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#2591280 - 12/13/18 10:12 AM Weird inconsistant studder in the engine
Andrewh Offline
master

Registered: 02/17/03
Posts: 7912
5.9 mag in a 65 coronet, using stock efi injectors and TB, with MS2 running it.

Not everytime, but more often than not, the engine will shudder or skip.
if I am driving, I can hear it catch and feel the loss of power, and sometimes when I am stopped at a light, it will kill the motor. Like I turned it off.
It restarts instantly, or if I am driving, it just skips a beat and keeps going.

There isn't any diesling or chugging when it quits at a light.

I can't recreate it consistently either.

A couple of years back I did have to replace the coil. Stock coil driven by the ms2.

It idles fine when it isn't happening.

Anything obvious I should check for?
Having a hard time wrapping my head around what might cause an intermittent miss like that.

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#2591292 - 12/13/18 10:40 AM Re: Weird inconsistant studder in the engine [Re: Andrewh]
stumpy Offline


Registered: 01/19/03
Posts: 29723
Loc: Grand Prairie,Texas
Did you check for loose wires?

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#2591325 - 12/13/18 11:51 AM Re: Weird inconsistant studder in the engine [Re: Andrewh]
skicker Offline
Son of Doc Fiberglass

Registered: 06/09/05
Posts: 4168
Loc: Western Md.
I had something very similar with a stock ignition...found condensation in the distributor... shruggy
It was intermittent with no rhyme nor reason... twocents
_________________________
Loving all the tears... bawling

Sorry Doc...

We'll try again in 2 years...up

Edited...Looks like it will be 6 years...biggrin

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#2591351 - 12/13/18 12:52 PM Re: Weird inconsistant studder in the engine [Re: Andrewh]
67Charger Offline
master

Registered: 01/20/03
Posts: 2966
Loc: Quartz Hill, CA
There are 2 cheap parts that will cover the entire spectrum. The crank sensor mounted by the bellhousing, and the ignition pickup plate inside the distributor. Most likely the crank sensor failing. I bought a truck non-running for $300, replaced the $40 crank sensor and sold it for $1500; Took me a bit to find it because I had to learn the system, but the system is REALLY simple.

Crank signal tells it when to fire the ignition and injectors. Cam sensor (distributor pickup) tells it when its at #1.

Now, the MS2 thaws a curve in this. I run a MS2 in my Charger on a 496. I have a similar tiny skip, but its enough to reset the logs as if it was shut off. Looking at the loggers, it looks like a crank signal loss, which makes it think the engine was shut off.

I would try a new crank sensor first.

Also, check out this link, TONS of good info if you dig around.

https://troubleshootmyvehicle.com/chrysler/3.9L-5.2L-5.9L/index-of-articles-1
_________________________
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Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race

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#2591696 - 12/14/18 07:28 AM Re: Weird inconsistant studder in the engine [Re: Andrewh]
Andrewh Offline
master

Registered: 02/17/03
Posts: 7912
so that part was removed.
but I will check the logs.

it is now using the distributor for that signal instead.

a shutter wheel was put into the distributor to give it that signal for the ms2.

it was originally a painless prototype system using their old perfect engine managment system. they added that to the distributor instead of using the old crank sensor on the back of the motor.

something kept blowing fuses (which I found was a wiring rub) and I couldn't figure it out, so I replaced the computer with MS.

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