wont rev after rebuild

[nivapilot]

Hi all
My HDJ 81, of 1991 vintage has finally been nailed together, and it doesn't want to start....

I have the 12/24volt changeover switching relay....When I hit the key, all I get is a buzzing from the changeover relay..
Now if I put an earth cable from the secondary battery to the engine, it fires up as it should, but then only rev to 1600rpm.

Only thing I can put my finger on at the moment, is the kickdown cable is jammed in the open position.....would this be part of the revving problem?

And is the 12/24 volt changeover relay goosed?
Any help will be fully appreciated.

 

[Julian Voelcker]

OK, I would check the engine earths as a starting point.

As for the low revs shouldn't be down to kick down cable - actually just disconnect it on the pump to rule it out.

What work has been done to it?

Are you getting any smoke?

How is it running at tickover?

 

[Beau]

If the revs are being limited, could it be fuel related...

I think the 80 series Pump run a drive by wire mechanical fuel Pump which means no electrics involved. If it is being limited, maybe it is not drawing enough fuel

Any smoke, how does it idle, does it build up the revs quick as usual or is it slow?

 

[nivapilot]

The engine was taken out for a complete stripdown and rebuild. Replaced pestons, crank and 1 rod with second hand good items, new rings and bearings....newish pump was fitted by previous owner..head wasn't touched and all timing marks were triple checked before final build.
Refitted into engine bay and hook everything up.

Unfortunatley, because I bought the car with a blown engine, I don't know how it drove before.
I have rechecked all 4? engine earths and cleaned before refitting. Offside battery main earth to block, small earth point at rear of head, large ring under rear of inlet manifold and 12/24 volt changeover relay to block......don't think there are any more.

As for the revs being limited, it's as if there is exactly that, a rev limiter on line.....1600RPM and that is it....every time, no variation.?

engine seems to tickover/idle ok and doesn't seem to be slow to rev up.
Little smoke, but only had it running for 1/2 hour so far, so I expected a little smoke to start of with, after running for about 10 minutes smoke dissapeared.

After the rebuild this has now been a bit dissapointing.

 

[Dave Docwra]

Valve clearances were they checked? Are the Fuel lines connected correctly & sealed?

 

[nivapilot]

No, valve clearances were not checked, I assumed(could have been a mistake) that they would be ok, so haven't touched the head at all..although the engine does start, on the button, so the head and valve clearances can't be far off? Although in saying that, there was a fair bit of pressure coming through the breather connected to air filter housing.

Fuel system has been pressurised via the priming pump to check for leakage.

Any ideas on where the 24volt timer relay is located? I have found the 12/24 volt changeover relay, and the starter relay, but can't locate the "12/24 volt switchover timer relay".

The system seems to operate partly correct and I need to check it out properly.
Many thanks

 

[adrianr]

If that part was faulty it would not start?

 

[karl webster]

Alan, ive tried ringing you.

Give me a shout when your phone has signal

 

[nivapilot]

That is the problem adrian, it doesn't start until I put a jump lead from the nearside battery negative to the engine. which is by-passing the 12/24 volt changeover relay?

 

[adrianr]

Apologies - had not read the post completely!!

Can you pull the replay apart and take a look inside - OH and do speak to Karl, he knows his stuff.

 

[nivapilot]

Have spoken to Karl....what a man. ...he has suggested a few things, which I shall try out tomorrow...
I haven't taken a great deal of notice of the relay construction.....I doubt that you could dismantle it , but that was one of the things that Karl said could go wrong, and do quite often. ....I am slowly getting my head around what and why...so here's hoping.

 

[Towpack]

If you're 100% certain the relays have been reconnected correctly check the switching supply to the 12/24v relay is good under load. The starter solenoid contacts are known for giving trouble, the 12/24v relay isn't IMO.

Diesl engines need only air, compression and fuel to run. Assuming the first two are OK the revving problem has to be fuel. Disconnect the outlet pipe from the fuel filter/lift pump in the engine bay and rig up a fuel supply with some sort of container to give the IP a good gravity fed supply. if the problem still exists it must be IP related IMO.

 

[adrianr]

given it sticks at the sakes revs? could it be a governor problem in the pump - i.e. its been set at that level for some reason?

 

[frank rabbets]

Are you sure the throttle pedal linkage is moving all they way accross on the pump end?
Could be that it's just not opening fully?
Frank

 

[nivapilot]

She runs and revs loverly, boy am I a happy bunny.

Karl suggested the filter in the tank, amongst other things, so first thing this morning out came the rear seats, move the carpet, and off with the tank unit/pick up pipe......dunno what was in that tank, but it sure as hel wasn't diesel.....seemed to be a mixture?, smelt a bit like parrafin? and white spirit?.....veg oil?..bio diesel?...anyway sucked it all out, and there was the first clue, gummy substance lining the tank where the fuel had sat...filter looked ok, washed it out with petrol anyway...but both pipes, pick up and return were both gummy as well......

Back up the front end, checked the linkage opened fully...ok.... removed, both feed and return pipes from the pump and connect to a 1 gallon can with neat diesel in it...bled it and fired her up........bugga...still the same.. ...wonder what would happen if the primer is pumped whilst revving?.....whoa...3000RPM...gotto be the pump surely?....everything else has been by-passed by this stage.....

OK, wonder if when the new pump was fitted by previous owner, the garage cocked up and mistimed it to get it to run???....what would happen if we loosen and turn the pump? nothing, that's what, tighten back up again.... hang on a minute....why no fuel coming out of the return to tank?....it comes out of there when you bleed the system....

Another mate arrived and said, "must be an air leak on the manifold", tried some easy start sprayed along the mani....no leaks.....

ALL of a sudden diesel starts coming out of the return to tank pipe....try it now and she revs....she runs a treat.....something must have been gummed up/stuck inside the fuel pump, and freed off with the neat diesel going through it....

Learning curve here....vehicle had been stood for 18months, and whatever was in that tank, was starting to gum up the works...whenever you don't want to use your motor for some time....make sure the last running you do is with neat diesel in the tank...

MANY THANKS for all the suggestions and thoughts you lads have put out to me, it was much appreciated.

Now all I need to do is get some more diesel in the tank and prepare her for an MOT..

 

[karl webster]

Great stuff.

They can b a bugger to bleed at times. You may find that the filter housing needs replacing if it lets air into the system and makes the fuel run back.

Glad its running anyway.

 

[nivapilot]

thanks Karl.

 

[Gav Peter]

Happy days

 

[nivapilot]

Happy days

Oh yes.
As far as I can see at the moment, it's a warning light out on the dash, for left turn...and fog light not working...hopefully bulb.

But I start my shifts again on tuesday, 6 days on and three off...so might still be a couple of weeks before test.

 

[Towpack]

Probably some poor quality bio diesel. I found all this crap in the filter when the LC developed fuelling problems after using some bio: