He says he has spark so easy start should give at least a cough my guess is no compression have seen it with snapped camshaft I would pull a rocker cover and see for movement...
Land Rover Discovery 1 V8i 3,9 L EFI doesn´t start
- Thread starter Trotti
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He says he has spark so easy start should give at least a cough my guess is no compression have seen it with snapped camshaft I would pull a rocker cover and see for movement...
AllanWorms
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- Whangarei, NZ
Quite possible. A compression test should show a difference there.
I like videos - to see if things sound right too.
So often, people don't notice some detail, which helps pinpoint in issue.
Side story: I came across a Nissan 2.4 one day, that the headgasket was so badly blown between cylinders, you've have to crank it for about 2 minutes and it would slowly start to fire on 1 cylinder, then eventually another would kick in, then once it was on 3, it would run long enough for the 4th to eventually kick in... then you could drive it
I like videos - to see if things sound right too.
So often, people don't notice some detail, which helps pinpoint in issue.
Side story: I came across a Nissan 2.4 one day, that the headgasket was so badly blown between cylinders, you've have to crank it for about 2 minutes and it would slowly start to fire on 1 cylinder, then eventually another would kick in, then once it was on 3, it would run long enough for the 4th to eventually kick in... then you could drive it
Quite possible. A compression test should show a difference there.
I like videos - to see if things sound right too.
So often, people don't notice some detail, which helps pinpoint in issue.
Side story: I came across a Nissan 2.4 one day, that the headgasket was so badly blown between cylinders, you've have to crank it for about 2 minutes and it would slowly start to fire on 1 cylinder, then eventually another would kick in, then once it was on 3, it would run long enough for the 4th to eventually kick in... then you could drive it
The V8 in my 101 which had only done 14K klm... I recommisioned it with brand new champion plugs leads electronic dizzy coil etc rebuilt the carbs etc...had a misfire on at least 2 cylinders spent ages checking everything then with a simple spray bottle of water on start up worked out by which exhaust port on manifold gave off steam and hey presto moved leads around no change moved plugs and bingo misfire moved with plugs now got Beru plugs...
The speed at startup was between 130-160.
When the spark plugs were out, all had a spark. I have already changed the ignition amplifier, but without success.
At the moment I don't have a video of the startup, but in the next few days I can post one here.
AllanWorms
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- Whangarei, NZ
Does the engine SOUND like it should, with compression? Hard to hear, on a V8, compared to a 4 cylinder anyway.
The timing light should get triggered by the spark and if you check the timing while cranking, will tell you if it's timed roughly right. The advantage of the inline tester, is that you can SEE the spark, basically the same as it will be happening in the cylinder. I wouldn't rush out to buy one yet.
I still think it should make some noises, if there is spark in some/all/any cylinders and either petrol or easy start.
If rovergauge is seeing that cranking speed, then the signal to the ECU is functioning (and the trigger is the distrubutor must be too). Minimum cranking speed is 120, I believe, so you're exceeding that... which could mean the battery and starter are is good working order... or it could be the engine is too easy to spin (I've never check my actual cranking speed in my Disco)
The ECU doubles the injector firings under 400 RPM, so it could be flooding itself, if it's injecting fuel: Again, I'd disable the fuel pump for the meantime (Little fusebox by the battery (P125)... fuse 6? - cuts power to the pump relay. Verify.)
It'd be good to see if the plugs are wet too.
The timing light should get triggered by the spark and if you check the timing while cranking, will tell you if it's timed roughly right. The advantage of the inline tester, is that you can SEE the spark, basically the same as it will be happening in the cylinder. I wouldn't rush out to buy one yet.
I still think it should make some noises, if there is spark in some/all/any cylinders and either petrol or easy start.
If rovergauge is seeing that cranking speed, then the signal to the ECU is functioning (and the trigger is the distrubutor must be too). Minimum cranking speed is 120, I believe, so you're exceeding that... which could mean the battery and starter are is good working order... or it could be the engine is too easy to spin (I've never check my actual cranking speed in my Disco)
The ECU doubles the injector firings under 400 RPM, so it could be flooding itself, if it's injecting fuel: Again, I'd disable the fuel pump for the meantime (Little fusebox by the battery (P125)... fuse 6? - cuts power to the pump relay. Verify.)
It'd be good to see if the plugs are wet too.
The engine does not sound different to me.
Thank you for your advice! I will check the engine when the fuse for the fuel pump is out.
If you try to start the engine and look at the spark plugs, they are wet.
https://youtube.com/shorts/_qx0pEkMVFI?feature=share
Here is a link to a video of starting the engine from last year. I will record a new one in the next few days.
Here is a link to a video of starting the engine from last year. I will record a new one in the next few days.
autoclassic
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- Suffolk, UK
Had a similar issue with my '93 3.9 RRC auto last year. Would quit while driving but would restart. Eventually would not. Disconnected radio suppressor from coil, no further trouble! Also use non-resistive NGK spark plugs BP6ES to have best chance of firing the mixture.
discool
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That’s exactly how the engine would sound if the 12volts at the coil was missing, for an example the spider immobiliser has an issue.
Also fit replace the distributor cap with a Genuine Part and reroute the plug leads in to their clips.
If you have replaced the rotor hopefully you didn’t pull it straight off without pressing the reluctor down first, other wise the springs in the distributor will have disconnected, therefore a partial rebuild is required.
Attachments
Genuine parts cap & don't use the rotor arms that have the metal strip riveted to them.
As above, if you did pull the rotor off without pressing down on the reluctor (the 8-point star shaped thing under the rotor) a quick check is to turn the rotor arm with your fingers until it stops & release it. It should go smartly back to its original position.
