frustrated

[nitroguy]

hi all I'm a the end of the rope can't tune my tmaxx 3.3 tried everthing sealing the engine fuel lines tank glow plugs new carb called traxxas just runs like crap wont idle right it will work ok not good just ok then just die this is a brand new truck i might have put about 12 tanks of fuel in it my son has a hpi firestorm with the Nitro Star G3.0 Engine its about 3 years old unbeliveable never had problems with it works perfect never touched the carb in two years still held its tune so i dont know what too do any help would be great thanks.

 

[MudSlinger33]

The 3.3 can be a pain in the rear to tune sometimes. Read the tunning flowchart at the top of the nitro section and see it that helps.
Next time you post a question, please use punctuation. It makes it much easier for every one to understand you.

Sent from my XT907

 

[synnyzter]

Hmmm 3.3 is one of the easiest on the market to tune. Did you over tighten your hsn at any point? I've done this and it can damage the needle, and I ended up just grabbing a new Carb cheap online and fixed the issue.

Reset needles to factory according to book. Set your throttle needle gap at a 1mm gap and leave it! Make some wide open runs, adjust hsn till its tuned for performance.

Then adjust the lsn to get a good idle, don't use idle screw or throttle trim to adjust idle.

Rich on the lsn will idle it down.

If your needles aren't damaged and you tune in the correct order above, and you have no air leaks and the carb is fine the only other issue would be the bottom end which is unlikely but possible on a new engine. A bad bearing or something... I'd pull it apart and inspect it if it was me.

Also a bad breakin could be the cause. Did you track your engine temps at all? Be sure not to go over 270 once tuned. I tune mine to performance and always keep an eye on temps just to be safe especially when its very hot outside.

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---------- Post added at 6:16 PM ---------- Previous post was at 6:11 PM ----------

Oh and I also have an HPI 3.0, it is bulletproof and runs forever. I've abused mine and its as strong as ever lol.

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[hulkmaxx]

Man I had a 2.5 giving problems tore the engine down resealed it still would not run right. I fought that thing for 2 days. Pulled the engine off upgraded to a old .21 Picco engine, tossed the old 2.5 in the box. Decided to build me a beater rig for the summer, Installed the 2.5 of course problem was still there. I had a new carb laying around figured what the heck put it on truck ran like a new engine. I tore the carb down and could not figure out what the problem was.

 

[synnyzter]

Man I had a 2.5 giving problems tore the engine down resealed it still would not run right. I fought that thing for 2 days. Pulled the engine off upgraded to a old .21 Picco engine, tossed the old 2.5 in the box. Decided to build me a beater rig for the summer, Installed the 2.5 of course problem was still there. I had a new carb laying around figured what the heck put it on truck ran like a new engine. I tore the carb down and could not figure out what the problem was.

Lol pretty much same thing that happened to me. For me it was a jacked up needle when I compared them. Thank god for dollar hobbyz though

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[Rolex]

Then adjust the lsn to get a good idle, don't use idle screw or throttle trim to adjust idle.

Rich on the lsn will idle it down.

Not correct on that info.
The lsn is not there for the sole purpose of setting the idle speed. That's what the idle screw is for. Too rich on the lsn makes for a sluggish takeoff and too lean causes an overheat that you can't correct with the HSN.
Set the LSN for a good takeoff without lag and then set the idle screw with the brake trigger full on and the trim to full off. Just use the trim knob for cold starting and warm up.

 

[Childresshunt]

+1 on what rolex said

 

[synnyzter]

Well I have tuned half dozen 3.3s exactly that way and it works perfectly. And with a proper tune on a 3.3 you won't need to trim anything cold or hot. Just let it warm up for 60 seconds before you race off.

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---------- Post added at 3:34 PM ---------- Previous post was at 3:32 PM ----------

Oh not to mention my friends do it this way now as well. Trust me it works with the 3.3 for a perfect tune.

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[Rolex]

It doesn't matter if it works for you or your friends. You've just been lucky.
Your information is still wrong and that's why I'm correcting it.

 

[synnyzter]

Well I'm not saying this is how all engines should be tuned as its not at all but for fresh 3.3s it does work and works well. I know not all are the same but its not luck lol, it works for 3.3s whether you believe it or not.

I simply shared this because I have had so many 3.3s and have worked on so many of them and I know how to tune them well. Doesn't matter if anyone listens or believes me as I don't care lol. But...it works, and I know it works. I give more advice on them than other engines because of experience, won't see me giving any in piccos...

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---------- Post added at 5:45 PM ---------- Previous post was at 5:39 PM ----------

Meant to say...this is why its considered one of the easiest to tune and keep tuned. Its a widely known means but I guess different people, different forum, different locations. Etc....

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[Rolex]

I'm not about to spend the day going back and forth with you, but there's not one person in the world who will say that your info is spot on and mine is bogus.
The LSN serves a very specific purpose when tuned precisely, as it should be, and so does the idle screw.
We all make a point of correcting incorrect advise here because we don't want guests thinking we're clueless and telling others that they read it on RCNitrotalk.

Your info is NOT correct and I'm telling you that again. If you want to keep insisting that you and you alone have discovered a magical new way to tune an engine, then I'll remove your posts.

 

[Zdragon71]

I agree with rolex. On every engine I've tuned including many 3.3s the LSN is for adjusting throttle response. If you over tune the lsn and make up for it on the hsn you can get a "false tune". Which will cause overheating issues.

 

[synnyzter]

did you not read the post entirely? I didn't "discover" anything...I just found that was what I ended up with in the end time after time so...that's just a shortcut and I've shared it, others do the same thing. I'm highly involved in my local rc community and there are 3.3 spec classes and its just common knowledge locally, not a secret special anything lol. Remove it if you want, don't much care, I'm just sharing an easy way to accomplish something that works apparently only in my community..? I agree its not typically a good idea at all...I know this but if it works it works, so far be it from me to say otherwise.

Remove it if ya want, I'm not the arguing type anyhow so...won't hurt my feelings one bit. I'll continue doing what works, like anyone else would.

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---------- Post added at 6:41 PM ---------- Previous post was at 6:37 PM ----------

Yes lsn is for throttle response, but it just ends up being "right there"....that's how many people do it at my 2 tracks.

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