2000 Mercury 200hp EFI wot intermittent problem

[cuffey100]

Will run fine at lower rpms but seems to starve for fuel at 3/4 to wot. Primer bulb remains firm even when problem arises Have had it tied up at local mercury dealer several weeks only to get it back and still have problem. I changed the fuel filter, they installed fuel pressure regulator. Still have the problem. The last time out it started hesitating at WOT then died. Would not start for a few minutes and after several attempts it started and ran fine for remainder of trip but I did not get it over 4500 rpms. This problem has been going on for 9 months. Please help

 

[Coloradolakeboy]

Re: 2000 Mercury 200hp EFI wot intermittent problem

If you are having a bog or a hesitation, and/or lower than normal rpm's, you should have the ignition tested. You will need an ohm meter with a DVA adapter. The symptoms sound like the stator might be on the way out, but just don't throw parts at it, get it tested.

 

[Texasmark]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Back in the early days of my mechanin life, plugs would leave you hanging at the higher rpm's on automobiles. First I would ensure that your fuel filter is clean/new since you know that you have fuel to the engine, and the fuel pump is what pumped the bulb up after you were underway.....so you don't have to suspect it. Then I would move on to new plugs. If you are worried about bad gas problems, you could move up to premium or/and add something like Sea Foam (available at most upscale auto parts stores....autozone, WM, to name a couple) or Marine Sta-Bil.

Come back and tell us how it is going/went.

Mark

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

I'll try one of the additives(Marine Sta-Bil). I've already changed the fuel filter. Also what is a DVA adapter?

 

[Coloradolakeboy]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Look at page 3 on this link it will explain what a DVA is.
http://issuu.com/cdielectronics/doc...t.xml&backgroundColor=000000&showFlipBtn=true

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Problem still happening. Removed the fuel tank check valve. Fuel pressure is good (35 psi). Fuel in VST is clean. One other symptom that may be a different problem is while increasing rpms while in neutral, engine leans out and dies. It idles great until I raise the rpms then it leans and dies. This problem is consistent fuel starvation but the dying at WOT is intermittent and may be a ignition problem. I never have WOT problem until I get over 5000 RPM's. It dies abruptly when it acts up but I usually can restart and continue the day without any problem as long as I don't get over 5000 RPM's. I've had it in to a Certified Mercury repair center and they haven't been able to fix it. Now I'm thinking that it may not be an electrical problem because of the way that it dies abruptly at WOT. Sure would like to get this problem behind me as its been a problem for over a year. Any help would be greatly appreciated.

 

[CharlieB]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Fuel pressure to the injectors should be constant. Rev'ing in Neutral does not require much fuel so the motor MUST BE loaded, in gear, either in a test tank on on the water. If fuel pressure falls off then you start checking into the fuel supply, either the primary supply isn't keeping the VST filled or the high pressure pump is beginning to fail.

If the pressure holds fine, pull the spark plugs for inspection is soon as it dies. Are they dry, on each one? Individual injectors screens may be somewhat plugged, restricting flow volume needed for WOT.

 

[Faztbullet]

Re: 2000 Mercury 200hp EFI wot intermittent problem

What is your voltage when running at WOT? If motor is overcharging it can causing the stator to overheat and shut down. This model has separate rect/reg's and are known for their bad connections. They can also make the ECU and fuel pump act goofy.

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Going to the lake today for testing fuel pressure under load. I suspect that I'm losing fuel pressure at WOT due to intermittent voltage drop at the pump. The motor runs great until it dies abruptly then may not crank for several tries then usually has a hesitation for a minute or so but will eventually will run on all cylinders as if there is no problem. I usually can duplicate the problem by throttling to WOT immediately but I'm very reluctant to due so because of fear of leaning/detonation.

I read this in the service manual on cking voltage at the high pressure fuel pump.

3. Ignition key in “ON” position and engine NOT running.
(–) terminal of fuel pump. 1.5 volt or less (voltage should rise to 12 – 13.5 volts after approximately 30 seconds.

4. Engine being cranked. (–) terminal of fuel pump. 1.5 volt or less. Bad ECM or bad fuel pump.

Mine measures 2.2 volts while the pump is running and then goes to 12.5 when pump stops. What does the 2.2 volt instead of 1.5 volt or less mean?

