I'm having a perplexing starting problem on my 1999 / 5.2 / 4x4 Dakota: I was driving down the highway in light rain while pulling my 6x10 cargo trailer when I heard a bunch of misfires and then it died. Now it won't start. There are no codes from engine computer and the check engine light is not on. The battery is fully charged and it cranks like normal.

I have good fuel pressure. The injector circuits are able to flash my test lamps and I can smell gas, so I'm assuming my issue isn't fuel.

I have good strong spark up to the center tap of distributor (checked with a spark plug at the distributor end of the wire), but no spark down any of the plug wires. I replaced the cap, rotor, distributor pickup (aka cam position sensor) and crankshaft position sensor, but the problem remains. The distributor turns when the engine is cranked and the rotor is in the exact proper position when the engine is at TDC. I would add that the old rotor looked damaged, as the spring which contacts the center post looked twisted.

I've eliminated everything I can think of . . . does anybody else have any other suggestions?

Larry

 

you need to check actual spark strength from the coil see if its enough also check the coil primary and secodary circuits

 

I've always checked the coil with a spark plug at the distributor end of the wire . . . what do you suggest?

Larry

 

Timing chain, bad distributor, timing problem

Or PCM died on you

check TDC to how the rotor should be positioned for the proper cylinder

Look at the rotor with the cap off to see if the rotor is turning at all as you crank the engine

 

they make a tester that is adjustable that is the air gap it can still arc across. Dont forget coil wire to ground is just a preliminary check to see if you have any spark the spark still has a lot of resistance to go through before it fires the plug so if its weak at the coil it will never make the plug fire

 

Yup, checked all those already.

Larry

 

I guess I've never had an issue with a "weak" coil . . . but after thinking about it I figured it was as plausible idea as any, so I ordered up an adjustable spark tester from RockAuto.com. It should be here before I can look at the vehicle again, plus it was under $5 so I figured it was no-brainer.

thanks,

Larry

 

RYCOMA79, YOU DA MAN!

My coil could only spark across a gap of about 1/16th inch . . . my new coil can jump spark across well over 1/2 inch. The truck fired right up with the new coil. I've never experienced a coil fail suddenly like this. I replaced this coil in the spring and was warned against using a "auto parts store coil". I'm told the the OE coil is made for Chrysler by Delphi, they're much more spendy, by I'm going to order up one as a spare for my four Dakotas.

Larry

 

Larry can you check the resistance on the primary circut and the secondary circut as well on the bad coil I want to compare them to mine. if you need help doing this let me know I can walk you through it you will need a volt meter that can read ohms. glad to hear you got it fixed and I'm going to buy one tommorow I've never used one either so here's hopeing that's my issue causing the rough idle

 

Sorry, but I had to leave it at O'Reilly's when they exchanged it for a new one.

Larry