Replaced some vacuum lines.. Now this happens - Rolls-Royce and Bentley Forums
 
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Old 04-02-2019, 07:05 PM Thread Starter
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Replaced some vacuum lines.. Now this happens

HOLY SMOKES FOLKS!!

Okay.. Today I replaced some VERY tired vac lines because I'm certain that they are original and were loose as can be. That's all I did. Now the engine idle is crazy fast and the idle adjustment screw won't bring it down to normal. It was running just fine before I changed 3.. stupid.. little.. vac.. lines.

Don't get me wrong.. I love this car but holy crap.. She's wearin me out.

HELP!

Thnx in advance to you brilliant people!! LOVE YA!

Phiilip
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Old 04-02-2019, 07:46 PM
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Is the engine misfiring too when started from cold or just idling too fast?
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Old 04-02-2019, 10:35 PM
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Hmm... idle screw isn't lowering the idle?? strange. These cars as you know have lots of little gremlins. Holy crap is an understatement . My Idle is a bit high in my opinion but the mechanic turned it up because when i would drive at speed, say on the highway, then get off the exit and then lets say I arrived at a stop light, the **** thing would stall out, I didn't think turning up the idle was the solution but I guess its a lot cheaper than some other crazy solution. I digress. If you pull off a vac line does it stall?

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Old 04-03-2019, 10:26 AM Thread Starter
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Hey Guys,
I did pull off one vac line and it did not stall.
And yes it did backfire a couple of times when I was trying to throttle it out of fast idle.

I'm gonna mess around a lil bit more later today and see what becomes of it.

Phillip
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Old 04-03-2019, 03:50 PM
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I once accidentally disconnected one of the short U-shaped vacuum hoses from the carb and the engine would race on start-up and continue to rev above normal RPM and misfire or backfire if I pressed the accelerator pedal. Once the engine warmed up it would settle down to normal RPM and the misfiring ceased. I removed a couple of spark plugs and noticed that they had white deposits signifying a very lean mixture and that's when I started to look for vacuum leaks and discovered the disconnected vacuum hose. In my case it was one of the short U-shaped hoses between the weakening device and the carbs. Hopefully you have a similar issue which could be easily rectified.
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Old 04-05-2019, 12:31 PM Thread Starter
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Quote:
Originally Posted by shadow 11 View Post
I once accidentally disconnected one of the short U-shaped vacuum hoses from the carb and the engine would race on start-up and continue to rev above normal RPM and misfire or backfire if I pressed the accelerator pedal. Once the engine warmed up it would settle down to normal RPM and the misfiring ceased. I removed a couple of spark plugs and noticed that they had white deposits signifying a very lean mixture and that's when I started to look for vacuum leaks and discovered the disconnected vacuum hose. In my case it was one of the short U-shaped hoses between the weakening device and the carbs. Hopefully you have a similar issue which could be easily rectified.
I'm experiencing the same thing. I checked the spark plugs and it looks like I'm running a little lean. I also put the old U shaped vac hose back on and didn't seem to change anything.
After a bit of warming the engine will settle down to a slower idle.. If this does not fix itself..I can live with it

Phillip
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Old 04-05-2019, 09:44 PM
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Still sounds like you still have a vacuum leak somewhere, maybe the hose to the distributor advance mechanism or possibly the 2 narrow hoses that fit under the carb air intake. Another possibility is that your choke cam is sticking but that would cause black sooty spark plugs. The weakening device could also be stuck, you could try spraying some WD 40 into it as that sometimes helps free it up.
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Old 04-06-2019, 02:44 AM
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When you adjusted the idle screw did u see the shaft move as you loosened it? If not you may have to adjust the linkage to the accelerator pedal to let the adjuster go down ,if it has no free movement

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Old 04-07-2019, 05:01 PM Thread Starter
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Thanx for the heads up guys.. I'll do more sniffing around for vac leaks and possible linkage issues. I'll post my finding.
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Old 04-08-2019, 12:07 AM
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There has to be something basic about this problem
Old vac lines car runs OK
New vac lines car does not run OK, so something along the way during the pipe replacement has introduced the problem. Run the car and spray WD40 around the lines you changed if you hear a change in engine revs then the lines or line is drawing in air and burning the WD40.
Are you absolutely sure you changed the vac lines and reconnected in the proper order?

Pretty certain as the problem has been introduced it will be a simple fix

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