Hey, I have a 98 Ram 1500 5.9L 2wd, automatic and I am having an issue with it just dieing on me at random times. Some times it will restart instantly, other times it can take up to an hour before I can start it again. When it does it, it will just crank over and not even try to fire.

So, I have fuel pressure, injector pulse and power to the coil. I swapped out the ASD relay for good measure. The MAP, ECT, IAT, IAC, TPS, PCM, ignition coil, cap, rotor, plugs, wires, camshaft position sensor, and crankshaft position sensor have all been replaced in the last year. Everything except for the PCM, IAC, and TPS have been replaced in the last two months.

Now, when it died on me tonight, I had no spark from the coil. I checked the coil for power with a digital multimeter and I had it, but what I didn't have was the ground from the PCM. And yes, I had someone cranking the engine when I was checking for it, however as fast as it grounds, I am not sure if the digital meter can pick up on it, I will recheck with an analog meter.

So, where I am at currently is the crankshaft position sensor, the coil, or the PCM. Anything else that can influence the spark? How exactly does the stock anti theft system work? Does it interrupt spark or fuel?

 

The coil could have a crack that is deeper inside of it. If this is the case, it could bench test good when cold, but after it warms up from usage, the crack can expand & cause your issue. Are there any codes showing when you scan? If not & you must guess at 1 thing, I would say install a new coil. Notice I said new, not a junkyard one, because that could have the same issue! Also, make certain you check all fuses & ground connections, battery connections before you start buying parts.

 

Test the coil by firing it manually. Jump the ASD relay so coil is powered, then, stick a wire into the ground side, and tap it against the valve cover, or some such, see if you get spark. If you do, prolly crank sensor.

 

Thanks for the replies. Forgot to mention that I did check all fuses and grounds already. No codes are being thrown. One weird thing is that the coil moves around inside it's little metal housing, I have never seen one do that, so it's definitely on my hit list. If I can replicate the no start condition, I will give the coil test a shot. Also, when it comes to sensors, I never go to the junkyard, always buy them new.

 

Just a repeat basic check, even if you did it already, and that is solid battery terminal connection. In addition to that, whether the leads are in good conductive condition. I had mine actually corrode enough to fall off.

That is all.

 

Went through, checked all grounds twice, changed the coil again and the ECM again. Still acting up. I am thinking that it's something to do with the security system. When using the key fob to lock the truck, sometimes I get the security light and a working system and sometimes I don't. When it's not giving me spark, it won't arm or activate the security system. Any ideas on how to test this?