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EFI Engine Surge

OK. I understand the carburetor thing now. I just read it wrong this morning. Also, ignore my comment about cleaning the MAP sensor. It was early and I was thinking Ford (MAF sensor) not Harley. Glad you caught that I made a mistake and didn't spend a bunch of time on it.

Still, the fact that unplugging the O2 sensors does not set a code or warning seems mighty strange to me. Does anybody else have an '06 that does this? Maybe it's normal for that model and year. It could be a firmware problem that doesn't affect performance.

You say the problem starts after you've driven about 1.5 miles as 25 MPH. If you started up the engine and immediately moved out, it seems to me that would be about the time that the engine would reach temperature and the EFI would try to go into closed loop mode and would be using the O2 and other sensors as input.

Anybody: Is there a way to know that the EFI is in open loop or closed loop mode? In a car, with a good OBD2 program running on a lap top, you can tell what mode you're in. We're badly in need of something like that for this problem. It would be awful nice to know if the O2 sensors are part of the problem or just a red herring.

A couple other thoughts:
See if there's some way to test the injectors for pattern and flow rate. Maybe one of the injectors is failing when it gets hot.

I read something the other day about getting the injector connectors mixed up. I don't remember what the symptoms were, just that you have to be careful to get it right.

Before you decide that it's the computer and spend a bunch of money, ring out the connections between the various sensors and the ECU just to make sure that it's not a bad connection giving the ECU bad information. It's probably a fruitless exercise but it might just save you some money.

klinkcol (is that Colonel Klink inside out and backwards?) where are you located? I'd sure like to look through that Maintenance and Electrical manual to see what kind of details it has for the EFI system. Once upon a time (you know, that's how fairy tales begin) I had to become an expert on the Bosh K-Jetronic Fuel system so I could teach a VW dealer how it was supposed to work. No firmware in those days though. It was all hardware.
 
TQ, I did not pull the speed sensor out. I did remove the Crank Position Sensor and it was clean. Fuel pressure was checked by HD. I went for a 20 mile ride at higher RPM’s in all gears to include full throttle applications to the rev limiter and the bike ran fine, but still hade some RPM fluctuation at steady throttle. Then next time I run the bike, I will open up the fuel cap and listen for any hissing noise. I have a full tank and will also check when the low fuel light comes on. Thanks.

Burt, Concur with the O2 sensors. My next step is to disconnect the aft O2 sensor and check to see if there is 5V when the bike is running after the engine is at operating temperatures. I plan on getting TTS Master Tuner or HD Race Tuner. I believe both can loge data that will allow me to trouble shoot this problem and hopefully solve this issue. Testing the injectors flow rate will be a later step. I do have the 8 deg (smaller) Injectors, but never had cold start problems and the bike ran fine for 32,000 miles with the exception of some small RPM fluctuation at steady throttle and HD said no problem existed. The injector wiring is correct. I checked resistance for all ECU wires with the exception of the idle control solenoid. One thing to note, is on the electrical diagnostic manual for the 06 DYNA, one of the schematic pages has the aft O2 sensor wire where the front one should be and the same with the front, but believe this schematic not correct seeing the bike ran fine for many miles.

Thoughts: Computer is sensing the engine it is running rich or calling for lower than required fuel at about 2300 RPM’s low engine loads and leans the engine out. This causes the drop in RPM’s and starts the RPM fluctuation. The problem continues to escalate until the bike is not drivable. The computer stays in this mode until the bike cools down. This could be caused by a number of thing, but too many to start replacing.

It is COLONEL KLINK. “COLONEL” is an old call sign, not a rank. Currently in the Jacksonville FL area.
 
klinkcol said:
SNIP
I do have the 8 deg (smaller) Injectors, but never had cold start problems and the bike ran fine for 32,000 miles with the exception of some small RPM fluctuation at steady throttle and HD said no problem existed.
SNIP
Click to expand...

This comment makes it seem like you really have had the problem all along. It's just gotten worse now as whatever part is causing it dies.

I'm stuck now. Your plan to get a tuner that can log what is happening seems the best course of action at this point. Of course, I'm still on my first cup of coffee and I'm not quite back in my body.

Have a look at this link. There's not a lot there but maybe you can call them.
http://www.technoresearch.com/Products/Direct-Link/Direct-Link.htm

Here's another type of scanner to look at. It works with a PC to display what is happening.

Daytona Sensors LLC - Twin Scan 88 Low Cost Scan Tool

I'm thinking about getting it myself just cause it looks so slick.
 
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bfmitch said:
Here's another type of scanner to look at. It works with a PC to display what is happening.

Daytona Sensors LLC - Twin Scan 88 Low Cost Scan Tool

I'm thinking about getting it myself just cause it looks so slick.
Click to expand...

Got one. Great little tool. The one I have is the old style that gets its power from the bike. The new version (can up-grade your old ones for a few pesos) is USB and takes its power from the laptop. It will record while riding if you are trying to debug an intermittent problem (which NEVER happen when you are trying to find them!). Lets you read and clear the codes without trying to decipher what the bike is saying in flashing at you or reading out on the radio.

TQ
 
Thanks guys. I think the Twin Scan 88 is the way to go. I prefer to do the work myself instead of dropping $100 to HD not including getting the bike there and back home. I plan on checking for fuel leaks in the tank and O2 voltage this weekend. Will let you know what I find out.
 
Problem solved. On the plug that connects to the throttle position sensor, One of the Three pins was loosely connected to the wire.

Problem: While driving the bike at low throttle and low engine load settings (25MPH in second gear) steady throttle, RPM would drop, just like closing out the throttle or turning the engine kill switch off and then back on. This would worsen throughout all RPM ranges, and require adding some throttle to keep the bike from stalling at idle.

My final drive back to the HD Dealer, the check engine light came on and stayed on with an associated code. Told the Dealer I believe it was the throttle position sensor issue. The code that came on was throttle position sensor. The dealer replaced all three pins. The bike is now running, but still has a slight RPM flux at steady throttle. Hopefully I will get another 35K before the next major issue.

Thoughts: Should have done a wiggle test when checking the pins and wires. Replacing the spark plugs the first time did not fix the problem but remember moving the connector to the throttle position sensor because it was coming in contact with the rear cylinder heat fin. This issue could have been identified using a Daytona Sensor Twin Scan II, TSS Master Tune, or Screaming Eagle Race Tuner.

History of warrantee issues fixed by the dealer: Two transmission main shaft bearings, front isolation mount (motor mount), front fender crack, front heat shield crack, numerous front brake master cylinder leaks around the top gasket.
 
Was the connector terminal poorly crimped to the wire or was it that the male and female terminals didn't fit together well?

Never mind. I just saw the answer.

Have you replaced the handlebars? I'm wondering if the crimp may have gone bad while pulling the harness out of the old handlebars.

Anyway. Glad you got it fixed.
 
my 06 heritage does the same thing. I was thinking it was an injector problem but when I took it to the dealer they sprayed carb cleaner around the head gasket area and the bike almost stalled out. ended up being rear cylinder head gasket was blown.
 
Good troubleshooting technique to find head gasket leak. But better to use WD40 or some oily solvent that will not attack paint (carb cleaner will remove engine paint whether black or silver) JMO.
 
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