300 Tdi Auto (145k) Low Speed - Misfire? Hunting?

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.

auf_wiedersehen_pet

Well-Known Member
Posts
2,456
Location
The Solent
Hi All,

Since purchase in 2006 my ultra reliable Disco as been a dream to own. Then in September it wouldn’t start. The AA fixed my "exciter wire" but two days later it conked again. A new starter was fitted and two days later it conked yet again. It appears the new starter was duff and this was swapped at the supplier’s expense. That’s when the fun started.

As soon as I started to drive it away from the garage something didn't feel right. At car park speeds (1,000 rpm) it felt "stuttery" as if the revs were on/off/on erratically. On the road, it pulled and ran fine apart from the 1,000rpm mark (typically 20+ mph, whiff of throttle to keep it moving in traffic) when it feels like a misfire/stutter/hunt.

It went back to the garage and after weeks of tests it was pinpointed to a STC 1734 throttle potentiometer. The prices in the UK were extreme so I purchased one from Les Richmond in Melbourne which cost £800 with delivery, insurance and customs fees. After several weeks it arrived in the UK and was fitted to the Disco.

All was well until last week when the symptoms arrived again. At low speed it misfires/stutters/hunts badly. It literally feels like its firing every 2nd/3rd revolution as it lurches through car parks. I also feel that it is running rough at most of the rev range but this could be paranoia!!!

I’d love to know your thoughts. What would you guys do? I can’t replace the throttle potentiometer every six weeks at £800.

Could there be an underlying problem not caused by the throttle pot which “went away” for a few weeks to confuse me?

Could the pot be faulty after 1k? It did arrive in a LR box dated 2004 which is very naughty!

Additional info.
ECU chipped last December for £500
Kenlowe Fan
K&N Filter
Silicone Hoses
Gas Flowed Intercooler

Any suggestions would be welcomed as we have snow on the way and it looks like I’m going to be on the bus :{
 
Hi All,

Since purchase in 2006 my ultra reliable Disco as been a dream to own. Then in September it wouldn’t start. The AA fixed my "exciter wire" but two days later it conked again. A new starter was fitted and two days later it conked yet again. It appears the new starter was duff and this was swapped at the supplier’s expense. That’s when the fun started.

As soon as I started to drive it away from the garage something didn't feel right. At car park speeds (1,000 rpm) it felt "stuttery" as if the revs were on/off/on erratically. On the road, it pulled and ran fine apart from the 1,000rpm mark (typically 20+ mph, whiff of throttle to keep it moving in traffic) when it feels like a misfire/stutter/hunt.

It went back to the garage and after weeks of tests it was pinpointed to a STC 1734 throttle potentiometer. The prices in the UK were extreme so I purchased one from Les Richmond in Melbourne which cost £800 with delivery, insurance and customs fees. After several weeks it arrived in the UK and was fitted to the Disco.

All was well until last week when the symptoms arrived again. At low speed it misfires/stutters/hunts badly. It literally feels like its firing every 2nd/3rd revolution as it lurches through car parks. I also feel that it is running rough at most of the rev range but this could be paranoia!!! Q

I’d love to know your thoughts. What would you guys do? I can’t replace the throttle potentiometer every six weeks at £800.

Could there be an underlying problem not caused by the throttle pot which “went away” for a few weeks to confuse me?

Could the pot be faulty after 1k? It did arrive in a LR box dated 2004 which is very naughty!

Additional info.
ECU chipped last December for £500
Kenlowe Fan
K&N Filter
Silicone Hoses
Gas Flowed Intercooler

Any suggestions would be welcomed as we have snow on the way and it looks like I’m going to be on the bus :{

really not sure but i would be looking at the injectors ?? Are any leaking
Plus 800 quid for any 300 tdi part if daft you could have bought a whole one for that and taking he parts you needed and flogged the rest but hey whats done is done like i said i dont know much aboot the ecu 300 s
 
really not sure but i would be looking at the injectors ?? Are any leaking
Plus 800 quid for any 300 tdi part if daft you could have bought a whole one for that and taking he parts you needed and flogged the rest but hey whats done is done like i said i dont know much aboot the ecu 300 s

The injectors can go on the list for the garage to check/replace.

I don't like the word "daft", I prefer the word obsessive!! :)

I did debate buying a 2nd hand motor but didn't want to "scrap" a good LR for one part. Also, there's the risk of buying a 15y old Disco, how long will the part last. I trawled all of the breakers/eBay to no avail.
 
This is why I'm daft, sorry I mean obsessive!
:):)

Picture002-1.jpg
 
Back
Top