1999 mercury 200 efi starts but won't run

[bobimo]

1999 mercury 200hp efi s/n og886278 installed rebuilt powerhead, set timing, had injectors cleaned, fuel pressure at 36 psi. motor will start but dies in about 3 seconds, with timing light on number 1 plug still get fire after the engine dies, while trying to restart, sprayed starting fluid in manifold and engine will continue to run. removed manifold cover, check spray pattern on injectors all had good spray. rebuilt pulse fuel pump, can get fuel out of the outlet line while pumping the squeeze bulb, but cannot get any flow out of the pump while cranking engine, removed plug on bottom of vst and it was full of gas. any suggestion on what to try next. thanks bob

[JOE54]

possible ecu not running elect pump , watch fuel psi

[EuropeanAM]

DON'T spray starting fluid into the engine- that's a good way to destroy a powerhead.

Does fuel pressure remain at 36 psi even as the engine dies?

[bobimo]

fuel pressure varies between 28 to 36 psi while cranking, also put meter on one of the injector leads and you could see it vary between 12.5 volt and 8.5 volts, my meter is not fast enough to read this correctly. Can I tried to start motor with manifold cover removed. this would allow me to see the injector spray pattern and would eliminate one problem, so I could start looking at something else. checked all plugs and they were all firing. bob

[JOE54]

NO SIR do not do that, what does fuel psi do when engine is dying

[EuropeanAM]

+1... DO NOT attempt to start with fuel management box unbolted!

Fuel pressure must remain constant or the engine won't run (or run properly). Might check the ECU connection and make sure it's clean, properly seated, ring LOCKED, and connector locked in the stainless retaining bracket. Also verify a good ground to the ECU plate (from fuel management box).

[bobimo]

The fuel pressure never goes below 28 psi and returns to 36 psi as soon as the motor stops. the ecu connector has been checked and looks ok, ground from the ecu is good. I did notice when I pulled the stator off of the old motor that couple coils look like they had been hot. About three week before the motor quit the voltage rectifier had failed and were replaced. I performed the continuity check listed in the manual and everything checked ok

[EuropeanAM]

The fuel pressure should never be dropping below 34 psi. If it is, there is a problem (need to also make sure the regulator reference hose is connected to the CORRECT fitting, and that the ECU MAP sensor hose is connected properly.

[bobimo]

hoses are connected correctly. tested ecu map sensor by pulling vacuum on the hose and the reading decreased. used and old efi mercury tester and everything that I could test with it was ok. I pulled the cover off of the manifold and verified that the injectors are spraying gas. Question why does the engine try to start and shuts down like it is out of gas. I added a little gas oil mixture to each cylinder and the engine fired and ran until the gas ran out. so if i can see the injectors firing with the manifold cover removed why want it spray when the cover is on, which would make the motor continue to run. out of options, will double check all wiring tomorrow.
reading in the mercury shop manual and it states the stator should have a ground wire coming out of the harness, cannot find one on my motor. thanks again bob
p.s. I did notice that when the motor was running the fuel pressure was varing around 34 psiand not dropping below 32 psi

[EuropeanAM]

You wouldn't happen to have a friend that has a 200 EFI (or even a 175 EFI) and might let you borrow the ECU to plug into your engine and see if the engine starts and remains running, would you?

NOTE: If it's a 175 ECU, don't take it out on the water (should not hurt to start and run for a short period on a flush attachment).

Wondering if you don't have driver problems in the ECU.

Also- does your engine still have the Detonation/Advance/Idle Stabilizer module?

[bobimo]

I disconnected the injector harness from the ecu and grounded one side of the injectors, the engine start and ran I would toggle the injectors by removing the ground and reconnecting the ground. I think I have a ecu problem. yes it still has the idle stabilizer and detonation modules. happy 4th bob

[bobimo]

what ecu will work on my motor mine is 824003a26

[EuropeanAM]

824003A8 would work as well.

Triple-check to make sure you have spark on ALL cylinders.

Completely disconnect the stabilizer and detonation modules ***. Make sure there is a jumper between the White w/Black (Bias Circuit) terminals of the two switch boxes. See if the problem persists.

*** These CAN be removed completely- but if removing them, a complete Sync-n-Link procedure must be completed.

ECU Suggestion: If you find the problem persists after the above, AND you have good spark on all cylinders, I would suggest sending YOUR ECU off and having the drivers replaced. www.simonperftech.com can do a good job on those.

[bobimo]

disconnected the idle stabilizer and detonation modules, jumper the bias circuit, and all plugs are firing. tried two different ecu's and
the the motor did the same start but won't run. going to replaced the connector for the ecu to the motor and check the motor harness

[EuropeanAM]

You might also want to take a good look at the reeds in this engine. Hopefully the pistons are in the engine correctly, too...

[bobimo]

what would I look for on the reeds, how could the pistons be wrong. The only thing reset on this motor was the timing pointer, could that throw my timing far enough off to cause this problem. I used the method of setting the pointer at .462 as the manual stated.
I had to move timing indicator about 3/8 inch clockwise looking from the front of the motor.

[JOE54]

P in the S side and S in the P side, and UP where DOWN is suppose to be , take light or bore scope and look at top of pisson see any marks or letters

[lpugh]

The fuel pressure never goes below 28 psi and returns to 36 psi as soon as the motor stops. the ecu connector has been checked and looks ok, ground from the ecu is good. I did notice when I pulled the stator off of the old motor that couple coils look like they had been hot. About three week before the motor quit the voltage rectifier had failed and were replaced. I performed the continuity check listed in the manual and everything checked ok

You sir have a serious starvation issues, obvious as pressure goes up when demand goes down
Could be caused by low voltage to the injectors , a driver side problem including poor grounds or a restriction in the supply side

[bobimo]

checked pistons all were ok p on the port side and s on the starboard side. checked injector voltage and all were toggling between 30 volts and 70 volts using a DAV adapter, indexed flywheel and all timing marks were ok. removed front cover and checked injector for spray and all had good spray pattern. checked that all plugs had a good spark to ground. fuel pressure is 39psi on my gauge when motor is not running and varies between 34 and 37 psi with motor running. cleaned filter on fuel regulator. motor will occasion run about 30 seconds and then die, most of the time it hits a couple of times then dies, sound like it is running out of gas. can the reed valves cause this problem. bob

[EuropeanAM]

Reeds can cause any number of problems.

Have you tried a totally separate, KNOWN CLEAN/FRESH fuel source, plumbed directly to the engine (with 50:1 Pre-Mix fuel)? If not, that would be advisable at this point just to rule out contamination.