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t maxx 2.5 with major problem

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ThEnItRo1

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ok i broke in my engine with top fuel racing fuel. it ran great, i put in another brand, with the same % of nitro, nd it ran great, then all of a sudden it will fire up, but when i give it gas it dies, it will idle for like 10 seconds then die out, I've tried tuning it alot, leaning it, and fattening it, but it still does the same thing. i changed my glow plug to a brand new 1, nd nothin changed, i tried adjusting my throttle linkage, and still nothin happened.

I'm at a major loss with this thing.

i really need some help guys, please help me!!!!

thnx.
 
does it or will it stay running with the glow ignighter on it and when you take it off it dies. if that is the case it may be the new pluge you bought is bad also.it does happen not often but i does happn. it may be glowing inside the plug but if the end is not then it is bad.
 
yea it will run with the igniter in, but it will still run for about 10 secs nd then die, with the igniter in.
 
I would put the needle's back to factory and start your tuning process over. That is really the best way to rule out if it's a tune issue or something else. You always need to tune rich to lean anyway not the other way around so you may just be hurting yourself more than doing good if your just turning your tune settings without really knowing which way to go. Sometimes if mine get out of tune for whatever reason thats what I do it won't hurt it to be rich and may run bad but atleast you will be able to idle enough to get the motor to warm up where you can dial the tune in. Thats another mistake a lot of people make is never tune a cold engine it will be totally pointless get the motor warmed up then dial it in.
 
Nothing to major, i dont think anything is damaged or going to cost you money. Just the change in fuel needs a new tune. Somtimes the change in oil % can be damaging but i dont believe your having any issues.. just to get it to idle for alittle longer just try to turn your trim up and it should idle really high but then slowly turn it back down. then if it still dies just turn your idle screw clockwise in small turns. 1/8 typically is the usual increments but in another words just small small turns when making adjustments. Then see if it will atleast idle for longer than 10 seconds.
 
Revo 3.3 said:
I would put the needle's back to factory and start your tuning process over. That is really the best way to rule out if it's a tune issue or something else. You always need to tune rich to lean anyway not the other way around so you may just be hurting yourself more than doing good if your just turning your tune settings without really knowing which way to go. Sometimes if mine get out of tune for whatever reason thats what I do it won't hurt it to be rich and may run bad but atleast you will be able to idle enough to get the motor to warm up where you can dial the tune in. Thats another mistake a lot of people make is never tune a cold engine it will be totally pointless get the motor warmed up then dial it in.
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yes i have put it back to factory settings many of times and tuned from there, i do in fact know which way to go when tuning. the only thing i was sketched out about was when i ran it fat, when it would idle, there would be smoke coming out the exhaust. i didnt know if it was good, then running fat, when id give it full trottle, it would die.
 
I'm not doubting your tuning abilities I was just suggesting putting it back to factory I didn't know if you had tried that yet. After you get it running idle it way up just to be able to get the motor warmed up and time for you to adjust the tune then idle it back down after you get it where you like it. If it still won't idle is the motor reving before it dies or does it just die. If it is reving before it die's then your lsn is too lean if it's just die's your lsn is too rich.
 
Racer 1966 said:
What plug/fuel are you using now? A lot of problems are solved by just using the right plug.
Click to expand...

Yeah, same thing happened to me. Put the ignitor in and would run for around 15 seconds and then stall out, and if I removed the ignitor it would stall right away. If you are using a lower nitro content fuel, use a hotter plug and if a higher nitro content, use a medium plug.

For example: I am using the sidewinder 20% nitro. I made the mistake of putting in the McCoy MC8 (Medium plug), and kept having these problems. When I changed to the McCoy MC59 (Hot plug), it fires right up and stays running for me again.

ie: 20% = Hot plug / 33% = Medium plug
 
i have the standard traxxas brand plugs, and i have 30% nitro fuel. i had it running with that type of plug and that fuel, for about 1 tank, then i put in another tank, and tried to run it nd it wouldnt run, so i changed the plug, and it still didnt run.
 
i can only get my 2.5 to run well with a 20% fuel and as far as plugs go i would change to the O.S LC3 hot plugs i use them year round and never have problems
 
I was told by a old racer once that the castor content of the fuel has more effect on the type of glow plug than the % of fuel,So that isnt right?Traxxas told me 20% to 30% use med plug anything higher use a hot plug. maybe thats why i could never get a trx engine to run right,LOL
 
BamaFan said:
If it still won't idle is the motor reving before it dies or does it just die. If it is reving before it die's then your lsn is too lean if it's just die's your lsn is too rich.
Click to expand...

? . so if the idle is right it won't die ?
 
maddmaxx65 said:
I was told by a old racer once that the castor content of the fuel has more effect on the type of glow plug than the % of fuel,So that isnt right?Traxxas told me 20% to 30% use med plug anything higher use a hot plug. maybe thats why i could never get a trx engine to run right,LOL
Click to expand...


I was told at my lhs that you will need a hotter plug to burn the lower% nitro because it does not ignite as easily as the 33%. So if you use a medium plug with the lower % nitro then the plug wont be hot enough to sustain ignition and thus the reason you have to keep the ignitor on the plug to keep it from stalling out on you.
 
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That's not neccesarily true. I run 20% and use an os lc4 medium plug in my Savage XL and used the same combination when I had my T-MAXX 3.3. It's most likley a tuning issue. Sounds like the lsn is too rich. Was the glow plug wet when you took it out?
 
Now that you mention that, I think I do remember the medium plug being a bit wet when I removed it. However, I know for sure that the medium plug that I was using at the time was brand new.But I did not retune the lsn or the hsn when I replaced it with the hot plug. Anyways, this was what the owner of my lhs told me. Not saying that you dont know what you are talking about, but I also take his opinion into consideration when he gives me advice seeing as he has been in the business for 20+ years.
 
does it run if you have no waight on the tires, in other words if you hold it with the tires off the ground how long does it run for? the reason i ask is because i had the same prob u got. it ended up being my bell clutch, as werid as that sounds. every time i started it up it would run but as soon as the tires hit the ground it would die
 

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