Project Bentley

If you can hang fire a few days that'd be great. I've got a couple of last things to do to the car before it goes - for my own satisfaction I want to cure the misfire by myself and offer up final proof that I'm waaaaaaaaaay better at this than professional garages ;):D
 
Changed the ignition coil out today - misfire getting better, slowly but surely. Got two HT leads arriving Monday to replace the last of the old ones. If that doesn't cure it entirely then I'm definitely throwing in the towel.
 
Riiiiiiiight then.

Got spark on all 8 cylinders. Had test lights on them, definitely sparking. But if I pull the HT lead off A3 cylinder the engine note doesn't change at all. So attention now turns to the injector on that cylinder - just got to work out how to get it out of the manifold!
 
Best of luck with fixing it, always loved the updates to this thread.

Beyond my wildest dreams in terms of ability, but kudos for being able to manage the old girl for so long :)
 
JRS said:
Fast running out of things that can cause a misfire if the injectors are good!
Click to expand...

Sheer cussedness? Maybe the engineers followed the apparent approach to the rest of the car and used parts in a completely novel way which are undocumented so you'll be left saying "I've no idea why you'd connect that to there, it has no benefit"? Good luck anyway, it'd be a good send-off if you can get that bit sorted.
 
At the end of the day engines are all simple devices - they need air, fuel and spark at roughly the right time and they'll run.

Got spark. Timing ought to be spot on. Pretty sure that there's air getting through the inlet manifold. Which leaves fuel.
 
Gosh, what a surprise! It's still running like ****, at least at anything approaching WOT. I've had the injectors out of cylinders three and four on the drivers side (A) bank. Gary blew air through them with a compressor. The one from cylinder A3 had a fairly weird spray pattern, so today I swapped the A3 and A4 injectors.

And yet A3 is still dead - if you pull the HT lead off while the engine is running, the engine note doesn't change at all. So to summarise - cylinder A3 dead, cylinder A3's injector suspect, move suspect injector to different cylinder, cylinder A3 still dead.

What. The. Hemorrhaging. ****?




***edit***

It's getting a bit bad now. I can generally stay patient with cars misbehaving, but I have to admit to having properly lost my **** over the last two days. Full on raging, throwing tools around, bear-with-sore-head deal. I once said on here that I was extremely bored by the Crewe factory idea of 'good enough' - I'm now beyond 'bored' and into 'white-hot furious' territory.
 
Last edited:
Dup said:
Did you use the same power source for the injector?
Click to expand...

Literally all I did was take the A3 and A4 injectors out of the inlet, swap them over, and reconnect the fuel lines. And the problem stayed exactly where it was.

Had them all out again this morning - confirmed that we've still got spark, confirmed that both A3 and A4 injectors flow to at least some degree, still got a dead cylinder. I should add that we've got compression (120psi on all 8 cylinders). I just don't get it.
 
Stupid question, but have you actually checked for spark on the plug and not just on the lead to it?

If you've run the compression test properly (all sparks out etc.) then it's either not getting fuel or spark, are you able to remove the injector but keep it connected to power and place it in a jar/can to see if it's actually putting out fuel?
As Dup has suggested, it could well be the wiring to injector A3 if that injector works fine on A4.
 
InvaderGIR said:
Stupid question, but have you actually checked for spark on the plug and not just on the lead to it?
Click to expand...

Yeah, did that this morning.

InvaderGIR said:
If you've run the compression test properly (all sparks out etc.) then it's either not getting fuel or spark, are you able to remove the injector but keep it connected to power and place it in a jar/can to see if it's actually putting out fuel?
Click to expand...

They aren't powered, they're just constant flow injectors stuffed into the manifold - pressure is varied by the fuel distributor according to the amount of air coming into the engine, nothing particularly advanced. The injectors themselves are just spring-loaded valves with a nozzle on the end - once the fuel pressure is high enough (3.6bar in the case of the R-R/Bentley L Series engine) the valve opens and they spray fuel.

I'd have taken the A3 injector out and ran the engine to see what it's doing, but with the hard fuel lines going from the fuel distributor to the injectors it's a bit hard to run them like that. And I'd rather not bend the hard line in case it fractures!
 
Just read the entire thread, sadly due to age a lot of the image links are now broken but it has seemed like a great project (subjective, I know).

I was thinking a few pages back, "after all that work, should have it tuned by a pro" just to get the engine running near to 100% as possible. Seems like there are a few bits to fix before that's even possible, but do you think you/Gary would have the chance for it to be dyno'd and looked at before passing it on?
 
I'd hate to see you throw in the towel- however understandable- you've come so far with it, I hope you stick with it for the end result, alas an old Bentley......

I assume the end result was always known and wanted, thus,keep with it.
 
Quick update- will do a proper post soon, with photos.

We were scouting for parts the other day and found someone selling the whole fuel distributor and air sensor assembly. So Gary pulled the trigger and purchased. Then we spent some time today tearing into the engine bay to swap the systems out.

I'd love to be able to tell you that we got it running today. But we didn't - rain, a lack of charge in the battery, rain, a bit more rain, snow, hail and finally rain put paid to things. But tomorrow, come hell or high water, I'm getting this ******* thing running on all eight cylinders!
 
After charging the battery overnight, I got the car running this morning and took it for a drive. It's running a lot smoother
icon14.gif
 
Gary over text message to me this afternoon said:
I've just gone to have a go at the old fuel unit. I went to have a look at the adjuster screw and found bugger all in the hole. No blanking screw no adjuster screw, just a ******* hole straight from the outside of the body. I don't think that helped the fuel mix. What a load of ******* ******* :mad:
Click to expand...

And that, ladies and gentlemen, may just explain some of the trouble we've had....:eek::mad::rolleyes:
 
You must log in or register to reply here.
Back
Top Bottom