have you timed how long the glow plugs are receiving their voltage?
Low voltage to glow plugs?
- Thread starter Agile
- Start date
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The plugs are powered only while the dash light is on and thats about 12 seconds.
But thats not the problem because even with the plugs directly powered continuously it does not solve the problem.
It is more likely to fire then but often fires up briefly and dies after three seconds!
Tony
But thats not the problem because even with the plugs directly powered continuously it does not solve the problem.
It is more likely to fire then but often fires up briefly and dies after three seconds!
Tony
The cold start mechanism actually advances the injection pump timing slightly, and should increase the idle speed fractionally at the same time....I'm confused by your idle speed reducing!
John
I am sorry, I misquoted what it does when the lever is operated when hot. It significantly alters the sound from the engine and slightly INCREASES the speed.
The cambelt was changed 15 k ago. Its always possible the belt was not connected correctly when that was done. The Haynes book seems very vague about checking the timing position! It assumes its correct when you start and you replace the belt into the same relative position! It does not mention any holes for locking timing pins!
I have always been suspicious of the timing on this car but I dont have any experience of timing a diesel engine and the subject seems difficult to find out about. The engine seems more noisy that I would expect???
There are adjustments in both directions on the cold start lever which would give considerable adjustments to the running timing. Where can I find instructions on setting them?
Tony
It is possible to lock the injection pump and camshaft position on the TUD5 engine......I actually use centre punches for this. Its not necessary to lock the flywheel but thats possible too.
I doubt if the timing is one belt tooth out, but you never know....
Regarding the cold start advancer, when the engine is hot there should be around 6mm play in the cable - when the engine is cold the moving plate should be tight against its stop.
These engines were always noisy - particularly when it was originally introduced as a 1400cc.
John
I doubt if the timing is one belt tooth out, but you never know....
Regarding the cold start advancer, when the engine is hot there should be around 6mm play in the cable - when the engine is cold the moving plate should be tight against its stop.
These engines were always noisy - particularly when it was originally introduced as a 1400cc.
John
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Interesting! This morning I disabled the cold start and it fired a little on the first try.
Unfortunately, that was not sustained and I ended up having to manually power the plugs for about a minute a few times to get it to start at all.
With the engine running, but still cold, I operated the cold start lever and it did speed it up and make it run more evenly.
It does power the plugs to some degree when the engine starts. I think I will have to add a "plug on" light inside!
So unfortunately I am no further forward with a diagnosis. Everything seems to check out correctly.
There is a lot of possible timing adjustment using the cold start lever.
I am very happy timing a petrol engine but have never done it to a diesel. How does one time a diesel?
Does a retarded timing make the engine overheat? Because the fuel consumption is so good I doubt that its far out in normal hot operation.
Tony
Unfortunately, that was not sustained and I ended up having to manually power the plugs for about a minute a few times to get it to start at all.
With the engine running, but still cold, I operated the cold start lever and it did speed it up and make it run more evenly.
It does power the plugs to some degree when the engine starts. I think I will have to add a "plug on" light inside!
So unfortunately I am no further forward with a diagnosis. Everything seems to check out correctly.
There is a lot of possible timing adjustment using the cold start lever.
I am very happy timing a petrol engine but have never done it to a diesel. How does one time a diesel?
Does a retarded timing make the engine overheat? Because the fuel consumption is so good I doubt that its far out in normal hot operation.
Tony
Diesel engines have fixed timing courtesy of the toothed timing belt.
Some diesels can be 'tweaked' timing wise because there is a vernier adjustment (elongated bolt slots, if you like) to connect the driving pulleys of the camshaft and injection pump to their respective units.
Your engine doesn't have these, and although it is possible to adjust the pump timing and pump delivery to some degree within the pump it does require specialist gauges and knowledge......best left to a diesel expert!
Anyway, as you apply battery voltage to the glowplugs - assuming they haven't burnt out by now- and the engine still doesn't fire up I think we can assume the fault is elsewhere.
Perhaps the diesel fuel is returning back to the fuel tank overnight? You'll find a rubber bulb in the fuel lines - get someone to squeeze it as you crank the engine over.
Is there a bleed nipple where the fuel supply enters the diesel pump? If there is, open it slightly and pump any air out.
The next thing - already mentioned - is the engine compression. Although the engine should have miles left in it, its service history may be vague. As diesels need heat and fuel to get them going, poor compression means poor heat for starting in the cold. The heat comes from good compression, good cranking speed and glowplug assistance.
John
Some diesels can be 'tweaked' timing wise because there is a vernier adjustment (elongated bolt slots, if you like) to connect the driving pulleys of the camshaft and injection pump to their respective units.
Your engine doesn't have these, and although it is possible to adjust the pump timing and pump delivery to some degree within the pump it does require specialist gauges and knowledge......best left to a diesel expert!
Anyway, as you apply battery voltage to the glowplugs - assuming they haven't burnt out by now- and the engine still doesn't fire up I think we can assume the fault is elsewhere.
Perhaps the diesel fuel is returning back to the fuel tank overnight? You'll find a rubber bulb in the fuel lines - get someone to squeeze it as you crank the engine over.
Is there a bleed nipple where the fuel supply enters the diesel pump? If there is, open it slightly and pump any air out.
