95 Dakota club 3.9L
A while back the timing chain failed bent the valves (all 12) Since then I've replaced the timing set (gears and chain) and I put some rebuilt cylinder heads on. 12 new pushrods (I kept the rocker arms and lifters, they seemed okay) I replaced the tps because I broke it on accident.

I got it back together and it won't start. It will start with the throttle partly open but it doesn't run very well. It's backfiring and sputtering and it won't stay running at idle.

Currently I have the timing cover off to verify the timing is correct, the cam gear at 6 and the crank gear at 12, the distributor points at #4. After a little googling I found that this is right.

Because the cam turns 2 times while the crank turns once, is it possible for the crank to be off 360°?

Any ideas?

 

A crank off 360* would .. be back in time. A crank 180* out would be fixable, but if the two dots point to each other, they'll be in time with each other (and you describe them pointing at each other.)

I'd do the "set TDC on cylinder 1" and make sure that the distributor is pointing to cylinder 1. It's not uncommon to get a dizzy 180* out on reassembly.

RwP

 

360 degrees would be back at tds or where it started if the arrows are pointing to each other your golden. For every two rotations of the crank the cam will only rotate once. I would double check the distributor and also check if all wires are in correct place.. Good luck

 

Thanks for the reply, I have put the 1 cyl at tdc for the intake stroke and it does point at 1 on the distributor. The two dots line up perfectly. I did have a harness not plugged in, the temp sensor next to the thermostat housing. I'm not sure if that's got anything to do with it.

 

No that will be either one of the temp sensors for coolant or intake air temp. This makes me wonder if the "rebuilt" heads you got were built right or set for TDC. I also think firing order as rx7dude mentions. I also wonder if the cam got moved when changing the heads. I've never done the heads on mine so I don't know if it is exposed enough you might bump it while doing the job.

 

If the arrows on timing gears are facing each other is should be timed correctly since the gears only go on one way to cam and crank.. I'd look at position of the distributor might be 180 out or the wires are wrong.. It can be possible that the fuel injector harness plugs are on the wrong injectors when reinstallation.. That's just a thought something to look at

 

Thanks for the reply. The fuel injector wires are all labeled and installed correctly though I have not checked for pulse.

I did not remove the distributor gear, there's no way it's 180 out. I have confirmed from multiple sources that with the cam gear at 6 and the crank gear at 12 the engine is at tdc intake for #4 cylinder, while both gears at 12 it's tdc intake for #1 cylinder. This makes sense as the harmonic balancer indicates tdc intake on the timing cover for both of these cylinders.

I just don't know what else to do...

 

Thanks for the reply. I'm not sure what you mean by heads built for tdc as they don't have anything to do with the timing.

The cam gear and the crank gear only go on one way. I'm also not sure what you mean by the cam got bumped, with the heads and intake manifold removed the cam still isn't exposed.

I'm almost certain at this point it's a sensor or maybe some unknown vacuum circuit not working.

I got my heads from this site:
http://www.shop.headsonly.com/DODGE-MAGNUM-39-V-6-REBUILT-CYLINDER-HEAD-RAM-DAKOTA-RAM-39.htm

 

That's the site I plan on using if I change mine. I never changed my heads that is why I asked about the cam and I had assumed because a 4 banger Mitsubishi motor head I changed had the cam in it that there might be some chance of the head needing to be set in a certain way. If the heads are good then you are probably right.

 

Yeah my 3.9 is set up a bit differently than that, I just need people to bounce ideas off of.

I am no expert by any means, sometimes we pay so much attention to the big details we forget the little ones. I'll throw it back together and inspect everything.

As far as that site goes they are great, they don't have an upfront core charge. They send you a return sticker free of charge and you just put your old head back in the packaging and drop it off at a UPS.