[ajaxn47]

I have a EFI 2002 Road King, TWIN CAM 88. At just under 6k it started to develop an intermittent miss. I have tried troubleshooting it for about 200 miles and 95% of the time it runs great but it decides to miss occassionaly at any rpm, speed, hot or cold. I have replaced plugs, wires, and even the intank fuel filter, been all over the wiring harness looking for shorts or loose connections and found nothing. The dealership can't work me in for a month. Service tech says it is unlikely that the problem would be with the ignition module or sensor. Anybody have any ideas?

 

[HIPPO]

What modifications on the bike? Security system? Does the engine lite come on even temporarily?


Might be hard to find, generally it's best to get a sensor value readout with the digital technician.

Some of the easy stuff to try is to make sure the battery cables are tight, as well as all the chassis grounds and ECM and sensor grounds. It is best to undo them and clean them before retightening them.

 

[ajaxn47]

re. missing 2002 road king

Thanks, The bike has no mods but it does have the security system dealer installed. I checked the battery cables and they were clean and tight. I felt that if the problem existed in a loose connection or short that it would become worse when I went over uneven pavement or rough surfaces but that has no effect on it. When the miss does happen I can accelerate and the bike runs fine. The local dealer has it now as a "walk-in" and it is not on his schedule. If he can't get to it by the weekend I may go in a pick it up. I hope the diagnostic equipment detects the problem.

 

[HIPPO]

When the miss does happen I can accelerate and the bike runs fine

If it were a Marelli bike one would suspect the TPS with this symphtom, could be it still holds true for a Delphi bike.
The DigiTech is a great tool, but it is only as good as the guy running it. Good luck.

What rpm range are you talking about?

 

[ajaxn47]

Thanks Hippo, The miss can happen at any RPM range or under any load conditions. The dealership called today and said the sensors and module were fine. They said that I needed a new higher intake (free flow) and to complete a new "download". My mufflers were low restriction and the intake needed to be increased? I am confused. I never heard of decreased exhaust back pressure causing an intermittent miss but I told them to conduct the necessary work. I pick the bike up Saturday. I am skeptical but will wait for the road test. I'll let you know how it turns out.

 

[HIPPO]

Well, low restriction mufflers is not the same as no mods. It might be possible that the bike may have been marginally lean at times and if this is the case a stage 1 reflash would probably help.

Since the reflash is intended for the SE intake kit it sort of makes sense that they would want to add it.

It's only money.

 

[ajaxn47]

I hear ya hippo! Yes, I didn't mention the mufflers because I didn't understand what diferrence the exhaust back pressure made. Seems these bikes have intake and output tuned to the point that the dealership needs to make the installs? This bike ran fine with the low restriction mufflers for some time and I just overlooked them when considering "cause and effect". You're right "only money" but if it gets rid of the miss and protects my warranty I will gladly pay for the intake and download. You seem pretty knowledgeable. I wish I had talked with you earlier! Thanks!

 

[ajaxn47]

Hippo, I picked up the bike from the dealer today. They installed the Stage 1 intake and did the download but the miss stilled occured. Upon further diagnosis the technician detected an intake leak. I did not get to talk with the tech but the service manager stated that although it was rare a "seal" could leak. I assume he meant intake manifold seal. Anyway, the miss is gone and she runs fine. I don't run my bike hard so maybe it is just my style of riding but I can't detect any appreciable difference with the Stage 1 intake in the way the bike runs. With the Twin cam 88 EFI I would have to say the Stage 1 intake is a nominal improvement. The dealership did a fine job however and I am pleased to have it running without the miss so the money, in my case, was well worth it.

 

[HIPPO]

Good to see you have a much sunnier disposition then the "does not play well with others" Hippo.
While the cause was a lean misfire as we suspected, the "upon further diagnosis" generally doesn't go over to well with me.

At least in this case you got the intake kit and the reflash for your money.