Won't start when engine is cold

This site contains affiliate links for which LandyZone may be compensated if you make a purchase.

bigscousefish

New Member
Posts
3

I have an R Reg Discovery (80,000 miles) it starts first time when cold but after a run and the engine gets hot it will not start again until the engine cools down. I have changed diesel filter, checked all connecting pipe- work thinking air in system. Called AA out on time when I could not get it started - he checked over fuel line but could not find a fault, said could be pump. AA man got it started by spraying Easy Start in air filter housing - started first time with that. Any one got any ideas?
 
Next time it won't start, loosen one of the injector pipes at the injector and turn it over, do you get fuel spraying out?

Sounds like its the injection pump, as they heat up the clearances inside the pump open up enough to reduce fuel pressure...

Next time it does it, pour of cold water over the pump and try it again, if it starts then you know its pump related...
 
Because it started up fine using AeroStart, (di-ethyl ether spray) that would suggest there's fuel being injected, and that the timing is OK.

Low compression is to be considered, and due to the symptoms I suggest you FIRST check the valve clearances and make absolutely sure they are set to the correct clearances.

It is possible or even likely that the valve clearances REDUCE when the engine heats up, and if the clearances are too small to begin with when they reduce as the engine heats up there may be NO clearances, and not enough compression at starter motor speeds to fire it up on diesel.

That needs compression ratios of about 15 to 17 : 1 or more, but ether spray will light up at as low as 4 : 1 compression.

Once the engine is running the compression losses MEANTIME may be small enough not to notice but DAMAGE WILL BE BEING DONE if this is the cause of the problem.

Easy to check this out, and I suggest you do it before you go another mile.

CharlesY
 
I may not have made it clear that when valve clearances reduce to NIL, the valve seats will not SEAL tight, and may then leak air out of the cylinder as the starter shoves the pistons slowly up on compression strokes. Enough air may leak past one or more valves to reduce the effective compression to not a lot, but once it is running, the process happens so fast it doesn't leak enough to cause ignition problems.

If this is happening, the valves and valve seats involved are at severe risk of serious damage, and that involved a "head off" job which I reckon you might prefer to save for another day ... month ... year!

Set the clearance carefully as per the book, and TEN THOU on all eight valves will be fine if you don't have the book. That's 0.25mm in Heathen Frog measures.

CharlesY
 
If an AA man came near my motor with a can of easy start, he'd be removing it from his arse.....

Yes indeed, and especially if the cause is tight valve clearances because the extremely violent in-cylinder detonation with a valve not quite seated means the main force is transmitted up the valve stem, across the rocker, and onto the cam-follower and camshaft, none of which does any good at all.

RobCSH is right to caution all LandyOwners against any ether-based starting potion. Extreme damage can be caused in short order using these things.

Be warned .... and the usual wisdom says if ever you begin using these things, the damage in the engine will mean you MUST go on using it.

Charles.
 
Back
Top