Anyone know anything about Mercury Class One Race Motors????

[rivergames]

Went to fire up Mercury Class One Race Motor in GN and the injection ports are not opening to receive fuel. We've looked over everything we can. Fuel is flowing to the rails. What are the possible issues???

This is a Thunderbolt EFI system.

Motor was just Dyno'd. I'll make calls tomorrow, but trying to get this figured out tonight.

 

[mjc]

Injectors need work, have them cleaned and flowed.

 

[monkeyswrench]

Not a Merc guy, but check fuses and connections. Usually if injectors are gummed up, it will run like crap, but still light. Sounds like either the ecu isn't supplying signal (crank trigger or ?) Or the injectors can't make a complete circuit.

 

[rivergames]

Not a Merc guy, but check fuses and connections. Usually if injectors are gummed up, it will run like crap, but still light. Sounds like either the ecu isn't supplying signal (crank trigger or ?) Or the injectors can't make a complete circuit.

Motor was just Dyno'd by Burmmet and worked great. We're missing something here

 

[rivergames]

So when we 1st fired, it instantly almost lit. Then died. Then just turned the motor. The computer is readying something wrong and not sending power to open the injectors to allow fuel in.

 

[DarkHorseRacing]

Bad ground somewhere?

 

[n2otoofast4u]

Just tossing shit at wall because I’ve dealt with it.

Crank position sensor… wasn’t too close and got whacked?

Cam Sync…. Not loose and rotated?

Not knowing a lot about that setup, can you not plug it in and see the data as it turns over?

Edit after re-reading…. If the system isn’t commanding injector timing, then either you lost the 5v power to the injectors, or the rotational sensory that they are dependent on shit the bed…. Or a ground

 

[Outdrive1]

Didn’t you just rewire the motor? Something is missing

 

[monkeyswrench]

Just tossing shit at wall because I’ve dealt with it.

Crank position sensor… wasn’t too close and got whacked?

Cam Sync…. Not loose and rotated?

Not knowing a lot about that setup, can you not plug it in and see the data as it turns over?

Edit after re-reading…. If the system isn’t commanding injector timing, then either you lost the 5v power to the injectors, or the rotational sensory that they are dependent on shit the bed…. Or a ground

The crank trigger and cam sensor...yep, I've done both at separate times

Check and make sure the 12v ign and start wires aren't tied together through anything. Done that as well, only powered ecu while cranking, would only "cough" sometimes when backing off the starter.

And of course, check your grounds. Those pixies (electrons) find paths through stuff running to complete their circuits when their normal doors aren't open.

 

[n2otoofast4u]

Is this a keyed ignition switch, or switch and start button?

 

[Nail It]

I had a similar issue when trying to fire a class one motor that had sat for 25 years. Make sure the crank position sensor that mounts to the bellhousing is getting the correct signal from the 4 tabs/notches on the flywheel. It will not fire without that signal.

 

[DaveH]

since it ran fine on they dyno, i doubt its a bad sensor. more likely you dont have power hooked up correctly.

some older ECU's had a constant power feed and an ignition key on feed. if yours has that make sure they are not reversed.

almost all ECU's trigger the injector on the negative side......with the key on, check to see that 12v is getting to one side of the injector.

another simple test is to see if you have spark. hook up a timing light and crank it to test.

 

[wzuber]

This is a GN race boat.
Pretty sure it has a lanyard style kill switch (mercury) and a push button to start.

 

[rivergames]

since it ran fine on they dyno, i doubt its a bad sensor. more likely you dont have power hooked up correctly.

some older ECU's had a constant power feed and an ignition key on feed. if yours has that make sure they are not reversed.

almost all ECU's trigger the injector on the negative side......with the key on, check to see that 12v is getting to one side of the injector.

another simple test is to see if you have spark. hook up a timing light and crank it to test.

We have spark on the plugs. I will check tonight to see if we are getting 12v to the side of the injectors

 

[rivergames]

This is a GN race boat.
Pretty sure it has a lanyard style kill switch (mercury) and a push button to start.

Correct. We have a push button starter and a mercury style kill switch. The plugs are getting power. I am seeing the injectors not opening to allow fuel into the motor.

 

[rivergames]

I had a similar issue when trying to fire a class one motor that had sat for 25 years. Make sure the crank position sensor that mounts to the bellhousing is getting the correct signal from the 4 tabs/notches on the flywheel. It will not fire without that signal.

We had the motor fired yesterday when we dropped some race gas in the top of the motor. Then it quickly dried up when it ran out of fuel.

 

[rivergames]

Well.... If we can't figure out the issue tonight, she will be dropped off to Mr. Brummett tomorrow to solve the issue.

 

[lbhsbz]

This is a GN race boat.
Pretty sure it has a lanyard style kill switch (mercury) and a push button to start.

lol…then check the kill switch.

 

[wzuber]

lol…then check the kill switch.

No shit sherlock.....
I was replying to Dave H. regarding a "key switch". Try following along.

 

[lbhsbz]

No shit sherlock.....
I was replying to Dave H. regarding a "key switch". Try following along.

Somebody piss in your cheerios this morning?

 

[DaveH]

Correct. We have a push button starter and a mercury style kill switch. The plugs are getting power. I am seeing the injectors not opening to allow fuel into the motor.

its unlikely you can "see" the injector pulse. we are talking fractions of a second at idle speed or less. even a noid light ( small device to test injector outputs) barley blink at start. not saying you dont have an issue with the injectors firing, but doubt its not the ecu doing its thing.

