bucking pickup

[3stagevtec]

I drive the single cab diesel Nissan Frontier at work and when driving in a low gear (2nd or 3rd) and crusing at a low speed, the vehicle begins to 'buck' back and forth really hard... hard enough at times to throw you around in the cab!

to stop this bucking, i will either have to floor it or upshift to a higher gear. Is there something wrong with the vehicle or is that just how the diesel works?

thanks

[equipped2ripp]

diesels don't work like that

any loss of power?

the fuel system might need checking... the lines, filter or pump

if the van's under warranty, send it back to the firm to check.

[3stagevtec]

i don't thing there is a loss of power, it seems normal to me. when acclerating at a medium to high rate with the vehicle, it drives smoothly. it is only when trying to cruise at a slow speed (~20 - 40km/h) in a low gear the bucking occurs.

when i went to obtain my driving privileges for the company i work for, the Frontier i drove (another one) did the same thing...

a while back, the check light was coming on every now and then while driving. when the vehicle went for its scheduled service, it was said that there was water in the fuel system. that was fixed.

could it be water again?

[sweeks]

Not sure nah but bleed the fuel filter and see if it improves....

Also try another diesel (gas) station. You might be getting water in the diesel at the pumps.

[Dragsta]

How the engine idles, rough or smooth?
it can be fuel filter...bleed the filter to getout the water, it supposed to have a water trap...
there iz also a tiny filter that does be somewhere in the Fuel line. not sure where.

[3stagevtec]

the engine fires up easily and idles smoothly. i'll see if i can bleed the fuel filter... have a feeling is bad diesel we getting

[mrboxman]

are you keeping your foot on the x?
or is that kinda feathering it?

[srnoth]

Is it something you are doing to the X? Because diesel pick-ups are very torquey at low speeds in the low gears. When coming up the hill by me in 2nd, it is very bumpy, and if I'm not careful my foot bumps the gas pedal up and down, causing the pick-up to 'buck' as you put it. Maybe the throttle cable is loose?

[3stagevtec]

^ no, it happens with constant pressure on the acclerator no matter the road conditions.

have to ask, how do you bleed the fuel filter? is it a simple task (like just turning a screw) or it involves a longer procedure. b/c i won't be able to interfere much with the company vehicle.

i believe it is the 2.7L Nissan diesel engine

[bleedingfreak]

Under the fuel filter is supposed to be a butterfly valve used to remove the collected water in the fuel filter.

Get wide container and position it under the filter housing as best as you can.
Loosen the butterfly valve slowly and the water will likely start to drain out.
Use the hand pump at the top of the filter housing if need be.
When all the water is out and diesel starts to come out clean, retighten the butterfly valve.
Remove the container, clean up and bounce starter...

[sweeks]

Actually come to think of it.... some of the frontiers had this problem and yes it is fuel related.... start by bleeding the fuel filter (see previous post by bleedingfreak), and if this doesn't work, then change the fuel filter and where you fill up.

Try to those steps and let us know how it goes.

[tr1ad]

maybe the clutch/pressureplate

[3stagevtec]

Is it something you are doing to the X? Because diesel pick-ups are very torquey at low speeds in the low gears. When coming up the hill by me in 2nd, it is very bumpy, and if I'm not careful my foot bumps the gas pedal up and down, causing the pick-up to 'buck' as you put it. Maybe the throttle cable is loose?

so i'm driving the Frontier at 3am this morning and remembered what you said about the rough roads, so i decided to check and see if that could really be the answer... and guess what.. it is!

the majority of roads i (and other workers) drive through are very rough. so we never thought it was the roads causing our feet to 'play' on the throttle... when i tried it on a smooth road, the vehicle drove normally. then i deliberately played with the throttle and it began bucking again...

so there it is, a boring end to my thread...

(note: i had a doubt that it was water in the fuel system because the engine check light wasn't coming on. before when there was water in the fuel system, the check light was flashing every now and then...)

thanks for all the suggestions everyone...

[tr1ad]

glad it was finally figured out

[srnoth]

Glad I could help - when you mentioned 2nd gear it sounded just like what happened to me. I find you have to consciously not allow you foot to move to stop it from happening. Lucky for me though its just a short stretch of road.

[MonsterPower]

hmm...sounds liek yuh running through de roads of barrackpore or de field roads...

[3stagevtec]

hmm...sounds liek yuh running through de roads of barrackpore or de field roads...

busted!

Glad I could help - when you mentioned 2nd gear it sounded just like what happened to me. I find you have to consciously not allow you foot to move to stop it from happening. Lucky for me though its just a short stretch of road.

what made it hard for me to figure out is that i wear steel tip shoes when driving, that really takes away alot of the pedal feel you get. so i never knew my foot was actually 'playing' on the throttle pedal..

amazing how simple the solution was... and no one at work could have figured it out