I have a survey from Jeep

MrMopar64 · **Posted:** Tue Sep 18, 2007 5:52 pm

BlackLibertyCRD wrote:

I'm going to pull a 3,000 lb trailer cross country a month from now. I am betting with my mod it will pull better and not shift out of gear as much as before. The mountain passed OK to downshift but not small hills. I think the computer knows when a engine is starving for fuel under load and downshift to make up for it. It has alot to do with throttle position and the speed you are going.

In all the by-back vehicles I've looked at in my times at Chrysler I've never seen any problems with fuel pressure, rail pressure instabilities, etc. so I doubt any affect the lift pump will make on towing and downshifts. The actual engine torque has never been an issue either and has always been what's it's calibrated to be, regardless of the presence of a lift pump. The 545 software uses a torque signal from the engine along with engine rpm, vehicle speed, etc. to determine upshift and downshift points. What you're seeing is the trans being torque limited for protection (it sends a value to the ECU) so when appropriate the trans will downshift in an attempt to restore the engine power with less torque (operate at higher RPM) since peak power is at 3800rpm and the torque is lower here than at say 2000rpm. The torque is also limited on the engine side for certain gears to not damage the converter so this torque limitation can also be reached easily while trailer towing which will cause the vehicle to slow down and subsequently downshift.

Additionally, the fluid flow through the trans cooler is different in lock-up vs. non-lock-up. As trans temps spike up while towing then the OD can be turned off for protection and the trans left in 3rd lock-up to demand higher RPMs thus higher flow thru the cooler.

Joe Romas · **Posted:** Tue Sep 18, 2007 6:18 pm

MrMopar.
Thanks for the input

So what your saying is they have taken away the diesel's main selling point, it's low end torque, to baby the inferior transmission :cry:

This combination is not suitable for towing a trailer that's well within the set towing limits. Anyone ready for a class action :?:

Cowcatcher · **Posted:** Tue Sep 18, 2007 6:33 pm

MrMopar,

There are two major issues with the CRD that we are all taking shots at randomly and perhaps not hitting. They are as follows:

> Air in the fuel

> Random complete loss of power

I know that you don't believe the air issue can be solved by a lift pump but it is a serious issue for some with stock setups and others with modified setups. Dealers have no solution nor do they seem to be able to get one from Chrysler. If the lift pump is not a solution what is?

On the second item what causes it? It doesn't seem to throw a code and can only be resolved by letting it sit for a while then doing a re-start. It is very dangerous and may get someone seriously injured. I have had it happen once in traffic where there was no place to park or turn off for a mile and it was no fun. Had it happened under other conditions it might have been fatal.

Thanks

BlackLibertyCRD · **Posted:** Tue Sep 18, 2007 7:58 pm

Threeweight wrote:

Would you mind sharing the mailing address to which the survey is supposed to be returned?

Might be nice if a few folks here sent them additional feedback.

I'd really suggest giving them the full list of substantial issues these CRD's have, including fuel filter/fuel starvation/air in fuel, weak torque converters and transmissions + the "de-tune" F37, CCV system and the longevity issues it will cause, the crappy air filter/air box design, and poor dealer support.

That said, I absolutely love mine, and would also share that with them. Short of it having problems that leave me without transportation, I would not consider getting rid of it, as there is nothing else on the market that comes close to being a replacement.

DaimlerChrysler
Research Department
P.O. Box 10072
Toledo, Ohio 43682-4121

BlackLibertyCRD · **Posted:** Tue Sep 18, 2007 8:36 pm

MrMopar64 wrote:

BlackLibertyCRD wrote:

I'm going to pull a 3,000 lb trailer cross country a month from now. I am betting with my mod it will pull better and not shift out of gear as much as before. The mountain passed OK to downshift but not small hills. I think the computer knows when a engine is starving for fuel under load and downshift to make up for it. It has alot to do with throttle position and the speed you are going.

In all the by-back vehicles I've looked at in my times at Chrysler I've never seen any problems with fuel pressure, rail pressure instabilities, etc. so I doubt any affect the lift pump will make on towing and downshifts. The actual engine torque has never been an issue either and has always been what's it's calibrated to be, regardless of the presence of a lift pump. The 545 software uses a torque signal from the engine along with engine rpm, vehicle speed, etc. to determine upshift and downshift points. What you're seeing is the trans being torque limited for protection (it sends a value to the ECU) so when appropriate the trans will downshift in an attempt to restore the engine power with less torque (operate at higher RPM) since peak power is at 3800rpm and the torque is lower here than at say 2000rpm. The torque is also limited on the engine side for certain gears to not damage the converter so this torque limitation can also be reached easily while trailer towing which will cause the vehicle to slow down and subsequently downshift.

Additionally, the fluid flow through the trans cooler is different in lock-up vs. non-lock-up. As trans temps spike up while towing then the OD can be turned off for protection and the trans left in 3rd lock-up to demand higher RPMs thus higher flow thru the cooler.

Maybe I word it wrong. I was having problem with air in the fuel causing loss of power and or torgue. If the torque signal was low, I can see why it would downshift. The lift pump mod alone is not getting rid of the air in the fuel head. I tee a hose and check valve from the fuel head to the return line to bleed off the air from the top of the fuel head automatically while the engine and pump is running. I know I have more power for I can smoke the rear tire if I want. Thats something I wasn't ever able to do before. As soon as I get time, I going to hook up the trailer and pull it over a few bridges here. I will know the difference as it was before because it's the same trailer I pulled up from GA.

I have a survey from Jeep

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