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Ballast resistor / idle miss question
https://slantsix.org/forum/viewtopic.php?t=15482		 Page 1 of 2
Author:  SuperSlant [ Thu Dec 22, 2005 4:51 pm ]
Post subject:  Ballast resistor / idle miss question
Hello, my name is Mike and i am a slantaholic. :twisted:

I haven't spoken up much around here due to my 1980 225 volare operating smoothly and with little trouble these past couple of years, but starting a few weeks ago i noticed a slight miss at idle speed every now and then, it was nothing to serious but as time went on it has gotten worse to the point of idle quality being completely degraded.

Any way i'll cut through the chase, i did the rag over the muffler pipe test to see if it sucked the rag in every time it missed but did not see it get sucked in once, so as far as that goes i doubt the valves have any part in this problem, (hydraulic lifter type setup) so moving on i checked all of my spark plug cables,distributer(electronic ignition),and corisponding conections with no noticable problems, however when it came to checking the single ballast resistor i noticed that it was quite warm almost hot to the touch and that it had no resistance according to my volt ohm meter.

My haynes repair manual for what its worth recomends a reading of 1.12 to 1.38 ohms for the single ballast resistor but like i said mine had NO resistance at all i.e. 0.00 ohms,so i'll wrap this up by asking if the fualty resistor is to blame for the miss at idle? or is it just a contributing factor to a more complex problem.

I have done most of the work on this vehicle like the super six conversion and all that but i am still some what of a novice when it comes to the nitty gritty of problems so any help suggestions,critisism will be much apreaciated.


Thanks in advance and Merry Christmas -Mike
Author:  emsvitil [ Thu Dec 22, 2005 5:13 pm ]
Post subject: 
Are you sure the ohmeter is set to the correct range? (or if the ohmeter is correctly working)

Ballast resistors tend to fry and goto infinite resistance.


With the car running test the voltage before and after the ballast. If there's a voltage drop, the ballast is working.
Author:  SuperSlant [ Thu Dec 22, 2005 5:34 pm ]
Post subject: 
I used the 2k range first, that yeilded .000 to .007 ohms (my meter can be a little off due to the battery in it going low but that was what i got checking it several times, just for the heck of it i tried the next range up (20k) and got a reading of 0.00.

However i also checked the voltage while the engine idled and got 14.2 volts before the ballast and 9.5 after, wich to me doesn't make sense due to the low resistance as said by the meter, i'll try again with a fresh battery in the meter and see whats up.


EDIT!

I am a dumb @$$ after swaping batteries in my meter i checked the resistor again only to find out that its doing its job, the previous readings were obscured due to 1: the meter not reading lower then 1 ohm (cheapo ratshack digital volt ohm meter) and 2: the low battery, so if 14.2 volts before the resistor and 9.5 volts after is normal then i guess my problem lies elsewere.
Author:  dakight [ Thu Dec 22, 2005 6:57 pm ]
Post subject: 
To measure a resistance of 1 or 2 ohms you need to use the lowest scale on your ohmeter ( that is 200 on mine). Any reading on a 2k or especially a 20k scale would be meaningless if the target resistance is only a couple of ohms. 2 out of 2000 is 1/10 of 1 percent which is probably pretty close to the expected error of most meters.
Author:  emsvitil [ Thu Dec 22, 2005 7:20 pm ]
Post subject: 
Ok, it's not the ballast so I'd check:

PCV valve
Valve Adjustment.
Author:  SuperSlant [ Thu Dec 22, 2005 7:23 pm ]
Post subject: 
Quote:
To measure a resistance of 1 or 2 ohms you need to use the lowest scale on your ohmeter ( that is 200 on mine). Any reading on a 2k or especially a 20k scale would be meaningless if the target resistance is only a couple of ohms. 2 out of 2000 is 1/10 of 1 percent which is probably pretty close to the expected error of most meters.
Yup i already figured that much out but mine only goes down to 2k.

So according to the inacurate reading on my meter the resistor could be any were from 1.00-1.99 ohms, man i need to get a meter with lower range settings, but is an aproximate 9.5 volt drop from 14.2 volts normal for this type of resistor?
Author:  SuperSlant [ Thu Dec 22, 2005 7:26 pm ]
Post subject: 
Quote:
Ok, it's not the ballast so I'd check:

PCV valve
Valve Adjustment.
No valve adjustments as its a hydraulic setup(no adjuster screws on the rocker arms) and the pcv valve was replaced recently and is up to par.
Author:  emsvitil [ Thu Dec 22, 2005 7:29 pm ]
Post subject: 
Actually sounds about right.

BTW, I use the Harbor Freight cheapie ($2.99 on sale) meters.
They break, you throw them away.

