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Please HELP me get my EFI running

boardhauler

Contributing Member
Hello everyone,

I could use some expertise and troubleshooting help. Sorry for the long post, but, details.......

I have a Mercury 30HP EFI 2006 with power trim and remote control (NEW).

I purchased it used. It appeared to start and idle perfect.

I noticed that the factory LP fuel filter was missing. I ordered the correct part, and put in a Sierra in line plastic fuel filter.

I filled the clean tank with ethanol free gas, 3 1/2 gallons.

The first time out on the water it started & ran great for about 2 miles, then I noticed a power drop while at wide open throttle. It still ran on plane. When we got to our destination (2 miles later) it started stalling when idling. It would start right back up. If I left it at idle it would stall. If I pushed the throttle it would run. We ran back to the ramp. It stalled on idle multiple times at the ramp.

Back at home on the ears, it started, but would stall unless I turned on the fast idle lever.

I mounted the correct factory LP filter (plastic bowl w/screen inside)
I opened the fuel reservoir, removed the HP pump and pressure regulator, cleaned everything including the intake screen, float, passages and seat (only minor stains, no gunk)
I put on a new High Pressure fuel filter
Put dielectric great on plug connections, and other connectors.
Replaced the spark plugs (the old ones looked fine)
Replaced the water pump, plate, housing and gasket (the old one was ok, wear on the SS housing and rubber tips)
Replaced the lower unit oil (the old oil was black, but no filings or debris)

I ran it on the ears and the tach read approximately 1000-1050 RPM at idle (which is a bit fast, 850-875 is spec) I have a video of this.

We took it out on the water today.
It started right up.
Right at the ramp/trailer, when shifting to reverse, there was not power, only weak idle speed
We pushed off, drove away and it ran out good (maybe a little weak, it was hard to get on plane, I have a 380 lb Avon RIB)
We drove about 4-5 miles in chop, wakes, and wind. On and off plane. Then trolled around for 10 minutes.
When I tried to put the throttle down again, it would not get on plane, a minute later it stopped running, dead in the water.
It would not start
Got a tow home from a great guy, that saw me paddling to anchor.

It won't start on the ears
Nothing

I checked the plugs and they look fine
After cranking, I did not smell fuel like I expected when I removed the plugs
I grounded 2 of the plugs, cranked it and saw a spark on each
I put 12v direct to the HP pump and heard it run
I pushed the schrader valve on the fuel rail and fuel came out (I don't have a proper pressure gauge, but I read at least 20psi on my bike pump gauge).

Any ideas?
 
Chris,

It reads 35 psi when I am cranking it. Drops to zero when I stop cranking.

I don't hear the HP pump running with the key switched on only, should it run? (I did check the pump by applying 12v direct and it runs).

Does the VST hold pressure inside? When I reassembled it, I used the old gasket, it was a bit flat and had what looked like residue from someone using gasket sealer on it (clear or dark colored, hard, like indian head shellac). I did/do not see any leaks, but if it is made hold hold air pressure, it may not be working.



Hook a fuel pressure gauge up and get a true PSI reading....
 
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There is a grommet on top of the fuel pump that seal the outlet of the pump.... If you did not get that seated correctly you will loose fuel pressure.. which seems, to be what is happening... Pull the VST apart and look at it.
 
Ok guys, I have a 2006 60hp 4 stroke mercury EFI. After about 10 min of running WOT it starts missing on #2 and #3 cylinders. I have narrowed it down to no fuel on those two. I have changed plugs, coils, injectors and tried a different ECM from another 60hp mercury and still no change. Fuel pressure from the VST tank is 46psi continuously. Could it be the low pressure fuel pump causing this? Also I have had two boat mechanics look at it and no codes are showing. Any help would be appreciated thanks.
 
Ok guys, I have a 2006 60hp 4 stroke mercury EFI. After about 10 min of running WOT it starts missing on #2 and #3 cylinders. I have narrowed it down to no fuel on those two. I have changed plugs, coils, injectors and tried a different ECM from another 60hp mercury and still no change. Fuel pressure from the VST tank is 46psi continuously. Could it be the low pressure fuel pump causing this? Also I have had two boat mechanics look at it and no codes are showing. Any help would be appreciated thanks.

Please start a new thread for your question. We're still working here on some issues/questions about my specific motor. Thanks.
 
Chris,

Thanks. I'll get it apart tomorrow and check back in. I do remember that it was tight wiggling the HP pump back down into the bottom of the VST housing.


There is a grommet on top of the fuel pump that seal the outlet of the pump.... If you did not get that seated correctly you will loose fuel pressure.. which seems, to be what is happening... Pull the VST apart and look at it.
 
There is a grommet on top of the fuel pump that seal the outlet of the pump.... If you did not get that seated correctly you will loose fuel pressure.. which seems, to be what is happening... Pull the VST apart and look at it.

