jke82

ok so i just got my trx3.3 engine broke in and im now trying to get it tuned up problem i keeprunning in to is a pretty fast idle problem. my hsn is tuned well so i know thats not the problem my lsn and idle screws are the paina, adjustments to either one make no effect on the idle it still wants to try to keep going what am i missin here?

t9dragon

My Feedback: (11)

Check the throttle trim knob on the radio, it should set at 0.

jke82

nope its not that before i started break in i zeroed the servo and made sure im at zero on the trim.. im onluy 7-8 tank in to the engine is this normal for new engines? its been broken in to the letter of the instructions from traxxas i just cant get the idle down

t9dragon

My Feedback: (11)

Adjust the trim knob once you have it running and see if that works.

jke82

its definately not the trim nob im new but im not that new its some kind of tuning issue i know that much, idle gap is set at 1mm lsn and idle screw adjustments dont affect the idle at all. it just wants to run fast, my hsn is tuned cause when you let it go and open it up bat outta hell ya know any other ideas?

t9dragon

My Feedback: (11)

So when it is sitting still idling does it want to move?

Or does it want to run fast as you are driving it?

jke82

well it doesnt sit still unless im on the brake other wise its trying to jump away. if i just let it go it will idle and run at about 10ish mph i just cant get it to sit still....thing has to have add  LOL

t9dragon

My Feedback: (11)

Are you using the stock radio?

jke82

yeah its the stock radio but not stock servos, i get no interference of the sort nothings causeing it to glitch or anything like that what i mean by the jumping is that the engine is reving up and starting to engage the clutch and then it starts moveing i just cant get it to idle down

jke82

well ive been up and down checking it again just now, no air leaks no radio glitches no reason it should be idleing so fast that it wants to take off i just cant wrap my head around it...

jdoug

Check how far open the carb is when your just sitting there (take air filter off and look)...no need have the engine running at this point. The opening should be very small, maybe a millimeter. Then apply your brakes and see if the opening gets smaller. If it doesn't, then keep your brakes on and back the idle screw out, it will close the gap. When you've done that, then back your trim knob (if the carb opening is bigger before hitting brakes) to close the carb to the new setting.

Sometimes the spring in the carb is kind of weak to pull it back all the way, that is why I hit the brakes when adjusting idle screw on the engine. Also, make sure that you are adjusting the idle stop, not the low end needle. When you've successfully closed the carb a little, then start your truck and see if it idles. From here, you can keep it running with the brakes on and adjust the idle stop screw (out for a lower idle).

jke82

ill give this a try but as far as the carb gap being closed when the brakes are applied it doesnt move everything is aligned pretty well as far as that goes ,so the carb is closeing okay its just not having any effect on the idle ill give it a whirl in a few and keep you guys posted

jke82

ok so just tried  all of that with the idle gap and still to no avail it keeps running fast no matter how rich or lean the lsn or closed the gap is on the idle set it either stalls out completely or idles fast as can be GRRRRR!!!!

t9dragon

My Feedback: (11)

Could be your clutch.

jke82

how would the clutch affect the idle engine speed? thats a new one on me....

t9dragon

My Feedback: (11)

The clutch could be loose causing the pinion to spin and then the spur

Krawlin

Everyone keeps trying to help you but you always say "No, it's not that." Since you seem to think nothing anyone is saying is right, why did you even bother to post?


Anyway, your problem could be many things-

1. Your HSN might be too lean. The HSN controls fuel inlet at all speeds, so if you adjust your HSN, you must adjust your LSN accordingly. Try richening the HSN, if it stalls, lean out the LSN a bit and see if it idles at a normal speed and takes off without any bogging or dropping in RPM.

2. Your radio trim and idle set screw are out of whack. You say it has different servos, so did you make sure that the transmitter and receiver were on and trim set to zero when you installed the servo arm? If not, remove the servo arm, turn on the transmitter and receiver, set throttle trim to 0, place the servo arm back on the servo so that the carb slide is all the way in. Remember the engine should not be running for anything here in #2. Now remove your air filter, and while applying the brakes on your transmitter, turn the idle adjustment screw so that there is about a 1/16th inch (or 1mm) gap between the end of the carb slide and the carb body. Now let off the brakes. If the slide opens up more, adjust your trim so that the servo is applying very light pressure to the carb slide when it is closed to idle gap.

