Deisel Stutter - in between power and coasting in top gear.

Submitted: Friday, May 24, 2013 at 20:16
ThreadID: 102397 Views:2048 Replies:7 FollowUps:15
This Thread has been Archived
Hi all - figure I will throw this one out there for people that know all about deisels.

Specifically it is a Ford Transit van 2005 2.4TDCi (turbo common rail) that I use for general travel. I have had no luck on any motor forums. The symptom while not a problem is annoying and I would really like to know what it might be ... as in ECU, dirty injectors, whatever - if an easy fix it would be nice - but it seems most "suggested fixes" involve lots of money.

When in cruise (usually 6th gear) and with your foot pretty much steady on the accelerator, when I am just at that tipping point where the engine transitions from very slight power to very slight coast or vice versa (possibly at the point the engine and diff are "disconnected" due to the little bit of play in the gear trains and 0 power trasfer) the bloody thing stutters a couple of times in quick succession (less than a second) as in power off / power on before it runs smooth again either coasting or driving. Speed at the time does not seem to matter be it 60 or 100 ...

I can get it on flat road, or in the bottom of a small valley where power changes from coast to drive are not large.

It never happens under load conditions either coasting or driving, only if you hold your foot steady and reach that "in between" mode.

The only other thing I will add is that it does tend to smoke a bit say if you sit at the lights for a while, when taking off (generally 1st and 2nd) it can blow a bit of smoke in the headlights of the car behind (only really noticeable by me at night more than day) but generally not continue once you accelerate past these gears unless you are really heavy on the throttle. No idea if this is related.

Ken
Back Expand Un-Read 0 Moderator

Reply By: d04 - Friday, May 24, 2013 at 21:12

Friday, May 24, 2013 at 21:12
injectors need cleaning had the same problem on my Patrol
AnswerID: 511780

Follow Up By: KenInPerth - Friday, May 24, 2013 at 22:22

Friday, May 24, 2013 at 22:22
I know this is not the same, but I did use some injector cleaning additive for an extended period but that made no notable difference.

Who did you get to do your injectors and what cost - from what I have found out it seems an expensive excercise if it will not resolve anything.

Can they do any king of a "yes / no" test ??
0
FollowupID: 790064

Reply By: 08crd - Friday, May 24, 2013 at 21:52

Friday, May 24, 2013 at 21:52
Is it a drive by wire or does it have an accelerator cable. If it is drive by wire, the accelerator potentiometer could require replacing.
AnswerID: 511783

Follow Up By: KenInPerth - Friday, May 24, 2013 at 22:16

Friday, May 24, 2013 at 22:16
Sorry - should have posted it is drive by wire.

I did replace the accelerator pedal (complete assembly) and it seemed to make a difference for a while but I would not say it went away - and has slowly worsened again.
0
FollowupID: 790061

Follow Up By: Ross M - Friday, May 24, 2013 at 22:18

Friday, May 24, 2013 at 22:18
O8crd
My thoughts exactly. It could be the throttle position sensor TPS become worn after many KMs and it sounds like it does it when it is from moving from the most worn parts of the resistance inside the unit.
Basically it is a high tech volume control.

A check of it's operation and it's resistance reading over the full movement may reveal a fault.

Ross M
0
FollowupID: 790062

Follow Up By: KenInPerth - Friday, May 24, 2013 at 22:25

Friday, May 24, 2013 at 22:25
I replaced it around 90 to 100K and it has now only done about 120K

0
FollowupID: 790065

Follow Up By: 08crd - Friday, May 24, 2013 at 22:31

Friday, May 24, 2013 at 22:31
MAF pot may have the same issue, the flap stays in a fairly stable position at coast.
Then on slight acceleration or deceleration it moves from that position.
You should be able to borrow one from a wreckers and it's only 2 minutes to change it.
1
FollowupID: 790068

Follow Up By: KenInPerth - Friday, May 24, 2013 at 23:13

Friday, May 24, 2013 at 23:13
Thanks for that tip - but I am in Electronics.

The "pot" makes sense but what is MAF short for and where would I expect to find it ??

I guess my mechanic will know what you are suggesting ?
0
FollowupID: 790075

Follow Up By: 08crd - Friday, May 24, 2013 at 23:41

Friday, May 24, 2013 at 23:41
The MAF is a mass air flow meter, it tells the computer how much air is going into the motor. Very important with a diesel as they don't have a throttle butterfly valve, like a petrol.
Basicaly the diesel just lets as much air in as possible and regulates fuel according to how far you pushed the accelerator, well that's how it used to work.
These days, everything is fed back to the computer, because they don't want you blowing heaps of black smoke(unburnt fuel).
You will find the MAF meter between the airbox and the turbo inlet. It may be flap actuated or a resistance wire device( they use temperature sensitive wire to give feedback).
Anyway like I said, I'm sure if you went to a wreckers and asked to put one in an test it, they wouldn't have a problem.
1
FollowupID: 790077

Follow Up By: KenInPerth - Saturday, May 25, 2013 at 12:38

Saturday, May 25, 2013 at 12:38
Just pulled mine out and it is has two small components mounted between 2 sets of pins inside the sensor tube.

