Classic/Antique Car Repair/1971 R-R Corniche

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Expert: - 8/25/2009


Question
The car idles well but when I accelerate the car misses and backfires but having reached 20mph works fine. The SU`s damper pots are topped up with oil.
Running  her in the garage as soon as you open up the throttle she starts misfiring the as the engine picks up revs it works fine?

Answer
Hi Robert:
Your description makes the diagnosis a bit tricky, which means it could
be one of several things, so lets look at the most likely first.

1. The fact that she is only having trouble taking the gas at first, points
me into the direction of the fuel pump. If you have the original pierburg
fuel pump, it could be going bad. If you have noticed a humming from the
fuel pump when the ignition switch is on, that would be a good indication.
Tapping the fuel pump with the handle of a screw driver a few time will sometimes
temporarily fixed the problem.

2. Also, check your spark plug wires by re-seating them. One could be loose and
this would cause arcing initially, but would settle down and fire correctly
at higher speed. Also a foul plug would exhibit this behavior until hot.

Let's eliminate these two items above before looking elsewhere.

Classic/Antique Car Repair

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Vern Bullock

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Visit my website at: http://www.classytransportation.com/ I can answer most questions about autos built in the 60's 70's and 80's. Specifically, Lincolns, Rolls Royces and the Excaliburs. Mechanical issues and technical questions are my expertise. I also have a general knowledge of most older automobiles. Keep in mind, I can only provide answers if the questions are very specific and complete. Without details, I can only speculate and that's not good for solving your problem.

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I have owned and maintained Silver Shadows for over 10 years now. I find most mechanics and even Rolls Royce mechanics have very little knowledge about these automobiles. I have researched these cars in quite a bit of detail and can pretty much tell you what is wrong, if you can describe the behavior in detail. I have saved quite a few RR owners a lot of money and aggravation due to improper diagnosis. I am the owner of Classy Transportation, LLC a luxury limousine service specializing in antique cars, classic cars, vintage cars and exotic cars.

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I hold a BS degree in computer science and a MS degree in mechanical engineering.

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