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DON'T BUY THE CVT FOR OFF ROAD!!!

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#121 ·
Dawson,

While sitting there trying to get going up the hill, have you tried this?

Put your foot on the brake. Turn off the engine. Retart the engine. Put it back into 4wd and low if neccesary (with or without the esp on) and then floor it.

Also, do you have an oil cooler on your Pat?
 
#122 ·
Dawson said:
I'm in Aurora, CO. I've spoken online with a couple other Patriot owners on the forum, but no one with an FDII. STILL have yet to see another Patriot out on the trails and have only seen a handful on the roads.

I'd love to go out with another FDII and check it out.
Click to expand...
If I wasn't thousands of miles away I'd be there! I only wish I had scenery like what you've got out there too wheel in.
 
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#124 ·
drenglish,

Renaming it might be a good idea, but as to retiring it, I don't know.

There is good eveidence that at least some Patriots might have problem when attempting to climb long steep hills. It is not known whether this is a common limitation to ALL Patriots or not.

The problem has not been resolved.

Do you really want to just give up on it?
 
Discussion starter · #125 ·
Agreed JeepFan!

I will try that the next time I get in the situation. I will also be in Detroit in two weeks where my buddy's Jeep shop is. Maybe, if I have time, I'll have him hook it up and see what he can find.

I will admit the name of the thread could have been chosen better, but I was pissed, as many would be in this situation. Try spending 25k for something that doesn't work! But, we're all cool now, no grudges here...
 
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#126 ·
Hey Dawson...

Since you've taken yours out and bounced it around a bit...lemme ask you a question. You get a lot of noise from the front suspension when you're out playing?

I went out to a job site today, and was driving on some rough graded roads...most of the surface was 2-3" lava rock. Nothing major, a Hyundai could have made the trip. The rattling and popping coming from the passenger side front was loud. Like, hear it with the AC on and the windows up loud. I'd hear it occasionally from the rear, but most of the noise was coming from the front side.

Sounded like the wheel was "snapping" back into position from under tension...the only way I can think of to describe it. Sounded a lot like an old mustang I had with a loose shock tower.
 
Discussion starter · #127 ·
I have noticed a sound similar to that of my old dodge pickup's helper springs coming from the front. Other than that, nothing much. Not sure what should be, if anything, moving around in the suspension that much. Does concern me sometimes. May want to take it in and just ask?!
 
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#129 ·
I have a couple of ideas, but I need someone like Dawson who has had considerable experience with the problem to test them out.

One idea has to do with it not being the torque converter or CVT at all, but something else like the Engine Control Unit shutting things down because of some sensor like oil temperature or maybe just bad software. On one site some guy was having a similar problem with a car that also used a Jatco, I think it was a Mitsubishi, The only thing that made it go away was to totally shut the car off and restart, thus "rebooting" all the computers.

Another idea has to do with the engine's torque curve and the torque converter stall speed. Engines develop their maximum torque at some RPM (sweet spot). I don't know what it is for the spark retarded Patriot engine in "crawl mode" but let's say it's 3000 rpm. The torque converter stall speed is the maximum speed the engine can turn if the car is not moving and the torque converter is in operation. All of the engines power in this case is just going into heating transmission fluid.

The TC is kinda like a slipping clutch. It transmits some torque to the wheels to get moving. but but slips enough to allow the engine to not quit running when the car is not moving or first starting out.

Once the car reaches some small forward speed, which again I do not know for the Patriot in crawl mode - but it's fairly small say two or three MPH, the torque converter clutch kicks in, locks the torque converter out and all engine power goes to the transmission and wheels. Just like a regular car with a non-slipping clutch.

The force required to hold the clutch against slipping, the belts against slipping, and to operate the hydraulics is provided by the transmission oil pump at the end of the torque converter spindle.

So let's say we are moving up the hill at a steady pace near the engines torque sweet spot and decide to let up on the gas for some reason. This could cause the TC to unlock and now we can't get the engine torque back up because it's sweet spot is above the TC stall speed. Lower engine RPMs can also make it harder to maintain enough transmission oil pressure to prevent slippage.

If my second idea is close to the truth it say the proper way to get up the hill is to put you foot on the floor while car is starting up the hill and still moving, and to keep it there all the way up and just let the crawl mode and traction control get you there....if you are going to get there.,,there are limits of course. The more weight you can get out of your car the less torque needed to climb, but still this is no Wrangler.
 
Discussion starter · #130 ·
It does seem to get further if I can keep it to the floor, but usually I'm following someone so they can pull me up if needed. If they slow down, I slow down. But I will try the shut down thing.
 
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#131 ·
I guess if at possible they need to have enough of a head start that you won't have to slow down because of them, at least until you get past the steepest part.

Here's one more idea, just in case you do get stopped. Take the car out of 4wd but keep it in low. Turn the ESP COMPLETELY off so that you see the ESPOFF letters appearing on the odometer in place of the mileage numbers. Give it gas. Instead of the torque to all four wheels it will be going ,ost;y to just the front wheels. This gives you your best chance for wheel spin. If at least one wheel spins fast enough the TC will lock up. While the wheel is spinning pit it back in 4wd and turn the ESP back on. Good luck!!
 
#132 ·
Calculations - evidence of a design flaw

I went out to the parking lot, started my FDII, put my foot firmly on the brake, put it into drive, and stepped all the way down on the gas.

The engine peaked out at 2500 rpm, which would be the torque coverter stall speed.

This link shows torque and Horsepower curves for the 2.4 L engine (4B12) eingine in my Patriot FDII.

Peak torque out put is shown as 167 ft-lbs @ 4100 rpm

At the torque converter stall speed of 2500 rpm, available torque from the engine would be no more than about 147 ft-lbs.

Using my calculations from an earlier post and assuming a weight of 3800 pounds for the Patriot with a couple of occupants and some gear, we see that we should be able restart on about a 39 degree slope without the TC locked up. With the TC locked up we could continue to climb (don't lift your foot from the gas!) a slope of 45 deg.

This means that without a high stall speed torque convertor there is a region where we could get trapped, if we had to stop, between 39 and 45 degrees without being able to continue on even though the engine would be capable of it.

Inasmuch as this could be an unneccesarily hazardous situation to be in due only to the characteriistics of the torque converter and not the rest of the powertrain, I consider this to be a design flaw for off-road use.

It is, however, not to hard to alter the stall speed characteristics of torque converters, and some high-performance car oriented people do that. What we need is a torque converter stall speed closer to 3500 or more RPM for off-road use.
 
#134 ·
Thanks for the link, that is for the original engine developed in 2005 and it was first used in the Mitsubishi Outlander. The Outlander now uses a 220HP 6. Originally it was 140 HP and now it's 172, there are a number of features about the engine that got my attention. They originally used 0-20 weight oil, the current recommendation is 5-20, still a very light viscosity. The sparkplugs are iridium, and the tiiming gear is a "silent chain". Sounds good to me!
 
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#136 ·
Thanks, I was wondering about that. I like that they use a timing chain, that 60,000 mile rubber belt change has always been a pain (Subaru).
 
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#138 ·
I am not sure exactly when my Pat was built. How can I tell? Assuming it was built before the off-road software mod, how can I tell if the software mod was performed prior to me picking up my Pat about 3 weeks ago?
 
Discussion starter · #139 ·
Don't waste your time with details... Take it in and have them re-flash the computers. Takes them about a half hour and you'll be SURE you have the latest updates. I recommend this for EVERY ONE.
 
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#140 ·
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Jdog
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