3. Your LSN or your entire tune is not right at all. Reset all of the needles to factory settings and then adjust accordingly. Remember, always tune the HSN before the LSN, because the HSN is what controls how much fuel gets to the engine no matter what. Once you get the HSN tuned for performance, adjust the LSN so it will take off without bogging down, it should be crisp throttle response, and should not drop or increase in RPM as it sits and idles. If it slowly drops in RPM as it idles, the LSN is too rich, if it slowly rises in RPM as it idles, the LSN is too lean. This is based off of having a 1/16 inch (or 1mm) gap at idle.


On the clutch issue, a messed up clutch would not cause an engine to idle high, but rather idle slow, cause it to stall alot, and always want to turn the wheels with a normal/slow idle. Usually that happens when the spring(s) are broken. Broken clutch spring(s) will also cause a nasty bog on take off, and clutch shoes that are too grippy will do the same thing. Too soft of a clutch spring(s) will also cause a nasty bog on take off. A high idle in general though will cause the clutch shoes to slightly engage, causing the truck to want to move forward. Your problem is not the clutch, but your high idle problem will cause a clutch problem if you do not correct it soon, as the clutch shoes are always engaged and trying to turn the wheels, but they are slipping alot and building up alot of heat and glazing the clutch bell with clutch shoe material.

jke82

well i was saying those were not the problems because the weren't most of what was said i have already tried as far as the tuning being out of whack sure could be a possibility but again these are the things Ive already tried and still cant figure out the issue. now for what ive tried so far today because daylight is gone ive spent all day on here and outside on the car trying things and still high speed idle so ill make a list of what ive tried an see if anyone can add something new to the table
-servos are at zero trim is at zero when brakes are applied there is no more movement in the carb at the idle gap
-retuned from factory to performance again hsn is set great car runs fast and fun nice blue smoke trail good speed no bogging down
-lsn pinch test for the car to shut down takes about 2-3 seconds throttle response seems plenty crisp to me wheelies on demand all that jazz no problems there as far as i can see
now here is where im getting the issues, adjusting the idle screw does two things only either stalls out the car or speeds up the idle i cant get it to slow, on the other side of that when the lsn is adjusted i get the same results ive tried fiddleing with one then the other then both going back and forth between resets to factory settings high speed runs to clear out the engine and so forth  but the idle will not slow down. now the engine is just off of break in im now on about tank 13 ish counting break in, is it possible that its still wearing in ive broke in 3 other engines all traxxas on seperate cars for the time ive been in this hobby and never had a problem like this. i am by no means an expert but i definately know my way around the cars and how to tune but common there has to be something im misssing


ps. ill take the clutch bell apart and take a look at the clutch for kicks but its a new engine, clutch, bell , the carb its all new power train and i still cant wrap my head around it

Krawlin

So if you make the idle gap smaller and it stalls, lean your LSN out a bit. and richen the HSN slightly. If you adjust one thing, you have to adjust the other accordingly, otherwise it throws everything off.


I guess the old saying holds true..... "Traxxas quality for you......."


BTW, some punctuation would make your post a lot more readable.

buggy fanatic

My Feedback: (16)

did you get the idle problem fixed?

Krawlin

Well obviously he didn't as you can tell by the time/date he posted, it was only about an hour ago and he hasn't posted since saying he solved the problem.

cumquat

what fuel and glow plug are you running? i had a simular problem with my pro .15, it was running hot and a touch fast. you should be using a hot plug for under %20, a medium for %20-%25 and a cold for %25+. also check that its shimmed properly for your fuel. any idea what the temp its running?

Dan M

My Feedback: (1)

Sounds like you have an air leak .

larryf333

My Feedback: (2)

How could you perform an accurate pinch test with it idling high? You couldn't. Take Krawlin's advice and start over, yet again. Obviously you're not doing something right. You know which needle is which, right? Also, have you checked for air leaks? They're a pita to track down, but can cause alot of problems, just like yours.

nargargle

I think he is running too lean on the LSN.  If it is dying in 2 to 3 secounds and not increasing RPM first then that is his problem.  When he tries to back out the Idle speed screw he is shutting off the fuel flow to the engine.  Richen the LSN and the Idle will come down.  Anouther thing is I notice my Idle gap is about .5 to .7 mm when tuned for good idle speed.  At 1 mm it will want to run high.

Just my few thought.  Maybe it will help.