trx 2.5 tuning issue

[Mike02vr6]

Well I take my maxx out after it being dormant for a few months (would start it ...let it warm up then do wd40 it to make sure it didnt seize). The last time I drove my truck it was like 55-60 degrees outside, The temp now is around 40ish now I am having huge trouble keeping the truck running it sounds like it is loading up and almost backfiring yet at the same time the truck is starting to overheat. I am not running WOT at all. I do have to keep my finger on the trigger or else it dies.I am running a McCoy-9 plug and trinity monster fuel 20% nitro (the only fuel I have run since I got the truck) its a brand new bottle. Does anyone know what could be goin on here? I Pulled the head last night to see if maybe it was rusted or something but all seems fine. Smooth walls no scratches, gouges or rust. Please help me. You guys are the best.

Michael

P.S. I also adjusted the LSN about a 1/4 in to lean it out some.

 

[lykan]

Did it start overheating before or after the LSV adjustment?

It is possible to mask a lean LSV with an over rich top end. A lean LSV adnd an over rich top end might be your issue? ON the low RPMS it starves for fuel, and lube (gets hot) the seconnd you hit the throttle, it boggs down and gets almost to rich to run. A

Also if you have a lean LSV it will want to die when you ty to advance the throttlle..

Is it possible that one of your fuel lines developed an air leak?

BTW the cooler the air, the more the mixture leans out. Cooler air is denser, hence more air in the same cylinder space.

Usually when it gets colder you have to richen up the mixture a bit to provide enough fuel and lube for the tempurature.

I could see if its about 20-30deg cooler, and you leaned out the LSV where it would be running acutally a bit on the lean side to begin with.

Hope my limited knowledge helped.

 

[Mike02vr6]

thanks man I will look into that tonight maybe that is the issue. The only prob w/the LSN is I got a new era 3pt cage that blocks the already limited access to the LSN. OH well thanks for the input.

 

[lykan]

ON my trx .15 I had problms getting to the LSN, what I did was flip the carb around so I could get to it.

 

[Mike02vr6]

OH yea the carb flip! I forgot about that I have to search to see how to do it now. Thanks for reminding me. that should help alot.


~Michael

 

[lykan]

If you have any tunning issues at all, or ant to do any work on he LSN the carb flip has to bed one LOL, twice now for me.

BTW I had B:flaming:tch of a time. Until I found that somehwere on the web.

 

[Mike02vr6]

ok issues again w/the blasted motor. I replaced all the fuel lines and put the carb back to factory. it took forever to finally get the motor started but now it wont stay running, it stalls usually before I take the starter away. A few times I kept it running only for a min or two. It seems almost like its flooding when I hit the throttle. Should I back out on the LSN? right now its about flush. Any other suggestions from anyone?

Thanks
~Michael

 

[lykan]

The factory settings are very very rich. Try turning in the HSV a little bit. keep the lsv at factory until you can get it to at eleast idle ok.. Since you changed the LSV back to factory you may have to adjust the idle screw.

 

[Mike02vr6]

so your thinking its not staying running due to the HSN?... Iwas thinking for somereason the LSN...but I should lean out the HSN? Thanks for the info.

~Michael

 

[lykan]

Well I can't really tell you exactly what to do since I can't see the engine in question. I can tell you this.

The factory settings are usually over rich #1 for break-in #2 so you dont fry your engine on the first tank.

I know for a fact if both your needles are at factory settings it will start. It will however be rich.

The LSV is a pesky touchy evil thing if your not full aquainted with it. With factory settings, the LSV will function ok, at least enough to get you moving and idleing fine.

From the start when you get your engine the factory usually recomends leaving the LSV alone, and only leaning the HSV 1/4 at a turn until you get performance.

Soo ayup ,keep the LSV at factory. Lean the HSV from factory in 1/8 to 1/4 turns (inwards) until you get some performance. After a few times out, if you feel comfortable with your tune. Then you can try to play with the LSV.

Too many people have issues keeping their nitor's running and starting. One of the first things they do is start tweaking the LSV. Thats where they get into trouble.

Leaning the HSV too much - you'll get too hot you'll know it.
Richening the HSV you'll flood out, and bog -- you'll know it.


Lean the LSV too much -- it won't start you have no idea what's wrong
Richen the LSV too much, -- it will flood as well, again no idea why it wont start or stay started.

To me the LSV is just a new guys nightmare/death trap. it caused me a LOT of frusteration.

Hope this helps out a bit

 

[Mike02vr6]

its actually does help me out. Once I tuned my truck last yr, the thing flew and I never had to worry about tuning. Now this yr the only two things that changed was the temp and I went to the McCoy mc9 plug from the mc59. Unfortunately noone in this area happens to have the 59's in stock wtf huh? So I will try what you say and pray to the rc god

 

[lykan]

Good luck let us know how it turns out , would like to know when you get it running good.

 

[SkyMaxx]

Did anyone here think about the fact that he is trying to start an RC that has been sitting idle for some time. It has been flushed with WD-40 (not very gasket and seal friendly, not to mention doesn't burn as readily as nitro fuel) on a regular basis. Now, add the fact that he is trying to start cold steel on a not so warm day.

