Lisa Clark

The code we're getting is P 1391. Looked up the code for map sensor and that's not it. Wish us luck. First, gotta find where the heck the crank shaft sensor is.

dave1123

On the 4.7L, it's above the starter.

97grand4.0

OOOOOHHHHH it's not a 4.0!! , plastic manifold. Had to really tease THAT one out. Good catch Dave.
P1391 is crank OR cam sensor. Funny tho, rough running doesn't really sound like either. ..more like fuel or ignition just to narrow it down LOL

Lisa Clark

Will tackle the crank shaft sensor tomorrow. Did I mention I AM NOT A MECHANIC😂, I just play one on TV. Seriously, I'm ready to stick some dynamite in it's tailpipe and that would take care of the problem.

97grand4.0

LOL Yeah. In all seriousness, you should be taking it back to the shop that did the work and find a place for that stick of dynamite there.

Lisa Clark

They said that they could not figure it out and that they didn't want us to stick anymore $ into it. The said to go to dealership😱

dave1123

You know, it could have dropped a valve seat which may have been the cause of the no start to begin with. Then the ether ignited in the manifold because of the slightly open valve. The only way to check is to do a compression check. Those engine have a reputation for valve seats loosening up in the heads. They also have a problem with timing chains jumping and destroying everything on that bank. Personally I wouldn't take one as a gift, or sell it right away.

Lisa Clark

Well, that is just soooo incouraging. Will keep posted as to how we fare with cranky sensor

dave1123

I'm not trying to scare you, just make you aware of the faults that are common with this engine. They tried too many new things when they manufactured it. The connecting rods are made from hot forged powdered metal. The camshafts run on bare aluminum in the heads so that if oiling stops, they seize. If the hydraulic valve anchors stick, the rockers come off the cams. The 3.7 V6 is the same basic engine with the same problems. The one big problem is jumped timing chains because the tensioners fail to hold them tight. When that happens, the valves hit the pistons with resulting destruction.

Many people have no problems with them, but when they do, it's costly to fix.

Lisa Clark

I appreciate your advice and knowledge. Iv spent $850 already and another $33 for new crank sensor. That was the one thing this 2004 had going for it, the engine was good. Replaced a bunch of other things since 2013. How much more? Guess I'll find out😵

97grand4.0

You should have stuck with us in the first place.
They said ...what? for 850 bucks, (more than I spent for my Jeep 8 yrs ago) ? 850 to replace a plastic manifold. ok. Well people that can't turn their own wrenches are at the mercy of some unscrupulous people. Did they give you back the old part? That is your right to request it. I would want to see the hole that was blown in it by starter fluid. Were they a licensed repair shop? They promised to fix it by replacing an 850$ part. I feel your pain

dave1123

There's a plastic end cap and seal on that manifold that was ripped off, probably destroying it's method of being held on. It would be like removing the throttle body on a 4.0L, then starting it up. It's probably like a core plug from the molding process, I would imagine. Rockauto carries the seal for it.

97grand4.0

Can they glue another cap on?

Lisa Clark

It's not that we're unable, it's a time factor. We are down to 1 car now due to his BMW blowing a head gasket ( sucks to be us) so we thought this would be a quick turnaround. Didn't need d part because my husband went to shop ( very reputable) and saw them take the manifold off. He's a German trained auto electrician from years ago and can also do repairs but like I said TIME was a factor. He's going to put the crank sensor on today. I'm just cranky....must need a crank shaft sensor😂
really appreciate all the help and support from all of you. Keep ya posted.

dave1123

Just relax with a Starbucks double caramel latte.