Bucking

irunmiles · **Posted:** Fri Mar 14, 2008 8:40 pm

On three occasions this week, my CRD bucked so violently that it threw me forward against the seatbelt. I'm at 77K miles, and I've had no problems with the drive train. The first two instances, I was using cruise control at ~65mph. It bucked so hard it scared me, and I actually looked in my rear view mirror to see if I was leaving any parts behind. Tonight, the same thing happened at ~40mph. I plan to take it into the dealer on Monday, but I doubt that they will be able to reproduce the bucking. Any insights into this problem would be appreciated.

warp2diesel · **Posted:** Fri Mar 14, 2008 9:13 pm

Go out to your primer pump and pump it up and crack the bleeder, air in the fuel can cause bucking and with a wrench you can check this in a few seconds. If you have air check under the heater plug on your right as you look at the filter for fuel leaking out after you pump the hand primer. Air is a lot thinner than fuel and will get sucked in so fast that it will drive your engine nuts. Don't waste any of your time or the dealers time before you check this. If you have a burned plug or fuel under the plug, the filter head needs to be replaced. Three of us in my town Aurora, IL have had it done so far.

Steve

irunmiles · **Posted:** Fri Mar 14, 2008 11:06 pm

Thanks for the advise warp2. I hadn't considered air in the fuel, but now recall reading posts about it. I'm a bit overdue for a fuel filter change, so I may go ahead and do that and bleed at the same time.

Reflex · **Joined:** Mon Jan 29, 2007 8:48 pm **Posts:** 567

I had this happen when using cruise control in the past, however it only happened when I was in heavy rain and there was wheel slippage while in cruise between 60 and 70mph. I disengaged cruise and the problem dissapeared.

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

I have experienced this violent bucking way back, but not when using cruise control. It happens at shift points-- like 65ish and 45ish.

I suspected the transmission at the time and still do. The "shuddering" and the hesitation that everyone has experienced (me included) is not nearly as bad as this-- it maybe the same cause-- but when this extreme It is very violent. It is the kinda thing that makes you thing you left something on the road. Feels like you were manning an anti-aircraft gun or something.

It went away after a trans reflash and torque converter. I also started regularly burping the air out, so that may have helped as well. It still had the shudders and hesitation until I hooked up the lift pump. Since then... it runs like a top.

I would also check the trans fluid and disconnect the battery for a few minutes to induce a computer relearn. Neither could hurt really...

warp2diesel · **Posted:** Sat Mar 15, 2008 10:28 am

...and check before you change the fuel filter. The replacement head comes with a new filter. Then pick a lift pump option and do it.

Steve

irunmiles · **Posted:** Sun Mar 16, 2008 9:24 pm

Once again, this forum saved me a trip to the stealership. I changed the fuel filter, bled the air, and ran a full tank without the bucking returning. I hope that problem is behind me and it was in fact air in the fuel system.

Bucking

Who is online