Just curious. All of those things add up to a stubborn to start and even more stubborn to keep running engine.

One, the engine will need to get up to temps and stay there for a bit in order to properly maintain the idle and stay running...regardless of throttle inputs.

Two, the engine will need to burn up the remaining WD-40 that may have stayed in the engine. This additional oil added to the fuel will create an artificial lean situation. The engine will heat up despite the WD-40 because as it breaks down under combustion, there is no more lube to it. So you have a lean engine firing up.

Three, WD-40 loves to eat things made of rubber/silicone. I wouldn't be surprised if some of the gasket seals are deteriorated from regular flushings with WD-40. May want to check them for damage as they can be a major source of air leaks.

Finally, be nice to your engine on a cold day. Set the LSN and HSN at factory presets. Get the hair dryer out and pre heat that engine for a bit. Once you get it started, give it some gas and run the rpms up to build up some heat so the engine will expand as it should and operate where it likes (temp wise). Once it is warm, then tune for performance. Tweak the HSN to the rich side, but you can afford to lean from factory presets (look for the nice trail of smoke and cooler running temps).

All in all, Lykan has given you some great information. But there were some key clues that you dropped that are also big reasons for your engine not wanting to stay running.

 

[lykan]

Thanks Skymaxx, for adding what I had missed. For soe reason the whole not ebing started thing left my mind the second I read it.

I also thought about the hair dryer to heat it up before hand. Again, that one slipped my mind.

I will definetaly second the idea about the hair dryer. If I leave my truck under the heater in the car, it starts right up. If I forget, or its dirty and I throw it in the back I have a hell of a time getting it going.

 

[Mike02vr6]

sky thanks for the input. I will look into what you have said. One thing though is the truck actually ran for about 1/2-3/4 of a tank before I got frustrated (sp), and finally shut it down. But I bet your right w/the gaskets being eaten away. So I should pull the engine off, pull the carb and backplate off and inspect the gaskets in this area? Any where else too look? Ohh header right? Thanks again. Not sure what I would do w/o this website.


~Michael

Oh yea the truck is always stored in my computer room (3rd bedroom of my home) near the heater. I pulled the head the it seemed nice and clean inside no rust or scratches. Pulled the air cleaner and put new zipties on to hold down and make sure no leaks from there. Well I am outta commision now cause wonderful new england weather decided to give us akick in the arse w/one more snow fall. Looks to be about 4or 5 in. Will let you know more. Gonna check the gaskets tomorrow or day after.

 

[SkyMaxx]

I would only worry about the gaskets/seals in the carb. The back plate is probably fine. A little harder for the stuff to get down there. The gasket for the header is only a cardboard composite. Nothing to really worry about there, but doesn't hurt to check. Just be careful removing the header as the gasket might be stuck to it and the engine. Tearing it would require a replacement, and that might not be so cool.

 

[Mike02vr6]

ok thanks, Now something that I have been trying to figure out. Sometimes when I start the truck I put my finger over the exhaust to kinda choke it into starting (not all that often mind you cause i did have any trouble like this until now) But today and yesterday I had my finger over it for quite some time (like 5-10 sec while trying to start it) This more and more is making me think I have some kinda air leak in my carb because I didnt get the hydrolock. Does that sound like something that would make me look closer to the carb?


~Michael

 

[ZANDOR]

when you put your finger the exuast this caueses fuel to move to the carb.ie priming the carb. if your holding it there for that long you are flooding the motor............

Originally posted by zandor22
when you put your finger the exuast this caueses fuel to move to the carb.ie priming the carb. if your holding it there for that long you are flooding the motor............

are you using elc start or pull start???????????

 

[Mike02vr6]

soooo after all this tuning and retuning, and putting back to factory to check and checkin the glow plug to make sure its working, and pulling the head, and carb can't find anything wrong. So Chrisexv6 and myself stare at the motor in disbelief and I say..."hey what the hell lets just try the Mc-59 instead of the mc-9 wtf could it hurt right? Well we replace the plug...try tofire her up Some sputtering, stalls...try again, more sputtering...idles..give it gas she dies. OK lets try once more, we fire it up unburned fuel flies out the exhaust and the motor screams to life, and is running like a champ now. Thanks guys for all your help, from now on I will keep the med-hot plug in my motor and now I have to retune from factory. Does anyone run a cold plug in their 2.5 motor? and do you do with much luck? Thank again for all your help.

~Michael

 

[Mike02vr6]

Well back to the beginning again.. still having trouble getting this blasted truck running. I pulled the motor off today the ezstart was a little bit loose but I dont think that would be the problem w/the truck not running right. I cleaned up the motor pulled the head everything looks good. No scoring no rust glow plug seems fine. But it feels like the motor over heats quickly and then doesn't wanna run. But getting it started is a bear. It cranks and cranks, then sounds like it is loading up and almost like a backfire, then nothing. Then when I get it running it seems like it takes for ever to get up to speed the first few times I run it then the truck takes off and runs like a champ for a little while. Has anyone else had this prob?

Thanks,
~Michael