no spark intermittent

[badluck]

I could complain about it but having a boat is a good problem to have. 2007 indmar 5.7 hard starts cold and hot. Crank it cold several times and it usually fires up. If I run it for 20 min shut it down and start it within 5 min it will fire right back up. Let it sit for 10 min and same thing, gotta crank serveral times. Fuel pressure is good, no bleed off. What parts could be bad? At first I thought it was heat related but it will do it dead cold too. I can pretty much guarantee after running it and letting it sit for 10 min the no start will happen. Ignition control module is my first thought. crank sensor, cam sensor, what else? No lanyard, so thats not it. 800 hours, serviced every 80 hours. oil,plugs,rotor,cap,impeller,trans,v drive fluid and fuel filter. Any ideas? Control module is 180$

 

[SBMech]

Since it's intermittent, you can pretty much rule out mechanical issues, no spark/injection pulse could be crank sensor hot soak issue. Testing it will save you money over throwing parts at it.

 

[4Waters]

Check grounds as well

 

[Shlbyntro]

Some marine engine systems are wired to derive ignition source power from the alternator. If yours is one of these, it could be an intermittantly bad alternator. Next time it does it, be ready to jump power from the hot power post on the starter to the purple wire going into coil. If it starts right up, that's your issue.

Other culprits could be your iac getting jammed, or possibly a bad map sensor as well. This is where a scan tool would be handy

 

[Yellowboat]

Start with your grounds and connection. Then move on too testing crank/ cam position sensors.

 

[badluck]

iac?

 

[SBMech]

Idle Air Control Valve

 

[SBMech]

When it finally starts is it loaded up or does it start like nothing was wrong?

 

[badluck]

Starts like nothing’s wrong

 

[Yellowboat]

Normally when an iac goes bad it won't idle worth a shit. Think like a carb with a bad vaccumm leak.

 

[badluck]

Will the iac stop spark? It does not even fart. Just turns over

 

[badluck]

It runs great

 

[4Waters]

Will the iac stop spark? It does not even fart. Just turns over

How do you know it has no spark, have you checked it or are you just thinking that's it

 

[Shlbyntro]

The iac wouldnt stop spark. But I have seen them jammed wide open to where the engine wouldnt start and almost seamed like no spark until after it fired on several occasions.

Verifying spark when this happens again would be the first step to know which route you need to go

 

[buck35]

A plug in spark checker is about 4 bucks at oreiillies.

 

[4Waters]

Get one of these.

https://www.harborfreight.com/90-in...a-yvJzoYGNms8DPWnvtl1r-NWO-WhCXIaAmJLEALw_wcB

 

[racetrash]

Try a diff prop??

 

[monkeyswrench]

Get one of these.

https://www.harborfreight.com/90-in...a-yvJzoYGNms8DPWnvtl1r-NWO-WhCXIaAmJLEALw_wcB

....Or use a kid, they have small hands to reach the plugs too

 

[4Waters]

....Or use a kid, they have small hands to reach the plugs too

It's a good lesson

 

[Shlbyntro]

It's a good lesson

I tend to forget and have to relearn this lesson at least a couple times a year. Always seams to be on outboards too :/

 

[badluck]

Used a timing light to verify no spark

 

[monkeyswrench]

Used a timing light to verify no spark

Where's the fun in that?
J/K...probably the best way, don't have to worry about damaging a boot either.

 

[Yellowboat]

Timing lights just tell you spark is going too the plug... not that you actually have spark. When I was in my teens had a truck that we could not figure out why it ran like shit, until we pulled the plugs

 

[4Waters]

I tend to forget and have to relearn this lesson at least a couple times a year. Always seams to be on outboards too :/

Try an MSD with a Pro Power coil (55,000v), after you get your breath back and get off the floor it's burned into your head. LOL But I did learn that lesson a few times before the incident

 

[badluck]

I pulled a plug and it looks great. They have about 4 hours on them.

 

[badluck]

How do I test the ignition control module?

 

[Headless hula]

Sketchy ground. Corrosion, swelling paint where they are attached to the engine....


Pull em, scrub paint and retest.


90% of the time is a shitty ground.

 

[rrrr]

....Or use a kid, they have small hands to reach the plugs too

This reminds me of my debut as a sprint car team mud scraper and gofer. The crew chief was holding a Vertex mag, and he told me to grab the wire dangling from it.

I did, and he spun the drive gear...shocked the f*ck outta me, everyone in the pit got a good laugh.

 

[rrrr]

Check the cap & rotor, check under the cap and make sure the little nipple has good contact with the rotor same goes with the shaft, make sure there is no corrosion on it.

