Cam Position Sensor - Code 42

[forgetaboutit]

Carbed 2000 Dyna, Still an 88, Andrews 21, Supertrap 2into1. Tensioners, 07 cam plate and bearings 2 years, 10,000 miles ago. 40 on the clock now, bought used as a bone stock  garage queen at 6K. Ride fairly aggressively between 3K and 4K rpm.

About 3 tanks ago, switched to 89 octane to save some cash. Never heard any pining.  Also picked up a set of refreshed 06 heads. Waiting on some new adjustable push rods and thought I would put 4oz of Seafoam in the gas to "clean things up" before opening her up. That tank is done and now on a fresh tank.

Hickuped a few times recently, ignored as it is a carbed bike. Yesterday she hickuped and I noticed the check engine light flashed. A few minutes it came on and stayed on. Shut her down for a few minutes then fired back up, light went out and retuned home. On the way flashed and a hiccup one more time.

Question – Is this all a hell of a coincidence? Did I do this with the gas and seafoam? Is there any way to clean the sensor or is it toast for sure? Don't want to spend the money if I don't have to but also don't want to get stranded somewhere either.

[Hossamania]

Check for vacuum leaks. It could also be a dirty or bad MAP (mass airflow) sensor.

[cheech]

Question – Is this all a hell of a coincidence? Did I do this with the gas and seafoam? Is there any way to clean the sensor or is it toast for sure? Don't want to spend the money if I don't have to but also don't want to get stranded somewhere either.

Yes it is. No way Seafoam or lower octane fuel tainted your cam position sensor.

[cheech]

Should also mention that a flag pops up in my mind.

You do the cam work yourself?
If you have a 07 up plate. What rear cam sprocket you using?
None of the stock roller chain setup 07 up used a CMP sensor therefor has no raised "rib" for the sensor to read.
Daytona Twin Tec for those years and as far as I know most other aftermarket carb ignitions don't utilize the CMP.
You didn't mention if your bike has stock or aftermarket ignition.

[forgetaboutit]

The bike does have a CMP - I used the Andrews sprocket with the raised rib. Stock ignition. Ben in there for about 2 years, other than this, the bike has always run like a champ.

I'll follow the trouble shoot tree best I can, I don't have a break out box. I'll also check / clean the MAP as well.

[rigidthumper]

Those sensors typically last less than 20 years. If it were mine, I'd pull it and see if it has shavings- if so, pop the cam cover off and inspect contents. If not, replace the sensor.

[forgetaboutit]

Rigid, the bike looks and runs so good I sometimes forget it is 20 years old. I have changed everything rubber including motor mounts and belt (PIA). This winter I did the swing arm bearings / bushings, she was getting a little twitchy and that fixed it.

[cheech]

Well Rigid covered the debris on the sensor.
Btw, wasn't the factory rev limit 5500?
If in budget I'd consider aftermarket ignition module.
21's are lower end but you'd be able to wring it out more. 
So if anything there's that and the CMP you could forgetaboutit 

[smoserx1]

Daytona Twin Tec for those years and as far as I know most other aftermarket carb ignitions don't utilize the CMP.

Even the superseded factory modules don't utilize the CMP anymore.  The original module PN was 32478-99.  If a replacement module is  32478-99A, B, or C it won't use the CMP sensor and will ignore it if it is still there.  Seeing how you can pick one of these up for about $100 used and the replacement CMP is about $67  that is what I would do (or go aftermarket).  The original module in my 99 FLHT died at about 114K.  During its life I got the 42 code several times for no explainable reason.  Some say the CMP sensors have a bad reputation for reliability.  It is nice to know you can get rid of it.

[forgetaboutit]

Cheech, what do you mean about "21s" -yes I would very much like to forgetaboutit

Cheech and smoserx1 changing to a later module seems like a good idea. However, is this where the mileage is stored? If yes, how do I a) reprogram a used one if one can be found -  or would I have to live with whatever mileage is in there? And b) would an aftermarket ECM be able to be set to my current mileage? Finally, any recommendations on a specific module?

[Coyote]

You don't have to worry about your mileage. It's in the speedo.

