crank and cam position terouble codes

L

Lawrence Mackey

Guest
On my '95 Riviera, trouble codes indicate problems with the crank and cam position sensors.
Buick dealer diagnosis indicated problem possibilities are cam sensor, crank sensor, timing chain, cam magnet, harmonic balancer, or wiring harness. Dealer wanted $1500.plus dollars to repair. I didn't want to spend big bucks on this car, so I did the repairs myself in my spare time over a two month period. I replaced everything mentioned above except the wiring harness, which I examined visually and it looked ok. The end result, (after a lot of hard work), was the problem was not fixed. The same trouble codes are still there, and the engine runs the same as it did before the repairs,(starts ok but stumbles a little under certain load conditions).
I'm told thats because its running in "open loop" mode due to no cam signal being present. I just had it diagnosed at a different Buick dealer who came up with the exact same diagnosis as the first dealer, (the replacement of all of the parts that I already replaced). Somehow I think
something is being overlooked. Anybody have any suggestions? :confused:
 
Remove the cam sensor and eyeball through the hole while jogging the engine. There is a magnet in a plastic mount in the camshaft sprocket. The plastic mount breaks and the magnet flys out. You then loose the cam signal. The ECM then sees the loss of the signal and changes the fuel injector control to a guessed value. When running with the magnet missing a fault code 41 is present. The car will want to lug due to timing of the injectors. The magnet can be replaced with epoxy or by tearing down the front of the engine. Replacement of the magnet is easiest by cutting a hole in the fender well and remembering the position of the frame member. The hole in the timing chain cover can then be viewed straight on. Serpentine belt, ECM cover, water pump pulley and washer reservoir must all be removed. Several web sites show this procedure.
 
Problem fixed! I took a chance and bought a used computer box (powertrain control module) at my local junk yard. It's just a 5 minute job to replace it and all the problems are gone. Two different Buick dealers and two independant repair shops all had the diagnosis all wrong. Either they were all trying to rip me off, or they all don't know how to diagnose problems. And based on what they all said, I did a lot of unnessery work myself. Well, anyway, it's fixed now. Hallalooya!
 
I can see you are happy Lawrence, but you don't have to post the same post twice for that reason! :D
don't worry pal I fixed that for ya!
 
seems to me that the dealer was out for the big bucks. how could they say it might me the crank sensor when the code read cam sensor.
 
This is where you try to repair the symptoms and not the root cause.
They needed to test for the signal to & from the computer. :confused:
 
You must log in or register to reply here.
Back
Top