Low Idle

I have had my scoot dyno tuned twice and each time they told me they had tweaked the cold idle due to it idling low...and I have tweaked the warm idle. But it seems that it lasts only a few days then it's back to a low idle at startup...by low I am saying from 500-750. Any ideas on why this could be happening? TC88...M-M EFI...PC-III with custom map from the dyno tune. Once she warms up she seems to be ok....just replaced the plugs this weekend.

Is it a Delphi or MM unit?

I had the same problem on my RK. There is a temp sensor that sometimes fail and the TPS sometimes has to be reset. Not all dealers have it figured out.

Originally Posted by GrayRider

Is it a Delphi or MM unit?

I had the same problem on my RK. There is a temp sensor that sometimes fail and the TPS sometimes has to be reset. Not all dealers have it figured out.

MM..............

[chnpostal]

Originally Posted by BigAlsRK

TC88...M-M EFI...PC-III with custom map from the dyno tune. Once she warms up she seems to be ok....just replaced the plugs this weekend.

Originally Posted by GrayRider

Is it a Delphi or MM unit?

Skimmer............

[rk custom]

Originally Posted by chnpostal

Skimmer............

busted

[chnpostal]

BigAL........here's a cut & paste from a cut & paste I did before....."over yonder"..........I was just waiting for you to post up here in the good tech forum


Most of this was from hdforums.com in the "do it yourself" section. I'm just going to cut and paste the instructions with modifications and some tips afterwards. If you have a good digital voltmeter that can read millivolts, it might be best to start from scratch. And resetting the ECM by pulling the fuses is a must.....it has to re-learn the idles after you've adjusted them.


Quote:

the pre-2002 fuel injected bikes, the ones with the M&M fuel injection systems. I am not a tech., in any way, shape or form but I am very interested in having my bikes run well. This procedure is what Harley is now teaching in its courses and it works great.

1. Park the ISC fully extended, then unplug, with the motor cold.
2. Set the TPS at .25-.30 with both idle screws out. (275mv is optimum)
3. Screw the hot idle into .52-.54 range.(530mv is optimum)
4. Screw the cold idle into .64-.68 range.(660mv is optimum)
5. Pull the two idle fuses for 10-15 minutes, to reset readings, and plug them back in.
That's It!!!

This really works well and it only takes a few minutes. It ensures that the TPS is set right, which is a pre-requisite for proper idle setting. Good luck.

You'll have to pull the connector on the TPS first and slip a small single strand wire into the right side pin then plug it back in (in order to read voltage). Don't let it short out to ground, and take your positive readings from there. Negative goes to any good ground on bike. Just be sure that the bike goes through the startup cycle before you pull the ISC plug (check engine light goes out). When setting the cold idle, you'll have to turn the throttle to get at the screw. Do not let it snap back, it can move the ISC out of position. When you remove the 5 and 15 amp fuses, to make sure that the ECM bleeds down and resets, hook a wire from the cold side of the 5 amp fuse socket (the one with 0 volts on it) to ground and wait 30 minutes instead of 15 (just to be sure). After you're done and have plugged the ISC back in, before you start it, cycle it through (let the engine light go out) about 4-5 times watching the ISC extend and retract. It should always stop in about the same place. When you crank it, the engine should go to cold idle and start stepping down as it warms up. After it's warm, the hot idle will probably be too high (mine was). Best thing to do is use a tach, clamp on or otherwise, and turn the hot idle to 1000 rpm's. Bike should then be good to go.

Be careful with the TPS, it is very touchy, and it only takes a tiny movement to adjust. It's probably going to move on you when you tighten the torx on it.

You might want to clean out the butterfly and intake before you start. If there's any gunk in there, it can hold the butterfly open and mess up your settings. Also, make sure that the throttle cables have some slack in them, they can bind and throw everything off as well.

You'll probably have to redo the PCIII zero throttle procedure to get it back in sync too.

CN......... great post... I dont have a MM but do work on a lot of bikes....

this goes into my stash of fixes...


thanks

Mikuni







































just sayin'.....

Alcohol.....then you wont care...

[Xkvator]

jus' keep blippin'...

[ridingjerry]

Agree with above.


You need to be riding, not idling.