Hi Everyone, I just joined and this is my first post in the chatroom, I hope someone can help. I have a '78 W200 4x4 360 2bbl automatic that seems to have an ignition problem. In the last year or so it's been fouling the spark plugs on a regular basis, but would run just fine for a good while after installing new plugs. Well it started running bad and missing again so I installed a new set of plugs again and it did'nt help a bit this time. I hooked up a timing light to each wire with the engine running and the back plug on the driver's side was'nt firing so I replaced the wire with a known good one - still no spark, so I figured the next thing to do would be to replace the distributor cap and rotor button so I went out a bought new ones - installed them and the non-sparking cyl was firing - took off up the road and it ran terrible - pulled 'er back in the shop and now the same cyl was'nt firing again as well as the passenger side rearmost cyl. I replaced those 2 spark plugs and it was running fine again - took 'er up the road and it started missing again - pulled 'er in the shop and now the second plug on the passenger side is'nt firing ! ! ! :VHOT: I then pulled the electronic ignition box off the fire wall and noticed that the clear sealer that seals the unit in the back has come loose and was stuck to the firewall, I had another box from another old Dodge truck but it has 5 pins where the one on my rig has only 4 pins, so I decided it might not be a good idea to try it, it don't want to burn something up. Now I know it probably has to be one of three things: 1) electronic ignition box 2) the pickup in the distributor or 3) the coil. If anybody can help me figure out which one it is I'd really appreciate it.
Thanks, Matt
Speed Dragon
11-22-2005, 12:11 AM
I've run a 5-pin ECU on a 4-pin harness for a while with no problem, so it shouldn't hurt anything for you to try it out, just to see if that's the problem. I would bet it's the pickup though, cause they can definitely mess one up if they go bad. You may just want to swap in another distributor, in case that one is worn out. You can usually pick up an regular old Chrysler electronic distributor pretty cheap from the junkyard, same for the ECU.
And welcome to DodgeTalk:gr_patrio
VanMoreSon
11-22-2005, 09:26 AM
Seems if it were the module it wouldn't affect any one plug.....
I'd try a new set of plug wires to eliminate that possibility. I recently replaced the module on my '77 van with a 360. The new one has 4-pins versus the original 5-pins. A note in the box states "All replacement modules for Chrysler now have 4-pins". I wondered how this could be, but I replaced it and it works fine (and was only $18, with a lifetime guarantee!). Pretty sure the old module was the original and the sealer on the back had melted all over the fire-wall but had been that way for over 4 years...
My problem was the engine dying unpredictably after putting in a rebuilt distributor and carb. I replaced the coil, ballast resistor, cap & rotor and the module (plugs & wires were recent)...but it still died. Finally, I demanded a different distributor and that was it... the first rebuilt was defective!
Since this it was a '77, I figured it was due to have all that stuff replaced anyway...
Chump
11-23-2005, 03:46 AM
Are your plugs fouled with black carbon? Look inside the tower of the coil, this is where the coil wire plugs into and see if you see any oil leaking, if you do, replace the coil. The coil could also be weak or you may not be getting enough voltage to the coil. With the key "on" check voltage at the plus side of the coil, it should be around 11 volts? With the key in the "start" position this voltage should drop to around 6-8 volts? The distributor pick-up can be checked with an ohm meter, there are 2 leads that come out of the distributor and terminate in a plug. A good pickup asm should read 150-900 ohms when you check across both wires. The pickup asm in the distributor needs to be adjusted with a brass .006 feeler gauge. The 5 pin ECU will work as the extra pin/wire goes to the second side of the ballast resistor and isnt used. The ECU also gets it's gound from the fender and it's mounting bolts, make sure this clean and snug. Battery and charging system working good?
Have you replaced the ballast resistor, these do fall apart over time, I replace this at every tune up, it's cheap. The diagram below shows the adj for the pickup asm, it shows 2 pickup asms, you will have only one on your year truck.
If the ballast resistor goes bad, it will run as long as you have the key in the start position, once you let it go back to the run position it will die. Basically it will run as long as you are cranking it.
