V8 disco 1 has no spark

marjon said:

Because by the time I posted that it had been established the immobliser had been removed bypassed.

I think you reading a bit too much into the smileys.


J

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Discool always take the michael, it is about time I got used to it.
He has his uses but the attitude.....
At least he doesn't just do it with me!!!

sierrafery said:

...fuse F3 sattelite fusebox 1(on top of interior fusebox) but if this was blown the engine would not run as well cos it feeds the pump too...

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Thinking better, you should check that F3 though cos i just realised that if you run a wire from battery directly to the coil the pump and ECU(both fed by F3) will get the feed from that wire from battey through S292/HJ7 as in the diagram i attached previously

sierrafery said:

Thinking better, you should check that F3 though cos i just realised that if you run a wire from battery directly to the coil the pump and ECU(both fed by F3) will get the feed from that wire from battey through S292/HJ7 as in the diagram i attached previously

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Quite!
I hope @discool is listening!!!

AMAILES98 said:

The car runs fine if you run a wire from the positive battery terminal to the coil.

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To help us all, you do mean that the car runs fine if you leave this connected, don't you?

And secondly, in view of the above, is it still connected to the original wire or did you disconnect that and replace it with the jumper wire?

Stanleysteamer said:

Quite!
I hope @discool is listening!!!

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Not so funny cos if the ignition switch's pos 2 was interrupted as you suspected first i really doubt that the car could "run fine" with a wire from battery to coil cos that 10A fuse should blow instantly by backfeeding the whole vehicle's electrics and then nothing would have power except the coil, ECU and pump .... i didnt want to butt in to ruin the ignition switch theory but IMO it's not the case here.

sierrafery said:

Not so funny cos if the ignition switch's pos 2 was interrupted as you suspected first i really doubt that the car could "run fine" with a wire from battery to coil cos that 10A fuse should blow instantly by backfeeding the whole vehicle's electrics and then nothing would have power except the coil, ECU and pump .... i didnt want to butt in to ruin the ignition switch theory but IMO it's not the case here.

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I don't honestly think it's the ignition switch either hence what I said about where to start testing and then where to continue. When this sort of thing has happened to me it has been a wire elsewhere rubbing through or breaking. or a connector coming apart.
If the fuel pump and ECU are running fine then I imagine the break is in the wire after that junction between it and the coil.

His answer to post 24 will clarify.

Stanleysteamer said:

So OP says there is no voltage to the coil, yet you say "power is as far as the coil is OK" How can both be true? Power could still be getting to the EfiECU but still not to the coil. But this may be a good point to start looking.

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That was because the “link” was in place

Stanleysteamer said:

OP jumps from Batt positive to the coil and hey presto it starts and runs, which very clearly implies that, no, he doesn't have power to the coil via the ignition switch and its subsequent wiring. .

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Correct but only position 2 which doesn’t provide power to the starter relay thats position 3.

Stanleysteamer said:

The OP did not make it clear whether it keeps on running with the jumper wire disconnected or not. you seem to be assuming that he disconnects the jumper wire and it still runs, which makes little sense to me.

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There’ no mention of what the did with the link, but removing the link the engine would stop… but as you lack the knowledge on the EFI engine etc etc.

Stanleysteamer said:

As for "all the fuses" I have no idea if it has any or where they area as, although I have 3.9 Disco sitting on my drive, it is under tarps and I have better things to do at the moment than start crawling over it, under it or inside it.
I also have no Haynes for it as I bought it on a whim cos it is lpg and I have yet to get stuck into it

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Correct

Stanleysteamer said:

Parts of, or even all of, the ignition switch may well be OK, which I said he'd simply have to eliminate, but I am not convinced that the connection between +ive to the switch and the wire to the coil is still there, although it ought to be.

Why not try to be more positive and less patronising.?
I notice that @marjon said more or less the same as I did in post#8 yet you didn't take the p!ss out of him.

