Main ECU Connector Contamination...

I have been experiencing some rough idling and some surging at speed and found out the Corroded Wire Harness Connector may have been the culprit. After cleaning the Connector, for the second time in a year, my idling & surging has subsided.

Be Carefull and don't use a wire brush while the battery is connected, CAREFUL this connector is HOT/Electrically speaking and may Short something out. After some cleaning, I took some silicone and sealed the wire sides of the connector to reduce moisture from entering.

This is the largest connector about 3" wide by the triple tree as pointed out below.



The arrow points out where most of the corrosion was found in the female connection.



The arrow points out where most of the corrosion was found in the male connection.



I just found a wiring diagram



and it appears that the 2 High Voltage Coils (one for #1 & #4)(one for #2 & #3) pins in the Wiring Harness sit right next to each other with no Isolation. Thus any dirt/corrosion causes a leak path(shorting) between the pins causing Irregular/Intermittent poor running conditions. (These 2 pins sit tooooo close to each other with the voltages involved)

I cleaned them last night and......

I did a run tonight and it is SMOOOOTH as silk with no Surging/More Even Power throughut the RPM Range and a Smoother idle.

Can't wait to see how the Gas mileage is with a full tank.....it has been between 28-32 mpg with this unsolved condition.

Let me know if anyone else uses this fix with their results. This is something the Mechanics will probably Never Diagnose....at least mine didn't.

Just thought if you are having some wierd problems, this may be something to look at.

I've been living with my 2004 having an occasional miss at idle for some time and think this thread ought to be given a bump for all the new folks.

Found the same corrosion in the same connector. Attached are a couple of more photos. Cleaned as much as possible with a dental pick and contact cleaner, then packed both ends of each pin with dielectric grease to keep the water out and slow new corrosion. Runs like a champ now!

Location of the connector under the gas tank:



The evil corrosion:



Thanks to 03HiYoSilver for finding this and the original thread!

Bob

Good info, Thanks.

I treated all of my connectors (or as many as I could find) with this:

ACF 50

I put in on, in, and around with a Q Tip. Especially the back of the connectors. Also treated the insides of all the bulb sockets as there was corrosion starting there too.

I would be carefull of silicone as some of it is very corrosive. I believe there is an elecrical grade just for this type of application. Silicone grease is also good though.

Excelllent stuff. I am sure there are others.

Your are Welcome Bob & S76!

Glad it helped you out. I have had my bike in to the shop multiple times with 3 5-Star mechanics and not one saw this or fixed it. This is one item that is often overlooked by most shops and not on their Radar for inspection.

This little maintenance can solve many headaches and Mysterious Problems.

Anyone found the location of this connector on Gen II bikes?

It is NOT in the vicinity of the triple tree on my '07.

03HiYoSilver,

WOW! this thread popped up just as I started noticing a kind of "WA WA WA" surging while trying to mantaining speed. along with an occasional sputtering. I read this thread and tried the fix and certianly that was the problem. the corrosion was not bad but it was clearly the problem.

Kevin,

I am tickled this solved your problems... these connectors can cause sooo much havoc just under the Radar and Won't Code. All it takes is soooo little corrosion to interupt the slightest of voltages. Even many 5-Star mechanics don't know or acknowledge such a situation (or even listen to me).

So when things get a little intermittent, off I go to the connectors first before anything else.

Glad it worked for you!

The Honda GL1200 had a problem with burned out stators because of corrosion in a gang connector where high-voltage passed through, moisture got in, corrosion caused resistance which caused more heat. Rinse and repeat. Eventually the stator would burn up and lead to costly repairs. The trick was to (once or twice a year), pull and clean the connectors and pack them with dielectric grease.

Some hard-wired the connectors (soldering them) to bypass the butt connectors and the mechanical contact problems. I found that including the PM step 1 or 2 times a year worked fine and left me with the option to disconnect either side if the need ever came up.

See, Its just this sort forthright magnanamous chit thats makes this forum so damn good ! Thanks HiYo ! My bike lives outside...covered but still....and this thread will save me when Zig wont Zag !

Blessings,

Bobby

03HiYoSilver said:

Kevin,
I am tickled this solved your problems... these connectors can cause sooo much havoc just under the Radar and Won't Code. All it takes is soooo little corrosion to interupt the slightest of voltages. Even many 5-Star mechanics don't know or acknowledge such a situation (or even listen to me).

So when things get a little intermittent, off I go to the connectors first before anything else.

Glad it worked for you!

Click to expand...

Silver, can you say more about exactly how you cleaned it out? Here's why I ask. What tools and techniques did you use? Do I need to disconnect the battery for sure? Is an ice pick useful at all? :blink:

03, Same as yours! Took mine apart tonight and found some. Pic's not too clear, but you can see it. Found it in 2 connectors.

James,

I used a small steel brush, BUT make sure you don't touch the adjacent contacts to avoid shorting. I did not feel like disconnecting the battery which would be best.

As Checkwrecks stated above: "Cleaned as much as possible with a dental pick and contact cleaner, then packed both ends of each pin with dielectric grease to keep the water out and slow new corrosion." would also work.

I think an Ice Pick would be too large to get into the small holes of the connector.

Hope this helps and let us know how it worked out.

so any idea where it is on the GENII? worth a look for me

Aww hell I'm just being lazy, I'll find it on the GenII and post some pictures

I found this post yesterday searching for the same symptoms as everybody else, surging and stumbling at between 2500-3000 RPM when just tooling along. It had just started doing it last week. Last night I lifted the tank and sure enough found the same corrosion. I trimmed one of my wifes emery boards down to fit in the connector to avoid shorting anything (thanks for the heads up), packed it with dielectric grease and WHOO HOO! What a difference.

Thanks to 03HiYoSilver for the discovery. Can you imagine the dealer finding this problem?

Peter_MA said:

...Can you imagine the dealer finding this problem?

Click to expand...

Yes! If they'd become members of this community!

Peter,

Glad this was able to help you out!

It is amazing how much intermittent problems the connectors can create... and the little buggers won't throw a code either.

Many more Happy Miles & Smiles to ya....

I tried to find the said connector and couldn't pick it out but I did not take the t-bar off and it looks from the pictures that is where it hides. My 05 surges much more than I would like.

DailyCommuter said:

so any idea where it is on the GENII? worth a look for me
Aww hell I'm just being lazy, I'll find it on the GenII and post some pictures

Click to expand...

I've got an 08 with a miss that's getting worse so I thought I'd have a look. I found the connector on the left side behind the side plastic, tucked between the water hoses that go to what I think is the thermostat. Pull on the harness and it'll come out from between the hoses. Then just pull back the black rubber cover and there's the connector.

There was a liitle white powery residue but nothing like in the previous pics. I cleaned it up best I could, squirted some dielectric grease in the connector and hoped for the best. No fix, :glare: still missing. Next?

08FJR,

Sorry to hear about your problems...how many miles on your bike and did you make any changes recently?

The GenII series has different Connector Issues that may be your problem as discussed here:

https://www.fjrforum.com/forum//index.php?s...13632&st=20

Hope this helps....