Surging Defender

[strazzman]

recently, (since the weather has cooled down) the engine has started surging, It only does it at a certain rev range. Most obvious doing 57-59 km in forth gear on a flat stretch of road whilst maintaining a constant speed. When the engine and pump have warmed up the surge is noticably less, but still there. Looking through 59 pages of previous threads not much has been written about surging diesels. one clue could be a chafed fuel line allowing air into the fuel line. In the mornings the motor takes a few seconds of cranking to start, once started takes a few more seconds to settle into a smooth rythem. Other than that the motor is fine. Should I be concerned about the surge?. What could be cousing this to occur?. Vechicle is a 1995 Defender with 55000k on the clock.

[DEFENDERZOOK]

<span style="color:darkred">it hasnt even been run in yet.......

have you checked the pump timing?</span>

[LRHybrid100]

The starting problem sounds the same as the one Langy had - turned out to be a split fuel hose.

As Langy found, if there is a hole in the fuel line then once switched off all the fuel in the lines will run back into the tank - hence the reason why it takes a couple of turns before firing up.

This would also effect the running lean - that’s if a diesel can do this? and possibly giving the symptoms given

HTH

LRH

[LRHybrid100]

oh and have to agree, motor should run like a dream with such low Kms!!!

LRH

[sclarke]

Let me confuse all of you......

My Fender Surges at 100kmh
It starts 1st pop, suged since i've had it but comes good at 110kmh....

So as for air in the line my case i would doubt it....

OK hear is the next thing i noticed....
When it surges the lights dim.....
I had a similar problem some years ago in a Volvo. Turned out to be the Alternator getting an internal load (short) and pulling the engine down... and the electrics.

I'll change my Alternator and see if mine improves.....

I thought orig that the pump was not Fat enough... ie not enough fuel but as it clears after 110kmh it cant be that.
I cant pick mine surging at any other gear. so it is rev related, but i cant get it to do it in 4th...

I'll play and let you know of my outcome...

[UncleHo]

What's the posibility of a waxed-up filter :?: That problem usually does not present itself until it starts to get cool we found that that a Wynns diesel conditioner works well in older diesels [img]style_emoticons/<#EMO_DIR#>/smile.gif[/img] But I would definataly check that chaffed line.

[MickG]

I have recently had a problem with the engine surging on my Manual S2 Disco. Had a remapped ECU fitted a few months ago and all was fine but recently the revs contiinue slightly when changinbg gear - like you have left your foot on the accelerator accidentally and then take it off. It only seems to do this in 2nd or 3rd gear. On 2 occasions it has also surged when in low range which gives you the fright of your life and nearly sent me over the edge on the first occasion. Have had he ECU checked and all is showing no faults so no idea.
Anyway, that's my story soI'll keep watching this thread to see if any solutions arise.

Cheers, Mick

[disconut]

Mine has a slightly different surge problem. When coming down the range in 3rd gear at 60 k/hour no throttle or brakes, all is good. When it slows down to 50 / 55 klms on a flatter section, and touch the throttle lightly to hold 60 k/hr, it surges. Has been doing this since new. It has not been checked out to date. Does any one else get this on light throttle application during big downhill runs?
Trev.

[one_iota]

The surging on a Tdi and Td5 could be different. As I understand it the Td5 has electrics designed to avoid excessive surging. I've not experienced or recognised this phenomenon with my Tdi.

[disconut]

My TD5 powered DII ES Auto did not do this down the same hill. It used to run in 2nd with the air con on as an aid to braking and hold 60 klm/hr.
Might just be a manual thing?
Trev.