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Dave Burbidge
Experienced User
Username: ovation

Post Number: 35
Registered: 8-2009
Posted on Monday, 10 October, 2011 - 16:13:   Edit PostDelete PostView Post/Check IP

My Bentley Mulsanne 1982 has a starting problem. The engine turns over and runs for a second or two then stops.If I leave it for half an hour or so it starts OK but then if I turn it off the same thing happens.
I have replaced the distributor and coil and all spark plug leads.Good strong spark from the coil.
I noticed today when I took it for a run the car back fired when I accelerate.
Car was running perfectly until this problem occurred. I thought maybe the fuel pump I can't hear it when I turn on the ignition. But then it suddently starts.
Any suggestions would be much appreciated.
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Richard Treacy
Grand Master
Username: richard_treacy

Post Number: 2427
Registered: 4-2003
Posted on Monday, 10 October, 2011 - 17:12:   Edit PostDelete PostView Post/Check IP

It sounds like a fuel pump interlocking issue, and may simply be a bad relay. The relevant relay marked FUEL PUMP located in the fusebox compartment.

Being an early, carburettor car I assume, your car does not have an engine running sensor to fail. Your symptoms sound like a failure in the fuel pump interlocking as the fuel pump only operates when the engine is being cranked by the key or running. On ealy SZ cars, the fuel pump is interlocked to the oil pressure instead of a full engine running relay.

Hence, observe whether the oil pressure lamp extinguishes. At that point the fuel pump relay in the fusebox should enable the pump.

In reality, you could safely bypass the interlocking by putting a temporary bridge across the relay so that the fuel pump runs whenever the ignition is turned on.

RT.
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Dave Burbidge
Experienced User
Username: ovation

Post Number: 36
Registered: 8-2009
Posted on Monday, 10 October, 2011 - 20:58:   Edit PostDelete PostView Post/Check IP

Thanks Richard will check it out tomorrow. I noticed the fuel pump didnt work when I disconnected the fuel line so you are most likely correct. Would be great if its the relay.
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Dave Burbidge
Experienced User
Username: ovation

Post Number: 37
Registered: 8-2009
Posted on Tuesday, 11 October, 2011 - 13:21:   Edit PostDelete PostView Post/Check IP

Interesting ! I swapped over the aerial relay for the fuel relay. No difference . I took the wire off the fuel pump cut out on the oil filter housing to make the fuel pump was running and it was OK. I then took off the fuel filter bowl and there was at least 10mm of brown solid sludge in the bowl and very clogged filter element. Bob Chapman put me on to this as I thought it was the pump. Lets see what new filters do . I bought one for my Spur to be on the safe side.Lets see if that fixes it .
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Jan Forrest
Prolific User
Username: got_one

Post Number: 263
Registered: 1-2008
Posted on Tuesday, 11 October, 2011 - 21:01:   Edit PostDelete PostView Post/Check IP

It's unusual for a blocked filter to only affect starting. Normally I would expect it to cut or strangle the engine under normal driving conditions. At least that's what I've found on a variety of cars, both petrol and diesel. With a Rolls having such a high fuel flow it should have made it struggle to maintain forward momentum a lot of the time. I can only assume that it was the large flow overhead that the pump gives compared to the actual quantity used that kept it going for so long once started.
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Dave Burbidge
Experienced User
Username: ovation

Post Number: 38
Registered: 8-2009
Posted on Wednesday, 12 October, 2011 - 10:37:   Edit PostDelete PostView Post/Check IP

I agree it didn't seem likely.
I changed the filter and it operates perfectly. I did notice that once after cranking it a few times the engine gave a big cough and started as if a slug of fuel suddenly arrived. This filter has obviously not been changed in 30 years !!! The element was completely clogged with brown sediment. Only $17 so its well worth staying on top of these.
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Dave Burbidge
Experienced User
Username: ovation

Post Number: 39
Registered: 8-2009
Posted on Saturday, 15 October, 2011 - 11:46:   Edit PostDelete PostView Post/Check IP

Guess what ? it has done it again , started perfectly I took it for short run came home the engine started easily three or four times . Came back half an hour later and the same problem .
Fuel pump definitely working.
Any further suggestions would be appreciated.
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Jan Forrest
Prolific User
Username: got_one

