[Blockhead97]

Today I was out for a short ride to pick up some stuff about 25 miles up a highway, while on the highway doin about 75mph I felt a miss but I blamed it on my wrist on the throtle. On the way back I experienced the same thing on the hwy., again shrugged it off as nothing.
I get on the surface streets heading back to the house, while sitting at a light and as it turns green I take off. Not all out, but enough to get ahead of traffic to change lanes. Well... This is where I got freaked out. While rolling up the throttle, and changing lanes the engine makes a loud crack and the system seems to shut off for less than a second. I eased off the throttle out of shock, look at my gauges (Electraglide) and I see my engine idiot light on red.
I kept on going to get home with no other events, but now I am really concerned that there is something wrong and about to go bad.

The bike is a 1997 EFI FLHTCI with a stage II upgrade.

This has got me shook up to the point I want to take it in and have it looked at, but I am looking for any comments that might help me when I take it to the shop.

[cowboy]

sound's like it could be a loose or chaped wire , just hit's a bare spot & shorts out for a split second & back to running , double check under your seat , or any place you might have taken a part off of tank/ faring front

[chucktx]

your service manual will give you instructions on how to retreve codes from your bike.....follow them and see if there is a problem.....also what cowboy said!!!!......let us know!!..........

[Blockhead97]

Ok, I took the advise about the loose electrical conections. Good one, since I didn't think about that and it made sence. But...
Well I did the same trip up the hwy and I'm accelerating and my engine does the same thing as described before, but since being aware of something maybe goin on with the bike I now can describe things better.
What I thought was a miss, is actually the EFI backfiring but with out the bang. It sounds like a loud sneeze, and then the engine cuts out bad then regains normal running. This has happened while doing 25, 40, and 85mph.

I'm concerned now, since everyone talks badly about my version of EFI. Mine has always been problem free, but now I'm wondering if my honeymoon is over with my MM EFI.

Any ideas?

[Tomflhrci98]

I would keep looking at connectors and electrical condition. Take your side covers off and check and recheck all electrical connections there. Open up the nose cone and look for dirt or debris that might affect the cam position sensor. Follow that wire back to its connector on the frame by the trans. Idle the bike and do a wiggle test on all these wires. I am always suspicious of the crank position sensor everytime I remove my oil filter since I have to push on it hard to get the filter wrench in there. Wiggle that one while its running and follow that wire back to it's connector too. If you haven't changed plug wires it is definitely time to do that. Don't forget the injector connectors and coil connector. Sometimes when you take those off (like they had to do to change injectors for the stage II upgrade) the steel wire clip gets lost and someone may not have put it back on. Intermittent problems are a bitch so have patience.

What else... thinking thinking... Oh yeah, buy a manual it will show the whole wire harness. Also, change the fuel filter, that's a pain in the ars to do and no one ever does it, but it might help. Thump the fuel relay with your finger while it's idling, Maybe that's the intermittent problem or just buy a new one. (those last two where long shots. They would feel like it just ran out of gas I think)

Good luck.

[Lucifer]

If you have the service manual see what fault code comes up. It'll give you a direction to go. If you don't, order one and while waiting for it double check the electrical, make sure battery cables make good contact and the grounds are solid.I'm leaning towards an electrical problem, because with FI and sensors thats where most of the problems are. If the MM system was doing fine for 10 yrs,why would it intermittently stop??My guess is loss of elect contact or a sensor.
Good luck , hope your fix was as easy as mine.(Electrical)

[Blockhead97]

Well I spent half the day this last weekend diggin into everything on the scoot, hoping to find a loose or broken wire but I found nothing of the sort around the engine.
This is where I am perplexed... I did find out that my wire harness for the rear tail lights were corroded and loose, jiggled them while the bike was at idle and no miss in the firing. Just that my tail lights were flickering everytime I moved the main plug.
I had to clipp and strip them, then had to crimp & solder them to new spade/clip connectors. I shrink tubed them for added protection as well, so now the tail light harness is solid and no more flickers in the lighting.
The next day I took a couple hundred mile ride, and whaddaya know no more interuptions in the engine.
I am thinking I must have "fixed" the problem while moving and making sure all of the EFI connections were tight, but I am wondering if my tail light harness problem could have been the culprit? Could a short in the tail light harness cause my EFI to go haywire?

[skull2007]

god only knows when it come to efi, i'm having the same problem. i'll be looking at the same thing tomorrow

[chucktx]

i would say no. the tail lights have there own circuit......but i guess stranger things have happened!!!!
case in point.....about 40 yrs ago, was working on a cab over peterbuilt with a v12 detroit in it. cab was tilted full over and i am working on the tail lights. i have a 12v source in my hand trying to trace a short. i touched the 12v to the tail light wire and the engine started!!!!!! bout crapped my pants!!!! harness was rubbed by the starter and the tail wire was on the solonoid. im glad no one was working on the engine, or truck in gear!!!!!!!!!
found the short!!!!!!!!!!!!11

[VYBR8ER]

There are 2 things that I would check after I found out what that engine fault code is, with a chuff out the intake when you are trying to accelerate there is a good chance that you might have an intake leak. Another thing that will drive you batty is the temp sensor which when going bad will give you the symtoms that you mentioned. There is nothing bad about having a Mag-Mar injection system, they just require some tuning once in a while. If you haven't had the hot and cold idles set up properly I'd have it looked into once you fix the temp sensor. Most people are scared of the Mag-Mar system because they don't understand it. Find a tech that isn't afraid and they can make it sing!

[Blockhead97]

Well, as a recomendation I had the bike serviced by a local indi to check the wiring under the rear fender and check for fault codes. Happy to have found that the wiring was fixed correctly by the stealer, and after that the mechanic checked for fault codes - None found...
I guess with me pushing on the injector plugs, and all other connections on the EFI unit fixed a ill fitted connection? I did spray carb cleaner down the throat while it was running may have added to the "fix", although the throat was very clean to begin with so I dunno...
I think it it happens again I will pull the EFI out and fit new manifold seals, and put new O-rings in the injector ports? Since I did spray cleaner on those, I am thinking I may have clogged up a dry spot leak? The bike did sit a few years, so I am thinking that may be my next thing to do it it starts up again with the coughing.