The next thing - already mentioned - is the engine compression. Although the engine should have miles left in it, its service history may be vague. As diesels need heat and fuel to get them going, poor compression means poor heat for starting in the cold. The heat comes from good compression, good cranking speed and glowplug assistance.
John
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I have been priming the fuel supply from the start of these problems. It only takes a 1/3 squeeze anyway.
The adjustments on the cold start will give considerable adjustment of the running position. Thats based on the difference the set movement makes to the engine operation.
If the lever was proportional the its only moving over perhaps 30% of the available movement.
Where could I find instructions on setting up that lever?
Another oddity to me is that it seems so temperature related. Just the slightly lower temperature overnight for last two weeks and it has gone from easily starting every morning to become impossible without serious manual intervention with long plug preheat before trying to start it.
If it was compression related I would have expected it to be difficult to start weeks ago. In any case there is no blue smoke from the exhaust and no blowback when revved with oil filler open!
Tony
The adjustments on the cold start will give considerable adjustment of the running position. Thats based on the difference the set movement makes to the engine operation.
If the lever was proportional the its only moving over perhaps 30% of the available movement.
Where could I find instructions on setting up that lever?
Another oddity to me is that it seems so temperature related. Just the slightly lower temperature overnight for last two weeks and it has gone from easily starting every morning to become impossible without serious manual intervention with long plug preheat before trying to start it.
If it was compression related I would have expected it to be difficult to start weeks ago. In any case there is no blue smoke from the exhaust and no blowback when revved with oil filler open!
Tony
If the lack of compression is valve related there won't be any other symptoms. I doubt that the problem is being cause by the cold start device, most of them no longer work after a few years, in fact I don't remember ever having a car that it did work on, they have all been to old.
Try giving it a sniff of easy start, if it goes immediatly that will eliminate fuel problems.
Peter
Try giving it a sniff of easy start, if it goes immediatly that will eliminate fuel problems.
Peter
Thats a good point Peter.
However, if there was a valve problem would the car still return such a good mpg of 63 compared with my other two 106s which are only 55 mpg?
Can you offer any suggestion as to why it seems so temp related? It starts fine all day long and only fails to start first time in the morning? The problem has only been for the last three weeks since the overnight temp fell about 3-4 degrees, that seems to have changed from always starting with no problem to virtually never starting.
Can I measure the compression usefully myself with the cheap gauges from Halfords etc?
Tony
However, if there was a valve problem would the car still return such a good mpg of 63 compared with my other two 106s which are only 55 mpg?
Can you offer any suggestion as to why it seems so temp related? It starts fine all day long and only fails to start first time in the morning? The problem has only been for the last three weeks since the overnight temp fell about 3-4 degrees, that seems to have changed from always starting with no problem to virtually never starting.
Can I measure the compression usefully myself with the cheap gauges from Halfords etc?
Tony
Hi Tony
You can do a compression test yourself, see here:
http://www.ebay.co.uk/sch/i.html?_t...=diesel+compression+tester&_sacat=0&_from=R40
The loss of compression at cranking speed need not have much effect at higher revs as the time interval between strokes is much shorter so less compression and heat is lost. The air is not reaching a sufficiently high temperature to ignite the fuel, you should have tell tale white smoke from the exhaust while cranking which indicates unburnt fuel, on a warm engine the heat loss is of course much less.
A drop of 10C ambient temperature will give a theoretical drop of 200C in the combustion chamber at a 20-1 compression ratio.
Peter
You can do a compression test yourself, see here:
http://www.ebay.co.uk/sch/i.html?_t...=diesel+compression+tester&_sacat=0&_from=R40
The loss of compression at cranking speed need not have much effect at higher revs as the time interval between strokes is much shorter so less compression and heat is lost. The air is not reaching a sufficiently high temperature to ignite the fuel, you should have tell tale white smoke from the exhaust while cranking which indicates unburnt fuel, on a warm engine the heat loss is of course much less.
A drop of 10C ambient temperature will give a theoretical drop of 200C in the combustion chamber at a 20-1 compression ratio.
Peter
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Recently the exhaust on my "X" reg 106 has failed and I have been using this "T" reg.
Priming the fuel made starting much easier and I found a jubilee clip on the fuel pipe at the primer was showing a slight leak of fuel. It was not very loose but tightening it stopped the slight weep and also removed the need for priming.
Result the car now starts at the first turn as it should do. Took some while to get there because it seemed so unlikely but that was obviously the problem all along!
There is still a problem with significantly less power than the other car but the fuel consumption is correct so not an engine fault as such. It seems to apply at any throttle position.
The car has been well maintained and cam belt changed about 10k ago. What is the effect of a rather clogged fuel filter???
Tony
Priming the fuel made starting much easier and I found a jubilee clip on the fuel pipe at the primer was showing a slight leak of fuel. It was not very loose but tightening it stopped the slight weep and also removed the need for priming.
Result the car now starts at the first turn as it should do. Took some while to get there because it seemed so unlikely but that was obviously the problem all along!
There is still a problem with significantly less power than the other car but the fuel consumption is correct so not an engine fault as such. It seems to apply at any throttle position.
The car has been well maintained and cam belt changed about 10k ago. What is the effect of a rather clogged fuel filter???
Tony
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