ThunderMax module for Marelli injection system?

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Apr 10, 2017 | 01:41 PM

troverman

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From: NH

ThunderMax module for Marelli injection system?

Guys, hoping you can help me out here. I have a nice '99 Road King Classic with EFI. It runs great, but has issues starting when the ambient temp is low (around 40F or colder) and also hot-start issues after a short heat soak.

In both cases, the symptoms are the same: the engine cranks, tries to fire, and dies. Upon re-crank, the engine fires and usually 'kicks back' with a puff of smoke out the air cleaner. Re-cranking again will basically cause the engine to just crank and crank without firing. Cracking the throttle open while cranking usually gets it running, but no other way.

So I've contacted Zippers, and they tell me there are two options: a full conversion which includes a new intake manifold and ECM, or just a ThundMax module which replaces the stock ECM but also includes two new O2 sensors, which I'd have to drill and weld bungs into the exhaust for.

Just the module is $899. The whole changeover is $2095.

Thoughts?

Apr 10, 2017 | 02:41 PM

0ldhippie

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From: Santa Cruz

There is also switching over to carb which is what must folks do. There are few folks out there who are any good with mm injection any more and parts are hard to come by, but they are out there. It is a pretty simple system. Sometimes a good cleaning will get it working again, always worth a try. Otherwise if ya are set on staying fi the thundermax is a good option unless ya can get a used '02-'06 setup for a dime. Good luck.

Apr 10, 2017 | 02:47 PM

troverman

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From: NH

I've thought about the carb option, but even that is not cheap or simple. I think I'd have as much money into that conversion as buying the ThunderMax setup.

Obviously, EFI has advantages over carb when working properly.

Apr 10, 2017 | 08:29 PM

OlAndrew

Road Captain

Joined: Mar 2016

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From: Dewey, Arizona 86327

Might wanna try a new engine temp sensor. Those are known to go bad over time and lead to weird symptoms. Your problem sounds temperature related, so it seems likely? Sensor is about $45 if I remember correctly.

Apr 10, 2017 | 08:39 PM

Road Star

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From: Orange County

Quote:

Originally Posted by troverman

I understand your concerns. I did the carb conversion and it is not going to cost you $900. After selling my old parts, I was only about $300 into it.
On the other hand, I wish I had a dependable FI system. If the bike is a long-time keeper, go for the upgrade. Otherwise, take the $1000 or $2000 and upgrade the whole bike. You can get the newer frame and good fuel injection and not have to worry. Except when it comes to upgrades, then you gotta Dyno it, there's another $500- $600.
With all the crap I went through with my bike this weekend, I'm thinking about just buying a new Road Glide or Low Rider S.
Or, maybe just win one!

Last edited by Road Star; Apr 10, 2017 at 08:43 PM.

Apr 11, 2017 | 06:43 AM

troverman

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From: NH

I've thought about buying a brand new Road King, but I actually am fairly attached to my old bike. I'll probably tinker with it and just keep it.

Apr 11, 2017 | 11:24 AM

xcbullet

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Joined: May 2015

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From: mid Michigan

I'm running power commander 3 . Just searched on eBay there is one for $25

08 HARLEY DAVIDSON TOURING POWER COMMANDER 3 PCIII USB DYNOJET *BAD*
$24.95FAST 'N FREE
That's junk but there is one for 84$ for your bike
http://m.ebay.com/itm/00-01-02-03-Ha...%257Ciid%253A7

Mine is a USB which is the better one for that year. If you can find one

Last edited by xcbullet; Apr 11, 2017 at 11:33 AM.