So I assume this is the resistive wire type you mention - not that expensive for a new replacement ($60) so maybe worth a try ...

Like a lot of problems you can spend a lot of money trying things to fix it with no result, and it is rare you find someone that has actuay experienced it and found the absolute cause.

We seem to have so many controls and sensors these days that add complexity it is a wonder anything works .... and on the converse side given there are so many controls and sensors it is probably a wonder we don't have more trouble than we do. This is certainly the case with electronics these days ....
0
FollowupID: 790097

Reply By: Ross H3 - Friday, May 24, 2013 at 22:15

Friday, May 24, 2013 at 22:15
Is this auto or manual If auto take note of rpm when occuring and see if can be duplicated in another gear if not it maybe lockup converter issue
AnswerID: 511786

Follow Up By: KenInPerth - Friday, May 24, 2013 at 22:29

Friday, May 24, 2013 at 22:29
Should have posted it is manual so that does not apply does it ??
0
FollowupID: 790067

Follow Up By: Ross H3 - Friday, May 24, 2013 at 23:07

Friday, May 24, 2013 at 23:07
Well the cheap fix would be drive in 5th gear so that does not apply does it ?
0
FollowupID: 790074

Follow Up By: KenInPerth - Saturday, May 25, 2013 at 08:53

Saturday, May 25, 2013 at 08:53
Ross

You might have misinterpreted my answer as "sarcastic" ?? It was actually a question as I misread your email. That is a problem with the written word as against the spoken word. Apologies.

When I re-read it you did say "if it is auto" and so I did not need to ask the silly question.

I should have posted in the original text that it was manual transmission.

I apprecitae all input from everyone ...
0
FollowupID: 790086

Reply By: garrycol - Saturday, May 25, 2013 at 12:14

Saturday, May 25, 2013 at 12:14
Have you have the codes that have been logged in the ECU - that should be telling you exactly what the issue is (or at least where to look further).
AnswerID: 511805

Follow Up By: KenInPerth - Saturday, May 25, 2013 at 12:17

Saturday, May 25, 2013 at 12:17
Yes have done that too with my mechanic and no error codes.
0
FollowupID: 790095

Follow Up By: garrycol - Saturday, May 25, 2013 at 15:32

Saturday, May 25, 2013 at 15:32
In that case it must be something relatively minor if it has not registered any codes.
1
FollowupID: 790101

Follow Up By: KenInPerth - Saturday, May 25, 2013 at 16:17

Saturday, May 25, 2013 at 16:17
One day I might find out ... as I said, annoying more than a problem ...
0
FollowupID: 790103

Reply By: Member Bushy 04(VIC) - Saturday, May 25, 2013 at 14:26

Saturday, May 25, 2013 at 14:26
Ken I own a 2.5diesel and had the same problem, it turned out to be the lint filter on the injector pump . Did not see it myself but there is a gauze type filter were the fuel line goes into the pump.
Would get a resectable diesel mesh to do it.
This may or may not be the same as your problem but it may give a mech a start point
Hope this helps Bushy.
AnswerID: 511809

Follow Up By: KenInPerth - Saturday, May 25, 2013 at 14:52

Saturday, May 25, 2013 at 14:52
I am happy to have any possible options on the table.

I have a good mechinic I can talk to (although the Transit is not something he sees a lot of) and we bash out all these ideas. He certainly knows deisels though.

0
FollowupID: 790099

Reply By: D-Jack - Saturday, May 25, 2013 at 19:06

Saturday, May 25, 2013 at 19:06
My CRD Triton was doing similar. A simple fe-flash of the ecu (latest software) fixed it completely and instantly. was also blowing a bit much smoke, (or vapour particularly noticable at night) and the reflash fixed the problem.

MAF - you can get specifit aerosol cleaner to clean them - they often need cleaning.
AnswerID: 511814

Reply By: Rangiephil - Saturday, May 25, 2013 at 20:59

Saturday, May 25, 2013 at 20:59
Funny we just discussed this on the AULRO forum. My D2 TD5 does this and another D2 owner has the same thing.
All my sensors are reading perfectly and I have been using Chemtech for several tanks so my injectors are clean. I have a brand new MAF, and my MAP is reading perfectly. In short the engine goes perfectly.

I know the TD5 is a different engine to the 2.4 Duratorque but they both have EGR.

I reckon it is simply the ECU enabling the EGR and then switching it off, and on and off etc . Maybe there is no or not enough hysteresis on the switching action.
Regards Philip A

AnswerID: 511819

Sponsored Links

Popular Products (13)