02 Dakota No Spark
 

Hi everyone!, well I have done a little prior searching but have not come up with an answer to my problem. I purchased a 2002 Dodge Dakota SLT two wheel drive automatic with the 4.7 liter V8 just 2 days ago from the original owner. The truck only has 108k original miles.

It ran like a sewing machine up until the second day, I got up drove it to Walmart come back out and it wouldn't start!. Had it towed home and did some basic shade tree diagnostic work on it and come up with no spark on any of the coils. I checked some fuses but that's all I really know how to do on these trucks because this is the first one I have ever owned.

A few of the articles I have read say these trucks are a complete nightmare especially with the 4.7 L engine so I hope I didn't go wrong. It seems there are several things that can go wrong with these like cam sensors, crankshaft sensors computers etc... does anyone have any suggestions of where I should start first before I start throwing a ton of money in this thing? It is such a nice clean low mile truck that I would like to keep it.

I do have other questions about the 4.7 L engine but that can be put on the back burner for now. Any advice or tips will be greatly appreciated, thank you, Owen

Do you hear the fuel pump prime when you turn the key on? The coils and fuel pump receive power from the ASD relay, it cycles for 1.5-2 seconds at key on, and when engine is starting/running. If you can hear the pump prime at key-on, then the ASD relay is good.

Hi, i do hear a noise coming from the gas tank.
should i check that relay anyway?

If you hear it at key-on, then it should be working. If you want to make sure, pull the 12 volt connector on the coil and use a multimeter from the orange wire to a known good ground - should get a steady 12V signal when spinning the engine over. If that shows good, check across the orange and black wires in the same coil connector. You should see a pulsing 12V signal - some meters may not be fast enough to detect it though.

I assume your spark test was holding a spark plug against a good ground while plugged into the coil and spinning the engine over?

The ground side of the coil is pulsed by the PCM, and calculated by the positions of the tone rings as read by the cam and crank sensors. Note that changing the crank sensor is a bit of a PITA on the 4.7, it's prone to get stuck in the block (swedge fit).

Its an actual spark tester, but yes basically same method. I'll try volt testing it tomorrow.
God, what happened to the good old distributor and carburation setup Lol! I was hoping to possibly throw some performance goodies at this Dakota in the near future, but im second guessing it now :icon_doh:.
Thanks so much for the tips and information, I'll be needing more im sure.

when treated well, the 4.7 is a good design (according to most people). IT still has it's shortcomings regardless.

FYI, an independent testing facility tinkered with some GM LS COP factory coils, and determined that they put out the same amount of spark as a 25 amp magneto, and way more spark than an MSD HVC coil at the same pulse frequency (they didn't have a good magnitude difference). The reason is that a COP coil fires 1 time every 2 rotations, where a standard coil fires 8 times every 2 rotations. This gives the coil a longer dwell time to make a more powerful spark.

Wow that's some cool information on the spark/coil. My High school auto tech instructor had a mild build 02 Dakota with the 4.7 and it ran pretty darn hard and that's what actually inspired me to buy this one, but of course he never mentioned all the draw backs of the 4.7 Lol.
My buddy said just find a 5.2 or 5.9 and build that instead.

The 4.7 is respectable. The biggest issue is knowing how it was taken care of in the past. If they have not been sludged, You can use the 2008(?)+ HO cams and intake and not really have to do much with the long block.

If it's been sludged, the timing chain tensioners might warrant some attention. It's not a direct correlation, but poor treatment is poor treatment.

I've heard about the sludge or foaming issues.
The original owner included the maintenance records from the dealership and it is showing he had the oil changed every 2000 miles and after the factory warranty expired he had them start using Quaker State 10w-40 conventional.
It say "At owner's request" on the sevice readouts.

Not a whole lot has been done other than normal wear and tear replacement item's like tune-ups, shocks, wipers, tires, water pump, ect...
He said he always ran Seafoam through it once a month.

sounds like you got a good one.

The foaming at the filler neck is normal and can be safely ignored.

Do the voltage checks on the 12 volt side of the coil system and see what you find.