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Old 07-04-2009, 08:03 AM   #1
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Default Engine Tuning Question

I've been following the Ron Paris tuning method and my car runs great but fails the pinch test. It will hold 260-280* all day long which I am fine with but when I do the pinch test it dies immediately. My needle balance was originally too lean on the hsn and too rich on the lsn. Runs great now!
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Old 07-04-2009, 08:05 AM   #2
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I've been following the Ron Paris tuning method and my car runs great but fails the pinch test. It will hold 260-280* all day long which I am fine with but when I do the pinch test it dies immediately. My needle balance was originally too lean on the hsn and too rich on the lsn. Runs great now!
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Old 07-04-2009, 10:10 AM   #3
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Anyone?
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Old 07-04-2009, 10:19 AM   #4
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Since it dies immediatly, you want to richen your LSN until it revs up slightly and dies in 4 seconds. LSN has a big effect on temps too.
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Old 07-04-2009, 10:37 AM   #5
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It seems really rich as it is though. If I let it idle for a bit and try to drive again it's ok as long as I am slow on the throttle at first till I clear it out. If I hit it at a low speed at that time it just dies. Not sure but I think that's known as flame out right?

It runs great now though but I seem to have to keep my idle up to keep it running still and if I lift the wheels off the ground it idles up quite a bit higher. Is this normal?
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Old 07-04-2009, 10:42 AM   #6
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If you lift your car off the ground the wheels still shouldn't spin. Richen LSN and lower idle and do the pinch test.
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Old 07-04-2009, 10:51 AM   #7
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I can't though, you're not upstanding what I'm saying.

It will just hold an idle now, it's better then it ever was. I don't understand why it rev up when I pick it up. It runs great on top end now. Before I was too rich on the LSN and it was covering up for a lean HSN. After several passes it would lean out but now it's great up top. If I richen the LSN more it doesn't want to idle. I have the LSN a lot leaner then it was before. Atleast 1 - 1 1/2 turn.

Just want to make sure you understand what I'm saying.

Also sometimes when I let off the throttle from a WOT pass it holds the RPMs for just a second or two then drops.
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Old 07-04-2009, 11:47 AM   #8
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If the RPM's are still high, that means you have a lean LSN. You want to richen the LSN then raise the idle speed to get it to idle reliably.
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Old 07-04-2009, 03:30 PM   #9
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take the advice you have been given about the lsn. It sounds lean to me also and the idle is too high. the wheels shouldnt spin when off the ground. You had to idle it up because it isnt getting fuel at idle. give it some !!
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Old 07-04-2009, 03:38 PM   #10
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idle and lsn are connected together, you cant tune the lsn and leave the idle alone,


You say your already rich, but from what you have told us your lsn is to lean, but you say its running awesome. its hard to say but i would think your hsn is to rich, lsn is to lean.
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Old 07-04-2009, 04:26 PM   #11
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I would say something is wrong with the clutch. Idles fine on the ground and then idles higher off the ground. Sounds like he is super lean on the bottom to keep it running and it wants to die as he accelerates because the clutch is already engaged.
Just something to think about
It is pretty hard to diagnose tuning problems through the PC.
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Old 07-06-2009, 07:56 AM   #12
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The clutch is fine, it's new as well as the springs. It runs awesome when I go WOT but down low it acts too rich and sometimes stalls out of the blue and it is flooded out. I can't even get the damn thing to run now. I'm going to get my local R/C club to take a look at it.

It's a new engine with about 10 tanks though it. I broke it in using the heat cycle method and it started very good right out of the box.
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Old 07-06-2009, 08:10 AM   #13
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The fact that the engine flames out when you grab a fistful of throttle from idle means it's either lean on the bottom, or you may have an air leak somewhere. The idle rising when you pick the car up off the ground is another symptom. Double check your idle gap. It might be too small to allow the engine to run when the LSN is set correctly. Usually that gap needs to be 0.5-1.0mm
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Old 07-06-2009, 08:19 AM   #14
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I think I have the idle screw around 1.5 mm just to keep it running and it still doesn't want to. Should I set the idle screw to around 1 mm and start over again?
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Old 07-06-2009, 09:48 AM   #15
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A lean low speed needle could sound like a rich low speed needle.

If when you let the car sit and slam full throttle and you get NO smoke you are lean on the low speed needle.

If you slam full throttle and you get a ton of smoke your rich.

If you have a light smoke trail and it still acts weird you have an air leak.

What fuel are you using?

Best thing to do would be to take the car to the track and make some knowledgeable friends.
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