When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hello all, tis i, NorthernCustomCruiser. I got completely locked out of my account so i had to create a new one!
Ill start off by informing you all that this is a non olds engine. Its a 1977 360 dodge class C rv to be exact. Ive been stranded in different autozone parking lots for going on a week now and can not seem to get this figured out.
Ive traced my problems to low voltage at the ignition coil while both starting and in the run position. Im to the point where id almost rather rewire everything to the ignition so that i know that non of the wires are bad as ive replaced darn near everything electrical on the firewall.
If ANYONE can help me troubleshoot this and figure out where my problem lies i would eternally be in debt. I can not figure this out with the knowledge i have stored in my brain...
With engine off and key in run position im getting 6.5V from the positive side of the coil and alittle over 1V from the negative.
Using the ohm meter i get around 2 ohms of resistance between the red and yellow wires attached to the voltage regulator. (Disconnected from said voltage regulator and key in off position). Alittle over 12V at battery.
What does this mean and what more can i do to troubleshoot this and find the culprit? Im new to the volt meter and ohm meter as well..
rather than me explaining it, google "voltage drop testing" Basically you can narrow it down to a portion of a circuit, either the neg or pos side. BTW, you might want to find out what voltage should be present at the coil, you might be running a balist resistor as well which would drop voltage on purpose
It does indeed have a balist resistor, i replaced it as i suspected it being bad. How much resistance should it have?
Also at coil with engine running im getting about 10V at the positive terminal and 4.5V at the negative and only 5.5 between the two.
Note that the voltage on the coil+ terminal will be slightly lower than the battery due to the ballast resistor.
The voltage on the coil- terminal will be the voltage drop across the distributor and the electronic control unit (assuming this is the system you have).
I don't know if the numbers you posted are correct for the ignition system; I'm just trying to help you understand what you are measuring.
Read through the info at the link above and see if you get some tips to help you troubleshooting the system.
Last edited by Fun71; August 5th, 2018 at 11:51 AM.
Alright so inside the dash where the ignition runs through the ammeter, it must be connected in order for the engine to start however while the engine is running if i disconnect the battery positive and negative its miss seems to clear up a bit and it smoothes out more. If i have both neg and pos disconnected and key in run position there is 12V between them but if i connect them to their terminals on the ammeter it gives me weird readings. Is the ammeter bad and causing my issue? Why is the engine smoothing out once i disconnect them while its running even though it wont start with them disconnected?
Heres the connections, if it helps at all. Its also got a fused wire coming off of it that goes into the relay in the second picture which i also cant identify
I guess what i really need to know is what are normal readings for the ignition coil volt wise because i suspect my chugging, rough/uneven idle and missing is due to low voltage to the coil if thats even possible.
Ive really been going at this hard guys and have had many older fellas walk away scratchung their head unable to assist me in correcting this issue.
Don't disconnect the battery while the engine is running if you have any electronics in your RV. That is a redneck test to find out if the alternator is working on OLD vehicles. It causes the alternator to produce maximum voltage and can destroy your electronics. If your ignition smooths out when you do that though it suggests you have a weak ignition. Have you tried removing a spark plug wire while the engine is running and see if you get a strong spark? Is it a strong blue spark, or a weak yellow one? How old are your spark plugs? Have you cleaned or replaced the distributor cap? If it gets too corroded, cracked, or wet it can cause massive issues with the ignition system. Have you looked at the engine while it is running in the dark? That is the best time to look for leaking high voltage ignition issues. These are all simple diagnostics but I find the simple stuff solves most problems.
Cap wires plugs and all of the essentials have been replaced and re-replaced haha
if the alternator did produce maximum voltage due to the voltage regulator going out what might it fry that would give me weird readings? Im getting voltage to the coil but i believe its low and cant figure out why, ive replaced everything i can think of to solve this issue but i must be missing something.
I suposse i don't understand the ignition system fully enough to figure out why im having the problems im having. What ballpark voltage should i be looking for on both the ground and positive wire to the coil or at least what do you guys look for?
In the image I posted, it shows a dual ballast resistor. One side of the resistor feeds the electronic ignition module, so maybe on your setup there's an issue in that area and the control module isn't getting the correct voltage? That's about the best I can do with internet trouble shooting.
Ah a 77 Dodge Van, brings back memories. I had a grounding issue which resulted in a no start. I also had a pick up coil go bad as well. I know the ballast resistors can go bad as well.
Thanks all for all the suggestions, ive had trouble getting a new carb for it as all the ones ove gotten are poor quality and make it run worse or not at all.
Ive discovered a hidden leak above the cab that is extensive and is a real setback... Possibly a deathblow to this project...
However.....
I FOUND A 1973 OLDSMOBILE REVCON! This has eliminated any possibility of leaks so now i shall begin again.
August 5th, 2018, 10:23 AM
