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cam sensor light on newish stroker

Posted: November 4th, 2008, 3:18 pm
by Lightfoot
Hey everyone,
I put a stroker in my jeep a few months back and ive got about 500 mile on it, but ive had this problem since i put it in, and im hoping to fix it. First here is what ive got: the jeep is a 99 cherokee with just under 200k on it. The engine i believe is from a 95 wrangler. its a 4.6, with a comp cam, larger valves and a few other mods, including 24lb ford injectors. I did not build it but it was done by a reputable shop. My problem is that I keep getting a cam position sensor check engine light. I believe the code was odb11 po178. I have tried unplugging my battery, and resetting everything, but it comes back on within a few miles. I have also put a second sensor in it to see if that was the problem, and nothing changed. I have read that you sometimes have to adjust the timing according to the cam setup, and i was wondering if that might be my problem. Here are my cam specs if i helps at all.

part# 68-232
grind: a6 x4 250h-13
intake exhaust
valve adjustment: .0000 .0000
gross valve lift .462 .478
duration@ .006 tappet lift 250 256
valve timing open@ .050 open closed
INT. 13 btdc 56abdc
EXH. 62bbdc 13atdc

specs for cam installed: @110.0 intake centerline
intake exhaust
duration@ .050 206 212
lobe lift .2890 .2990
lobe separation 113.0

The engine seems to run well, doesnt knock as far as i can tell, and my plugs look decent, but im getting poor milage. like 12-15 highway.
Any idea what could be causing my issue?
is there any chance my relocation of the coil could have caused this?
Thanks for all the help
~lightfoot

Re: cam sensor light on newish stroker

Posted: November 4th, 2008, 6:14 pm
by SilverXJ
How does the gear on the cam and distributor look?

Re: cam sensor light on newish stroker

Posted: November 4th, 2008, 8:18 pm
by seanyb505
Thats about the mileage I got with mine for the first 1000 miles or so. It picked up from there. I had to cut the ears off my distributor to even get the engine to fire due to the cam positioning sensor.

Re: cam sensor light on newish stroker

Posted: November 5th, 2008, 12:57 pm
by Lightfoot
The gear looks good, I think its new actually. I am beginning to suspect i need to trim my ears and rotate a little bit. From what i gather this does not do anything on a stock engine because the sensor compensates for it, but with a different cam, i might be a bit outside of what it can compensate for. How can I figure out where is the best spot to lock it down? Can you use a timing light on these engines to effectively figure it out? Most of my experience is on way old trucks, like 50-60's, so this is new to me. Thanks a bunch
Lightfoot

Re: cam sensor light on newish stroker

Posted: November 5th, 2008, 2:05 pm
by SilverXJ
http://www.angelfire.com/my/fan/dist_index.html probably the best write up on how to do it.

-Chris

Re: cam sensor light on newish stroker

Posted: November 5th, 2008, 6:02 pm
by dwg86
Doesn't the cam sesor tell the injectors when to fire, and the crank positon sensor tell when to spark?

Re: cam sensor light on newish stroker

Posted: November 5th, 2008, 6:20 pm
by SilverXJ
On the later vehicles the cam sensor predominately controls the fuel synch. Don't know on the earlier systems.

Re: cam sensor light on newish stroker

Posted: November 5th, 2008, 6:26 pm
by Lightfoot
Alright, so I actually used that page to index my distributor the first time, and it has to be close to correct because the engine runs pretty well. I was just thinking that maybe the cam/ distributor gears were off by a few degrees or something. Ive been doing some serious searching of the internet for about 2 hours and after this, and realizing that the code is actually po340, not 178 ( not sure where that came from), :doh: it turns out that it is more likely a problem with my wiring harness, a ground, or the alternator. It also has little to do with timing at all, and like both you said about me, its all about the fuel sysem. hopefully i can get it sorted out. Thanks for the push in the right direction