Rough Idle with cam

[fontana]

I found this on the other board about how the cam sensor really works. It's the best explanation I've read...it even has pictures I'm surprised that this kind of tech hasn't made it to the gnttype website...very informative.

http://www.turbobuicks.com/forums/showthread.php?t=17681

Wayne

 

[Spl170s]

i didn't install mine or set it. the car was built by a well known buick perf shop in florida.

having the 206 setup i am sure the cam sensor is tweaked in....but maybe not quit enough.

Could this also cause some knock if it is out a little?

 

[litdog83z]

I had a rough idle, a hesitation, and knock at WOT too, and the car ran great otherwise, drove fine, pulled hard until 7-8 psi of boost and then started knocking like crazy..

turned out my cam sensor was in 180 out... car would crank ok, and fire and idle ok, but still a little rough.. finally got a new cam sensor cap to swap my cracked one out and found it 180 out and fixed it and it ran great after that... still leaves some to be desired on the idle, but that's probably something to do with my ignition missing

 

[QUIP'6']

mine did the same the sensor was 180 out

 

[Morkai]

Sensor 180 out

Would the car still run good WOT, and pull hard all the way past 20# if it were 180 out? I've tried about everything, mine idles like it's down a cyl and cuts off a lot. I even put the old stock injectors back in thinking the 50's were my problem. The only thing I haven't replaced or checked would be the underside of the intake gasket for leaks.

 

[corsair231]

Are you sure there are no vaccuum leaks? A manifold may leak under suction causing a lean idle but when driving it is not as evident and boost may even make it go rich. Have you put a scan tool on it? Fuel pressure set correctly? Too much lifter preload can cause a rough idle as well. There is a good article about the importance of correct preload on the comp cams website. Because of too much preload mine idled so rough that it would shake the car. Since you are using a roller cam I am assuming that you have adjustable roller rockers as well which will make it easy to check/adjust. For the stock non-adjustable valvetrain you have to get different length pushrods. Concerning the coil pack. There is a discussion on this site about stock coils and the type II coils. One of the post claims that the stock type coils miss a lot at idle and the type II does not. He said that you can check it with a timing light to verify this.

 

[QUIP'6']

Would the car still run good WOT, and pull hard all the way past 20# if it were 180 out? I've tried about everything, mine idles like it's down a cyl and cuts off a lot. I even put the old stock injectors back in thinking the 50's were my problem. The only thing I haven't replaced or checked would be the underside of the intake gasket for leaks.

my car still ran awesome at wot it just idled for crap and had a tip in stumble try caspers new cam sensor top its adjustable with a light built in

 

[DonnieShort]

is there a common direction the wires coming out of the top of the cam senor point? my cam sensor is pointing the wires toward the passenger side of the motor .... buddies is pointed toward the drivers side. Does this matter...or is the orientation of the cam sensor different for all cars? sorry to sound stupid....trying to understand this.

The wires should be pointing to the driver's side like your friends, sounds like it could be 180º out.

 

[Morkai]

sensor

Well, I checked mine again, took #1 out and turned it over and lined it up. I could 'feel' the piston was at the top and my window was pointing towards the dr.side front corner.

Now I lost one of the stupid screws to it somewhere. Who's bright idea was to make them out of some metal that won't stick to a magnet.