Diesel starting problems!

My series 3 is fitted with a 2.5 diesel sherpa engine.

I have changed all glow plugs and bought a massive new battery.

Checked all my earths and now i have run out of ideas.

When i try to start it it spins but just not enough to kick in.
(if you know what i mean?!)

Iam going CRAZY, any suggestions would be great. wiring, starter motor etc.

P.s I checked all my glow plugs receive 12v power, which they do. but only when warming up. Should they always draw 12v when engine is running?

P.p.s I can bump start it down the hill and it drives no problem.

Cheers guys

when u say it spins do you mean it turns over but doesnt engage, has this got worse, or has it happened suddenly

sounds like the oil is thick from your cold weather. Try a different grade of oil? also check your engine earth strap is still connected, could just be a bad earth?

Ideally the starter motor should have a potential difference (voltage) of 12 volts across it's terminals when it's turning the engine. In reality the battery voltage will drop when a heavy load is put on it, due to internal resistance and some voltage will be dropped accross components in the starting circuit due to resistance. If cables become damaged or connections become corroded then the resistance of the starting circuit is increased, which by Ohm's law (V=I*R) will cause the current in the circuit to decrease which will mean the starter will turn slower. What needs to be done is to check that there is not a high resistance anywhere in the starting circuit. Unfortunately a multimeter is not effective at measuring the relatively low resistances that could cause a problem in a starting circuit, so the resistance has to be measured indirectly. Again Ohm's law can be used: For a given current, as the resistance accross a component increases so the voltage accross that component increases. Ideally a cable should have a resistance of 0 Ohms, and so regardless of the current passed through it, there should be 0 volts accross it. So applying this theory to the Land-Rover, turning the engine over with the starter motor there should not be a voltage accross any component in the starting system except for the battery and the starter motor. So to test the earthing of the circuit, measure the voltage between the negative terminal of the battery and the engine block, with the starter turning the engine. If there is a big reading on the voltmeter then do a similar test measuring the voltage accross each component in the earth part of the circuit path to isolate where the high resistance is. If the earth is good then check the voltage drop accross the starter solonoid and cables from the positive battery terminal to the starter (with starter turning).
If none of that turns up anything then assuming the battery is OK and there is not something mechanical stopping the engine turning freely then there is a fault with the starter motor or the starter motor is of the wrong type.

If the engine fires up when you bump start it you can probably rule out a fuel supply problem.
SO.........

Your glow plugs could very well be tired. Even if they get 12V, if the tip doesn't glow red hot it won't fire up. Mine started to glow mid length so were useless. A set should only set you back around 12 notes so definately worth swapping out. They only get a 12V supply during the first turn of the key(preheat). Once its running you shouldn't have a supply to the plugs as they're not needed.

To check your starter motor try shorting the starter solenoid with a beefy jump lead and if it turns over ok it could be a dirty solenoid. Obviously watck its not in gear and watch fingers!!!! Earth strap needs looking at to make sure its got a good earth too. If its slow to turn over you may need a new starter. If its got removable bushes fit new ones and clean the motor comutator with contact cleaner which may breath new life into the starter motor.

Cold kills even new batteries! If it turns over faster with jump leads from another vehicle its likely your battery is weak.
Hope this helps you a little
Good luck

Inside the fuel injection pump fitted to these engines there is an automatic COLD START DEVICE, which is set into action IF (a) the engine is turning at starter motor speed or less , AND (b) the throttle is fully OFF.

To cold start a 15J engine you MUST NOT have your foot on the throttle pedal, and there MUST be some slack in the cable or linkage to the throttle lever on the injection pump.

If either or both of these conditions are not fulfilled, the cold start device will automatically DISABLE itself, and cold starting will be very difficult - or it won't start on the starter at all.

If you can apply GLOW on the key, hold it glowing for at least 20 seconds, maybe 30, and use a watch to make sure you wait long enough! Then with no throttle but with the clutch pushed all the way down, turn the key to run the starter until either (1) the engine is fully running, or (2) the battery goes flat.

DO NOT LET THE STARTER GO WHEN THE ENGINE BEGINS TO SPLUTTER AND FIRE UP!!!

