Posting this on behalf of a friend that is a shop owner, pro engine builder and pro tuner with a dyno. We are baffled as to what is happening.

2009 Trike, new 117 kit, Redshift 575 cam, HPI tb, Freedom exhaust duals with Reinhart mufflers. Customer bike.

Tuning with PV, widebands.

Bike drops front cylinder when rev'd with no load (or loaded) at 3K RPM. Data logs show spark and injector pulses at these conditions, but cylinder drops out causing a huge hole at that RPM. Really messes with the tuning process.

Have tried disconnecting MAP sensor and then it can hit 3K without dropping. Suspect MAP sensor?, new one on order. Have tried 4 different maps from dynojet; same. Tuner has calibrator mode and IVO/IVC have been set.

Wondering about ECM, intermittent connection somewhere, exhaust length. May try different pipe if MAP sensor and temp sensor don't work. MAP load has been played with. Reversion tables have been played with, no diff.

Any idea what the heck is going on?

 

 

Unknown Bob. When I got there he was street tuning at that point.

 

I'd be more interested in the MAP read when it cuts out. Reason I say this is that it apparently fuels when the MAP sensor is disconnected. It could be a situation where the MAP sensor read is so off, the actual map doesn't recognize it - for instance reading well over 100 kPa. I doubt at 3,000 it is dropping low, but since the MAP reading will directly affect fueling, it needs to be looked at.

It sounds like the parts shotgun is coming out. If the bike ran well stock, I doubt that replacing things - including temp sensor and talking about the ECM - is going to help. How is a temp sensor read going to be off at only 3,000 - it isn't.

I would look at the MAP reading when the cut out occurs. At 3,000 it is highly doubtful the injectors will be at 40ms on the pulse width which would indicate tail biting. If they were, the injectors would be seriously mis-matched to the build. Also tell us what the injector pulse width is and the spark advance. For poops and grins tell us the temp read - I believe you will find it doesn't change as it goes through that range. I would always verify connections, but if the problem goes away when disconnecting the MAP that' s telling you something. Plus - looking at the data stream will tell you if something is flaking out. How did you diagnose a bad MAP and TEMP sensor?

These are things your friend the professional tuner and engine builder should know.

 

MAP is around 30kpa, pulsewidth as he recalls is around 8ms - this is with no load, just rev to 3K. Bike has 6.3gm/sec injectors and the map was setup for them. Temp read was 250ish.

 

 

Thanks Ed, that sets a direction for us to follow. Any idea if CDE is having an impact here? The exhaust on the trikes is quite lengthy. The last time the bike was run was with the stock 103 config and since it is now a 117 there is a lot more vacuum going on.