Thundermax issue

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crutter

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844
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Frederick, Md
Just finished building my motor and started it up. It runs and idles fine but the check engine light is on. My thundermax is not communicating with the front o2 sensor. Any ideas why? Yes it is hooked up and it worked prior to the build. Thanks for the assistance.
 

Marc

""The Chopped Baggers Guy""
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Check the wires, I had a similar issue. They got into the belt.. Wore a hole in the wire. It was my back.

Try swapping front to back to eliminate a faulty sensor... Itll run enough for you to see if the o2 is bad.. Have it hooked to your pc..
 

crutter

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Frederick, Md
I bought the unit used. The guy who owned it prior was a wire butcher. Had a bad solder joint. All fixed. Now the question is what is more beneficial....timing or compression? Have a 103 with se255 cams. Head gasket is .30. Have a occasional ignition ping. Do I detune or put a thicker gasket in there
 

Marc

""The Chopped Baggers Guy""
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Pay close attention to the o2 parameters, the big o2 can handle a wide band.. That way if it's tuned wrong it'll correct...

Don't detune, try to hit close and let the brains of the TM take over. You've got the absolute BEST Harley tuner made..
 

crutter

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844
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Frederick, Md
Oh yeah I know with out a doubt the tm is the best out there. I always run 93 brand name in the bike. I'll just ride easy and get the tune closer before I start messing with things.
 

Slowbagger

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1,196
I think if you have pinging you need to take a little bit of timing out in the rpm range that your experiencing it. It's crazy how much stuff you can do with the tmax. I want to have a base map made on a dyno with an experienced tuner but I doubt I do that anytime soon.
 

Zach

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5,785
Location
Portland, OR
Crutter - What is your chamber volume on the heads and what is your deck height? Have you measured your ccp since putting this together?

Those 255's are going to put your ccp above 200. Tuning is critical at that level. I would never trust an auto-tune system to precisely tune something like this.

Zach
 

crutter

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844
Location
Frederick, Md
I have not measured my ccp yet. I will today or tomorrow. I found out through research that the thunder max only auto tunes air fuel ratio. The ignition is a set map. The heads are bone stock and where put on top of stock pistons. I'm really thinking about just switching out the gasket.
 

Zach

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5,785
Location
Portland, OR
Correct - TMax only auto tunes AFR. Nothing on the market that I know of can auto tune ignition parameters.

I would leave the gaskets in. You improved your squish band by .015" by swapping to the .030 gasket. That is a good thing. Your pistons are probably .004" - .008" down the cylinder. The thinner head gasket is getting the squish to a more optimized number (.035" + or minus a few thou being ideal on street Harley's).

If you were wanting to change something I would consider a cam swap. I think your are going to end up having to dial back to much timing to keep it from pinging and most of the performance gains are going to be lost with the 255's.

I would call Zippers and ask them what base map you need to load. I'm guessing your ccp will be 203 - 210 when you check it. Remember to hold the throttle blade open when you check.

I hope you get it running good.

Zach
 
Last edited:

smokenjoep01

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1,257
Location
CapeFear NC
Oh yeah I know with out a doubt the tm is the best out there.

I would disagree. Have you had any experience with the TCFID?
And something that hasent been asked. What pistons are you using? That needs to be considered before you start any tuning adjustments.
 

Marc

""The Chopped Baggers Guy""
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ChoppedBaggers.com WORLD HEADQUARTERS.
I would disagree. Have you had any experience with the TCFID?
And something that hasent been asked. What pistons are you using? That needs to be considered before you start any tuning adjustments.

Not enough difference between to two to argue over, sometimes you can't improve any further. Just rename and repackage. Price is even the same.
 

smokenjoep01

Well-Known Member
Messages
1,257
Location
CapeFear NC
Crutter, that set up with a thirty thou head gasket is good to go.
Marc, no way. DTT and thundermax are no way the same. Like comparing a Pinto to a cadillac. There both cars!
Have you used a tcfid personally?
How many times have they had to ugrade firmware in the tmax?


Sent from my iPhone using Tapatalk
 

Marc

""The Chopped Baggers Guy""
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12,446
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ChoppedBaggers.com WORLD HEADQUARTERS.
Crutter, that set up with a thirty thou head gasket is good to go.
Marc, no way. DTT and thundermax are no way the same. Like comparing a Pinto to a cadillac. There both cars!
Have you used a tcfid personally?
How many times have they had to ugrade firmware in the tmax?


Sent from my iPhone using Tapatalk

Never used that, read there site. They do the same thing, according to there website.
 

Marc

""The Chopped Baggers Guy""
Messages
12,446
Location
ChoppedBaggers.com WORLD HEADQUARTERS.
Crutter, that set up with a thirty thou head gasket is good to go.
Marc, no way. DTT and thundermax are no way the same. Like comparing a Pinto to a cadillac. There both cars!
Have you used a tcfid personally?
How many times have they had to ugrade firmware in the tmax?


Sent from my iPhone using Tapatalk

Never used that, read there site. They say they do the same thing, according to there website.
 

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