Over-revving at start up

[Graham Smith]

Hi

My HDJ80 has developed a nasty habit. It started when we had the snow, and I hoped it would go away when it warmed up. It hasnt...

At start up it revs at 1800rpm, once it has warmed up this settles down to about 1000rpm and appears to be normal. This takes about 10 -15 minutes and seems to coincide with the oil temperature coming up to operating temperature.

The serious part of the problem, is that from start up I can be doing 40mph in 4 seconds without touching the accelerator. So I am having to use the brakes and intermittently drop her into neutral, just to get down the road without mowing every thing flat...

Any tips on where I can fine the gizmo that does this will be appreciated.
Or anyone fancy a race from start up without touching the accerator...

 

[Crispin]

Don't the 80 have the hand throttle for quick wsrmups? A lever or plunger on the dash.

Some one a while ago had this on for jump starting another car. They left in drive and the handbrake let go once they got out. They had to chase down the road.

Sent from TapaTalk

 

[Ecky Thump]

I recently had a similar problem to this.
For me it was the throttle linkage. The cables and the linkage on the top of the block were sticky and had years of crud on them.
After a thorough clean up, oil in the cables and grease on the linkages the problem was solved.
The plastic bearing surfaces on the semi circular affair on the head were seriously sticky so I stripped it, cleaned it and used a light oil to solve the problem.
Your issue may tally with old grease warming up rather than oil pressure As crispin said, it could relate to the hand throttle too

Just a thought

 

[Dave Burgess]

......

Some one a while ago had this on for jump starting another car. They left in drive and the handbrake let go once they got out. They had to chase down the road.

That was me

 

[Jon Wildsmith]

There's usually a cold start idle up device on the side of the pump, maybe that is playing up. Can't describe it to you as my memory of them is fading but it will be in the FSM and I think you can disconnect it.

 

[Andy Harvey]

UK models definately had the Cold start device from memoryon top of the IP. It is most probably this gone belly up - it can be disconnected - not all markets got it anyway.

 

[Brett]

The ACSD is on the side of the injection pump. It's a common leak point, I replaced mine due to a diesel leak.

If you remove the ACSD you will need to get hold of a blanking plate & I think you also need to adjust the pump timing to compensate.

This picture shows the ACSD removed & blanking plate installed.

 

[Graham Smith]

Thanks for all the replies, I will attack it tomorrow when the sun shines....
And I will have to eat some biltong after all this talk today... It made me very hungry at work.

 

[Graham Smith]

All sorted - adjusted a few screws, and its well behaved again...
Thanks

 

[ajnabi]

Hi Graham, well done.
Which screws did you fiddle with?

 

[Graham Smith]

Hi Graham, well done.
Which screws did you fiddle with?

On Bretts photo... where there is the plate on the side -I have a gadget with 2 screws whose heads point towards the radiator.
I adjusted them.

HTH

 

[goingdownsouth]

Thanks for all the replies, I will attack it tomorrow when the sun shines....
And I will have to eat some biltong after all this talk today... It made me very hungry at work.

Biltong!! Ahh yes that sounds like a good idea!

I had a near-death experience on the M6 the day I bought my Cruiser.

Driving merely at 70 I overtook a Lorry going up to about 85 in the process. When i got back in the middle lane the truck would not slow down. Took my foot of the pedal but it kept on accelerating..faster and faster.......... i was on 90 now and still going! First thought was the pedal got stuck thus kicked it a few times - no luck............doing 95 now

Engine revving hard!! Speed increasing by the second, then tried the brakes - no help, kicked the pedal - no change just keep on going ........100 coming up !!

Coming up quickly to a few cars - went around them and then pulled into nearside lane!

Time for action - thinking back to episode of Magnum PI - - engaged neutral - engine screeming now then switched the engine off ....turn on the hazzards and cruised onto the hard shoulder and came to a stop!

Looked around the engine bay with nothing obvious wrong - no tools on me thus quick phone call to the RAC and awaited the cavalry.

RAC man arrived - stumped! He was just about to get the flatbed out when i spotted something. After checking the linkage with the pump and choke I found a hexbolt that vibrated loose where it fixed the throttle flange to the side of the engine block.

I worked it out : While I was accellerating earlier this hex-fixing-bolt vibrated loose outwards and got caught behind the swivel flange with cable on the throttle. Thus not being able to return to the beginning/zero position it got stuck when i was doing about 90 and stayed there..........

Screwed the bolt back in and problem solved! New pants for me and all sorted!

This could happen to you guys as well - be prepared or loc-tite the bastard bolt in advance!

Happy driving!

 

[tomrichardson]

just to tag onto an old post.
i have just removed my acsd. i was doing the pump timing anyway and upon re-assembly found the acsd to be leaking slightly from the shaft, so off it came and set the timing (again)to suit.
but when i started the truck up this morning there was a lot more smoke than there used to be. it did clear when the engine got warm, but i was very surprised. i was just wondering if those that have also removed it have found the same thing or have i done something wrong?
i set the plunger stroke to 1.33mm at tdc. incidentaly before i reset it it was 1.54mm at tdc so quite far out. i was astonished at the little amount you move the pump to make considerable difference. the guy who did the seals on my pump and said "it'll be ok put back to the original marks" didn't mention that a hairs thickness makes all the difference.
cheers, Tom.

 

[Chris]

I had this with mine and all I did was backed off the rod that connects the throttle up device to the main lever. It cuts in below a certain temp and raises the revs until warm. Mine seemed to cut in even when it was warm outside and I nearly backed into a lamp post!

It's pretty simple. You can remove the whole device but it affects the engine advance too so I understand. So if you mess with it, you may get some tricky bits too that you didn't want. Far easier to back off the connecting rod in my view so that the plunger that comes out of the end of the mech doesn't raise the revs. Or turn it down s that it only idles up to say 1000 rpm instead.

Chris

 

[tomrichardson]

i did adjust those before, but it still used to rattle like hell against the throttle linkage on cold startup, so i just used to pull the hand throttle out to stop it. You could still feel it if you put your hand on the pump though.
i did start it again from cold this afternoon and it didn't smoke anywhere near like it did this morning so it may just be the fact i had messed around with it all, air in the system etc, and it needed to settle down.
i'll see what happens tomorrow morning. trouble is its got no tax or mot till thurs so i cant really take it for a good blast down the road till then.