AMC Eagle Den Forum

The Mighty 258 => The Engine => Topic started by: maddog on December 12, 2017, 01:15:05 AM

Title: odd running problem
Post by: maddog on December 12, 2017, 01:15:05 AM
I'm having an odd issue with the engine in Eagle Eyes. It starts no problem but once running it sounds like it's missing and runs really rough to the point that the car shakes while in gear, the shaking gets worse the higher the engine revs. I've changed the plugs, wires and rotor. The cap looks like it's still good, I do have another cap on the way just in case, but I would like to hear what you all think it might be. Oh I did look at the harmonic balancer while the engine was running but it didn't look like there was any unusual movement coming from it.
Title: Re: odd running problem
Post by: maddog on December 13, 2017, 11:29:50 AM
well I put the new cap on and it didn't change anything. I did find an odd squealing sound that after some investigating is coming from the harmonic balancer, so it looks like I need a new one. i do have one question though will the balancer from a 4.0 work on a 4.2 because if so that would help a lot.
Title: Re: odd running problem
Post by: maddog on December 18, 2017, 08:38:50 PM
well I have replaced the harmonic balancer and it didn't help much more than to stop the engine from shaking really bad. I have replaced the plugs, wires, cap, and rotor as well as reset the timing and it is still missing, any help would be greatly appreciated. FYI this is my only car and I need it to go job hunting seeing as I got let go from my job.
Title: Re: odd running problem
Post by: amcfool1 on December 18, 2017, 11:47:38 PM
 hi, are the plug wires in the correct order? bad motor mount? good luck, gz
Title: Re: odd running problem
Post by: maddog on December 19, 2017, 12:05:02 AM
i had those thoughts myself but the wires are in the correct order and both mounts look to be in good shape. I'm starting to think it is being caused by the engine restore I put in it.
Title: Re: odd running problem
Post by: hillbilly on December 19, 2017, 05:14:50 PM
I had the same problem a couple months ago, turned out to be a weak coil.
Title: Re: odd running problem
Post by: maddog on December 19, 2017, 07:23:58 PM
i don't know how often coils go out but I know mine is only a few years old so it should still be good.
Title: Re: odd running problem
Post by: mudkicker715 on December 19, 2017, 10:11:22 PM
Coils can be checked, via resistance. Google that as i forget exacts. Anyway a couple years back i put an amc branded coil on my wheelhorse (yard tractor) it bit the bullet as in completely done. Newish coil and fire in the hole. Could be a coil on the Fritz.
Title: Re: odd running problem
Post by: maddog on December 20, 2017, 12:41:42 AM
ok I wasn't entirely sure if it could be checked or not, I will have to do that tomorrow when it is light out and not to mention a whole lot warmer. Oh a buddy of mine suggested checking the egr valve, where exactly is it located.
Title: Re: odd running problem
Post by: amcfool1 on December 20, 2017, 07:16:17 AM
egr is on intake, below carb. check all vacuum  connections. btw, does engine shake at all times, or only in gear? It may be trans. problem.
Title: Re: odd running problem
Post by: maddog on December 20, 2017, 08:35:59 AM
at all times and it gets more intense the higher the engine revs whether in gear or not.
Title: Re: odd running problem
Post by: maddog on December 21, 2017, 12:17:57 AM
well I checked the EGR valve and it's working properly also there was very little carbon buildup on it. I cleaned it up none the less and I am still having the same problem.
Title: Re: odd running problem
Post by: mo.eagles on December 21, 2017, 05:14:05 PM
Do you have a plugged cat.? Have you done a compression test?
Title: Re: odd running problem
Post by: mudkicker715 on December 21, 2017, 08:37:43 PM
My thoughts on a plugged cat are that you lose power. Not a shakey motor.  Maybe check resistance on plug wires as well as compression test as mentioned.
Title: Re: odd running problem
Post by: maddog on December 21, 2017, 11:57:48 PM
I don't have a cat on my Eagle. I replaced the plug wires as for doing a compression test I don't have the money to get a tester.
Title: Re: odd running problem
Post by: amcfool1 on December 22, 2017, 07:59:56 AM
fuel pump problems maybe?
Title: Re: odd running problem
Post by: maddog on December 22, 2017, 09:29:09 AM
no she's getting plenty of fuel. I'm starting to think that I lost a cylinder.
Title: Re: odd running problem
Post by: mudkicker715 on December 22, 2017, 10:06:41 AM
Just wondering if you have the same problem after replacing wires, maybe bad wires out of the box.. Not having money sucks when trying to fix a problem.   
Title: Re: odd running problem
Post by: maddog on December 22, 2017, 11:57:46 AM
yes it does. And the wires weren't new but they were ones that were known to be good, but it doesn't change the fact that it was doing the same thing before the swap.
Title: Re: odd running problem
Post by: mo.eagles on December 22, 2017, 08:43:01 PM
Maybe pull the valve cover and check the push rods . See if you have a bent one.
Title: Re: odd running problem
Post by: maddog on December 22, 2017, 11:38:13 PM
unfortunately until I can get some money I won't be able to do that.
Title: Re: odd running problem
Post by: Baskinator on December 29, 2017, 11:20:42 AM
I have had the stock ignition module go out in the past. Granted mine failed entirely, while driving, so it wasn't exactly the same problem. But the engine did seem to shake and miss a lot before I installed my MSD box. You should be able to take it out and have it tested at your local parts store. Not sure, but they may be able to test the coil also.
Title: Re: odd running problem
Post by: maddog on December 29, 2017, 06:42:22 PM
I replaced both the coil and module at the same time a few years ago but if they can test them then it's worth a try. Also since it started doing this it has also smoking whenever I take off from a light.
Title: Re: odd running problem
Post by: amcfool1 on December 29, 2017, 11:55:02 PM
pull the valve cover and check to see if all pushrods are seated in their respective rocker cups. sometimes one can slip out, happened to me, and boy did the engine smoke! gz
Title: Re: odd running problem
Post by: maddog on December 30, 2017, 03:10:03 AM
as soon as I can get some work I'll be able to do that, but unfortunately no work means no money and no money means I can't afford to buy a new valve cover gasket.
Title: Re: odd running problem
Post by: Baskinator on December 31, 2017, 10:12:16 AM
When you do buy a valve cover gasket, get the permatex molded style. They are more expensive, but they're less prone to leaks and you can reuse them over and over.