of that tires / traction and sway bar resistance become more important.

Like Tyler, I've done a lot of wheeling in the Patriot and this is what's made a difference for me. As I said, YMMV.

Try dropping air in the front tires to 15 lbs, then try going over the curb. Maybe it will help you.

 

this happens in my fwd. problem is the traction control never really shuts completely off. stability control does when you push the button. you are probably breaking traction and the brakes are being applied to keep from slipping. then the ecu says hell no to your right foot input to avoid motor or trans damage. its just a 4 cylinder if you want to drive up ice covered hills i would recommend a sno cat also revving it up in these newer cars is never the answer.

 

I respectfully disagree on the traction control. I think hitting the "ESC off" button does kill the traction control, while the ESC function remains partially in operation.

IMO, traction control is a pretty useless invention. As you noted, when climbing a hill it applies the brakes and you lose momentum. When climbing hills in slippery conditions power is an enemy and momentum is a friend. You can control the power, but ESC kicks your friend in the knee.

 

ESP Full off is not available on FWD MK's. The only way to completely disable traction control is to pull the ABS fuse, however the engine reduction part of traction control will still be available

 

Exactly!
I've pulled off ABS fuse - put PAT to high curb (pics above) - 2000rpm engine ruduction still s#cks!

Does anybody have an idea how to remove this limit?

DIYs are welcome!

 

Pretty sure it would involve reprogramming the ECU and TCU... if it's even possible at all. Unfortunately, that's just the way all of these 4 cylinder CUVs are made these days.

 

I doubt it's the ESP; since the ESP (when working properly) goes active when the vehicle is in motion, not when sitting still on flat ground with the wheels blocked.

Probably more to do with the torque converter stall speed like Tyler explained, but changing the torque converter would mean PCM/TCM changes.

Some people have suggested something like a Sprint Booster / Pedal Commander helps with faster throttle response and getting the engine higher into the power band quicker, others say it's a waste of money.

A while back someone tried doing a stage 1 cam regrind (among other things), but they had problems due to the PCM and had to take it back out.

You can read about it here:

*Fastest Patriot in North America?

Hello there, guys and gals. We're nearing completion of a series of major performance upgrades, seeking to make this the fastest Jeep Patriot in the nation without the use of forced induction. It's been a lot of headache, but in the end, I hope this Pat proves to be the most powerful and fuel...

www.jeeppatriot.com

Maybe the cam regrind would work now that the HP Tuner supports the Patriot PCM at least a little. But it's not a quick, cheap, DIY fix that's for sure.

 

Its the torque converter stall speed, at/above which you start introducing a ton of heat if the output shaft cannot turn. This is a very compact and light duty 6 speed transmission with a little bitty torque converter, I think it's rated for 230Nm (169 ft-lbs) which is 4 ft-lbs more than our 2.4 engine is rated so it's right up at its limits - even if you could disable the limiter that's surely programmed in there to protect your transmission it would not be a clever idea to do so.

What you can do is first be realistic about what this vehicle can do and second adapt your driving style to work with the vehicle's limitations. Your total torque at the wheels is - absolute best case scenario - 165 ft-lbs times 4.212 first gear times 3.367 axle ratio.. about 2340 ft-lbs at the wheels.

By comparison a stock 2001 XJ (automatic) makes 230 ft-lbs times 2.8 first gear times 3.55 axle ratio - about 2286 ft-lbs at the wheels in high range. But it has 2.72 low range which means 6218 ft-lbs at the wheels.

We don't have a low range. Wish we did, even a 15% reduction like old Subaru Foresters got in a few non-north-America markets.

Anyway the transmission is fundamentally a good unit but it's built for small sedans and it's really at its limits behind a big 4 cylinder and in front of sticky all terrain tires on all sorts of terrains. There's a reason you couldn't get max towing with the 6 speed auto. I take my Patriot out camping and exploring but I treat it like an Outlander with skidplates. It's pretty good at that.

 

The Patriot is what it is, and it's not what it's not. It's a station wagon with good ground clearance. My FWD Patriot is great in the snow and it's comfortable on dirt roads and reasonable trails. It is not a Wrangler; it is not a Powerwagon. Can it be made to do things out of its comfort range? Yes, but that's not a good practice.

 

It's not the transmission torque converter its simply the lack of torque.

Example.

The 2014+ Jeep Cherokee KL 2.4 Trailhawk model. 184hp 171ft/lbs

In high range is is 171 x 4.71 x 4.08 = 3286 ft/lbs but it still struggles in high range

In low range which is 2.92 reduction = 9595 ft/lbs. In low range a 2.4 Cherokee TH has zero issues offroad in any type of obstacle.

Its quite simply torque multiplication or lack of it.

I can stall out my 5.7 grand cherokee in high range, I could stall out my 3.2 Trailhawk in high range, using low range gets rid of all the problems.

If the MK had a low range we wouldn't be having this discussion at all

 

If you get the gears low enough a lawnmower can pull a freight train!

 

I'd like to have this additional 18% of torque @4000 in critical situation, but not to be limited at 2000rpms

 

You could add 200ft/lbs more power to your vehicle it's still not going to do anything.

You NEED gear reduction in order to have the vehicle move properly in low speeds.

My Grand Cherokee with 390ft/lbs of torque will bog out and not move in certain situations unless I use the low range function.

 

You will need to source and install a torque converter with a higher stall speed, and accept the negative consequences in daily driving from that. That will allow you to go nowhere with the engine at a higher RPM while still being fully stalled.

 

A torque converter is NOT going to help anything.

Explain to me why my 5.7 Grand Cherokee bogs out the same way my Patriot and Compass did in certain offroad examples, but the problem goes away in low range.

Same thing with both my Cherokee KL's, they both have low range and when not in low range in certain situations they bog down and don't go anywhere?