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Addaam 09-22-2011 04:50 PM

Rebuilt 4.7...Will not idle
Hey guys. First time posting here but have been coming here awhile, really good site. I have recently purchased a '99 grand cherokee limited with the 4.7. It had a spun bearing so I pulled it out and replaced the crank, main and rod bearings, number 8 rod and piston and some timing components that had worn out. Got every thing back together and now I'm having a idle problem. When I first go to start it it will fire right up and attempt to idle for 5-10 sec or so then die. If you go to restart it you have to apply throttle to get it going and you have to keep it above 1000rpm's or it will die. Also the plugs on the passenger side bank are completely covered in soot while the drivers side look brand new. I'm assuming this is a sensor problem but I am out of ideas. So far I have replaced all the spark plugs, the iac, and the crankshaft position sensor. Oh and compression is good, timing is good and fuel pressure seems to check out. So dose anybody have advice, I could really use some help, thanks.

FlyinRyan 09-22-2011 04:56 PM

Re: Rebuilt 4.7...Will not idle
Stupid question but hows the battery? Dead batterys do all sorts of weird stuff on these.

Addaam 09-22-2011 08:02 PM

Re: Rebuilt 4.7...Will not idle
I just replaced the battery last month so as far as I know its fine. I keep meaning to check it just to do it though.

FlyinRyan 09-22-2011 08:04 PM

Re: Rebuilt 4.7...Will not idle
camshaft position sensor?

Addaam 09-22-2011 09:51 PM

Re: Rebuilt 4.7...Will not idle
That was on the list of sensors to replace, just hated buying a bunch of sensors without knowing exactly what is going on but what can you do I guess. Earlier though I was out looking at somethings when I noticed I had left my o2 sensor disconnected (after that cat), would that have anything to do with my rich condition?

FlyinRyan 09-22-2011 10:33 PM

Re: Rebuilt 4.7...Will not idle
O2s will do it...especially precat or upstream. downstream not so sure

2005JGC 09-23-2011 02:22 AM

Re: Rebuilt 4.7...Will not idle
It really sounds like you may be off a tooth on your timing. I would pop your valve covers off and verify.

Ultimately a sensor failure should throw a code if you have run it for 30 seconds give or take, and a sensor that is killing the engine should throw a code if its so out of whack the motor cannot keep running.

Addaam 09-25-2011 11:54 AM

Re: Rebuilt 4.7...Will not idle
I kept thinking it was slightly out of time but I've checked it three times, looks good. I wish it would throw a code, at least give me a place to start.

Scottina06 09-25-2011 01:01 PM

Re: Rebuilt 4.7...Will not idle
sounds like a timing issue to me

Frango100 09-25-2011 02:23 PM

Re: Rebuilt 4.7...Will not idle
Just last week we had an other member with the same problem, he also checked the valve timing 3 times and thought is was ok, but then lateron he discovered that he had used the wrong procedure. (seems that he didn't knew about the markings on the timing chain and only looked at the V8 mark on the sprockets)

Addaam 09-25-2011 04:52 PM

Re: Rebuilt 4.7...Will not idle
Well I think you guys are right about the timing. I'm pretty sure I did the same thing the guy in the link did. I reused my old chains and couldn't see any marks so I just put them on assuming as long as the v8 marks were lined up I would be fine. So time to tear it back apart.

Scottina06 09-25-2011 05:25 PM

Ouch......sorry bro

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