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I thought it would would be a one post reply from you, well maybe two but you’re sill in a non- technical waffle with more post.
As for Marjon he uses some logic in his technical replies and also without the waffle.
I fill sorry for you

discool said:

That was because the “link” was in place

Correct but only position 2 which doesn’t provide power to the starter relay thats position 3.


There’ no mention of what the did with the link, but removing the link the engine would stop… but as you lack the knowledge on the EFI engine etc etc.

Correct

I thought it would would be a one post reply from you, well maybe two but you’re sill in a non- technical waffle with more post.
As for Marjon he uses some logic in his technical replies and also without the waffle.
I fill sorry for you

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Why on Earth are you talking about position 3? No one ever mentioned the starter motor, neither of the two posters with the problems nor anyone else. Just you. He basically said that he could start it with the key but only if the jumper was applied to the coil. No need to jump the starter motor, where on earth did you get that from?

discool said:

So if the spark plugs are wet then fuel pump is running, so power is as far the coil is ok

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You've been forced to backtrack from the "power is good to the coil" as it obvs isn't but you aren't big enough to admit it. If it was then the poster wouldn't have a problem!

If he removes the link from the batt+ive to the coil the engine stops, obvs, no power=no sparks. Nothing to do with the Efi etc.

I'm not the one who needs anyone to feel sorry for them.
I've wired up enough kit cars and worked on enough others to be able to get well by and fault find on others. This problem is a basic one and will not prove to be hard to solve. Nothing to do with EFi.
You are just trying to muddy the waters.

Stanleysteamer said:

Why on Earth are you talking about position 3? No one ever mentioned the starter motor, neither of the two posters with the problems nor anyone else. Just you. He basically said that he could start it with the key but only if the jumper was applied to the coil. No need to jump the starter motor, where on earth did you get that from?



You've been forced to backtrack from the "power is good to the coil" as it obvs isn't but you aren't big enough to admit it. If it was then the poster wouldn't have a problem!

If he removes the link from the batt+ive to the coil the engine stops, obvs, no power=no sparks. Nothing to do with the Efi etc.

I'm not the one who needs anyone to feel sorry for them.
I've wired up enough kit cars and worked on enough others to be able to get well by and fault find on others. This problem is a basic one and will not prove to be hard to solve. Nothing to do with EFi.
You are just trying to muddy the waters.

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Of course the coil has an electrical connection to the EFI ECU.
Why ii’m sure u know why… as u say u own a 3.9.
I hope you will show that u have more M&E knowledge in your future posts but I doubt it.
I haven't seen much so-far since u joined landy zone.

discool said:

Of course the coil has an electrical connection to the EFI ECU.
Why ii’m sure u know why… as u say u own a 3.9.
I hope you will show that u have more M&E knowledge in your future posts but I doubt it.
I haven't seen much so-far since u joined landy zone.

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Your ego is the problem mate.
You still can't admit when you make a mistake. Instead you try to introduce stuff that has nothing to do with what anyone else has posted. It's called "whataboutery" by some. Like trying to bang on about position 3 and the starter motor, ffs.
You are quite a wise old bird and you do know stuff, but you don't know everything. Nor do I but the difference is that I don't have the ego problem so I can admit it when I get it wrong or don't know the answer.
I'd hate to have to walk in your shoes.
Anyway a personal argument on this thread really isn't helping the OP and the other guy with their problems, so why not just try and be helpful instead of picking a fight?

And I have built more cars and probably worked on more than you ever have. So my mechanical knowledge is very sound if a little old skool, but, as you'll know if you follow my posts, I am not so "up" in modern highly electronic system laden stuff, but I readily admit that and bow to the knowledge of others. Being very grateful when they help me with it.

On the positive side of the coil should be 3 wires - one for the RF suppressor, one to the ignition module and one is the power feed from the ignition switch circuit to power the coil and ignition module. ARE THEY ALL THERE?

