98 2500 4x4, 5.9 magnum no power to coil...

[pauper_72]

Hi all!
I have a 98 Dodge 2500 that is not getting power to the coil. Checked it because it would crank and not fire. Was not getting spark to the plugs. Tested wires leading from the distributor to the coil, nothing. Tested lines from the coil to (???) and still nothing.

The wires get lost in all of the wiring harnesses. Any thoughts where they come out or go to so I can check them? Got the Hayes Manual and the wiring diagram is really hard to follow.

Ok, so I will blame it on being a girl, but since I changed my last motor in my 92 Blazer, 4.3L, 4x4, I feel confident I can figure this out.

Thanks!
Cynthia

[89ltd]

the computer sends power to the coil, but it needs a distributor refrence signal, crank sensor signal ect. before it will do so. If the pickup coil in the distributor is bad, or the crank position sensor is bad or cam sensor is bad, the coil and the fuel pump will not get any power. You could also check the auto shut down relay. Start testing, my self , I would look at the distributor pick up coil first.

[pauper_72]

Thanks, will do that tonight and let you know! Again, thanks!

[1thunder]

yes the pcm receives signal from crank and cam sensors then pcm grounds auto shut down relay witch sends 12v to coil then pcm also dwells coil on the ground side so make sure you have 12v at pin 30 and 86 of auto shut down relay and check for codes in pcm if no codes check to see if there is an rpm signal when cranking this is read from the crank sensor and check if pcm is actually grounding relay if not it isnt getting crank or cam signal or pcm is possibly down due to no 12v or ground to pcm or faulty pcm oh yeh also if a 3 wire sensor shorts like in the trans or under hood sensors could shut pcm down but it is still good though just have to unplug one sensor at the time to see if it comes back to life i have run accross this a few times also
and make sure it's not something simple like the coil itself witch is common faillure on these trucks i'm just assuming you checked 12v at coil when engine is cranking over that is the only time 12v will be there you can check all day with key on not cranking you will get 0v this the easiest way and most efective way i know to check for no spark oh the relay pin numbers are printed under relay

[pauper_72]

Well, after checking ohms on crank sensor and cam sensor, I have come to the conclussion that it needs a "brain". After trying to crank it for a few minutes to check ohms, the PCM gets extremely hot to the touch.

Great for working on it in cold weather, but not so great for proper functioning.

Anyone know where to buy one relatively cheap?

[TurboDuck]

Try calling your local boneyards. If you get one and that's not the problem you'll still probably have to keep it. But it should be a lot cheaper than the dealer. You should check prices against the local Auto Parts stores, and the dealer. Sometimes the dealers prices are better than the part stores. If the prices you find seem extremely high, let me know. I've got a couple of "friends" in the business that give me great deals on used parts...... (Used price is usually about 1/2 of new.)

Or, if it's a 4x4 quad cab with 4:10 gears, and you just want to unload it....... :-)

Good luck, Gary.

[dadodgekid]

there is 30 amp , pink fuse in the fuse block under the hood. Open the cover on the block and the fuse should be on the left hand side in the middle somewhere. make sure it is not blown because it runs power to the coil. I had the same problem with my 1996 dodge ram 5.9 2wd
it should be labled on the cover ENG. control

[pauper_72]

Hey Turbo...
97 truck, 98 engine. Not sure of trans, but will find out for you.

Extended cab, red, rough, black bed, dented, 4x4...

give me 1500 o/b/o and its yours. Located in Detroit area.

[pauper_72]

Hi Dodgekid.
Fuses all good, tested relay too and its good. Thanks though... ;-)

[TurboDuck]

Hey Pauper, shoot me an email to Garye@kingoffice.com - I'm interested.....