Camshaft sensor for 2001 496
 

Does any one out there have any old stock merc #881666

is this a specific requirement?

The sensor is the same on a 2000 chevy 2500 with the 8100 vortech.

I know but no dealer around here has one

I'm pretty sure I've got a couple of them Dennis. I'll take a look in the morning.

That would be great thank you

Rockauto.com

Should be off the same vehicle mentioned before and you will have it in a couple days. Usually great prices.

They are all gone GM done away with them and there is a post about it. There is only one place left that has them. I have not tested them. All the new cam sensors will not work for 2001 thru 2004 or 2005 GM autos, trucks, RV's and so on , Along with none for the marine side as well, it was the same sensor that the auto / truck side used. Mercruiser, Volvo, PCM, Indmar. None If you have one for the 2001 thru 2005 496, it is an old one left on the shelf.

Read page 4 and 5 from the link below it will explain what is needed to use the new cam sensor.

http://www.offshoreonly.com/forums/g...0-400-rpm.html


496HO: would IAC cause this? 1 engine lagging intermittently lagging 100-400 RPM

I've got one if you still need it. give me a call, 604-315-0570

I had a issue with the cam sensor 05 496, you can use a newer style; if you cut the mounting boss down on timing cover. You will have to measure with depth mic and subtract difference from pick-up .040- .060 air gap, if I recall. my original air-gap was about .120. this created a night-mare. Engine was a 8.1 modified and a Whipple 3.3. No fault codes, tach would jump with engine miss only at certain rpms. Engine would temporarily lose sequence of TDC, then pick it up next 360 degrees, chased my ass thinking I was losing crank signal. Brought air-gap with-in spec. ran perfect.

Merc PCM 555 with software prior to level 091that has a problem and or bad crank & cam position sensor will not set a fault.

With level 091 software if the camshaft position sensor is completely bad or has bad circuit in which causes a signal not to be sent to the PCM, the engine will backfire and not start, if this happens stop cranking and try to start again. keep trying to restart. If the engine does start and two beeps from the audio warning takes place asap it can be more than likely be a bad bad cam PS. It should set a fault code if you can run the motor for 30 seconds straight..

Good information. The only time it gave a fault code; was if the sensor was disconnected. At that point; engine ran in batch fire and wasted spark.

Could you please tell me how you made out if you received the old cam PS (the one NLA). Did it fix your problem for your 2001 - 496 Mercruiser ? Also I have my cam sensors now for the older apps, I have 3 different ones that is suppose to take care of all the NLA ones.

My problem now is I have to match them up with what reluctor is on the cam gear. This thru Merc went by engine serial numbers. GM / Merc changed the cam gear reluctor 5 times thru out the years. 2001 is different than 2002 and another change in 2004 came about then 2 more down the road I believe. The cam sensor has to match or it will not work properly.

Anyways I am still digging and will test them this winter if weather and lake levels permit. Cost as of now for the cam PS are 100 bucks each, the 3 rd one totally different than any of them is 149 bucks. Again these are all NLA. cam PS for all the early 496's.

John, I ended up buying three NOS off of eBay. They are in my toolbox just in case. I can't remember if you posted or texted me the resistance specs. I'd like to test them if you still have this info.

Will add a tech that I know in Wisconsin just did the whole conversion with the lastest cam gear, timing cover, gasket, cam sensor and it still will not start. Our thinking is cam sensor can not read what ever reluctor is on the newest cam gear. He is going to swamp out cam gear to see what happens - maybe try the second newest cam gear / reluctor combo before this latest one by GM.

http://www.ebay.com/itm/151386523590...84.m1497.l2649

I got them from him for $95 each.

Brian its posted up here. Also the NOS ones will work for certain serial runs for the Mercruiser apps only. That's why I have to test mine out to work accordlingly to whatever the cam reluctor is in the Merc app for that year model.. I do have the pics of the different cam gear / reluctors used by GM / Mercruiser. The problem is which cam sensor work 100 % correctly with which style of cam / reluctor. That's the problem and that's why I have 3 different ones (cam PS) to work accordingly. I am doing this all on my own.

Brian here is the specs just in case. since I know them off the top of my head. also added the Crankshaft Position Sensor as well.

The normal resistance values is posted below for temps at 70 degrees. This is important because were ever you are testing these values, . try to get as close to that temp - 70 degrees - inside your house or if outside permits close to that temp. We had others test these around here outside with temps of 115 degrees and the sensor values were off so they thought they were bad.

CAM PS - A to B 24.04 mohms and B to C 24.05 mohms

Crankshaft PS - A to B 23.20 mohms and B to C 23.21 mohms

Thanks for the link. I just took a $99 gamble this will work for my 9/03 built 496.

Ebay says last one - and again it will only work 100 % correctly for certain mercruiser engine serial runs. When I figure out mine as well it will include free shipping for 100 bucks but again the 3 rd one will be 149. It is totally different than these.

You wont have to take the gamble and my price is the same for the correct sensor to work for the correct app.

I guess I wasn't following you on that you had some replacements in the works. My bad. It will be nice if you end up with plug and play replacements based on serial number.

The gamble is the crank and cam position sensors supply the PCM with inputs for the correct timing and RPM information. So again it is very important to have all of this correct before going in. That's why I will not sell any to I figure out what sensor will read 100 % correctly to the reluctor that the cam gear has.

IMO not worth 99 dollar risk for the 496 especially with cast internals. The correct timing depending on rpm is very important here thru out. I will post more info about this.

Also it would be very wise to scan your motor if fact you changed out the cam PS with one of these NOS to see if your engine is going into knock mode and or how many times per running. If that's the case wrong Cam PS for sure or a real problem with knock or bad gas / low octane or knock sensor problem of some sort. Good luck.