2006 180 Challenger won't start

[brian_hunt]

I have fuel on the spark plugs and engine is turning over great (new battery).

Some background:
We started having issues approx. 18 months ago – engine would run very rough at high RPM but fine at near idle speeds. I thought there was a water issue in the tank from old fuel, so dumped water remover and SeaFoam in tank and it usually cleared it up (worked 3-4 times), but the issue kept recurring even after using stabilgas and non-ethanol fuel. Issue went away but then starting issue started late last year. Changed spark plugs and it was fine for a while (no rough idle or need for seafoam/water remover any more), then thought it may be a weak battery issue so I put a new battery in (starter was disengaging after 1 or 2 cylinders would start firing). This did not fix the issue (even though battery needed replaced anyway) so I had to change spark plugs again and it fired right up. Now changing spark plugs doesn’t work and the boat left us sit (did not restart after sitting ~1hr) after running great for 2-3 hours.

My diagnostics:
12.6V at the plug for the ignition coil
Continuity and low resistance between ECM and ignition coil plug
Ignition coil resistance:
secondary winding (through coil) tests at ~10 kohms (spec is 9.5-13.5)
primary winding (the coil plug connectors) tests at ~1.8-2 ohms (spec is .85-1.15)
If this increased resistance is enough to keep from starting, it would probably explain the problems I've been having over 18 months. Is 2 ohms enough to keep from starting?

Even if this starts the engine, cost to replace all 3 is $300+, so I'm hesitant to change all three ignition coils out without knowing what caused the problem.

Any thoughts on what else I can check or what may be causing the ignition coils to go bad? Thanks in advance for any help you can give.

 

[brian_hunt]

I ran Candoopro and no faults are coming up. I tested each spark plug/coil and each could be heard. I tested a new ignition coil and it tested the same as the old ones, so I don't believe the ignition coils are faulty.

I pulled the fuel pump and put a new filter on, just in case that was the problem.

Any ideas what the problem could be??

 

[brian_hunt]

An update (been a busy past few days):
I tested for compression - low (90-100) in the back and middle cylinders. I used some marvel mystery oil and unstuck the rings and have about 140-150 now. Also figured out that I had salt water residue on the spark plugs. And a friend pointed out to me that the supercharger bearing was squealing, so I rebuilt the supercharger.
So apparently my fuel was fine but I'm getting saltwater into the intake or engine somehow. Any ideas where it could be coming in?

 

[Floridan surfer]

So is your boat running again? I'm about to start troubleshooting my boat, I had a similar experience with mine today.

Started up and ran fine. Turn it off and hung out on the beach for a couple hours, when it was time to go home, no start. Engine just turned over.

 

[brian_hunt]

So is your boat running again? I'm about to start troubleshooting my boat, I had a similar experience with mine today.

Started up and ran fine. Turn it off and hung out on the beach for a couple hours, when it was time to go home, no start. Engine just turned over.

Unfortunately I'm still having issues.
Quick update: I was concerned that I had water going in my supercharger intake hence the bad bearing. Since reinstalling my supercharger/inlet hose, I have not seen any salt or water on my spark plugs, but I've had the boat quit on me at the island twice since. My 3rd cylinder tested low ~110-120 psi and I used the marvel again and got the engine running again. The other two cylinders were fine. I'm concerned I either A) Have an intercooler leak and am getting water in the engine still or B) my rings are still sticking from the prior salt water.

 

[Floridan surfer]

when it's giving you no start problems, what is it do exactly? Does the engine just turn over and not come anywhere close to starting or does it try to start but doesn't run?

Are you putting the Marvel mystery oil down spark plug hole?

 

[brian_hunt]

It turns over but doesn't even sputter.
Yes, I'm taking the spark plugs out and putting a few ounces down each hole then cracking the engine with the spark plugs out. Makes a mess if you put too much in.

However when I was coming back the last trip out I got a new symptom: the motor was sputtering. I didn't shut it off until I was on the trailer for fear of not starting again. When I got back I had 150, 145, and ~140 psi in cylinders 1, 2, and 3. Started and ran perfectly in the driveway :/

 

[Floridan surfer]

In searching through this forum, I read something about it cracked intercooler. It may be something worth checking into. Maybe even disconnect the intake from the intercooler and see what happens.

 

[xintersecty]

In searching through this forum, I read something about it cracked intercooler. It may be something worth checking into. Maybe even disconnect the intake from the intercooler and see what happens.

Did you disconnect your inter-cooler? Have you ran it yet? Is there a way to pressure test the inter-cooler?

I had start issues and they were not like yours. My fuse block was cascading a short onto the ignition circuits.

 

[Floridan surfer]

I wonder how efficient this intercooler actually is? Wonder if it's at the potential costs outweigh the benefits.

 

[AnthonyB]

I’m having the same problem with my 2008 180 challenger, changed inner cooler still have same issues