Wow...cam sensor caused this

ThikStik

My sleep apnea is winning
Joined
Mar 27, 2002
Ive been chasing a tip in stumble , and low end balk. I can get a timing light and watch the timing jumping up..jerking around. I have a code that says timing hi/low...i think code 24. It happens after motor is warmed up. I have tried everything and today just disconnected cam sensor after engine was running....symptoms went away. I never knew a cam sensor could do this, and also figured it worked or failed totally. now , gotta wonder where to find one.
 
A vendor of the site sells rebuild kits or send it up to them an they'll rebuild it for you.
 
Oh cool....I know that all i need is the cap as theres no play in the rotor. Thanks...anyone know what vender it tis?
 
Scot W is who you are looking for (GNS performance). I highly doubt its just the cap though...Send him your complete unit and he will send you back a working unit. Great guy to deal with.

Bryan
 
Thanks Bryan...thing is , i still thought the cam sensor just controlled fuel inj pulse ....dont understand why timing is jerking around. I cant find the sticky thats supposed to describe the CS
 
check your crank sensor bracket to see if it's allowing the crank sensor to wobble. check the balancer to make sure it's tight and not wobbling and check the reluctor ring to make sure it's not making contact with the crank sensor.
 
Earl, Did try everything you mentioned except tightening damper. Also changed crank sensor. I dont see that damper is walking...but it is original part and had alot of detonation in its lifetime...so, maybe so?. Does anyone know how to find sticky thread regarding cam sensor? Thanks
 
Thanks Bryan...thing is , i still thought the cam sensor just controlled fuel inj pulse ....dont understand why timing is jerking around. I cant find the sticky thats supposed to describe the CS
DO YOU HAVE ROLLER CAM?I had a missing problem on my car hard to start and what it ended up was the cam sensor gear had knife edged due to not enough end play but the inj pulse out of time and ran like shit .thanks to Tom Robinson and Kevin B or i would probably still be chasing that one
 
Helped diagnose one engine that had just enough play in the timing chain that at about 2000 rpm it would jump out of the cam sensor window and then back in, so the timing was jumping 120 deg and making it stumble. Fixed it by setting the cam sensor to the spec and then rotating it another 1/8" or so (but don't ask which way :)).
 
i had an issue recently and replaced the cam sensor cap. Mine was breaking up at WOT, but not all the time. It like your issue came on with heat. If you have unplugged it and the issue went away then it looks like the cap. You took one thing out of the equation and its better, that's where I'd start. I got a new one from Tomco # 22008 for about $50. It's no fancy led one but an identical to the factory one. Good luck!
 
DO YOU HAVE ROLLER CAM?I had a missing problem on my car hard to start and what it ended up was the cam sensor gear had knife edged due to not enough end play but the inj pulse out of time and ran like shit .thanks to Tom Robinson and Kevin B or i would probably still be chasing that one
Yes, i do. Ill pull it and see...only thing...problem seems like it should be in the cap (hall effect switch) as it happens after warming up. Thanks.
 
Carl...your saying timing on damper was moving 120*?!!! jeez. Josh, thanks for that info....i feel like my problem is now backed up and will buy a cap.
 
Sorry to hijack, but I've heard "tip in stumble" a lot. What the hell is it?
 
No problem...Tip in stumble is simply when you push throttle just alittle past idle, it balks.
 
I wish i could find the sticky on the cam sensor. I had always figured it synced the ecm to the inj during starting and just did this once. So two things I need to understand are how often/much is it used to sync inj, and how can it cause my timing to vary if it doesnt have an igntion controlling purpose.
 
I'll tell you what I know.

the ignition module re-syncs on every cam pulse, if you are getting cam pulses close to the edge of the proper timing, the module can sync to the wrong cylinder and then sync back. That would put the ignition 120 degrees out of time, not something you would see well on a timing light. The ECM syncs on every cam pulse (I think) but on an improper cam pulse may re-initialize the ignition module which would revert it to base timing (10* BTDC) momentarily. (this is a guess though).

I recommend you pull the whole cam sensor out and replace it. Then re-time it "by the book"

Bob
 
Carl...your saying timing on damper was moving 120*?!!! jeez. Josh, thanks for that info....i feel like my problem is now backed up and will buy a cap.
Yes, with the timing light you would see a series of flashes with the timing mark-timing tab relationship where it should have been, about 20 deg btdc, then it would flash once with the timing mark way around from the tab, then back to normal, etc. I eyeballed the "way around" as about 1/3 of the way, so 120 deg which meant the next cam sensor window. Like Bob said, if the cam sensor pulses are there the ecm resyncs every pulse. If you unplug the cam sensor so the pulses stop the ecm just keeps going with the last resync, so if unplugging the cam sensor fixes a problem the problem is either in the cam sensor pickup, sensor position (timing chain, gear teeth, disc loose, bad bearings, or set wrong), the cam sensor processing circuitry in the ignition module (had a bad module once that made me think the sensor was bad, sigh), the ecm, or the wiring. I probably forgot at least one possibility, but that's a good start.
 
Interesting...so the CS is referenced by ECM after car starts. Thats great to know, and i dont understand why so may say this isnt the case...oh well. Ill buy a sensor. Thanks guys
 
the timing of the cam sensor is not measured or used, it simply allows the ECM to know which crank sensor pulse is which. The synchronization of this and control of the ignition module bypass and timing signals is controlled by a custom circuit in the ECM, so I don't know its internal logic.

in any case, it sounds like yours is flaky or adjusted at the edge of its allowable timing window.

Bob
 
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