You don't have to remove the dizzy to reconnect the springs but wrap plenty of cloth around the dizzy body in case you drop anything to avoid it disappearing into the engine bay or onto the ground never to be seen again!
As above, if you did pull the rotor off without pressing down on the reluctor (the 8-point star shaped thing under the rotor) a quick check is to turn the rotor arm with your fingers until it stops & release it. It should go smartly back to its original position.
You don't have to remove the dizzy to reconnect the springs but wrap plenty of cloth around the dizzy body in case you drop anything to avoid it disappearing into the engine bay or onto the ground never to be seen again!
Good evening, sorry for my late reply. I checked the compression on all eight cylinders today, as described in the Haynes manual. When cranking the engine, the compression goes from 7 bar to 8 bar, no more. The workshop manual says it should be either 10.2-10.9 bar or 11.5-12.2 bar. I'm not sure, but I think on this model it should be 11.5-12.2 bar or 170 psi minimum when the engine is warm. Could this be why the engine is not starting?
I also connected the battery + directly to the ignition coil + but the engine did not start.
I will link another video where you can see the spark and hear the engine firing sometimes. Maybe that will help a little.
I have ordered a bypass for the spider unit that will arrive next weekend, and I will install it as soon as possible to see if this is the problem. I will also take a look at the rotor and I think I have a rotor and distributor cap to change.
Thanks for your advice
Leo
I also connected the battery + directly to the ignition coil + but the engine did not start.
I will link another video where you can see the spark and hear the engine firing sometimes. Maybe that will help a little.
I have ordered a bypass for the spider unit that will arrive next weekend, and I will install it as soon as possible to see if this is the problem. I will also take a look at the rotor and I think I have a rotor and distributor cap to change.
Thanks for your advice
Leo
AllanWorms
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- Whangarei, NZ
So the compression is low in ALL cylinders? It's always one of the basics worth checking first.
The compression in that spark video sounds very wrong, uneven and lumpy.
It sounds like there is 100% a mechanical problem. If I had to guess; 1) maybe a jumped timing chain, or 2) a blown head gasket letting the compression out of, or even between, cylinders.
The compression in that spark video sounds very wrong, uneven and lumpy.
It sounds like there is 100% a mechanical problem. If I had to guess; 1) maybe a jumped timing chain, or 2) a blown head gasket letting the compression out of, or even between, cylinders.
It's the 8 bar that you're interested in, you want the maximum reading after a short period of cranking.
Test with all plugs out and the throttle wide open so the engine is cranking as fast as possible & there is no restriction on airflow or you won't get an accurate result.
How accurate is the gauge you are using?
Have you checked the rotor arm returns when released?
If you had disconnected the auto advance/retard weights & springs by pulling the rotor arm off you might get the odd fire but it won't run as the spark won't be at the right time.
Take the rocker covers off, crank & see if all the rockers are working.
Whilst you've got the left hand rocker cover (as you sit in the driving seat looking forwards) off you might as well check the timing.
Remove No1 plug - front plug left hand bank.
Put a long thin rod into the plug hole so it rests on the piston.
Manually turn the engine in its normal direction until both valves on No1 are closed & by watching the rod rise the piston is at the top of the stroke. (Should coincide with the TDC mark on the crank pulley)
If you go past - and you probably will - turn the engine backwards until the piston is at least halfway back down again before bringing it back to the top again.
Check that the rotor arm is now pointing to where No1 plug lead is on the dizzy cap.
And that all the other leads are in their correct position.
ETA. Check that the little carbon brush on a spring is in place in the top centre of the dizzy cap. This takes the current from the coil HT lead to the rotor arm.
Test with all plugs out and the throttle wide open so the engine is cranking as fast as possible & there is no restriction on airflow or you won't get an accurate result.
How accurate is the gauge you are using?
Have you checked the rotor arm returns when released?
If you had disconnected the auto advance/retard weights & springs by pulling the rotor arm off you might get the odd fire but it won't run as the spark won't be at the right time.
Take the rocker covers off, crank & see if all the rockers are working.
Whilst you've got the left hand rocker cover (as you sit in the driving seat looking forwards) off you might as well check the timing.
Remove No1 plug - front plug left hand bank.
Put a long thin rod into the plug hole so it rests on the piston.
Manually turn the engine in its normal direction until both valves on No1 are closed & by watching the rod rise the piston is at the top of the stroke. (Should coincide with the TDC mark on the crank pulley)
If you go past - and you probably will - turn the engine backwards until the piston is at least halfway back down again before bringing it back to the top again.
Check that the rotor arm is now pointing to where No1 plug lead is on the dizzy cap.
And that all the other leads are in their correct position.
ETA. Check that the little carbon brush on a spring is in place in the top centre of the dizzy cap. This takes the current from the coil HT lead to the rotor arm.
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I did the compression test with the spark plugs removed and at full throttle. After a short period of cranking, the pressure did not rise higher than 8 bar. The gauge is one from Ebay for 20€.
I will check if the rotor arm returns to it´s position when released. If the springs and weights are disconnected, can I just put them back on?
I have already checked that the TDC mark on the crank pulley and the position of the rotor arm are correct, but not the position and the valves. I am going to take the rocker covers off to check, if the valves are working.
I will check if the rotor arm returns to it´s position when released. If the springs and weights are disconnected, can I just put them back on?
I have already checked that the TDC mark on the crank pulley and the position of the rotor arm are correct, but not the position and the valves. I am going to take the rocker covers off to check, if the valves are working.
Yes, but you will need to partially strip the dizzy as the springs & weights are in the bowl shaped bottom of the dizzy under the plate.
Be an idea to find the relevant section in the manual or online.