Could be coil wire or bad coil.

It's an electronic fuel injected COP engine.

 

[Chris Lapoint]

It's an electronic fuel injected COP engine.

Lol should have read everything in its entirety , I retract my trouble shooting advice.

 

[guest hs]

Unscrew the IC module clean the screws read good and under the module and the clean out the threads where the screws go in.

 

[rrrr]

Lol should have read everything in its entirety , I retract my trouble shooting advice.

That's OK, I almost did the same thing.

 

[ElAzul]

Try an MSD with a Pro Power coil (55,000v), after you get your breath back and get off the floor it's burned into your head. LOL But I did learn that lesson a few times before the incident

View attachment 763483

Yeah those mofo's hurt. It doesn't even feel like electricity it's hard to describe

 

[mash on it]

Oil pressure sending unit

Dan'l

 

[badluck]

Made some progress today. 3.9 volts measured at the coil with key on. If I leave the key on for 10 seconds it goes to 12 volts. Then it starts no problem. During the 10 seconds with the key in the on position I hear a whining sound. At about 10 seconds the whine stops and I get 12 volts. The other day after the whine stopped I'd hear a click click. I think its a relay failing. Any ideas? Trying to pin point the whine. It seems to be ontop of the motor under the intake manifold cover.

 

[Yellowboat]

Fuel pump?

 

[guest hs]

I would trace down the purple ignition wire from the plus side of the coil to the relay then unplug the relay and test the purple wire from the ignition switch to the relay and see what the voltage is without the relay in the system

 

[Shlbyntro]

That whine almost sounds like the fuel pump prime. Replacing the relays is cheapest but may be an electric fuel pump that isnt jammed but internally shorted. Something is definitely drawing more power than it should which is throwing your ignition out of whack with that low voltage

 

[rush1]

Get one of these.

https://www.harborfreight.com/90-in...a-yvJzoYGNms8DPWnvtl1r-NWO-WhCXIaAmJLEALw_wcB

I made one of those in electric shop Jr high school, still have it still use it.

 

[badluck]

It seems like throttle position sensor is where the whining is coming from. When I disconnect the plug from the tps the coil reads 12 volts and there is no whine. Fuel pump prime stops way before this whine. This is a drive by wire setup. No throttle cable. So it starts up when I unplug it but dies immediately.

 

[DaveH]

im not convinced its a spark issue.

first of all being a DBW application, there is more to the TPS then the sensor. that is a servo motor with multiple position sensors....there is no commonality in the wiring between the ignition system and the throttle. some throttle servos go through a reset process when you key on and that may be the noise you are hearing.

it sounds to me like either a fuel pump/pressure issue. I have also seen injectors leak fuel and load up the engine. many engines hold fuel pressure even after the pump stops...to facilitate quick start up....but with a leaky injector the fuel slowly drips into a cylinder, partially flooding the engine and then with no pressure for the next start takes a couple cycles of the pump to get the pressure back up, not to mention clearing the flooded condition....in all making for a hard starting engine that runs ok once going.

anytime you have ignition system woes....the first order of business is to simply throw a set of plugs and wires at it. I have seen many intermittent issues go away from components that looked/tested fine.

 

[badluck]

Definitely an ignition problem. If the throttle body is disconnected 12 volts at the coil. 3.9 when it’s connected. Timing light shows no spark. Won’t start with 3.9 volts out of the coil. Starts every time when it reada12 volts. As soon as the tps stops whining the voltage goes to 12. It whines for about 6 seconds longer than the fuel pump. I definitely know the difference.

 

[Shlbyntro]

I'm leaning towards a possible bad throttle plate driver motor... shorted out windings in the motor are a strong possibility

 

[badluck]

Leaning same direction

 

[buck35]

I have a Merc 502 and had a similar problem a couple of years ago . No start or fire and die when I tried to shift. I took off the tps and cleaned it out, it was gunked up . No problems since, and it cost nothing but an hour or two of my time.
Good luck on your resolution.

 

[badluck]

Tried a new throttle body tps. No luck. Same sound same voltage.

 

[buck35]

Tried a new throttle body tps. No luck. Same sound same voltage.

Clean every connection you can find/ reach. Sounds like you have an electrical issue and that's not in my pay grade.

 

[Headless hula]

Iac?

 

[guest hs]

I would probably start looking real hard at that ECM. You really should get it scanned instead of throwing parts at it.

 

[HST4ME]

Mmmm MEFI 5 FBW ... fucking pain in the ass. I'd be looking at the throttle plate driver. If you can find someone with a Rinda Techmate it should scan it.