Erratic Ideal/Revs Gearbox or Engine?

[Flip-Flop]

Good Evening, I'm having some issues with with my Gen 3 3.0 , I've owned it for almost 6 years now and this is the first problem I have had, so I guess I can't complain

My Missus drives it mainly and she says at tick over it randomly sounds like it it's going to cut out, when pulling up to a junction etc, the revs will suddenly drop for a while then recover (she says that it appears to be worse when cold), also (this is the scary part) occasionally it will hunt forward, so for example as you are slowing to halt it will it suddenly increase speed slightly, lastly when running on a clear main road it will very occasionally lose power just for a couple of seconds (I've experienced this myself). Sorry for not being able to explain it better.

I'm not sure if this engine related or gearbox, I don't really want to take it to a garage without being for-armed with some knowledge of what the issue might be or from past experience I can just see myself just being ripped off.

Any advice, ideas would be appreciated, thank you.

[The Lang-Shankit Scunner]

Sounds to me like either a fuel delivery problem i.e when was last filter change? Or it could be throttle position sensor. Maybe even an idle control valve if it has one. Thats me cleaned out, someone will come to your aid more definitively shortly

[charvell]

Good Evening, I'm having some issues with with my Gen 3 3.0 , I've owned it for almost 6 years now and this is the first problem I have had, so I guess I can't complain

My Missus drives it mainly and she says at tick over it randomly sounds like it it's going to cut out, when pulling up to a junction etc, the revs will suddenly drop for a while then recover (she says that it appears to be worse when cold), also (this is the scary part) occasionally it will hunt forward, so for example as you are slowing to halt it will it suddenly increase speed slightly, lastly when running on a clear main road it will very occasionally lose power just for a couple of seconds (I've experienced this myself). Sorry for not being able to explain it better.

I'm not sure if this engine related or gearbox, I don't really want to take it to a garage without being for-armed with some knowledge of what the issue might be or from past experience I can just see myself just being ripped off.

Any advice, ideas would be appreciated, thank you.

Change the fuel and air filter first, fill the fuel filter with injector cleaner then take it for a good run

[Flip-Flop]

Thank you for the speedy reply;

Is changing the fuel filter relatively easy on the KNZ185 engines, is it a DIY job, are there any step by step (baby steps) guides at all preferably with pictures , I did search but it did not turn up anything relevant.

[charvell]

done mine before,, they can be a pig to undo, disconect the two fule pipes, undo the multi plug conector, undo the two bolts and lift the whole thing off... put the plunger in a vice and unscrewthe filter, then tack the plastic water catcher thingyof the bottom of the filter replace is reverse, put a little derv around the ruber seal. i alway put the delivery fuel pipe on first then pump the plunger this gets any air out of the filter, oh you can fill the filter with diesal redex. and you may not need a vice you might be lucky and be able to unscrew it by hand. hope this hepls,, i am sure that some one else with have an add on to this ..

[Flip-Flop]

Thank you. I've just ordered a filter kit so I'll give it ago, I don't have access to vice thought :S so hopefully I won't get stuck on that part.

[coolsv650]

Thank you. I've just ordered a filter kit so I'll give it ago, I don't have access to vice thought :S so hopefully I won't get stuck on that part.

If you can get in an oil filter wrench might help. the first one I did on my KZN130 needed the vice to undo, it was extremely tight.

Now I don't have a problem, oil filter wrench (strap type) and a 1/2 bar

[cold water surfer]

I have just had the same issue sorted on my 93 30lt ,turned out to be a broken wire for the coolant temp sensor.I was having the same symptons as youself apart from revs droping, mine allways surged up.Code 22 (coolant temp sensor)from a computer test.If full service dosent sort it ,this may be your problem.Have no idea if the 3rd gen is the same set up as mine though!
Good luck

[Flip-Flop]

Thanks, hopefully the filter will be here tomorrow and I get it fitted on Thursday.

I've searched for the answer and have not found out how to retrieve the ECU codes on the knz185 engines, is there a tutorial or post on it?

TIA

[Sancho]

Thanks, hopefully the filter will be here tomorrow and I get it fitted on Thursday.

I've searched for the answer and have not found out how to retrieve the ECU codes on the knz185 engines, is there a tutorial or post on it?

TIA

I DON'T KNOW THIS but wouldn't it be the same as on the 2nd gen 3.0, seeing as they're the same engine?

[Flip-Flop]

I DON'T KNOW THIS but wouldn't it be the same as on the 2nd gen 3.0, seeing as they're the same engine?

I thought the second gen (3.0) had the KNZ130 engine and the 3rd gen has KNZ185 but as you can probably tell from my post, I'm NO expert, lol.

[Apache]

A little hint for when you put the fuel filter back. As has been said, a bit of diesel on the seal, and then HAND TIGHT only. It doesn't need a wrench to put on, and shouldn't need a wrench to get off.

[mickey]

If you haven't access to a vice, just bolt the filter assembly back on to the mounting, upside down..You "might" be able to get it off with a filter removal tool or screwdriver...

As others have said..Its worth filling the filter with Redex too...saves on plunging and gives the injectors a neat shot of the hard stuff..

[Flip-Flop]

Thank you for all the suggestions and tips.

I now believe the cause of the problem to be BP's greener/cleaner fuel, the detergents in it apparently cause the injectors to stick on older diesel engines so I have been informed and the problem seems to tie in with when the missus fills up at a BP garage in Gloucester or one near Brize when she visits her brother, I'm still going to change the fuel filter now I have it and give her a shot of redex at the same time.

[mickey]

Thats an interesting point regarding the fuels..I guess when our rigs were constructed, diesel was just diesel..I have filled up at forecourts proclaiming their derv to be green this, envoironmentally that etc which is all very good, but leaves me wondering what the trade off is? I recall [Bushwhacker?] saying he filled up from the HGV pumps, assuming the gunk that eminates from them is the good ole fashioned no nonsence stuff..I like the thinking, but have been to embarrassed to pull up at one as yet...Maybe these lean, mean and green diesels are great for modern cars but not such a good deal for our more basic lumps?