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12Ht Surge

Posted: Sun Apr 22, 2007 1:31 am
by ellard
Hi there

I am after some advice/direction from the forum.

I have recently bought an old 1986 12ht 60 wagon - and I am having a problem which I am am unable to explain.

When driving the vehicle at idle (4wd or 2wd) it seems to want to surge (bunny hopping) - could it be the idle is set to low or is it a throttle issue?

What RPM should these be set to?

Thanks in advance

Wayne

Posted: Sun Apr 22, 2007 7:15 am
by MUD000
Put bigger tyres on it
It'll obsorb the tourqyness out of the motor
You will learn to drive it I did
I run 32 arount town & 35's in the bush & its so much better to drive on 35's
Cheers Dan

Posted: Sun Apr 22, 2007 10:11 am
by Shadow
its not a problem, just something you have to learn to get used to

The 2H's do it a bit too. You need very fine throtle control. When you hit a buimb your foot is bouncing just that little bit which is causing the bunnyhopping.

Some people put a block of foam under the throttle when doing the more delicate 4wding.

Posted: Sun Apr 22, 2007 1:38 pm
by dow50r
Heres some sort of explanation for you...i dont know if the 12ht pump does this like the hdft does...at idle, the pump governs itself....if the motor idles lower, the pump compensates...and adds fuel..then when it gets up to idle it removes it...and you kangaroo up the road :)
Dont let it happen...at this speed, you have lots of mechanical forces and not much oil...big ends suffer.
Andrew

Posted: Sun Apr 22, 2007 6:57 pm
by ellard
Hi there all

First of all many thanks for the explanation.

I suspected it could have been me and my driving habits (as I havent had it for all that long)

It just sound like the excuss I need to get off road a little more often to get familiar with the truck.

Many thanks again

Wayne

Posted: Mon Apr 23, 2007 12:09 am
by tuffsahara
yeah same with mine its wayy touchy i got used to it also if it bounces when it idles the govener needs to be adjusted the old man did it on mine and fixed the problem :armsup:

Posted: Thu Apr 26, 2007 12:10 pm
by beavis
try putting a heavier spring on the throttle cable on the pump, or an additional spring. You will also reincounter this problem when you decide to pump some more air into it

Posted: Thu Apr 26, 2007 7:03 pm
by Frankenyota
Did some injectors in a 60 series with a 12ht.
When i test drove it the throttle was very touchy, causing kangarooing if you didn't ease the pedal.
Asked our diesel repair mob and they said that it's a sign of the governer in the injector pump was worn.
Which mean't big dollars to overhaul :cry:

Glad i have a hilux.

Matt