It could be something as silly as the power wire fell off


Forget about anything else - just that one feed needs checking.
Your "spider" bypass may be faulty and interrupting that feed;
You may have a blown/missing fuse;
You may have a broken wire.
etc

Stanleysteamer said:

To help us all, you do mean that the car runs fine if you leave this connected, don't you?

And secondly, in view of the above, is it still connected to the original wire or did you disconnect that and replace it with the jumper wire?

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For clarification, all cables are left attached. I used another cable and jumped the battery to the coil. if this cable is removed the car dies.

without the said jumper cable the car cranks, we seem to have fuel but no spark.

originally we believe this to be a spider unit, so a bypass was bought. turns out it already had a spider bypass, but we tried the new one anyway.

I will go over all the things suggested and hopefully I can leave you guys with the fix.

Thanks for the help!

AMAILES98 said:

For clarification, all cables are left attached. I used another cable and jumped the battery to the coil. if this cable is removed the car dies.

without the said jumper cable the car cranks, we seem to have fuel but no spark.

originally we believe this to be a spider unit, so a bypass was bought. turns out it already had a spider bypass, but we tried the new one anyway.

I will go over all the things suggested and hopefully I can leave you guys with the fix.

Thanks for the help!

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So you have told us that the cable to the coil/fuel thingy is only working for the fuel.
Can we take it that the rest of the car's electric systems are working fine?
If so then the break must be between the coil and where the cable divides to go one bit to the coil and the other bit to the fuel management system. so that has saved you time looking in the wrong place.
Brilliant!
Happy hunting!

AMAILES98 said:

we seem to have fuel but no spark.

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If the fuel pump is running and the EML goes out without that jump lead from battery to coil then the problem is between that split point HJ7 and the coil as the rest from F3 to pump and ECU has power(shown with red)

sierrafery said:

If the fuel pump is running and the EML goes out without that jump lead from battery to coil then the problem is between that split point HJ7 and the coil as the rest from F3 to pump and ECU has power(shown with red)

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Thats super helpful,

Where is HJ7 located, under the steering wheel?
What does it look like?

Many thanks

Go back to my reply with the 3 attachments post 13, seems that you neglected it

Wow, handbags at dawn!

The ignition system on these things is not complex.
The common culprits for no spark seem to have been discounted. Because there is fuel it can't be the ignition amplifier. Because it runs it isn't distributor, rotor arm. leads, plugs or reluctor air gap.

AFAIK the coil feed from the switch has a join in it. There is a splice to feed the ignition amplifier. Trace the loom to find the splice, you might find it is corroded. You can also check to see if voltage from the switch is reaching this point of the circuit. Also, check the condition of the wire that connects to the coil, it is not unknown for the copper wire to corrode inside the insulation just behind the connector, if that is the case, cut off the connector and any corroded wire, crimp on a new connector and hopefully all will be well.

Hope that helps.

sierrafery said:

If the fuel pump is running and the EML goes out without that jump lead from battery to coil then the problem is between that split point HJ7 and the coil as the rest from F3 to pump and ECU has power(shown with red)

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There’s no problem with the operation of the EFI system as it runs ok, when the engine is started… as confirmed by the OP.
Its the ignition side which has the issue… no spark at the plugs, as stated in the OPs #1 post.

The issue is the lack of a spark plus the lack of a signal from the coil to the EFI ECU.

To resolve those issues will just be a simple single wire overlay installation.

sierrafery said:

If the fuel pump is running and the EML goes out without that jump lead from battery to coil then the problem is between that split point HJ7 and the coil as the rest from F3 to pump and ECU has power(shown with red)

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There’s no problem with the operation of the EFI system as it runs ok, when then engine is started… as confirmed by the OP.
Its the ignition side which has the issue… plus, as stated by the OPs #1 post no spark at the plugs.

discool said:

There’s no problem with the operation of the EFI system as it runs ok, when then engine is started… as confirmed by the OP.

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I've never said anything about problems with the EFI operation, all i did was to explain about what can be the reason of that missing feed to the coil