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Location:
Mornington Peninsula
Registered:
September 2002
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 Problems when accelerating (18R-C)
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Thu, 17 July 2003 22:26
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Hi all,
I've had this problem for a while and it seems to be getting worse. Everytime I push my foot down on the accelerator my car hesitates for a few seconds before the speed increases. It happens from 0km/ph and when I'm already crusing and want to increase my speed. Sometimes when it's cold it will back fire through the carby.
I've thought it could have something to do with fuel flow as it's getting too much or not enought. I've got a ram-flow air filter on there but a stock carby, should I change it back to the original air filter?
Any suggestions would be greatly appriciated.
Thanks 
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Location:
Canberra
Registered:
December 2002
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Re: Problems when accelerating (18R-C)
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Thu, 17 July 2003 23:15
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Sounds like a flat spot in the carby. Rebuild it and the problem will probably disappear. How long has it been since the carby was rebuilt?
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Location:
ballarat
Registered:
April 2003
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Location:
Perth
Registered:
May 2003
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Re: Problems when accelerating (18R-C)
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Fri, 18 July 2003 01:01
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The dodgy flat spot - you've got to love it 
First of all fck the ram flow off there shht you might as well stick carboard in there. get a K&N, if you can fork out the money for a carby rebuild do it but you will still have to get it tuned, which is what you should try before you get the rebuild done, get your air fuel mixture right and the timing and try some new or smaller sized jets, and your problem will go away.
I have a 350 holley on my 6 and have got it kind of tuned (need new jets) but it was doing all the dodgy back fires and flat spots thats all gone know though.
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Location:
Brisbane
Registered:
May 2002
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Re: Problems when accelerating (18R-C)
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Fri, 18 July 2003 02:40
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There's lots of things which could be causing those symptoms. It's all guesswork until you put the car on a dyno with a gas analyser jammed up the tailpipe. An experienced dyno operator will be able to diagnose the problem in 5 minutes. It costs money to put your car on a dyno, but it will probably work out cheaper than the "trial and error" method of replacing/rebuilding everything until it's fixed!
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Problems when accelerating (18R-C)
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Fri, 18 July 2003 05:30
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i agree with Norbie, go spend like $30 or whatever it is and have it put on an engine analyser. easy and quick.
as far as the popping out the carby thing goes? that happens under lean conditions. i have the same with my 34DMS weber as i removed the choke flaps, and it is lean when cold. i put a one size richer jet in and it is driveable when cold, and rich enough when hot to be very responsive.
as far as the hesitation when you poot your foot down? sound sremarkably like the accelerator pump is eithe rblocked, or the plunger is not working right. take of the air cleaner, and open the throttle when engine is off, you should see a little stream of fuel squirt in from the side of the throat. if not check linkages, check condition of plunger, check jets are clear.
basically, cold = fuel dropping out of intake mixture = popping
hesitation = lack of fuel = accelerator pump not working properly.
Cya, Stewart
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Location:
Brisbane
Registered:
July 2003
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Re: Problems when accelerating (18R-C)
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Fri, 18 July 2003 06:16
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have you checked the spark plugs recently?
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Location:
Mornington Peninsula
Registered:
September 2002
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Re: Problems when accelerating (18R-C)
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Sun, 20 July 2003 22:17
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Hey all,
Thanks for the help, It seems to be getting worse. Didn't have a chance to look at it over the weekend. Carby was rebuilt about 18 months ago. Spark plugs replaced less than 2 months ago (but probably need a clean.)
The choke on it is a auto but I've got it hooked up as a manual because of the extractors it wasn't heating up. Even when the choke is partly out it can still flat spot when it's warm.
It seems to be running fairly rich at the moment too, have to have a fiddle with the mixture.
A friend has got a dyno so I'll have to speak to him nicely and it should cost me a slab. It was put on the dyno about 18 months ago and basically cyl one wasn't working, compression was about 14 and cyl 2 was 215.
I'll see how it all goes.
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Registered:
November 2002
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Re: Problems when accelerating (18R-C)
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Mon, 21 July 2003 01:30
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Just before you try all the expensive parts replacement, testing and rebuilding options, go and buy a $7 can of carby cleaner from Super Cheap / Rocca Bros, take off your air cleaner, start the car, and spray the cleaner all down, thru and around the carby.
Replace filter and then go for a drive.
If the problem is still there, then look at the previously mentioned options.
Cheers,
Mitch.
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Location:
Mornington Peninsula
Registered:
September 2002
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Re: Problems when accelerating (18R-C)
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Mon, 21 July 2003 02:35
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That does sound a lot cheaper than a slab of beer. Will Auto Barn have it? They're fairly close to my work.
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Registered:
November 2002
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Re: Problems when accelerating (18R-C)
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Mon, 21 July 2003 02:38
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They sure will, they will have name brands as well as cheaper generic stuff.
Don't be afraid to use most of the stuff as well too, and rev the engine a bit while you are spraying it into your carb.
If this does not work, test the plug leads with a multimeter for their resistance, and replace any dud leads, then borrow a compression tester and check your cylinders for compression.
Cheers,
Mitch.
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Location:
ballarat
Registered:
April 2003
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Location:
Mornington Peninsula
Registered:
September 2002
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Re: Problems when accelerating (18R-C)
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Mon, 21 July 2003 22:14
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Yeah, it runs over sometimes (sign of a top quality car I was told  )
I'm going camping this weekend and have to take my car so I'll have a fiddle around with it one night this week and see how I go.
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Location:
Adelaide
Registered:
June 2003
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Re: Problems when accelerating (18R-C)
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Tue, 22 July 2003 03:37
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My brother's old 18rc had the same backfiring and accelleration probs, but only when it was cold the extractors made it worse, so we figured that it was a choke problem. When we pulled off the carby we found that there were little holes in the bottom of the carby and its mounting plate that were full orf silicone sealant, I guess we used too much , but that might have had something to do with the trouble. Blocked gas flow tubes can't be a good thing, as they are required for the carby to work right.
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Location:
Mornington Peninsula
Registered:
September 2002
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Re: Problems when accelerating (18R-C)
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Tue, 22 July 2003 04:22
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Looks like the best way to find out is the dyno. There is so many possibilities of what could be causing it, But one thing I'm certain of is that it has something to do with the Carby!
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Location:
Gold Coast
Registered:
October 2002
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Re: Problems when accelerating (18R-C)
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Tue, 22 July 2003 07:17
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my rc has had similar problems recently, like others said carby cleaner points plugs and half an hour of tuning and it was running fine again.
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