1996 Dodge Ram 1500 no spark

dodge
ram1500

#1

I have a 1996 Dodge Ram 1500 5.2lt ExtCab 4x4

Here is my issue:
We bought this truck knowing it didn’t run at the time, was told it just died. When I got it home, I put a new battery on it and grabbed a can of starting fluid for first test, figuring if it was a fuel issue it would fire and if it was an electrical issue then it wouldn’t fire… No spark… So we started at the top, replaced the coil, spark plugs, wires, cap and rotor… still no spark… replaced the crank position sensor, all the relays and fuses, even if they were good, didn’t take any chances… still no spark… noticed the ECM was from a junk yard so we replaced it with a pre-programmed one from O’Reilly’s… still no spark… next we replaced the entire distributor… sadly still no spark… we noticed that the throttle body was missing a couple screws holding sensors on so we decided to take the safe route and totally rebuilt the throttle body including replacing all the sensors on it… Alas we still have no spark, even checked to see if coil was getting power and and according to the volt tester the wires into the coil have no juice at all… So other than a wiring issue, what am I missing?


#2

Sorry to hear you changed a lot of parts out for most likely no reason. Whenever you have an ignition problem the first thing to check, in my book at least, is power to the ignition system. Once that is confirmed then you move on to checking for faulty ignition parts. Hopefully you already made sure no fuses were blown out, especially for the ignition system. If the fuses are all good then you need to trace wires from the fuse panel to the ignition area and see where the problem is at. Make sure the grounding is good also. You would be wise to invest in a factory service manual to guide you through the wiring. Ebay is a good place to purchase one at a good price. You have already spend more money than the cost of a manual on needless parts.

Looking at some data it shows fuses 4 and 8 in the distribution panel under the hood are important fuses for the engine operation. Make sure they are good. There is a shut down relay that should have power going to a dark green/orange wire for the PCM.


#3

Check the ASD relay.
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#4

This is a perfect example why it’s cheaper to pay a reputable shop to diagnose and repair vehicles, in some cases

You’ve been making guesses . . . and they’ve all been wrong

Instead of that, you should have gotten hold of the factory service manual, and the appropriate wiring diagrams

it’s not too late to have it towed to a good shop

So far . . . with the exception of the pcm . . . all the parts have been reasonably priced. But if you keep guessing, and guessing wrong, it’ll really add up, and this presumably cheap truck won’t have been such a good deal, after all


#5

Good idea to do some basic measurements.

Ignition coil primary should be around 1 ohm, secondary appx 11-16 k ohms.

Ignition hv cable between 250 and 1000 ohms per inch.

It looks to be a conventional-style electronic ignition system using a single coil and distributor. The PCM intermittently grounds the negative lead of the coil to charge the coil and fire the spark plugs. From what I can tell the power to the primary lead on the coil comes via the auto-shutdown relay, pin 87. That pin also supplies battery power to the injectors, and the o2 sensor’s heaters. So that’s the first place to check. (Applies to the JTEC version, which I presume you have.)


#6

changing out the parts didn’t bother me, since my daughter will be driving this truck I chose to take a “Better safe than sorry” approach and replace everything that could cause the problem that I knew of… As for fuses and relays, all are new, replaced them all…


#7

If something is causing a fuse to pop, replacing it will cause the new one to pop also. That is the purpose of fuses. You need to check them, not blindly replace them.


#8

I replaced the parts for several reasons, mainly because my daughter will be in the truck and I want it in good working order, another reason is because the mileage is high and I doubt anything has ever been changed, so better safe than sorry… last reason is alot of those parts didn’t look to be in the best condition, and the ecm it had was from a junkyard… as for taking it to a shop, I did that, only to find that in 6 months it had never been touched except to steal parts from it, I had to drag it off the property myself ( I had known this shop for years, had done alot of business with them )… And as for making guesses, I was eliminating all other possibilities…


#9

none of the fuses were bad when they were all replaced, I still have all the old ones… and none are bad now…


#10

Thank you, this is actually helpful… I hate dealing with wiring issues, but sadly I have no choice this time…


#11

This is beyond my comprehension . You bought a non - running truck with multiple problems and you are going to put your daughter in it . Most parents want the safest reliable vehicle they can afford for their children , a 1996 Dodge pickup will not meet that criteria.


#12

And most parents don’t know how to change a tire now days, let alone change their own oil or even do a tune-up for that matter… Don’t assume you know me or what I have done with my life… I have nearly 25 years in the automotive field, and the last 12 of it has been in parts, only because I can’t physically do as much as I could 15 years ago… Just because I ask questions doesn’t mean I am stupid, it means I am covering all bases and making sure I didn’t miss anything before getting into the wiring, I hate dealing with wiring issues… And just because I would rather my daughter be in an older vehicle doesn’t mean I am a bad parent either, my daughter has torn down 3 engines and rebuilt one of them with me, she helps me with most all of our auto repairs and upgrades… As for safe vehicle, putting your child in a safe vehicle and teaching them to be safe in any vehicle are 2 different things, any idiot can spend thousands on some new vehicle for his child, but someone who wants to make sure their child will always be safe will teach them all aspects of a vehicle and make sure they understand that being safe is something they have to do, not something given to them… At least my kids can change tires and do oil changes, as well as replace starters, batteries and alternators, and do basic diagnostics to figure out the problem…


#13

Since you have replaced all the relays and fuses I suggest you check the wire that ties to the auto-shutdown relay that I mentioned in my previous post to see power is getting to that wire. If no power is getting to it then we need to check the operation for that relay. Pretty simple test.


#14

I know for sure I have no power to the coil… I will check the socket for the relay on my next day off and let you know my findings, I got a copy of the wiring schematics for the truck, so it shouldn’t be too much of a total pain… thank you…


#15

Good job on getting the diagrams. It will make this job pretty simple now to find the problem using them and a meter to make the checks with. Power has to get to the PCM in order to get to the coil. Once that is solved hopefully you be good to go and have no more issues for a while.