Post Number: 267
Registered: 1-2008
Posted on Saturday, 15 October, 2011 - 19:24:   Edit PostDelete PostView Post/Check IP

Even if there aren't any visible fuel leaks it could be that the pump is sucking air somewhere along the line. This could be in the fuel line leading up to the pump or even in the pickup pipe in the fuel tank. If the filter is before the pump you might not have tightened it up correctly or the filter seal may have distorted while replacing it - assuming that it wasn't already damaged and was the real cause of the problem in the first place.
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Paul Yorke
Grand Master
Username: paul_yorke

Post Number: 807
Registered: 6-2006
Posted on Saturday, 15 October, 2011 - 20:26:   Edit PostDelete PostView Post/Check IP

Any spark ? whilst cranking and continuing?
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Dave Burbidge
Experienced User
Username: ovation

Post Number: 40
Registered: 8-2009
Posted on Monday, 17 October, 2011 - 10:15:   Edit PostDelete PostView Post/Check IP

yes the spark looks a bit weak if anything but it does have a new coil and distributor ( modern type) . I just tried to start it and it fired up straightaway but seems to be running underpowered ie not as smooth as it should be though.
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Dave Burbidge
Experienced User
Username: ovation

Post Number: 41
Registered: 8-2009
Posted on Friday, 21 October, 2011 - 14:44:   Edit PostDelete PostView Post/Check IP

problem turned out to be electrical. The bozos who put in the new electronic distributor and coil left the ballast in place , reducing the voltage on starting. Morale of the story don't let anyone touch these cars even for simple tasks.
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Bill Coburn
Moderator
Username: bill_coburn

Post Number: 1320
Registered: 4-2003
Posted on Friday, 21 October, 2011 - 21:35:   Edit PostDelete PostView Post/Check IP

Dave/ What you terminated your last remark with flies in the face of the whole philosphy of this Forum, the Technical Library and Tee One Topics for starters. For many years the Clubs' attitudes were invariably, if there is something wrong with your car take it to a fully qualified Rolls-Royce mechanic!

Well today this little population of specialists is retiring and or dying. Most dealerships now have staff that know how to read a computer screen and goggle at a thing called a distributor. There are still a few practitioners out there that do an excellent job but even they are a dwindling resource.

Certainly this Club has had a long standing iniative of encouraging younger ownership but when they find that a simple oil change and 'A' service can cost $1000, they back away faster than a nominee for a Federal Committee position!

For the past almost 10 years Richard Treacy and I have endeavoured to encourage owners to 'have a go'. They (the cars) are afterall only cars. They do not have spiritual properties, cannot levitate and do not lock themselves to avoid being touched by mortal (read non-RR tranied) hands. Unless we pursue this approach the current headlong destruction of our cars will not abate. If in the process damage is done so be it but hopefully there are enough Treacys and Yorkes and their ilk to support the starters and tryers even to do the simplist task.
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Jan Forrest
Prolific User
Username: got_one

Post Number: 268
Registered: 1-2008
Posted on Friday, 21 October, 2011 - 22:13:   Edit PostDelete PostView Post/Check IP

Bill: That's a bit harsh. Like many on this forum I take great pride (perhaps too great?) in my abilities to repair and service my 'just a car' Rolls Royce, although I have to draw the line somewhere. I've previously mentioned that my welding skills, such as they are, are rather agricultural and certainly not up to the standard I would want anywhere near The Old Girl. Other than that or some of the heavier lifting work I still espouse the 'can do' attitude of the club's ethos. If you don't at least try then you'll never know just what you can do!

However it would have helped a lot if Dave had mentioned at the start that he'd had this work done by someone else rather than just writing "I have replaced the distributor and coil and all spark plug leads" which was misleading at best. On other forums (some car based and many not) I've lost count of the number of times members have struggled to account for odd failures to work correctly only for the OP to declare that he's fixed the problem which was caused by a repair/modification that was never previously mentioned!

On the other side of the coin we have the owners who just don't have the time/skills/tools/confidence/physical strength to do much, if any, work on their cars. If they've got the cash to have it all done by the professionals, but still want to know that these hopefully well-trained mechanics aren't actually ham-fisted grease monkeys, who are we to tell them that they're wrong or refuse them advice?

If you'll excuse the vernacular: Take a chill-pill, Dude.