Another Ram truck problem...

[Magnumcharger]

Since the other question was answered so fast, I'll take a kick at the can!

My truck is a 1996 Dodge Ram 4x4 with a Magnum 318 and overdrive automatic.

The situation: While towing my loaded car trailer up a hill, the cruise control suddenly kicked off. I started slowing down immediately, and stepped on the gas.
The engine didn't increase in revs and the transmission didn't kick down. All I got was a hollow "roaring" sound from the engine - similar to sucking on a straw in a milkshake when the cup gets empty. (To me it felt exactly like when the transmission kickdown linkage on my old Road Runner came off the carb).

Finally, as I was on a hill, the truck slowed to a stop.

I put the truck in park, and revved the engine with no problem. Putting it into drive I stepped on the gas again, this time the truck - now in low gear - started to slowly move forward. If I pressed harder on the gas I just got the sucking sound again.

I nursed the truck like this to the top of the hill, then after reaching a level surface, the truck started to pick up speed. After a bit it upshifted to second then third and finally overdrive. Upon reaching the next hill, it wouldn't downshift again and I found the truck slowing down. I couldn't give it any gas more than a high idle and it crawled up the hill. On my first avaliable off-ramp I pulled into a service station and checked my transmission fluid. It was full. I checked the transmission kickdown cable...no problem.

After taking three hours where I would normally take an hour to get home, I parked the truck.

Any ideas?

[Tilar]

Just a wild ass guess, but if it has the electonic throttle control I'd say a throttle controller.  Only reason I'm saying this is because our busses have them and when they go bad it creates the exact same situation you described.

[moparstuart]

Just a wild ass guess, but if it has the electonic throttle control I'd say a throttle controller.  Only reason I'm saying this is because our busses have them and when they go bad it creates the exact same situation you described.

that was my guess the throttle positioning sensor !!!   did it ever jerk or act up on normal hills not towing like it was kind of kicking in and out of  Over drive or passing gear ?   

[gtx6970]

sounds like it was loosing fuel pressure

Just a wild ass guess, but if it has the electonic throttle control I'd say a throttle controller.

96 has a throttle cable as opposed  to the newer Hemi trucks are drive by wire. There for - if it's connected if you push the pedal down the throttle body opens

[Magnumcharger]

Throttle sensor was replaced once. I've heard they carbon up sometimes. I'll pull it out and check it over.
It really does sound like something electronical though.

[Stretch]

It sounds like fuel pressure to me aswell.

[moparstuart]

Throttle sensor was replaced once. I've heard they carbon up sometimes. I'll pull it out and check it over.
It really does sound like something electronical though.

we have had tons of TPS problems on our  94-2000 dodge delivery truck  weather v10, v8 or deisel  all of them go hinky

[ACUDANUT]

May sound simple, but what about the Transmission fluid level ?

[Back N Black]

also, sounds like MAP sensor, it measures load on the engine. in park no load and revs up fine.

[ACUDANUT]

Newer Dodge Trucks have a bad rap with it's transmissions and electrical problems.  Oh wait..It's a Ram and they no longer even say's "Dodge". OR FIAT. 

[Todd Wilson]

96 was the first year for the electronic transmissions.  It very well could be the TPS. If it wigs out it can keep the tranny from downshifting and the TQ unlocking which sounds like something it was wanting/needing to do pulling with the 318 on a hill.    I recommend in the future to shut the OD off when pulling especially with the 318. You will come to find out the truck will pull better and in most cases use the same or less fuel and its not putting a terrible strain on things.

Read here..........

http://www.dodgeram.org/tech/transmission/automatic/TPS_adjust.htm



Todd

[Stretch]

Most of the time the when it's the TPS you will notice a RPM spike here and there. The TPS signal drops out and the ECM thinks you spiked the gas and unlocks the converter. If I am reading the first post correctly it sounds like the more throttle input there is the more power it lacks. I would put a fuel pressure gage on it and see where it's at.

