On crank no fuel to throttle body mercruiser 305 EFI

[Alfgeiger1]

Sea Ray 2001 SD240 with 5.0L EFI GM 305 motor, on crank do not get fuel to throttle body from the injectors See no spray, hear the fuel pump. I can get it to start with starter fluid and then it runs fine, drove it for 30 mins on water, exercised idle to WOT, fuel spray to throttle body is perfect so thinking fuel pump is ok. Also assuming if it runs so well once started that the ECM is ok, is it just a sensor that is telling the ECM not to send gas to throttle body on start? If so which one? Don’t have a computer reader so can’t get any codes. I can go out there right now and the fuel filter is full, crank, no spray. Anyone have any ideas? THANKS!!!

 

[alldodge]

Welcome
Most likely we will need your motor serial number, but until then

Looks like TBV distributor

So it will not start on it's own but if it's given a shot of starting fluid it will continue to run?

Measure voltage at the Battery and then at the coil. Is both the Bat voltage and coil voltage the same?

Is the same reading at the coil with key on motor off, the same when cranking?

 

[Alfgeiger1]

Welcome
Most likely we will need your motor serial number, but until then

Looks like TBV distributor

So it will not start on it's own but if it's given a shot of starting fluid it will continue to run?

Measure voltage at the Battery and then at the coil. Is both the Bat voltage and coil voltage the same?

Is the same reading at the coil with key on motor off, the same when cranking?

0M086516

 

[Alfgeiger1]

Welcome
Most likely we will need your motor serial number, but until then

Looks like TBV distributor

So it will not start on it's own but if it's given a shot of starting fluid it will continue to run?

Measure voltage at the Battery and then at the coil. Is both the Bat voltage and coil voltage the same?

Is the same reading at the coil with key on motor off, the same when cranking?

Yes it starts with starter fluid. Will check the voltages, thanks

 

[alldodge]

Your motor breakdown

 

[Alfgeiger1]

Your motor breakdown

Thanks for this, I do use them for parts, when you say TBV Distributor do you think it is the entire distributor, could it just be a bad coil, like I said once it is started it runs great the entire time.

 

[alldodge]

Thanks for this, I do use them for parts, when you say TBV Distributor do you think it is the entire distributor, could it just be a bad coil, like I said once it is started it runs great the entire time.

It's almost never the coil
Most cases it's a bad connection or the old style module. The old modules had grounding problems, so Merc went from to 2 wire to a 3 wire module. The 3rd wire was a ground wire.

Do you have 2 or 3 wires coming out of the dizzy?

 

[Alfgeiger1]

It's almost never the coil
Most cases it's a bad connection or the old style module. The old modules had grounding problems, so Merc went from to 2 wire to a 3 wire module. The 3rd wire was a ground wire.

Do you have 2 or 3 wires coming out of the dizzy?

 

[Alfgeiger1]

View attachment 410255

When you say module is that the ECM Engine Control Module?

 

[cyclops222]

Many car and some EFI controlled engines have a very short ....Purging Period .....During the instant the starter is energized. About 1/2 second the engine sucks any loose fuel up, laying on or around the engine parts. To prevent back fires taking place.

 

[Alfgeiger1]

Many car and some EFI controlled engines have a very short ....Purging Period .....During the instant the starter is energized. About 1/2 second the engine sucks any loose fuel up, laying on or around the engine parts. To prevent back fires taking place.

Ok, but if i continued to crank for 5 sec wouldn’t i expect that the fuel would be delivered to the throttle body? After using starter fluid the injectors deliver fuel without issue once it is running.

 

[alldodge]

When you say module is that the ECM Engine Control Module?

No, it's the module inside the Dizzy
Looking at your pic I'm only seeing 2 wires

 

[dubs283]

No, it's the module inside the Dizzy
Looking at your pic I'm only seeing 2 wires

This is most likely the culprit. It is called the ignition sensor and located in the distributor, under the cap. It's a hall effect sensor that the MEFI controlled, tbi, thunderbolt ignition efi engine ecm uses as a crank position sensor

The two wire sensors are obsolete. Get yourself an oem, quicksilver brand, three wire sensor and make sure the ground strap is connected to the same stud on the flywheel cover as the main battery ground. Stacked right next to it is best

 

[Alfgeiger1]

This is most likely the culprit. It is called the ignition sensor and located in the distributor, under the cap. It's a hall effect sensor that the MEFI controlled, tbi, thunderbolt ignition efi engine ecm uses as a crank position sensor

The two wire sensors are obsolete. Get yourself an oem, quicksilver brand, three wire sensor and make sure the ground strap is connected to the same stud on the flywheel cover as the main battery ground. Stacked right next to it is best

If my engine s/n is 0M086516 could you recc the module part that would fit? Thanks

 

[alldodge]

If my engine s/n is 0M086516 could you recc the module part that would fit? Thanks

Sensor assy 892150Q02

 

[Alfgeiger1]

Sensor assy 892150Q02

Thank you