Rolls-Royce and Bentley Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
6 Posts
Discussion Starter #1
Hi I am new to the site and I have a 1990 Bentley Turbo R.
The problem is Running Rough. Firstly I replaces the Plugs it ran fine for about two weeks but then again started to run rough. I changed the fuel filter and I had the Full HT system checked Coils etc etc and all in good working order. All cylinders sparking even when running rough. I purchased new injectors and sleeves as they were hard as rock, replaced them and ran smooth as silk for about a hour then a small misfire and gradually got worse until I was back to the start Running rough as before. I replaced the plugs with some used plugs I have here just to see it it made a difference and yes it ran smooth again. Drove it for a hour with no problems. When I returned home I switched the engine off and as soon as I restarted it it was running Rough again as before. I am thinking that there is a problem with the ECU? Fuel head? electrical sensor? Can anyone please help?? :(
 

·
Registered
Joined
·
6 Posts
Discussion Starter #3
They look OK no soot or oil, No Smoke. I was looking at it again today and I removed the connection from the Potentiometer while the engine was running ROUGH and it sped up but smooth, I then replaced the wires and the engine slowed to normal idle speed but no more rough running, took it for a run and all OK. I then turned the engine off and switched it back on and yes it was running rough again so I removed the wires again from the potentiometer and replaced them and running fine. I think there must be a problem with the potentiometer as they have ceramic discs inside. How are they removed as I see no way it is fixed? And where do I get one from?
 

·
Registered
Joined
·
2,786 Posts
You do not have a plug issue. I would bet they are loading up after awhile. You may have old hardened vac lines and perhaps there is a breach somewhere.You may have bad dist caps and rotor. If the wires are original, they have to be replaced.
 

·
Registered
Joined
·
6 Posts
Discussion Starter #5
They are new Dist caps and the rotors are good. Yes I think I have the original leads. The vac lines seem Ok but I will get new tomorrow and replace.
 

·
Registered
Joined
·
1,118 Posts
If it's CIS injection. I would put the pressure gauge on the system to see what the fuel pressure is. You may have a bad regulator
 

·
Registered
Joined
·
1,118 Posts
CIS / K-jetronic is the same thing. If you're sure that you have a healthy ignition system and it's vacuum free, divert your attention to the fuel system. This is a mechanical system so you'll need a pressure gauge to check pressure. The FPR could have gone bad or the fuel distributor. If it's the FD, then it can be rebuilt but the only way to test is to use a fuel pressure gauge. There's a kit from Harbor Freight that has all the CIS fittings.
 
1 - 12 of 12 Posts
Top