Strange...Cam Sensor 180 degrees out

[87gninpa]

Sorry for the length, just want to explain the situation. Did the timing chain in my GN about 5-6 years (and 30,000 or so) miles ago. Had no problems, car has always run great. A few months ago I picked up a bone stock WE4 and ever since I got the car I noticed something was way different between the two. The GN only has basic upgrades (pump, injectors, TT chip, etc) but seems way slower than the WE4 from a stop and off idle, very sluggish. At boost, the GN easily outperforms the WE4. The tune on the car is perfect, BLM good, idles and runs 100%.

With nothing else to check, figured Id check the cam sensor as Ive heard they can be installed 180 degrees out. Put the enigne to 25 deg ATDC on the compression stroke and sure enough, it was 180 degrees out! Been that way for 5 years or so. Took the sensor out, reset it and the car started right up and runs great. However, its exactly the same as before. It runs the same set correctly as it did 180 out. Car runs good and I get 17 psi on 93 octane with no knock so Im not worried about anything, but why did it run so well when the sensor was 180 out and now there no change with it set correctly? Just curious so figured Id ask. Also figured it might help someone in the future questioning how the car would run with the sensor set improperly.

 

[TurboBuRick]

Could be a slew of things but if numbers look good then I would look for air restriction like a plugged cat converter or even a flat cam.

 

[EVIL]

i didn't think these cars could run if the cam sensor was 180 degrees out?
Mine would not even star once until i realized i installed wrong and fixed it.

D

 

[TurboBuRick]

i didn't think these cars could run if the cam sensor was 180 degrees out?
Mine would not even star once until i realized i installed wrong and fixed it.

D

They will run 180 out but you usually have a killer off idle stumble. FFT

 

[87gninpa]

No cat on the car and cam should be good (good vacuum & all rockers move equally when enigne is turned over).

The car will definitely run with the senor 180 out, never had an idle issue, stumble, etc. Very strange. Car runs great, just doesnt feel as strong as the stock WE4 until I get into boost.

 

[challengermike]

They will run 180 out but you usually have a killer off idle stumble. FFT

My car does sometimes stumbles off idle.does it affect performance also?I have always thought it should be alittle quicker.You have me thinking mine may be 180 out.

 

[TurboGN86]

i have taken mine and turned in 180 both ways set it with cam tool and had some performance both ways... never though to ask why. lol

 

[87gninpa]

Very easy to check Mike, worth a shot. Take the #1 plug out and put your finger over the hole. Rotate the engine by the alternator nut until you feel a puff of air from the hole. This ensures you are on the compression stroke. Once you do, rotate the engine until 25 degrees after the notch in the balancer is lined up with the 0 mark on the timing pointer. Take the cap off of the sensor and the window should be facing the drivers side headlight. If its facing the throttle body then its 180 degrees out. Only take 10 minutes and its worth a check.

Drove the car a bit more tonight and it runs about the same. Idles great, no stumbling at all, vaccum holds rock steady at 18 in. at idle in park. 17 PSI of boost with 0 knock @ WOT in 3rd gear, O2's around 780. Maybe there really is nothing wrong and my other car is one of those factory freaks that just feels stronger. Was really hoping some kind of improvement when setting the sensor properly. Just proof I guess that it can be 180 degrees out and you might never notice it.

 

[87gninpa]

i have taken mine and turned in 180 both ways set it with cam tool and had some performance both ways... never though to ask why. lol

Would certainly explain my situation, guess nothings wrong and Im just paranoid.

 

[Just a Six??]

i have taken mine and turned in 180 both ways set it with cam tool and had some performance both ways... never though to ask why. lol

When it's 180 out it runs in Batch mode. here is some good info from Steve Woods site.
Basics Cam Sensor

 

[RmvBfrFlght]

When it's 180 out it runs in Batch mode.

Actually it will still be running in SFI mode. Just that the injector will start to spray prior to the exhaust stroke instead of prior to the intake stroke.

RemoveBeforeFlight

 

[TurboBuRick]

When it's 180 out it runs in Batch mode.

When 180 out it will still be sequential. It fires the injectors on the wrong stroke.

From Steve's site: If the sensor is installed 180 degrees out (as if you were not on top dead center, but were one crank revolution out), then the fuel will be sprayed on the exhaust stroke rather than the intake stroke and the engine will idle badly, and generally not run well at all.

 

[TurboBuRick]

Actually it will still be running in SFI mode. Just that the injector will start to spray prior to the exhaust stroke instead of prior to the intake stroke.

RemoveBeforeFlight

Thanks RBF, I was typing when you were posting.

 

[87gninpa]

When 180 out it will still be sequential. It fires the injectors on the wrong stroke.

From Steve's site: If the sensor is installed 180 degrees out (as if you were not on top dead center, but were one crank revolution out), then the fuel will be sprayed on the exhaust stroke rather than the intake stroke and the engine will idle badly, and generally not run well at all.

I read that many times on Steve's site as well. Just dont understand how it runs the same now that its correct. Never idled badly and ran great. Passed emissions every year in PA as well.