 

[Outdrive1]

Andrew go to the auto parts store and get a “Noid Light Set”

 

[wzuber]

It that what ya use to help diagnose elec problems when you're annoyed af?

 

[lbhsbz]

Andrew go to the auto parts store and get a “Noid Light Set”

In my experience, those are useless.

Put your finger on the injector and crank it…if it’s firing, you’ll feel it click.

Or you could hook up a scope, but use an attenuator…the spike when it breaks is in the thousands of volts and it’ll let the smoke outta the scope.

 

[Outdrive1]

In my experience, those are useless.

Put your finger on the injector and crank it…if it’s firing, you’ll feel it click.

Or you could hook up a scope, but use an attenuator…the spike when it breaks is in the thousands of volts and it’ll let the smoke outta the scope.

We know the injectors work because it just ran.

Here’s another question, how much fuel pressure do you have at the rail Andrew? You’ll need to make 30ish psi to make them fire. Do you have fuel at the schrader valve when you push it in?

 

[lbhsbz]

We know the injectors work because it just ran.

Here’s another question, how much fuel pressure do you have at the rail Andrew? You’ll need to make 30ish psi to make them fire. Do you have fuel at the schrader valve when you push it in?

We know the sparklers work because it ran when they dumped gas down it. So if the injectors work and the sparklers work....it would be running. One of the 2 ain't working....or the injectors are working but it ain't no gas in it.

Empty tank and the goddam kill switch are 2 things that throw the best guys for a loop...lol.

 

[rivergames]

We know the injectors work because it just ran.

Here’s another question, how much fuel pressure do you have at the rail Andrew? You’ll need to make 30ish psi to make them fire. Do you have fuel at the schrader valve when you push it in?

Fuel pressure is at 75 psi. This is regulated a the black conjunction block on the bottom of the intake. The fuel line goes from the pump into this block. Then it Y's out to the fuel rail on each side. The conjunction block also has a fitting that connected to the fuel pressure gauge.

On the other end of the fuel rails, each end has a smaller hose that goes into a bypass valve that shoots the excess fuel back into the tank. I'm assuming the bypass valve is pre set to keep the fuel pressure at 75psi because there is nowhere to adjust the psi.

 

[Outdrive1]

We know the sparklers work because it ran when they dumped gas down it. So if the injectors work and the sparklers work....it would be running. One of the 2 ain't working....or the injectors are working but it ain't no gas in it.

Empty tank and the goddam kill switch are 2 things that throw the best guys for a loop...lol.

His uncle rewired the entire motor last week.

 

[rivergames]

We know the sparklers work because it ran when they dumped gas down it. So if the injectors work and the sparklers work....it would be running. One of the 2 ain't working....or the injectors are working but it ain't no gas in it.

Empty tank and the goddam kill switch are 2 things that throw the best guys for a loop...lol.

I don't think the injectors are working due to not allowing fuel into the motor. Gas is shooting into the rails, but the injectors are not shooting into the motor.

 

[Outdrive1]

Where does this go? Actually both of these wires

 

[rivergames]

Where does this go? Actually both of these wires

View attachment 1437801

One was a ground to the block. The other was for the water temp gauge, but my uncle ran a new wire to the sending unit.

 

[Outdrive1]

One was a ground to the block. The other was for the water temp gauge, but my uncle ran a new wire to the sending unit.

Ok Ground that ground just for the hell if it.

 

[rivergames]

The smaller ground to the block? It's not connected to anything?

We tried grounding both wires to the block already and the motor just kept rolling over

 

[lbhsbz]

with the key on (ingition switch...whatever gets flipped on to make it so it should run) do you have 12V measured at an injector connector with the negative probe on the intake manifold and the positive probe on one of the 2 terminals in the injector plug? What if you move the negative probe to the block? What if you move the negative probe to the battery (-)? As has been stated, in the ON position, you get a constant 12V to one side of the injector. The ECM pulses the ground.

You're either missing the ground pulse or you're missing the 12V constant.

Edit...or the 12V constant is going away while cranking because shit is wired wrong....I've seen that before, sorta fires as it's slowing down after shutting the starter down, but isn't spinning fast enough at that point to light off.

 

[Fun Times]

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If you'd like to see if the injector is physically spraying, connect your fuel pressure gauge to the rail, load up the psi by key, then pulse the injectors via a power source to turn the/each injector on and see if gauge drops psi.

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[bonesfab]

Sounds like there is a power wire off somewhere. The injector power wire is usually on a relay. Sounds like the feed wire for the relay is not hooked up or a bad fuse. Should be a 12-14 gauge wire..

 

[rivergames]

Took the boat to Brummett this morning (that's where the motor was dyno'd).

First off, that was my first time meeting Carson. What a great guy with tons of knowledge and really helped me out!

Computer was missing 1 hot wire to power the injectors. We didn't have any wiring diagram and didn't use the Merc wiring harness.

Brummett threw on the hot wire and made her purrrrr!

 

[rivergames]

 

[wzuber]

Stuff..........the more ya know!!
Kool it was simple enough to cure and your on your way to play.

 

[Sawtooth]

Sounds awesome Andrew, glad you and Carson got it figured out and running again! My friend Roy, GetReal here on the boards (RIP) had three of these turn key engines in his shop before he passed from when he and John Peterson used to race offshore. He actually sold off two of them but wouldn’t let go of the last one as he was going to put it in his new 21 Schiada RC. He was so excited and used to tell me “wait until you hear this deal, it’s going to rip”!
Thanks for posting this video, I finally got to hear one run .

 

[Hightyme]

Damn sounds pretty good running around in front of the house