'97 Ram Bucking while towing

[Marielw824]

The truck is a 97' Dodge with a 5. 9L Cummins and an automatic transmission so there is no tuner, the rest of the upgrades done are:

#10 fuel plate

4" exhaust

3. 5K governor springs

ATS stage 4 transmission

Pac brake exhuast brake

The "bucking" typically only happens after the shift to top gear with overdrive off, as soon as we get on the highway going 60 - 65 in overdrive, it goes away. Also it only happens when towing.

 

[EricBu12]

Im no expert on the modified transmissions, but Id say there is some adjustment needed to be made. . seems like it is trying to lock up too early

 

[georgej]

Since you're using more fuel while towing I would check the fuel pressure between the lift pump and the vp44. There should be around 12 psi at idle and not drop below 5-6 psi at 2000/2500 rpm. If the reading is low ,check the fuel filter and replace if it hasn't been replace in a while. If the pressure is ok it could be the apps (accellerator pedal position sensor)is getting worn. These are pretty expensive ($400)at the dealers but are available from genos garage and others on this website for around $160.

I have had an occasional bucking on my 01 but each time it was traced to electrical gremlins and has been fixed by cleaning the battery ,map sensor,or the after market power box connections.

There is nothing worse to diagnose than an intermittent problem and I hope you find out soon what your problem is and when you do post back here so's we can all benefit.

Good Luck

 

[The patriot]

I'm going the simple route. Have you tried replacing the throttle return spring?

 

[AClayton]

Since you're using more fuel while towing I would check the fuel pressure between the lift pump and the vp44. There should be around 12 psi at idle and not drop below 5-6 psi at 2000/2500 rpm. If the reading is low ,check the fuel filter and replace if it hasn't been replace in a while. If the pressure is ok it could be the apps (accellerator pedal position sensor)is getting worn. These are pretty expensive ($400)at the dealers but are available from genos garage and others on this website for around $160.

I have had an occasional bucking on my 01 but each time it was traced to electrical gremlins and has been fixed by cleaning the battery ,map sensor,or the after market power box connections.

There is nothing worse to diagnose than an intermittent problem and I hope you find out soon what your problem is and when you do post back here so's we can all benefit.

Good Luck

It's a 12 Valve dude... ... . 97'!

 

[AClayton]

Have you added any timing adjustments?... ... sometimes too much timing while towing heavy at low rpm's will cause some bucking.



Alan

 

[Marielw824]

FYI ... I'm the wife who is posting here but the original post/paragraph is hubby's writing. He did 'forget'/neglect to mention that we JUST (less than 2 weeks ago) had new, bigger injectors installed. We will call the shop tomorrow. It's a shop we've gone to many, many times and they have a great rep. ... . He's also going to replace the fuel filter too.



Thank you for all the replies ... it's giving us great info. and things to look at. Don't have much time. We're leaving soon with the RV for a 6 week trip for his job. Always the last minute. Sheesh!

 

[Prairie Dog]

Hi Marie, glad you took me up on my invitation (on RV.net) to check out the TDR site.
Good luck,
Scotty

 

[Bob V]

I had a 97 that had similar mods and I had the same problem. Try more/stronger throttle return springs. The throttle is too sensitive. There is even a TSB on this for stock trucks, with all the mods it is much worse.

 

[Marielw824]

Hi ... hubby replaced the fuel filter on Sunday. We picked up the trailer today from dealer who did recall work and VOILA ... NO bucking/chugging/lugging, whatever the best term is. The fuel filter WAS FILTHY ... so hubby is pretty happy IF that really cured the problem. Whole trip home (50 miles) it was smooth and didn't buck. Thanks everyone ... I don't know if hubby would have gotten to it being a fuel issue without you.