Chris,

Took the VST back apart today. The grommet at the top of the HP pump looks good and seated perfect. I attached a pic before I pulled it off.

Photo on 3-31-20 at 9.04 PM.jpg

I also removed the screen from the HP pump. It took some work and I wonder if it is even made to be removable, seems like it was melted in place. The screen is perfectly clean. Also, the fuel I drained from the VST was clean, as expected since I just cleaned it out a few days ago.

Photo on 3-31-20 at 9.04 PM #2.jpg

Is there a way to check my fuel pressure valve with compressed air?
Are there any tiny orifaces that have screens I should check?
Does the HP pump turn on with the key in the on only position? Or only when you crank the starter?

thanks for your help!
 
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While you have the VST apart, pull the regulator and clean the filter under it... Pay attention to the o-ring and direction of the screen... Not that this is your issue, you are already in there....

There is not pressure in the VST tank itself, but the system should not drop to zero immediately after shut down.....

Do you have a primer ball on this engine?
 
Chris,

I'll check the regulator again. I removed and cleaned it and the cavity the first time I opened the VST.

Yeah, the fuel pressure gauge on the rail schrader valve is reading 35ish PSI when I am cranking it (turning the key). It drops to zero as soon as I stop.

Yes, I am running a 3 gallon portable tank, with a safety valve and pressure/primer bulb.



While you have the VST apart, pull the regulator and clean the filter under it... Pay attention to the o-ring and direction of the screen... Not that this is your issue, you are already in there....

There is not pressure in the VST tank itself, but the system should not drop to zero immediately after shut down.....

Do you have a primer ball on this engine?
 
Chris,

The regulator is held down with x2 SS screws. I removed the small line (drain possibly). I pulled out the regulator with the return hose attached. The regulator has a rubber seat under it. It has a brass tube with 2 o rings on it that goes down into the VST.

I do not see any screens.

Looks like this.

Screen Shot 2020-04-01 at 12.01.30 PM.png
 
The fuel rail and injectors Should hold pressure after the pump turns off and should build to 40PSI or so. Something is leaking, it could be the regulator,injector or the fuel cooler. You are going to have to check all these components by process of illumination.

Pull the pump and rig your gauge to the fuel output side and power the pump while dropped in some fuel. Assemble everything, make some long jumpers, drop the pump in a small container of fuel and hook the jumpers to a battery that is far away.... Watch the gauge, remove the power....

Remove the fuel rail, secure the injectors and power the pump. None should leak...

Start with blowing orally through the regulator and see if it leaks, Apply some regulated compressed air to it 20psi will do and see if it leaks...

And so on...... with the fuel cooler..... Make sure the vst is full of fuel, the pump will make 35 psi of air pressure in the system and that will bleed back fast.
 
Chris,

So, I put the brass tube back in the regulator (out of the VST) and connected my mightyvac (hand vac pump) and it flowed fuel/sucked out with very little vacuum.

I then put a hand pump on the fuel rail schrader valve and started to pump it and it immediately flowed fuel through the regulator. It happened so fast, I didn't even see the pressure, but it was less than 15-20 PSI.

It seems like thats a clear indicator that the reg is bad, thoughts?



The fuel rail and injectors Should hold pressure after the pump turns off and should build to 40PSI or so. Something is leaking, it could be the regulator,injector or the fuel cooler. You are going to have to check all these components by process of illumination.

Pull the pump and rig your gauge to the fuel output side and power the pump while dropped in some fuel. Assemble everything, make some long jumpers, drop the pump in a small container of fuel and hook the jumpers to a battery that is far away.... Watch the gauge, remove the power....

Remove the fuel rail, secure the injectors and power the pump. None should leak...

Start with blowing orally through the regulator and see if it leaks, Apply some regulated compressed air to it 20psi will do and see if it leaks...

And so on...... with the fuel cooler..... Make sure the vst is full of fuel, the pump will make 35 psi of air pressure in the system and that will bleed back fast.
 
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I cleaned the regulator, used my oscillating tool to vibrate it, and it seemed to lock up better. I put it in a heated, ultrasonic cleaner and it now holds pressure to approximately 42 PSI before opening. I am running it through the cleaner for one more cycle. Maybe I can salvage it.

I pulled the injector rail. But I am unable to remove the injectors from it. They pull out a bit, but then the resistance gets were hard. I don't want to break them.




The fuel rail and injectors Should hold pressure after the pump turns off and should build to 40PSI or so. Something is leaking, it could be the regulator,injector or the fuel cooler. You are going to have to check all these components by process of illumination.

