No spark

[SIZZLESHANK]

Hello everyone, I recently acquired a 1992 dodge ram 50 from my granny for my first project car. It's been sitting for a few years she says it ran last time they ran it. The issue I'm now having trouble is the spark plugs aren't sparking. They've been changed, me and a buddy of mine sprayed engine starter into the motor, we can't turn it over. The wiring looks fine.

[geezer101]

Hi and welcome to mighty ram. So it's cranking but no start? First thing to do is try and pull error codes from the ECU. There is a run down on how to test OBD II on the site along with the table of error codes and how to read them. These trucks are notorious for having bad ECU's. You can usually spot a problem by cracking the ECU case open and visually inspecting for damage/discolouration on the PCB and/or swollen capacitors. If you can read the values on the capacitors and can wield a soldering iron, this isn't a job outside of your ability to fix (also look for crap soldered joints while you're in there - re-sweating a couple of sketchy joints can save you headaches later) No spark diagnosis - get a pocket voltage meter and test the positive side of the coil when the ignition is on. If you have voltage there, then the problem is on the distributor side of the ignition (bad ICM in the distributor) Beyond that - check ground leads from the battery and harness to the chassis and engine block (this is a good idea to do anyway) + check fuses and fusible links. Once it's running, connect your pocket voltmeter to the battery and see what your charging voltage is like so you can get an idea of the overall health of the electrical system.

[dash]

is the rotor in the distributor turning ?

[geezer101]

is the rotor in the distributor turning ?


That would be my next concern - blown timing belt. Check that you are getting rotation in the distributor and that the timing marks all look like they are aligned when the crank is set @ TDC #1

[dmr8x2]

hurray

[SIZZLESHANK]

Can you point me in the right direction where that post is for the obd2 guide? I've looked and haven't seen anything.

[geezer101]

It is in the manuals section under Haynes Pick ups and Monteros - http://www.mightyram50.net/d-50/Factory_Manual/manuals/haynes_Pickups_and_Monteros-1983-1993.zip

Tried looking for just a page covering OBDII code retrieval but got lost down the rabbit hole. You can do a google search and sites will come up with code descriptions but you need the specific guide for finding the fault like TPS, temp sensors, O2 location etc.

[geezer101]

Hmm, this looks helpful - https://www.troublecodes.net/mitsu/mighty-max-pickup-2-43-0l-montero-3-0l-1989-1996/

There aren't a lot of error codes these older OBDII's can throw...

[xboxrox]

Hello SIZZLESHANK :)

a) REMOVE ALL FOUR SPARK PLUGS & USE THUMB TO CHECK FOR COMPRESSION STROKE (YOUR THUMB WILL GET BLOWN OFF THE HOLE)
b) ENSURE THE BATTERY PASSES A LOAD TEST ~ FREE TESTING AT O'REILLY'S
c) O'REILLY'S RENTS COMPRESSION TESTERS FOR FREE ~ WITH PLUGS OUT, DO A COMPRESSION TEST (DRY THEN OILED CYLINDERS)

1) Use of a remote starter switch can help (with ignition key "ON" engaging the starter switch should produce a spark at the plugs
2) Determine #1 spark plug wire, look under the dist cap, note which terminal the rotor is pointing & mark the cap & spark plug wire #1
3) Attach a good spark plug onto the end of #1 wire ~ with key ON engage the remote switch & check for spark AT THAT PLUG
4) Verify spark plug wires are correctly installed on the distributor cap to coincide with the cylinder firing order
5) Test each spark plug wire with a good plug on the end
6) Check initial ignition timing, there is a tiny notch on the V belt pully closest to the engine, paint it white, use hands to rotate engine
7) With ignition switch ON & pully timing mark @ 7 to 10 degrees BTDC, rotate distributor left & right to observe a spark at #1 spark plug
8) If all good so far (good spark good compression good initial timing) then it might be a fuel problem
9) A 14mm tap & anti seize compound will cleanup aluminum head spark plug threads ~ NEVER remove or install spark plugs on a warm engine

Welcome to MR50 & good hunting finding the fix :thumbup:

[geezer101]

I'd check the wiring anyway. If it's been sitting somewhere long enough, rodents could've chewed on a section of the harness and killed a connection. Seen the little buggers completely sever harnesses in cars left in farm workshops...

[SIZZLESHANK]

Is the firing order for the mm and d50 the same?

[SIZZLESHANK]

For sure, it's been sitting outside for a long time.

[geezer101]

Firing order is the same for all 4 cylinder Mitsubishi engines.