[forgetaboutit]

Sweet –

One more question. If I continue to ride with this one that is acting up and it completely fails will I be stranded or just get a permanent engine light?

[Coyote]

Sweet –
If I continue to ride with this one that is acting up and it completely fails will I be stranded

Depends on if you have AAA. 

[forgetaboutit]

You're killing me

[cheech]

Cheech, what do you mean about "21s" -yes I would very much like to forgetaboutit

Cheech and smoserx1 changing to a later module seems like a good idea. However, is this where the mileage is stored? If yes, how do I a) reprogram a used one if one can be found -  or would I have to live with whatever mileage is in there? And b) would an aftermarket ECM be able to be set to my current mileage? Finally, any recommendations on a specific module?

21's  Your cams.
Read up on this: http://www.daytona-twintec.com/tc88twincamignition.aspx
I'm partial to their ignition products myself.
Various ignition curves, adjustable rev limiter, doesn't utilize the CMP.

[smoserx1]

If you want to try cleaning the cam sensor it is located under the round "timing" cover on the nose of the cam cover and removed with a single bolt once the round cover is removed.  You might want to pick up an o-ring pn 11288 first.  Be careful with the tiny screws holding that round cover on, they strip fairly easily.  No need to remove the entire cam cover for this.

[forgetaboutit]

Cheech – good reading. Right now an new one is a little rich for me – the Wuhan Virus has me a little short of cash. I am going to look for a good deal on a used ECM.

smoserx1 – I cleaned it already, took a chance on the O ring and it seems OK for now.

[smoserx1]

smoserx1 – I cleaned it already, took a chance on the O ring and it seems OK for now.

Ok, well you asked if a totally failed CMP will leave you stranded?  I can't say for sure but the way I understood it was if the CMP totally failed that original ECM would revert to a wasted spark mode of operation (it would fire on compression and exhaust strokes) and the check engine light would stay on all the time.  I also heard there would be a 50/50 chance of the bike starting and that would seem to imply it was still operating in single fire mode and assuming the first crank position trigger was the compression stroke), but either way it would seem you would not get stranded.  Another thing that used to happen to me when my original starter clutch started getting  worn it would slip sometimes (making that dreaded grinding noise) and that would sometimes trigger that other code (56 I believe, the one about the timing of the crank and cam sensors).  I got that occasionally with the old ECM.  When that original ECM died and I replaced it with the 32478-99A version I never got a cam sensor code again.  Years later I was replacing the Deutch connector housings under the bike where all the engine sensors connect and decided to just leave the cam sensor wires unplugged.  It ran fine ever since.  I too had already installed Andrews 21N cams and had paid extra for that special Andrews sprocket with the ridge in it, and in retrospect I never needed it.

[forgetaboutit]

Thanks, that gives me a little breathing room, I am on the hunt for a good deal on a used module. I agree that if I had known this when I did the cam and all I would have changed the ECM them.

To all who responded, I appreciate the help and respect the knowledge.

[forgetaboutit]

Finishing up this conversation, I found a simple fix . . . . just pulled the bulb from the spedo  – Kidding 

What I really did is take the advice from Smoserx1 and picked up an "A" module off of flea-bay for $97. Worked out quite well, I can sell my old module now, there is nothing wrong with it, should be able to get 40 or so.

After installation, I checked the new one for codes prior to starting the bike, it was clean. Started right up, I went out for about a hundred miles today, she is back to her old self.

Now I can truly forgetaboutit – Thanks to all, great site!!

[Pirsch Fire Wagon]

The only thing the older (2001 and before) used the CMP was for initial Sync on Start-Up - Not used after that. Any hicup or backwards-motion on the CMP Magnet sets the code (42). Your issue is probably elsewhere. Intake leak, carb seal, etc. Propane on and around the intake will identify if that's the issue.

One thing about "cleaning the out" with Seafoam and the other snake oil out there is, Often over a period of time grime and such accumulates and seals where gaskets and other surfaces begin to deteriorate. When it's cleaned it can expose failure points upsetting the atmospheric balance.

Best bet is always to remove, disassemble, sonic clean and reassemble with new on Carbs. Other than that they are VERY dependable and trouble free. And very cost effective over time.