You can check any 3 wire sensor on your car mith a Multi meter. Put the black lead to battery ground, the meter on DCV and back probe the sensor wires with the Key on engine off. One wire will read 12v. this is your power supply to the sensor. One will read about 5 volts. This one goes to the ECM. The other wire is ground. This is the one you want. You should see .10 volts or less on this wire with KOEO. If it's more than .10volts your sensor is bad. The only three wire sensor this does not apply to is some O2 sensors. The ground will show 1 volt or more up to 2 volts. The forth wire is the 12 volt heater wire.

[472 R/T SE]

On my first avaliable off-ramp I pulled into a service station and checked my transmission fluid. It was full. I checked the transmission kickdown cable...no problem.

May sound simple, but what about the Transmission fluid level ?

Whatever Bill says.   

[bull]

May sound simple, but what about the Transmission fluid level ?

Whatever Bill says.   

Right, but he said he checked the level and it was fine.

[ACUDANUT]

Yes he did Bull. I missed it. THANKS

[Magnumcharger]

Just a wild ass guess, but if it has the electonic throttle control I'd say a throttle controller.  Only reason I'm saying this is because our busses have them and when they go bad it creates the exact same situation you described.

that was my guess the throttle positioning sensor !!!   did it ever jerk or act up on normal hills not towing like it was kind of kicking in and out of  Over drive or passing gear ?   

Nope...never did anything unpleasent before it just up and started with this foolishness!

[Magnumcharger]

May sound simple, but what about the Transmission fluid level ?

Fluid level was checked at hot idle, in neutral as per the owners manual. Right on the high level line.

[Magnumcharger]

96 was the first year for the electronic transmissions.  It very well could be the TPS. If it wigs out it can keep the tranny from downshifting and the TQ unlocking which sounds like something it was wanting/needing to do pulling with the 318 on a hill.    I recommend in the future to shut the OD off when pulling especially with the 318. You will come to find out the truck will pull better and in most cases use the same or less fuel and its not putting a terrible strain on things.

Read here..........

http://www.dodgeram.org/tech/transmission/automatic/TPS_adjust.htm
Todd

I guess I should have mentioned that I was towing with the overdrive turned off.

[Magnumcharger]

also, sounds like MAP sensor, it measures load on the engine. in park no load and revs up fine.

I've just borrowed my Father-in-laws' code reader so I'll plug that in and check the faults, if they show up.
http://www.obd-codes.com/trouble_codes/dodge/

[Todd Wilson]

also, sounds like MAP sensor, it measures load on the engine. in park no load and revs up fine.

I've just borrowed my Father-in-laws' code reader so I'll plug that in and check the faults, if they show up.
http://www.obd-codes.com/trouble_codes/dodge/

if you dont have any codes I'd look at the fuel pressure.


Todd

[Beep Beep Dave]

I'll say the Cats plugged up...

Dave

[Stretch]

 A plugged cat is very posable. I've seen alot more pluged cats over the last year or so in my shop. I'm not 100% sure it doesn't have somthing to do with the changes being made in the gas formulation.

The ethanol in the "new" gas plays hell on small engine carbs. It evaporates and plugs the pilot port in small engine carbs in about 30 days here. (michigain). If it's that bad for the carb it can't be good for the catalytic converter.

Very good point Beep Beep Dave!

Jason

[TXcharger70]

I agree it could be your cat. I used to have a 96 2x4 318 and had that happen to me as well. But then again i had the same type of symptom when my tranny was going out

[Todd Wilson]

Well what did we find out?


Todd

[Magnumcharger]

So far I haven't been able to get back to look at the truck. I'm hoping this upcoming long weekend.
Several things I'm going to do immediately:

1. Check the TPS2. Check the ECM reader
3. Check the catalytic convertor
4. Check the Throttle (kickdown) control cable to the transmission.