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94 dodge b250 v6 3.9L NO SPARK.


fumblefingerso1
05-25-2008, 03:03 PM
(94 dodge ram VAN b250 v6 3.9L short wheel base) NO SPARK -- But before this problem, I had some strange intermittent issues that led up to the no spark problem.
Most of the time the vehicle runs real good. But. once in a while it would start running real rough, backfires a little. (Not everytime) i had to feather the gas peddle to keek it running, if i took my foot off the gas it would stall. there is some replay clicking sounds (INSIDE THE VEHICLE, INSIDE THE DASH, DRIVER SIDE) The relay clicking volume appears Louder then what ive experienced in the past with hearing clicking relays... head lights and interior lights flicker, voltage meter on the dash would fluctuate, The flickering lights and the meter symptoms acted strange all the time, even then it was running well.

Then all of a sudden it would just run like nothing is wrong at all. it will run fine for days/weeks/months. some times it bounces back and forth from running well to running bad everyday. ( i dont see a pattern )

Now i have no spark and it will not start. i tested for spark on the plug wire at the spark plug end - no spark.. i tested for spark on the wire that feeds the distributor from the coil - No spark.
where do i go from here ?
my friend who i bought the van from had the same problem. He had a repair shop check it out, they installed a new crankshaft position sensor, new alternator. New coil. it ran well enough after that for me to Buy it. Now i have the same problems my friend had with it, ( a year later )
The battery is kind of old, But its showing 12/13 volts.

if anyone has some good advice. let me know.
Thanks.

alloro
05-25-2008, 03:33 PM
My first thought based on your description is a loose ground wire. Look for any black wire that is attached to the engine or body and see if it's loose. If that doesn't solve the problem, then change the ASD relay on the firewall near the brake booster.

car56
05-25-2008, 03:54 PM
Hi, I have a 1995 3.9L (selling it, got a 2000 5.2), and I had problems with my PCM. The clicking you hear is the coil, either to the fuel pump relay or the ASD relay, or both. They should be on the firewall on the driver's side. I think a pattern you may recognize with this is to do with the weather and temperature, and I'll tell you why. I checked the voltage going to the coil on my fuel pump relay(low voltage is why they click), and it was intermittent. Then I checked the voltage going to the crankshaft and camshaft sensor, it was an orange wire, and it was about 5.5 volts. The PCM needs to see 8volts, so I asked myself why there would be low voltage. Well, the system is 12 volts, right? , and the ignition circuit sends a 5 volt signal to the PCM, and the crank/cam circuit is 8 volts, so how do they change the voltage on a DC system? I pulled the cover off of the PCM and could see through the dielectric gel that there was a transformer to change the voltage, but to transform DC you need to CHANGE the magnetic field, and you do this in a DC system by switching on and off. To accomplish this, you use a capacitor. I saw two caps, so I snipped the end of each cap and tested them, the large one(there should be two, one 470 microfarad, 25 volts, and one 220 microfarad 25 volts, I think the small one is for the 5 volts to the ignition circuit). The 470 microfarad cap was weak, so I bought one from RadioShack for $1.29 and voila!, no more problems! Before you get all nervous about doing this, remember that this is an electrical component like any other one(but be careful to disconnect the negative battery cable to power it down, avoid any static charge, but no big deal). I will tell you that this is the big deal with these PCM's and the rebuilders make a fortune fixing them for $1.29 and selling them back to you for $600.00. In any event, good luck, I will bet the farm that that is the problem.

fumblefingerso1
05-26-2008, 10:42 PM
Thank you for the excellent answer. I will take your advice and give this a try. It sure is nice to see someone who can respond with some intelligence... Not to say the other responces to my question were wrong or bad. I am mostly refering to what ive seen while researching other subjects and other message sites. when someone responds with something like. " I think it might be that red wire up under that fasher switch thingie but im not sure just cut them both.. i think " LOLOL. makes ya just want to find where the post-ie lives and drive over there and just bitch smack-em up side the head the head, Cut their internet cable, the drive back home. LOLOL .. Anyways. Thanks alot.

Dave A.K.A Fumblefingerso1

car56
05-26-2008, 11:07 PM
no problem Dave, remember, you can check the voltage going to the sensors for the 8 volts by just piercing or stripping a tiny section of the wire(you find the wire from the pinout schematic), and when you check the cap, just scrape away the dielectric gel by the caps(you'll see two of them by the transformer,their designation starts with a C). This is not to say that it's identical to mine, but it should be close. These Dodges are notorious for this problem, as evidenced by the tons of posts I've seen. Also, you only need to just snip one side of the cap to check it, if it's good just put a little solder on it to re-attach, being careful of course not to overheat or spill solder on the board, but that's why you just scrape away a little gel so ti protects the board. I kind of fumbled through mine, but it was surprisingly tough and I just stuck my pcm back on, fired it up and it never missed a beat again! Good luck again, and feel free to email me if you have more questions.

car56
05-27-2008, 06:41 PM
One quick thing, before you try my approach, you might just clean the connector going to the pcm, disconnect the negative from the battery terminal, unplug the pinouts, spray the crap out of it with contact cleaner and try that, I just did it with my van and(knock on wood) the computer isn't going ballistic anymore. Give it a try, who knows, it only takes a few minutes and some contact cleaner.

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