The resistance values read just like my more expensive meters, and they read down to 0.3 ohms (you can't zero them out, so remember to subtract the .3 ohms from your reading).

I do usually need to calibrate the voltage against my good meters, but even then the max error I've seen has been .2 volts on 20volt scale
Author:  Slant6Ram [ Thu Dec 22, 2005 7:29 pm ]
Post subject:  Keep an open mind.
Quote:
i doubt the valves have any part in this problem, (hydraulic lifter type setup)
Well, that means you can't adjust them, but it doesn't mean that one or more valves arn't burnt.

I would START by looking for vacuum leaks along the intake manifold gasket and vacuum hose system. Throttle shafts are common leak points as well. Then move on to refreshing the ignition system. All that stuff should be done regularly anyway.

I recently inspected several of the new style 'hardened valve seat' heads and found several valves which where burnt and in need of repair. The quality of qas has been pretty bad lately and it doesn't take too much ping to fry an already 25 year old valve.

Just don't fool yourself into thinking that it couldn't possibly be something like that.
Author:  emsvitil [ Thu Dec 22, 2005 7:31 pm ]
Post subject:  spark plugs & wires
How old are the plugs,wires, cap and rotor?

Your meter will work for this:
check the resistance of the spark plug wires & coil wire. Leave the wires in distributor cap so you can see if there's a problem with the cap
Author:  SuperSlant [ Thu Dec 22, 2005 7:57 pm ]
Post subject:  Re: Keep an open mind.
Quote:
Quote:
i doubt the valves have any part in this problem, (hydraulic lifter type setup)
Well, that means you can't adjust them, but it doesn't mean that one or more valves arn't burnt.

I would START by looking for vacuum leaks along the intake manifold gasket and vacuum hose system. Throttle shafts are common leak points as well. Then move on to refreshing the ignition system. All that stuff should be done regularly anyway.

I recently inspected several of the new style 'hardened valve seat' heads and found several valves which where burnt and in need of repair. The quality of qas has been pretty bad lately and it doesn't take too much ping to fry an already 25 year old valve.

Just don't fool yourself into thinking that it couldn't possibly be something like that.
True i have not checked the condition of the valves since i got the blasted thing so you could have a point there, also one of the rear most valve sets have a sort of clicking noise when the motor is active but i haven't the time or resorces as of late to pull the head and look it over due to the fact that the volare's my daily driver. As far as vacuum leaks go my throttle shaft bushings are as good as a secondhand carb can get, and as far as i can tell no aparent vacuum leaks are noticable(no surging or hesitation e.t.c. when warm) plus when i super sixed the old girl back in october of this year it ran as smooth as can be for a 25 year old car until just recently.
Quote:
Quote:
How old are the plugs,wires, cap and rotor?

Your meter will work for this:
check the resistance of the spark plug wires & coil wire. Leave the wires in distributor cap so you can see if there's a problem with the cap
The distributer along with plugs and wires were intalled new by a local garage about a year and a half ago.

Thanks for all of the helpfull hints guys, and emsvitil i will check distributer and wire resistance first thing tomorow.

peace - Mike
Author:  JDS [ Thu Dec 22, 2005 10:24 pm ]
Post subject: 
it's worth taking a look at the distributor weights. i had the same problem, found the weights had a little rust on the guide plate, and that after replacing the majority of the system....
Author:  emsvitil [ Fri Dec 23, 2005 1:46 am ]
Post subject: 
Check to see if the flapper valve on the exhaust manifold (under carb) moves freely
Author:  SuperSlant [ Fri Dec 23, 2005 11:05 am ]
Post subject: 
Update:


I checked the resistance of the plug wires including the one that goes to the coil and they vary from 4k to 9k ohms using the 20k range (the 2k range got no reading) with the coil wire being around 9.7k ohms is this normal for GE 7mm premium cables? and if any one is wondering my plugs are the Autolite 26 variety.

emsvitil:

My exaust flapper moves freely counter clockwise.

Next i'll try and check the distributer weights,but might not reply for a bit due to the fact that my monitor is about ready to croak.

Thanks again for all your help.


EDIT!

I started it up for the first time in 24 hours and she ran good like normal so i proceeded to take her for a test run around the block a few times and as soon as it was warm enough the same problems occured all over again, so perhaps the ignition coil may be going bad or i might have a loose connection or something but other then that i am kind of stumped as to what the problem is.
Author:  emsvitil [ Fri Dec 23, 2005 2:28 pm ]
Post subject: 
Some of that 9.7k resistance is the center carbon button, so you're good on the wires

Autolite 26, Don't you mean 66, as that's the normal replacement.
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