X308 Starting Problem

[Thin White Duke]

Hello.

I backed my XJ8 out of the garage this morning and this evening when I came to start it up, she wouldn't.

The battery was checked and found to be dead/duff. So a new one has been fitted and still my car won't start.

The engine is turning over but it just doesn't want to go that final nudge. There is now a heavy smell of petrol coming from the car. Could the engine be flooded from my attempts and starting? If so how long will be best to leave it to settle down? Overnight?

Thanks in advance for any help.

[NormanD]

Did you start it to get it out of the garage, then turn the engine off

Then try and resart

Many cars don't like that and as you say flood it as it's gone through the high fuel start twice

[SV8Predator]

It's such a common problem and so well-known to owners that I'm surprised this has happened.

If there is an obvious smell of petrol then it's well flooded and the bores have been washed of oil so that the engine is spinning but getting no compression.

Remove the plugs, clean them up. Maybe a squirt of WD40 down the bores.

Keep the accelerator pedal to the floor when you try to restart.

[Thin White Duke]

NormanD said:

Did you start it to get it out of the garage, then turn the engine off

Then try and resart

Many cars don't like that and as you say flood it as it's gone through the high fuel start twice

No, I only came to restart it after about 8 hours. The battery must've decided to go duff in the meantime and I tried to start her, silly me I kept on trying to start for about two minutes! Then I left it for an hour and came back and it still wouldn't start.

[Thin White Duke]

SV8Predator said:

It's such a common problem and so well-known to owners that I'm surprised this has happened.

If there is an obvious smell of petrol then it's well flooded and the bores have been washed of oil so that the engine is spinning but getting no compression.

Remove the plugs, clean them up. Maybe a squirt of WD40 down the bores.

Keep the accelerator pedal to the floor when you try to restart.

It's something that has never happened to me before. I guess I have learnt the hard way.

[jith]

Thin White Duke said:

SV8Predator said:

It's such a common problem and so well-known to owners that I'm surprised this has happened.

If there is an obvious smell of petrol then it's well flooded and the bores have been washed of oil so that the engine is spinning but getting no compression.

Remove the plugs, clean them up. Maybe a squirt of WD40 down the bores.

Keep the accelerator pedal to the floor when you try to restart.

It's something that has never happened to me before. I guess I have learnt the hard way.

Make sure the battery is fully charged, then push the throttle all the way to the floor and hold it there. This will switch of the fuel pump relay when you turn over the engine. DO NOT let your foot off the throttle until you here the engine start to fire then, when it does give it a few revs to clean the unburnt fuel from the cylinders and cats.

Jaguar were aware of this problem during development and rather than solve it by proper programming of the ECU they built in this procedure to permit a flooded start. I personally think it's crap, but that's the way it is.

J

[NormanD]

jith said:

Jaguar were aware of this problem during development and rather than solve it by proper programming of the ECU they built in this procedure to permit a flooded start. I personally think it's crap, but that's the way it is.

It's not just Jaguar it happens too

[Jaguar steve]

I'd suggest you don't use WD 40 down the bores. It's a petroleum based solvent that will contaminate and dilute your engine oil and won't have anywhere near the film strength required between the compression rings and bore walls that you need to restore compression. A few drops of engine oil from a can down each plug hole is a much better alternative.

I'd also consider avoiding the foot to the floor and continuious cranking method. Sure it it works - eventually. Problem is you may need to keeep going for quite a while which is ruinious to battery condition, wiring and starter motor. A much more sympathetic route is to remove the plugs and dry them off in the oven, shoot a squirt of engine oil down each bore and remove the fuel pump fuse in the boot.

Refit the plugs and turn the engine over whilst you modulate the throttle pedal and as soon as the engine tries to fire have an assistant replace the fuel pump fuse.

Either way you're going to need a strong battery or a booster pack.

[Thin White Duke]

Finally managed to get her going again. Thank you all.

[SV8Predator]

Jaguar steve said:

I'd suggest you don't use WD 40 down the bores. It's a petroleum based solvent that will contaminate and dilute your engine oil and won't have anywhere near the film strength required between the compression rings and bore walls that you need to restore compression. A few drops of engine oil from a can down each plug hole is a much better alternative.

A "few drops of engine oil" will just sit on top of the piston and do nothing. The solvents in the WD40 will carry the lubricant straight to the piston rings. And evaporate instantly as the car fires. So WD40 it is for me.

