i replaced the coil as it was beginning to go bad. i continue to have the same blue/orange spark and the spark itself is a thread hair width on the plug not a full good spark. wires test out good, cap and rotor are newish to new. it starts right up and idles fine until it gets warm. once the engine is hot it rough idles and if i stop it forget trying to restart engine for a while. once in a while when hot and rough idling it will all of a sudden "catch" and run like its supposed to (i didnt change anything it just happens) on another issue because i found a suspect wire going to the alternator i was at idle checking the alternator. i remove the ground wire from the battery during idle and it stalls 99% of the time. once in a 100 it just keeps on idling or maybe the idle speed dips for a second. if i am fast enough (rarely) i can touch the ground back to the battery and keep the engine running. pulled alternator (this sucks big time) and took it in to test (passed with flying colors). now as a test (dont ask me why i did this) i turned on the lights all the way and with the engine running pulled the ground - 10 out of 10 times it keeps running as though nothing changes. turn the lights back off and disconnect and it cuts right away. one other thing that surprises me every time. when i pull a plug out to check the spark (yes i have an inline tester but i wanted to see the color) i crank it a second to see the spark and bam the engine fires and runs. it does this for every plug. i have never really seen an engine just start right up with one of the plugs missing. in all my years of testing spark this way i have never seen an engine just start right up

 

What year van and what engine does it have?

 

It's an 89 318 (5.2), how can you not remember an 8 page thread..... https://dodgeforum.com/forum/dodge-r...s-by-hour.html

 

Well I guess the van no longer has issues with the foamy coolant and it's time to get 7 pages of responses about a weak spark.

 

If anybody can do it, we can!

 

it seems to disappear and is not constant
i also have/had the same type of leak as discussed in this thread. but after running it overheated, and refilling it my leak in this spot went away.
https://dodgeforum.com/forum/dodge-r...lant-leak.html

the spark issue is weird and i did replace the coil. the reason i bring up the thing about the charging system is to find out if there is some direct connection to spark power and voltage? or power out of the alternator? i took it to pep boys and they tested it out fine. i would assume if there was even the slightest thing wrong they are in the business of selling parts so they would have mentioned it.

to landyacht i have never heard of blowing the diodes in an alternator if you disconnect the battery when it is running, i have always done that as the first way to test to see if the engine is charging. ( you mention this in a thread that the guy has a charging problem)

i attached a photo of the radiator taken prior to the replacement of the head gaskets for your amusement landyacht.

i have no way of verifying if the spark gets worse as the van gets hotter.

van will idle all the way down to 5 cylinders when it is cold (disconnecting plug wires at the cap)

 

Try running the engine at night when the engine is cold and the engine cover removed. See if you find any spark jumping while the engine is running.

Also have you check the fuel pressure? And are the fuel lines well away from the exhaust system? Wondering if you are possibly getting a vapor lock in the fuel lines.

 

outside temperature during the day was 54, is that cold enough? i did pull cover this morning and with the garage door almost all the way down cranked to get the best look i could at the spark, the spark is a deep orange/violet. not the white blue i would expect. that was the first reason i turned off the lights. to make sure i saw it right. the other thing is the spark on the plug or when doing it from the wire to dist cap is a small hairline spark even on the plug its just a thread, not a full spark that fills up the tip. i did not readily see any random spark anywhere, and these plug wires are some of the few that i can hold without getting shocked from bad insulation. i also made an effort to keep the plug wires seperate as possible and away from metal. it still trips me out this engine fires right up when i have a plug out to test spark

no i have no way of checking fuel pressure and it was one of the things landyacht brought up to me in another thread about fuel pumps going bad as they heat up. fuel lines are in their standard path and do not run closely to the exhaust.

 

What is the input voltage at the coil? And how are you measuring the negative side from? Do you have the probes that allow you to connect to the power and negative wires to measure the voltage of the coil as the engine is running? If so what is its input voltage then?

 

13.4v at coil with engine running, the red probe is to the positive terminal on the coil the ground probe is at the main ground bolt at back of block., i am not sure what you mean about the type of probes i have? are you referring to measuring the voltage between the terminals? isnt that supposed to be up to 35000v?