Question about 4.7 engine?
#1
10-13-2010 | 07:13 PM
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Question about 4.7 engine?
Does anybody know what would happen (how would it run) if the 4.7 engine had the wrong right cam sprocket in it?
Today I took my vehicle to the dealer to get a p1391 problem looked at? Well we scoped both the cam and crank sensor and both have a good signal to the pcm. So we put a new pcm in and that didn't fix the problem? But we could adjust when the miss happened by putting different size spacers inbetween the cam and head. But once we disconnected the cam sensor everything ran good. The engine sounds like it has chain slap could this cause the light and miss to happen. And once pass the miss the engine runs good.
Today I took my vehicle to the dealer to get a p1391 problem looked at? Well we scoped both the cam and crank sensor and both have a good signal to the pcm. So we put a new pcm in and that didn't fix the problem? But we could adjust when the miss happened by putting different size spacers inbetween the cam and head. But once we disconnected the cam sensor everything ran good. The engine sounds like it has chain slap could this cause the light and miss to happen. And once pass the miss the engine runs good.
Last edited by ljhopp; 10-13-2010 at 08:52 PM.
#2
10-14-2010 | 06:05 AM
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From: South GA
Didnt you have sensor issues in the past or so you thought? Werent they crank and cam sensors? As for the wrong cam pulley? I dont know that there are after market pulleys and the only reason someone would use them would normally be to advance or retard the cams/timing.
Is this 4.7 bought from a junk truck or yours its whole life?
Is this 4.7 bought from a junk truck or yours its whole life?
#3
10-14-2010 | 09:56 AM
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We ruled the cam and cranks sensors out because we put a scope on the sensors and everything looked good going to pcm. I had a new pcm so I put the new pcm in to rule out the pcm. The problem still happened so, we then disconnected the cam sensor once the engine was running and the problem went away. So the dealer mechanic thinks the cam tone wheel may be the wrong one which is causing this problem happen.
I just looked up what would happen if the wrong came tone wheel was installed and the results said you would get a no start. So I think the cam tone wheel is correct.
Could a loose tensioner cause the cam and crank not to sync because the cam tone wheel is allowed to move a bit. So then the holes on the cam tone wheel and crank tone wheel aren't aligning up correctly so it then causes the engine to act up. Now once the engine is up and running we can discconnect the cam sensor and the problem goes away because it no longer is seeing cam tone wheel is out of sync with the crank tone wheel. My engine also sounds like it has chain slap.
If the timing has jumped a tooth would the engine still run normal once the cam sensor is disconnected?
I just looked up what would happen if the wrong came tone wheel was installed and the results said you would get a no start. So I think the cam tone wheel is correct.
Could a loose tensioner cause the cam and crank not to sync because the cam tone wheel is allowed to move a bit. So then the holes on the cam tone wheel and crank tone wheel aren't aligning up correctly so it then causes the engine to act up. Now once the engine is up and running we can discconnect the cam sensor and the problem goes away because it no longer is seeing cam tone wheel is out of sync with the crank tone wheel. My engine also sounds like it has chain slap.
If the timing has jumped a tooth would the engine still run normal once the cam sensor is disconnected?