No spark on 4 coils 2001 1500hd

1500hdjet52 · October 10, 2015

Here's what happened,

I live in SC, as some may know we just had major flooding.

I drove through water on the road heading to our local gas station. Water wasn't that deep maybe 10". I have a Cold air intake which may have helped water enter my engine. Yes, it hydrolocked. Had it towed home, removed the plugs, cranked it over and cleared the water out, then changed the oil.

Now, after doing that I crank it up, it sputters and holds a very low idle-250 rpm. It wouldn't go any higher, when I tried it would stall.

I got my coil tester out and only 4 coils were producing a spark.

Any ideas?

2001 1500hd 6.0

Chris · October 10, 2015

Could have submerged the computer or coils arent happy. Are they all on one side or front half or back half? I would start by replacing coils, plugs, and wires. Age could be a factor.

1500hdjet52 · October 10, 2015

Could have submerged the computer or coils arent happy. Are they all on one side or front half or back half? I would start by replacing coils, plugs, and wires. Age could be a factor.

You're right about the PCM, thet may have been damaged.

Two coils on one side, and two on the other.

I forgot to mention I swapped a good coil with one that tested bad and it still checked bad. The 4 coils do not seem to be getting a signal.

Chris · October 10, 2015

The 4 positions arent getting signal or the 4 packs themselves arent. Does it follow the coil or stay in that cylinder? And is it cyl 1, 2, 3, and 4 bad or are they staggered?

1500hdjet52 · October 10, 2015

The 4 positions arent getting signal or the 4 packs themselves arent. Does it follow the coil or stay in that cylinder? And is it cyl 1, 2, 3, and 4 bad or are they staggered?

2,4,5 & 7 are working, the rest are not firing. After swapping the coils the problem stayed in the cylinder. I basically verified the coils are good.

Chris · October 10, 2015

Take a test probe to the wires leading from the coils back. Find your break in the circuit. If you need a diagram you can register for alldata for like $27. They have great diagrams.

txab · October 10, 2015

I can almost bet your MAF is toast too

1500hdjet52 · October 10, 2015

I can almost bet your MAF is toast too

Would that cause the firing issue I'm having?

1500hdjet52 · October 10, 2015

Update:

I decided to check compression to see if anything may have been damaged mechanically. All check around 150psi Except #7 cylinder. Its at zero psi, further inspection with a bores scope shows the piston not moving.

This is definitely a problem I will be addressing....... But, this wont cause half the coils to quit working correct?

txab · October 11, 2015

Update:

I decided to check compression to see if anything may have been damaged mechanically. All check around 150psi Except #7 cylinder. Its at zero psi, further inspection with a bores scope shows the piston not moving.

This is definitely a problem I will be addressing....... But, this wont cause half the coils to quit working correct?

1500hdjet52 · October 12, 2015

Take a test probe to the wires leading from the coils back. Find your break in the circuit. If you need a diagram you can register for alldata for like $27. They have great diagrams.

Wires look good. Everything was fine until I hit the water. And right after the truck died I opened the hood, everything was mostly dry.

After myself, I blame the cold air intake, and after I take care of this the CAI is gone, back to the stock box.

I'm suspecting its the PCM more and more each day, it's down low and could have easily got wet.. There is a guy around here that will test PCMs for $100. Basically just lets you know if its good or bad.

Badass69 · October 12, 2015

Update:

I decided to check compression to see if anything may have been damaged mechanically. All check around 150psi Except #7 cylinder. Its at zero psi, further inspection with a bores scope shows the piston not moving.

This is definitely a problem I will be addressing....... But, this wont cause half the coils to quit working correct?

It actually could be. If 7 isn't moving you broke a connecting rod... could have easily damaged the crank position sensor or cam position sensor and thus you don't have spark on all 8.

You need an engine so once you have another one in there with working sensors you will know if the issue still exists.

Sent from my potato

1500hdjet52 · October 12, 2015

It actually could be. If 7 isn't moving you broke a connecting rod... could have easily damaged the crank position sensor or cam position sensor and thus you don't have spark on all 8.

You need an engine so once you have another one in there with working sensors you will know if the issue still exists.

Sent from my potato

That makes sense.....

You think i'll be wasting my time fixing this motor?

Badass69 · October 12, 2015

That makes sense.....

You think i'll be wasting my time fixing this motor?

Comes down to dollars and cents. If you can rebuild your original cheaper than whatever you are comfortable with otherwise running maybe not. That said until you open it up you won't know how bad it is. If a rod broke it could easily have screwed up the bottom of the cylinder so bad it's irreparable anyhow.... pretty good chance of that. Your crank will probably be junk too. The last one I had that did what yours did was a 350 years back.. heads were salvageable... and that's it.

From what I read you are in a state that miled out old junk is worth it's weight in gold somehow. If that's the case a reman might be up your alley like you mentioned. I know an 01 with 250000 kms (roughly 150000 miles)and either no engine or a junk one is worth maybe 500 bucks here.. But I can get LQ4's with under 100000 miles for 600 to 800 dollars here too...

Sent from my potato