No Spark and Stumped!

[FredFranzwa]

I had just left the gas station after filling up our 95 Explorer (200K) and the truck suffered a severe stumble, but recovered. When I looked at the gauges, the fuel indicator was dropping to empty and the airbag light was illuminated. I ordered parts (O2 sensors, EGR and plugs), installed them and started the truck, pleased with the noticeable change at idle, but I still had the guage problem. So I decided to take it to work and got down the street when the engine suddenly lost power and died. After towing it home, I checked to make sure that I had spark (it seemed to) so I focused on the fuel pressure and had none, but I questioned whether my pressure guage was working.After checking EVERY fuse, I decided to put on a new fuel filter and while the lines were disconnected, I turned on the key, but got a spurt of gas for a second, so I decided that the 2 yr old pump had failed, even though I could hear it running. After a new pump, I had the same no start issue, so I double checked spark and had none. I installed a new battery and a new coil pack, but I still have no spark. I put my multi meter on the crankshaft sensor and it is showing .426 ohms. Is this within specification? If so, does anyone have any suggestions? The truck is pretty rusty underneath-possible ground issue? Sorry for the rant, but I wanted to cover all of the symptoms and stuff that I've done in hopes that someone can help me figure out this mystery.

 

[Fix4Dirt]

I had just left the gas station after filling up our 95 Explorer (200K) and the truck suffered a severe stumble, but recovered. When I looked at the gauges, the fuel indicator was dropping to empty and the airbag light was illuminated. I ordered parts (O2 sensors, EGR and plugs), installed them and started the truck, pleased with the noticeable change at idle, but I still had the guage problem. So I decided to take it to work and got down the street when the engine suddenly lost power and died. After towing it home, I checked to make sure that I had spark (it seemed to) so I focused on the fuel pressure and had none, but I questioned whether my pressure guage was working.After checking EVERY fuse, I decided to put on a new fuel filter and while the lines were disconnected, I turned on the key, but got a spurt of gas for a second, so I decided that the 2 yr old pump had failed, even though I could hear it running. After a new pump, I had the same no start issue, so I double checked spark and had none. I installed a new battery and a new coil pack, but I still have no spark. I put my multi meter on the crankshaft sensor and it is showing .426 ohms. Is this within specification? If so, does anyone have any suggestions? The truck is pretty rusty underneath-possible ground issue? Sorry for the rant, but I wanted to cover all of the symptoms and stuff that I've done in hopes that someone can help me figure out this mystery.

could be a bad ground. all of thr coils have no spark, correct?

 

[Josh P]

Does the check engine light come on when you crank the engine to start? If not, assuming the bulb isn't burned out, either the crankshaft sensor connector is not making contact or the ecm is powering on. Other possibilities could be a shorted sensor, bad ground wire or the square wiring harness connector near the firewall has a problem. Another member, Postal_Dave is having the exact same issue and has not found the solution yet. Search for his posts, maybe some of the advice might solve your issue.

 

[J_C]

Did you mean .426 ohms as 0.426 ohms, or as four hundred, twenty six ohms? I don't know what ohm value it should read, but I'm pretty sure it should be far higher than 0.426 ohms.

Before you stated that you put a new battery in, I was thinking your alternator might have failed and drained it. That happened to me, got all kinds of phantom gauge lights and luckily made it home before it died (was only two miles away at a gas station and had someone jump me, didn't know yet it was the alternator instead of battery).

Maybe it still has, did you leave it sit for a while after putting the new battery in and the alternator might've drained it? Along the same line of thought, I'd wonder if your battery cable clamps have corrosion, would turn the headlights on to see if they're greatly dimming while cranking if not measure electrical system voltage anywhere except not on the battery terminal or cable clamp.

 

[DintDobbs]

@FredFranzwa Not calling you out, but you didn't mention the condition of your spark plugs and wires... Might be looking for a big problem where there's a little problem. Not likely they'd all give no spark at the same time, but make sure they're all connected securely and in good shape. Also a good coil pack means nothing if any of the associated wiring or harnesses are damaged, loose, or got water inside. If you're not the original owner, check for any signs of tampering with the wires, just for good measure.

Hope you get this sorted out sooner rather than later! Let us know what you come up with.

 

[FredFranzwa]

could be a bad ground. all of thr coils have no spark, correct?

Yes, all cylinders do not spark. I've taken jumper cables and put 1 clamp on the neg of the battery and the other lead on the engine, but no change. Is there a better way to check for a good ground?
I pulled the 4 wire lead that plugs into the coil and I have about 12v on each wire. I assume that this means my problem is the coil pack, but it's new and acts just like the old one that replaced it. I'm baffled and about ready to part it out.

 

[J_C]

I pulled the 4 wire lead that plugs into the coil and I have about 12v on each wire. I assume that this means my problem is the coil pack, but it's new and acts just like the old one that replaced it. I'm baffled and about ready to part it out.

I'm not certain about this, but it seems like the connector to the coil pack should have 12V on only one of the wires, since the other three wires are supposed to ground through the PCM.

If all else fails, another option is replace everything, meaning now the wiring and PCM. Did you ever do that test I proposed of putting a multimeter probe on battery positive, and a probe on each of the 3 PCM pins that the coil pack goes to, to see if it's grounding them?

AFAIK, if you measure good crankshaft (low voltage AC) input to the PCM (AT the PCM connector, to rule out wiring between the two), and it's not grounding those pins while cranking, and the wire from the coil pack connector to the PCM shows continuous (under 5 ohms) and infinite resistance to ground when not cranking, then I'd suspect the PCM next.