diesel help needed

[terrycra]

Hi does any one know of a good diesel engineer in the nelson tasman area here in new zealand,its very hard to find some one that knows what they are talking about when it comes to my 3.1 isuzu, cheers

[isuzurob]

What are you trying to fix??

[terrycra]

trying to work out why my 3.1 bighorn diesel ,revs up and down when idling ,more so when you first start it in the morning,seems that when you turn the heater blower up to about 3 it goes away,some times happens when it is warmed up,then it just goes away till the next time,i know that the glow plugs need to be done,but i dont think that is the problem,some say its the fuel pump some say a sensor and a lot of other things other than that it runs well with no smoke and good economy ,also seems that the colder the day the worse it is,may be i will just have to wait till summer. cheers

[geeves]

Ill give you an excelent one in Wellington but run your problem past us first. It might be an easy fix you can do yourself.

[terrycra]

Hi geeves i do not know how i can discribe it any better than my post ,that i sent at about 5.00 pm today any help thanks

[geeves]

it does sound more glow plug like but could be a sticky injector or pump problem etc. Yours will have a ecu controlled pump and these do wear the governor causing the hunting at idle you describ although it does it all the time. My Wizard is quite bad for this but always settles within 30sec or so. Ive had a few goes at fixing it.The Wizard doesnt have the ecu controlled pump.

[MrRevhead]

Hi terrycra, who have you been to locally? What do these run in the way of diagnostics? If it's ECU controlled a proper scan tool should output various sensors readings which will point in the right direction.
The trick will be getting it to do it when the scanner is attached!

[terrycra]

Hi it all most seems like it may be the weather ,to day here in nelson its been quiet warm,its ran good all day with no problems ,i am beginning to think that may be it has air leak,sucking the cold air in,and now after a warm day the air temp is warmer,does this sound possible ?

[MrRevhead]

No, not really
If you want I might be able to take a look next weekend but I'm not that familiar with the 3.1

[geeves]

in order of likely hood
faulty glow plug Test with a multimeter
front seal on fuel pump This seal can be done without taking the pump out but radiator. and all the belts have to come out first. Most diesel shops will tell you you need a full rebuild which isnt entirely correct
faulty egr valve Block off
faulty sensor or ecu One for the experts
low compression cylinder With the engine running is there lots of fumes at the oil filler cap?