Crazy ignition skip under load

[Frosty Rider]

I have been chasing this gremlin for awhile, no not the car, bike starts and runs fine, but when I put the engine under load, (hard throttle to put a Vrod or other Harley back in its place) the cuts out for a fraction of a second, and it will do it multiple times, but doesn't seem to happen in the gears like 4th and 5th, but its harder to get the engine under load at those speeds. so far I have done,

- battery is good, no power issues
- The bike has RamAir, and full Jardine exhaust with CAT delete installed
- Using Hanso tune for this setup, I have been using this tune for about 8-years with no issues, it actually gave me 130HP and 140Tq at the back wheel.
- TPS has been changed and it setup correctly, as well as the other sensor, don't remember the name of it Secondary sensor maybe? the one at the front of the throttle bodies.
- Vacuum hoses on the throttle bodies are good, no cracks or leaks
- Throttle bodies have been synced
- Scorpio alarm system has been completely removed, just because it was driving me nuts
- Auto Tune and Power Commander V was all removed, figured it was possible that they might be throwing some bad values.
- Connectors on the coils have been crimped and are tight
- Spark plug leads have been changed (they were new, but came from one of the early engine kits that dealers would get, waaaaaay back, so they were about 15 -20 years old when I got them)
- New spark plugs, and the gap was checked and set correctly on all of them
- Valve clearances were checked and any that were out were fixed, Cam chain and guides were replaced at the same time.
- the SEC I think it is has been disabled through Tune ECU
- Reinstalled the Hanso tune, and ran the 12-minute adaptation (original tune is no good to use due to the intake and exhaust mods)
- On deceleration there will be back firing, I think it is more than usual, and the exhaust connection joints have been tightened and sealed, pull the clutch in and the back firing stops.

I thought it might have something to do with timing being off, but that would be consistent and noticeable through all the gears and at start up, and the bike starts, idles, and runs fine if you don't push it. The other thought is that possibly the spark plugs leads or just one of them had degraded due to how long they sat, got them and a ton of other new parts from Triple Trouble, but not sure how they were stored through all that time. Possibly I have coil that is finally saying enough is enough and I'm not putting up with your crap anymore, but it if is one lead or coil I'm not sure how to track down which one, and it is about $1000 to replace the 3 coils and six leads all at once, but I may end up doing that anyway.

I have gone through a number of threads, but can't find something that falls along this line of trouble, so I'm looking for further clues, or something I might have missed or not thought of. I have the GT to play with, but it is nice to tear around on the Touring once in awhile I miss riding it running correctly, it does incredible burn outs. I have been leaning toward leads or coil, since on a few of my cars if one of those was bad, it was run fine if you were driving normal, but when you stepped on the gas to get up and go, you would get a miss in the engine just like on the bike.

 

[atomsplitter]

Rev limiter???????????

 

[Sparky59]

Coil , Ht lead, or my bet, is coil stak-on leads are now loose on coil terminals...

 

[Jhortz]

I'm having a similar issue and have been slowly working on it. I have seen one post where the issue was the fuel filter (sorry, I can't find it again) so that might be worth a shot, you seem to have chased all the other potential causes pretty well. I'll let you know if I ever find the issue.
You're also going to get a lot of people just throwing ideas off the top of their head at you here, some of them will speak with tremendous certainty too so be careful. Look for posts that actually explain why the person explains their reasoning for their suggestion, that's my advice anyway.

 

[Tripps]

I had a bad coil, sounds similar, and I double checked all leads and connections. Replaced the coils and never had another problem

 

[atomsplitter]

If it's fuel, a pressure gauge will determine pump output pressure, however it won't tell you if the filter is starving it under load. The ignition coil would be another area; I had one go out on my 99 Trophy 1200 and that failure wouldn't even let it start.

 

[R-III-R Turbo]

How do you know it's ignition cutting out?

And when did this start? Need to know if anything or anyone was at the bike, service works etc.

 

[TURBO200R4]

If it's fuel, a pressure gauge will determine pump output pressure, however it won't tell you if the filter is starving it under load. The ignition coil would be another area; I had one go out on my 99 Trophy 1200 and that failure wouldn't even let it start.

i am going to do some guessing on this one jmo
if you installed a pressure gauge then you could read the amount of pressure when it started then after you drove it a while and it gets hot to see
if it has lost pressure because of bad pump or filter is plugged up.
on a car you can put the pedal on the floor and actually run it out of gas and it will no longer shift gears because the motor will no longer gain enough rpms to shift.
hth