2.5 N/A Diesel running on 3 cylinders
running on 3 cylinders

Hi folks can anyone help out. I own a lightweight with a 2.5 NA diesel (early defender engine) which will only fire up on 3 cylinders.
Here's some recent history.

The head gasket blew some time back so had head checked and found to be cracked. Bit the bullet and did some major work. Sourced a replacement head which was skimmed and pressure tested and was a good one.
Fitted new pistons and rings along with new conrod shell bearings.
The bores were deglazed and no cracks found.
I've had all 4 injectors serviced and replaced the heater plugs and all the associated wiring too.

When i first tried to start it i kept getting air bubbles from the injector pump and it eventually killed the battery, so bought a new battery and replaced all the fuel lines, removed the tank selector tap(so direct fuel line from tank) and ended up getting a tow start from a friends landy and thankfully it fired up.

Now it fires up first time every time but only on 3 cylinders????
It will not fire up cylinder no1. I know its no1 as the exhaust manifold stays cold on 1 but hot on 2,3 and 4. Have swapped injectors and heater plugs around but still no joy. I get lots of white smoke showing unburnt fuel and is running like a bag of spanners and will never pass an MOT.

The injector has a fantastic spray pattern so know its not the injector pump.

Have checked the valve gaps and the tappits are doing their thing too.

I'm stumped.
Anyone have any ideas so I can bring this beauty back to life.
Cheers

 

First, do a leak down test to make sure the valve is closed. if you are not at 100% then the valve is not seated.

Open up the valve cover and hit the valve spring with a hammer, you should hear a loud pop. If the injector is spraying and the glow plugs are working then it has to be a mechanical problem. Sometimes when installing new rings, they fold over and doesn't make a proper seal on the wall. When you do the leak down test, if the pressure goes into the crank case, then its the rings.

A Land Rover dealer had a similar problem with a gasoline engine in a freelander. They changed every single ECM box, the injectors, sensors, switches everything you can think of related to the problem, they changed..Cylinder 1 was still not working. They brought the car to us and it took us 5 minutes to fix it, the firing order was wrong. Moral of the story, its easy to look over the simple things, start off simple, before going on to more complex things in the motor.

 

Wingnut, try swapping your glow plugs around and see if the problem moves with the plug. Glow plugs are somewhat fragile when tightening the power lead.

 

Hi Folks. Thanks for the replies. The advice is very much apreciated.

Swapped over the heater plugs and the problem didn't move so checked the new wiring and that was fine too. It was worth a try.

Took the rocker off and all the valve are operating ok(gaps spot on and new caps in place) but not sure if they're sealing or not.

When the head was skimmed the firm advised me he had put in new valve stem seals and bedded the valves in and it pressure tested ok. I really hope its not the rings cos I'm fed up of buying head gaskets and lugging that big head on and off! LOL

Does this test require a compression tester?? My mate has one but he's away till next week.

I tried to hand turn the motor and tried tapping both valves but its started throwing it down so rain has stopped play for today. Will hand turning the crank generate enough pressure to test the valves this way?

If I am losing pressure how would i be able to tell the difference between loose piston seals or poor valve seals??? I'm not sure how I would check if the crank case is pressurising or not.

Will keep you posted. Thanks again for your help

 

I've cured the problem and its now firing on all 4 cylinders!! Fantastic.

I tried all the suggestions and borrowed a compression tester and it was spot on. Great pressure and the valves worked great so at least I didn't need to flirt the head off again.

The tester I used went in the injector port so as a matter of routine i replaced the small metal washer that seats the very end of the injector. After another tow start it fired up and now runs a treat with no smoke on tickover. Something as simple as a 10p washer. Nice one....

I also spotted a leaking pipe i thought was ok so threw it away and solved the air bubble in the lines too.

Its going in for MOT on wednesday and am confident.

Just want to thank everyone for their advice. Nice one folks.

 

Congrats, I am pleased to hear that your diesel is back on her feet.

 

I accept with information: A Land Rover dealer had a similar problem with a gasoline engine in a freelander. They changed every single ECM box, the injectors, sensors, switches everything you can think of related to the problem, they changed Cylinder 1 was still not working.