[jith]

Jaguar steve said:

I'd also consider avoiding the foot to the floor and continuious cranking method. Sure it it works - eventually. Problem is you may need to keeep going for quite a while which is ruinious to battery condition, wiring and starter motor.

That is the method that Jaguar recommend. Any time I've used it, the engine fires within a minute, no longer. And it has never failed to start the car.

J

[Jaguar steve]

jith said:

Jaguar steve said:

I'd also consider avoiding the foot to the floor and continuious cranking method. Sure it it works - eventually. Problem is you may need to keeep going for quite a while which is ruinious to battery condition, wiring and starter motor.

That is the method that Jaguar recommend. Any time I've used it, the engine fires within a minute, no longer. And it has never failed to start the car.

J

Up to you how you approach the problem of course. Yes you're right - Jaguar's method works and probrably would have got the OP started but IMO it's barbaric.

I've only had to deal with a flooded V8 once so you may well have more real world experience than me. But I ever have to again I'd always choose the most mechanically sympathetic method I could devise.

I know my suggestion to the OP works too and has the significant advantage of much shorter cranking times than Jaguars' foot-to-the-floor and keep grinding away method and most importantly, it also offers a significantly reduced risk of either a crankcase explosion or backfire through the induction system. Both of these events are a significant risk with any flooded engine due to the build up of petrol vapour in the crankcase and breather system. I have seen both happen in a workshop and both events resulted in serious damage.

The downside of my method of course is it involves a lot more work than just grinding away on the starter and unless you have very long arms indeed you need a assistant to stick the fuse back in too, but I'd still suggest that's the way to go.

BTW: A new starter motor will cost you over £300 and by all accounts is a right PITA to change - starters are not designed or specified for continious operation and it's just not worth the risk of stressing it or burning it out.

[Jaguar steve]

SV8Predator said:

Jaguar steve said:

I'd suggest you don't use WD 40 down the bores. It's a petroleum based solvent that will contaminate and dilute your engine oil and won't have anywhere near the film strength required between the compression rings and bore walls that you need to restore compression. A few drops of engine oil from a can down each plug hole is a much better alternative.

A "few drops of engine oil" will just sit on top of the piston and do nothing. The solvents in the WD40 will carry the lubricant straight to the piston rings. And evaporate instantly as the car fires. So WD40 it is for me.

Oil down the bores is known to work, and has been done for way longer than I've been working on engines. Sure, some may well sit on the piston crown but enough will get where it's needed. A very thin film of engine oil is actually what forms the compression seal so by using oil you're introducing exactly what's needed to a bore washed engine.

By flooding the engine with petrol you've already contaminated the engine oil with excess fuel and run the risk of a crankase explosion due all the the petrol vapour floating about. IMO the last thing you need to introduce to that mix is a flamable solvent such as WD 40. I don't know exactly what's in WD 40 either so have no assurance it'll not compromise the catalysts either as it burns off.

Up to you what you use of course, but my choice would be to avoid it.

[Jaguar steve]

Jaguar steve said:

SV8Predator said:

Jaguar steve said:

I'd suggest you don't use WD 40 down the bores. It's a petroleum based solvent that will contaminate and dilute your engine oil and won't have anywhere near the film strength required between the compression rings and bore walls that you need to restore compression. A few drops of engine oil from a can down each plug hole is a much better alternative.

A "few drops of engine oil" will just sit on top of the piston and do nothing. The solvents in the WD40 will carry the lubricant straight to the piston rings. And evaporate instantly as the car fires. So WD40 it is for me.

Oil down the bores is known to work, and has been done for way longer than I've been working on engines. Sure, some may well sit on the piston crown but enough will get where it's needed. A very thin film of engine oil is actually what forms the compression seal so by using oil you're introducing exactly what's needed to a bore washed engine. I suspect WD04 will not have anywhere near the same film strength as engine oil in shear either so even if it works initially it may not retain that strength for long enough for the engine to fire. If that's the case you'll have to take all the plugs out and start from scratch again and in the process have taken years of the life of your starter motor.

By flooding the engine with petrol you've already contaminated the engine oil with excess fuel and run the risk of a crankase explosion due all the the petrol vapour floating about. IMO the last thing you need to introduce to that mix is a flamable solvent such as WD 40. I don't know exactly what's in WD 40 either so have no assurance it'll not compromise the catalysts either as it burns off.

You could quite reasonably say I'm taking a very cautious approach to all this, but I've been bitten in the arse often enough by not doing so to now go down the rouet of avoiding any additional complications.

In the end it's up to you what you use of course, but my choice would be to avoid it.