Pull the pump and rig your gauge to the fuel output side and power the pump while dropped in some fuel. Assemble everything, make some long jumpers, drop the pump in a small container of fuel and hook the jumpers to a battery that is far away.... Watch the gauge, remove the power....

Remove the fuel rail, secure the injectors and power the pump. None should leak...

Start with blowing orally through the regulator and see if it leaks, Apply some regulated compressed air to it 20psi will do and see if it leaks...

And so on...... with the fuel cooler..... Make sure the vst is full of fuel, the pump will make 35 psi of air pressure in the system and that will bleed back fast.
 
Update, some repairs, SOMETHING STILL WRONG

I got the injectors out, cleaned them. Sprayed Seafoam through them with compressed air while actuating them with 12 volts

x2 injectors have a very tiny white piece of plastic in them. Neither piece looks large enough to hurt flow enough to cause problems.

I put everything back together. The regulator now cracks at around 44 PSI to bleed off excess pressure.

When I crank it, the fuel pressure gauge reads a solid 40 PSI and does not leak down.

BUT, IT STILL DOES NOT START. I pulled the plugs and I don't see any fuel on them. It seems like the injectors are not firing OR maybe no spark.



The fuel rail and injectors Should hold pressure after the pump turns off and should build to 40PSI or so. Something is leaking, it could be the regulator,injector or the fuel cooler. You are going to have to check all these components by process of illumination.

Pull the pump and rig your gauge to the fuel output side and power the pump while dropped in some fuel. Assemble everything, make some long jumpers, drop the pump in a small container of fuel and hook the jumpers to a battery that is far away.... Watch the gauge, remove the power....

Remove the fuel rail, secure the injectors and power the pump. None should leak...

Start with blowing orally through the regulator and see if it leaks, Apply some regulated compressed air to it 20psi will do and see if it leaks...

And so on...... with the fuel cooler..... Make sure the vst is full of fuel, the pump will make 35 psi of air pressure in the system and that will bleed back fast.
 
Chris,

Yes, when cranking the tach jumps to about 500 rpm.

I charged the battery to make sure it was topped off.

Is it possible that the kill switch remote control circuit is shot? It's a new unit, but a aftermarket (not Merc).



Sounds like you fixed the leak down, for now.

Do you have a tach at the helm? If yes, does the tach move when you crank the engine?
 
Chris,

Yes, when cranking the tach jumps to about 500 rpm.

I charged the battery to make sure it was topped off.

Is it possible that the kill switch remote control circuit is shot? It's a new unit, but a aftermarket (not Merc).

I never suggest this... Have someone crank the engine and put a quick shot of Starting fluid in the intake...See if it pops over...

If it does, you have to verify that the injectors are firing...

simple question: Have you done a compression test..... The issues you just corrected with the fuel pressure will lean out the fuel mix and destroy the engine......
 
I used my multimeter to probe the injector connectors with the KEY ON. NO VOLTAGE, ZERO.

I assume each injector should have 12 volts with the key on (ECM provides negative contact). Just to make sure, I probed for a ground, none.



Rent a noid light kit from auto parts and see if injectors are getting signal to fire from ECU
 
Chris,

I don't know if my multimeter will read pulse.

Should there be 12 volts to the injectors with the key in the on position?

I will dig out the compression tester this afternoon. It does sound like good compression to me.

The power to the injectors is common and fused..... The ecm grounds injectors to fire them...
 
Chris,

Ok, well there is definitely no voltage at the injectors. The only fuse I see is the 20amp in the small yellow box above the ECM.

Are there any sensors that would cause the ECM to cut power to the injectors.

The ECM does not supply power to the injectors... The power is always there.... The ECM grounds the injectors to fire them... There is a fuse...
 
My compression gauge is too large for the Merc plug hole. I'll have to get another one.

The common wire (to all 3 injectors) is medium blue. I see the same color wire that goes into the ECM main plug.

The only fuse that I can find on the engine or in the manual is the single 20 amp.

The Stator has 3 separate voltage outputs. One to the rectifier (for charging the battery, One to power the ECU charge coil, and one to the exciter coil.

The regulator/rectifier reads 8.1 ohms on all 3 test points ( manual say .29 - .43 ohms).

The outputs to the ECU charge coil measure 8.5 ohms (the manual says they should be 1.1 - 1.7). The outputs to the exciter coil measure 22 ohms (the manual says they should be 11-16 ohms).

The primary coil of all 3 ignition coils reads 6.2 ohms (the manual says they should be .17 - .23 ohms).

The coil high tension lead (4.14) and cap (5.18) reads within spec.

Both the CPS are within spec ohms (187.5 & 190.8 ohms).

I am using a digital Exotech meter set to AUTO to read ohms. I may need to switch to a analog meter.

The ECM does not supply power to the injectors... The power is always there.... The ECM grounds the injectors to fire them... There is a fuse...
 
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