i have a 99 road king police bike with a tc88 and the m&m injection system. i had new cams and jugs put on and the updated cam plate installed and now im throwing the 42 engine code (cam position sensor) and its hard starting. if i reset the code and start the bike it will throw the code as soon as you blip the throttle. i took the crank sensor and cam sensor out and cleaned both to no avail. im wondering if there is a way to test the sensor before i go out and buy one. i have unplugged and cleaned the connector underneath the bike that the sensors plug into. i was wondering if there is a way to check voltages at the plug. i really dont want to probe the wires. is it possible that the updated cam plate would read wrong with the old cam sensor seeing as how the new models dont have cam sensors. what do the cam\crank sensors control? does anyone have a schematic on them and what they control? the bike runs fine once it starts and the engine lite will randomly go out while cruising.

 

I'm guessing that when you updated the cam plate you replaced the large rear cam gear with one that didn't have the cam timing lip on it (came in the kit). The old gear has a raised lip that was 180 degrees of the gear and it passed through the sensor in the cam cover. If you install a new gear (flat) without that timing ridge, you get exactly what you have going on. You can verify by pulling the cam sensor and rotating the crank.

In MM systems the cam gear is used to tell the ECM engine phase. In Delphi systems, the ECM knows it by slowdown of the crank on compression combined with reluctor teeth on flywheel.

 

excellent information. This is exactly what I was looking for. I will pull the cam sensor and rotate the engine and verify that's what's happening. Do they make the correct gear for the updated cam plate to use with the m&m injection?

 

No - you wind up using the old gears and chain.

 

Just pulled the timing cover and pulled the sensor. The gear does have a raised trigger on it about 2 inches long. Now I'm back to square one. Is there a way to test the sensors (crank/cam) with a multimeter?

 

The connector that you cleaned was known for the 12V supply crossing into the sensors. Did you spray cleaner into it and blow it out with compressed air? A factory recommended repair was to remove the 12V feed from that connector and connect it separately.

 

I did clean the connector with contact cleaner and applied dielectric grease to the connection. I did find that the 12 v line and the crank sensor had been rubbed through to the frame so I cleaned the bare wires and applied some black tape. But that didn't help. So I should re-route the 12v feed away from the sensor harness? How common is it for the sensor to just simply fail? I can't seem to find anybody that has ran a test on the cam sensor. To me it seems like if the sensor was totally bad the bike would not fun.

 

I replaced mine as Preventive Maintenance at 100,000 miles (along with several other pieces parts just because I didn't want to be screwing around with a problem 2 years down the road.) That has worked so far for me and I travel many miles from home still to this day even at 150,000 miles on it.

If I were in your shoes and it said that the sensor had failed, I'd get a new one. (Hell, the bike's 16 years old!)

 

Seems like there should be a way to test the sensor at the plug. I wish I had a diagram of the plug and what wire is what color at the plug. I'd like to rule out the sensor first before I go chasing bad wiring

 

Is there a way to use a piggy back or new ecm to ignore the cam sensor?