Keep the key turned to STARTER until quite clearly the engine has "overtaken" the starter motor, then release the key and give it some throttle to catch it and get the revs up a bit.

My TD5 Disco sits outside these nights, and at minus ten degrees C it starts first time every time, IF I wait till the glow light goes out (but actually the ECU keeps the plugs glowing!) and then I turn the key and run the starter for 10 to 20 seconds, as long as it takes to get the engine running smoothly on all cylinders.

One way to guarantee not to start a diesel on a cold day is to try to start it as if it was a petrol engine, stab - stab - stab at the starter as so many people seem to do.

With a diesel, set it up right in COLD START MODE, and run the starter till the engine is firing on all cylinders.

CharlesY

You say it bumps fine, but struggles on the key.
You also have a new battery, the starter would be a good place to look, either an issue within the motor (engages but turns slowly), or with the ring gear or pinion (doesnt engage).
One really rough way I use to test glowplugs is to disconnect them all, run a + wire from the battery to a loose end and 'flash' the end accross the pulg terminals, if theres a spark the plugs pulling power, if not then its probably dead, plugs can fail and still pull power so its not a sure test.

1914rick said:

My series 3 is fitted with a 2.5 diesel sherpa engine.

I have changed all glow plugs and bought a massive new battery.

Checked all my earths and now i have run out of ideas.

When i try to start it it spins but just not enough to kick in.
(if you know what i mean?!)

I can bump start it down the hill and it drives no problem.

Cheers guys

Click to expand...

Are you making any progress?
Will it start on the key now?

CharlesY

Dont know about 1914rick but I followed your advice and my 2.5 is starting a lot better.
Thanks for the tip.
Really valuable in this weather.

gipsybilly said:

Dont know about 1914rick but I followed your advice and my 2.5 is starting a lot better.
Thanks for the tip.
Really valuable in this weather.

Click to expand...

Hi gipsybilly,

Glad it's helping your 2.5 to fire up.

Petrol engines just start - or don't. Usually they do, and the first cylinder that fires turns the engine over so quickly that the other pots fire up immediately.

Starting a diesel is a gradual process - the engine builds up to it, and needs help from the starter for a while even after one or two cylinders are beginning to fire up. KEEP IT GOING, or you waste all the efforts up to that stage. The repeated compression strokes and fuel injection fill the cylinders with atomised fuel which then vaporises, and sooner or later it starts to ignite. Good glowplugs help a whole lot.

My tractor has a flame plug which literally sets diesel fuel on fire in the inlet manifold, and the flames and part-burnt fuel are then sucked into the 3 cylinders. It starts up smartly even on these cold days.

CharlesY

I agree entirely, cold engines have diffo effects at starting between a petty and diesel, a petrol doesnt run so well cold as the fuel condensates back to liquid and coats the cold walls of the chamber rather than burn, which is largely why you need a choke, where as a diesel relies on heat from compression to create ignition, heat which is easily soaked up by a cold engine, indirect compression engines seem to need glow plugs more than direct, some vauxhalls dont have plugs.
Flame plugs were popular on cummins engines, seen a few boats with them, and they work well, allthough I converted one to a manual switch as the electronic doofercationer went knacked.
Charles, does the n/a have an cold start advance solenoid on the pump, or is it just a stop sol.

dr pepper said:

I agree entirely, cold engines have diffo effects at starting between a petty and diesel, a petrol doesnt run so well cold as the fuel condensates back to liquid and coats the cold walls of the chamber rather than burn, which is largely why you need a choke, where as a diesel relies on heat from compression to create ignition, heat which is easily soaked up by a cold engine, indirect compression engines seem to need glow plugs more than direct, some vauxhalls dont have plugs.
Flame plugs were popular on cummins engines, seen a few boats with them, and they work well, allthough I converted one to a manual switch as the electronic doofercationer went knacked.
Charles, does the n/a have an cold start advance solenoid on the pump, or is it just a stop sol.

Click to expand...

The solenoid is ONLY an engine stopper. It shuts off the fuel supply to the high pressure stage of the injection pump - engine stops. When these fail, they usually fail CLOSED, like engine STOPPED. The immediate cure is to whip it out, lift off the little rubber tip, shove the rest back in, and drive on.