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Faztbullet, Will a high voltage be over 13 volts? Also where would the suspected bad connections be? Are you referring to the stator assembly leads?

 

[Faztbullet]

Re: 2000 Mercury 200hp EFI wot intermittent problem

That 2.2vdc is good, what manual mean is if it reads 1.5 v or less ECM/fuel pump is bad. Your reads more tha 1.5v so your good.

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

I found that the starboard head temp sensor wire has burn't almost into. Looks like the hood may have pinned it against the head and crushed the wire. Could this be the problem?

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

What is your voltage when running at WOT? If motor is overcharging it can causing the stator to overheat and shut down. This model has separate rect/reg's and are known for their bad connections. They can also make the ECU and fuel pump act goofy.

running voltage is 14.14 volts. I did notice that the tach was reading alot higher than it supposed to.

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

I hope that these results don't muddy the water but here goes:

Manufacturer: Mercury
Year: 2000
HP: 200 V6 EFI
Model: 1200413WD
Serial #: 0T156595


Problem(s): Intermittent Problem
1) Symptom(s): Running @ WOT motor dies abruptly. May not restart for a moment or so and usually has severe hesitation for several attempts to throttle up. Eventually will throttle up and may operate normally for rest of day. However, owner/operator usually doesn’t run over 4500 RPMs after the first shutdown. This problem ordinarily occurs @ 5000 RPMs or more. Note: Fuel bulb remains firm and problem seems worse with hood off
2) Symptom(s): Fuel starvation at idle (normally during warm-up) while applying throttle, motor will lean and die. Note idles very well at low RPMs.


Item #1 – Battery voltage
Key off 12.49
Key on 12.17
Key on motor at idle 12.94

Item #3 – Voltage in neutral
4000 RPMs 14.4 Volts

Item #4 – Voltage (boat underway)
4000 RPMs 14.14
Voltage @ WOT 14.4

Item #5 – Key on with motor off fuel pressure
37 PSI
32 PSI, 30 seconds after shut-off (pump)
30 PSI after 1.5 minutes

Item #2 – Fuel Pressure in neutral
2200 RPMs 35 PSI
3600 RPMs, fuel pressure drops to 30, motor dies.
Note: When motor dies HP fuel pump may not operate (for a few minutes) when key is turned on.



Replaced:
1) Fuel line (new)
2) Fuel filter / water separator (new)
3) Fuel pulse pump (kit)
4) Fuel pressure regulator (new)

 

[Faztbullet]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Remove the negative lead from ECU to fuel pump, Apply a jumper from pump negative to ground, this bypasses the ECU and now re test the engine. It sounds like the driver board in ECU is bad since pump does not come back on or the fuel pump itself is failing.

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Remove the negative lead from ECU to fuel pump, Apply a jumper from pump negative to ground, this bypasses the ECU and now re test the engine. It sounds like the driver board in ECU is bad since pump does not come back on or the fuel pump itself is failing.

I might mention that I can get the pump to restart by unplugging the ECU cannon plug and replugging.

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Remove the negative lead from ECU to fuel pump, Apply a jumper from pump negative to ground, this bypasses the ECU and now re test the engine. It sounds like the driver board in ECU is bad since pump does not come back on or the fuel pump itself is failing.

Just got back from the lake. Did exactly as you said, pump ran constantly as expected unfortunately same old problem. Thanks for helping with this.

 

[Faztbullet]

Re: 2000 Mercury 200hp EFI wot intermittent problem

Pull the ECU and send over to Brucatto and have tested. Call Tony or Linda to see what their holiday operations are.

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

I think that I may have found the problem. Note that the fuse is not blown. Have not lake tested yet, but relatively sure that this is why the problem was intermittent.

 

[cuffey100]

Re: 2000 Mercury 200hp EFI wot intermittent problem

I think that I may have found the problem. Note that the fuse is not blown. Have not lake tested yet, but relatively sure that this is why the problem was intermittent.

Whoo! Hooo! Lake tested and ran like a scalded ape. Thanks to all for your time and expertise.