The Lucas CAV DPS and DPA pumps used on 2.5NA engines contain a cunning automatic cold start device inside. It is entirely a mechanical device, very clever, and very effective.

This sets itself to COLD START MODE when two conditions are fulfilled,
1. the engine is turning at 100 rpm or less (including stopped)
AND
2. the throttle linkage is in CLOSED position - NO THROTTLE.

Note the AND word. BOTH conditions must be fulfilled or no cold start aid.

I stress here time after time, that the throttle linkage MUST have some slack, AND the throttle must NOT be adjusted as a means of setting the tickover speed. Tickover speed MUST be set by a separate little lever that leans on the fuel OUTLET union at the drive end of the pump.

What the automatic cold start device does is to start injection a little SOONER than normal, and it flings in excess fuel at the same time. This means that an aerosol spray of diesel is mixed in the air in the cylinder as the piston finishes a compression stroke, and the heat of compression vaporises some of the atomised fuel, which immediately raises the compression a bit more, and also fills the cylinder with diesel vapour, like GAS. If you keep it turning over there comes a point where the diesel GAS ignites, even just a little in one cylinder, and that helps the starter to keep the motor turning and soon enough the other cylinders will fire up in turn as the warmth of compression and fuel burning builds up the temperature.

It can take quite a while to get a cold diesel engine lit up, so a REALLY GOOD BATTERY and starter is important, or living near the top of a long steep downhill grade!

CharlesY

There are a couple of versions of the dpa, one has a hydraulic governor and the other is mechanical, just been looking at the exploded view at the cold start.
Bosch ve pumps on later engines in other vehicles have a seperate solenoid to advance the timing, which is switched off by a stat when the engine gets to a certain temp.

1914Rick was talking about a 2.5 Sherpa engine which is type 15J LandRover engine.
It uses Lucas-CAV DPS pump, so we don't need to worry about Bosch pumps.

CharlesY

Glow Plugs!!! They may pull 12v but dunt mean they are glowing though!

Indirect diesul engines are a right bitch to start if every glow plug not working, even with "easy start"

Jason2 said:

Glow Plugs!!! They may pull 12v but dunt mean they are glowing though!

Indirect diesul engines are a right bitch to start if every glow plug not working, even with "easy start"

Click to expand...

Frequent use of Aero-Start and all other ETHER sprays, is practically guaranteed to cause engine damage.

The most common damage is to the pistons, especially the collapsing of the "lands" of the pistons immediately under the top compression ring.

There are a number of better ways to get them running.
They all involve HEAT.

CharlesY

CharlesY said:

Frequent use of Aero-Start and all other ETHER sprays, is practically guaranteed to cause engine damage.

The most common damage is to the pistons, especially the collapsing of the "lands" of the pistons immediately under the top compression ring.

There are a number of better ways to get them running.
They all involve HEAT.

CharlesY

Click to expand...

I knew you were going to say that

And I agree but somtimes it's better to get the fooking thing going to rule out other things like injectors,air locks blah blah blah etc...

i had the same prob when i fitted my montego engine instead of the petrol and found that if i put an extra earth strap direct off the battery to the rocker cover started first time every time.

I know it's an old post, but having just had exaclty the same problem....
fuel solenoid shhuts when starter motor is cranked. Hence why it starts when towed but not on the key.
Put a light inline and if it goes out when cranking you will know, if so give it a seperate switch from live.

Ruari said:

I know it's an old post, but having just had exaclty the same problem....
fuel solenoid shhuts when starter motor is cranked. Hence why it starts when towed but not on the key.
Put a light inline and if it goes out when cranking you will know, if so give it a seperate switch from live.

Click to expand...

This is a sure sign of poor "engine-to-chassis-to-battery -ve" connections.

The voltage at the solenoid tag is going so low the thing is shutting off. You might want to take the solenoid stopper out and check it over, It may be on the way out, and they do fail, usually in the "Engine STOP" condition.

A separate "switch from live" is not a good solution and may not do any good.

Ideally, what is required is a really big fat earth cable bolted to the engine block with a BIG tag, all nice and clean, going right to the negative post of the battery.