2001 Mercruiser 5.0 efi wont start

[Jeffv321]

Hello,

I have a 2002 Sea Ray Sundancer 240 with the 5.0 efi and Bravo 3 out drive. Engine serial number is 0M090614 which I believe was manufactured in 2001. My problem: About two weeks ago I lost power at about 3000 rpm and I slowed to an idle; engine did not stall. Idled back to dock and was backing in and engine stalled once while going from forward to reverse; it restarted without issue. Boat sat in water at dock for two weeks and then wouldn't start or even attempt to. I hauled boat out and it's now on my trailer. What I've checked:
1- boat emits standard alarm when key is turned on and fuel pump? Can be heard running for about two seconds. Boats cranks fine but does not fire.
2- I've flipped the kill switch on and off during this procedure and it appears to be doing its job when off/on.
3- I've moved the shifter into forward while attempting to start boat and it shuts down when in gear so appears to be working.
4- I've disconnected grey wire from back of tachometer with no change.
5- there is no spark at coil wire to ground.
6- removed distributed cap which didn't look great, but again I have no spark to it so I'm not too worried about that yet.
7- I removed ignition coil and bench tested it and it appears to have correct resistance.
8- before I did any of the above I should note that upon attempting to start boat I see no fuel being injected, although I hear what I think is the fuel pump run for a couple of seconds like I've always heard it do. I tried some starter fluid with no results.
9- basically I'm missing two of the four (No spark, No Fuel, I'm guessing I have compression and timing)
10- I've looked at the main grounds, wires, and see no corrosion at all and they appear tight.
11- How do I know what ignition system I have ?? I have the round distributor cap and the ecm is mounted to the port riser
12- fuses under the dash all light up as good. Breakers are not tripped.
13- is there something that causes fuel to shut down when there is no spark from coil?

Hopefully I've provided enough for one of you experts to assist me.

Much thanks, Jeff

 

[NHGuy]

Try ohming the tach wire and once identified, remove it at the coil.

 

[alldodge]

Howdy Jeff

With the engine running fine until it slowed to an idle gets me leaning toward lack of fuel, either from low pressure or clogged fuel system. The issue with no spark is another issue.

In order for an EFI motor to turn the injectors on it must see at least 300 rpm. So if the distributer is not getting power the injectors will not work. With the tach wire reconnected, turn over the motor and see if the tach shows anything.

There are fuses and relays on top the motor next to the ECM. Check to see if none of the fuses are blown (they are under black caps). If no fuses are blown swap the two relays with each other and see if you hear the pump turn on again. What your doing here is finding out if the main power relay is at fault. If pump does not run after swapping then a relay is bad

When was the fuel replaced?

You will need a voltmeter. Turn key on and see if your getting 12V at the coli (Red wire).

 

[Jeffv321]

Thank you both for the replies. I'm at work today so this will have to be done tonight!

1- In response to NHGuy. As I recall the coil only has two wires. Red to the plus terminal, and white to the negative. The tachometer must attach to something else, and then be routed into the coil??

2- In response to AllDodge. I filled the boat full in May of this year and then put it in the water (fresh water Lake) We have used the boat very little this year sadly; maybe a quarter tank total in 3 or 4 outings. I've never had one issue with starting,stalling, or performance issues until the incident as posted. To clarify, the first I noticed any performance problem ever was as described at about 3000 rpm when I physically felt the boat slow down and lose power. I looked down at the tach and saw that it had dropped so I immediately throttled down to about 1200 RPM and it seemed to be running fine there. We were close to the dock so we continued at 1200 rpm until it stalled while forward/reversing into my back in slip. Again, it refired immediately without issue at that time.

By my engine serial number, can someone tell me what ignition system I have? I'm a bit confused on that from my research, and wonder if that would be helpful to trouble shoot. (I've seen different posts suggest different trouble shooting steps depending on ignition system; Thunderbolt IV, Thunderbolt V, MEFI3, MEFI4, etc.)

I'm new to this "electrical stuff" so I appreciate your patience and help! Don't be afraid to "Dumb it Down" for me either! Thank you for your help and time.

 

[alldodge]

Your serial number shows me (Merc site, and shop manual 24) you have a MEFI 3 ECM and TB-V distributer. The distributer firing is controlled by the ECM. Tach signal also comes from the ECM.

 

[Jeffv321]

Mr. AllDodge,

1- The three fuses under the black cap next to the relays appear to be good.

2- After switching the relays I still get the starting alert and the pump runs.

3- When grounding to the main engine ground with the black lead, and touching the red lead to the + side of the coil, I do see 12v.

4- When the key is off the tach needle sits at about 200rpm. When I turn the ignition to run it drops down to zero. When I crank the engine it stays steady at zero.

Thanks for your help and time, Jeff

 

[Jeffv321]

In addition, when I unplug the red/white bullet plug that comes from the distributor and check voltage at the other side (pink wire that goes right into wire bundle so not sure where it goes) I get 0 volts. Thunderbolt V trouble shooting indicates I have a bad Ignition module. ??

Much thanks, Jeff

 

[alldodge]

Only issue I see is your motor doesn't have an ignition amp. The MEFI 3 is what controls the spark. From what I read, this is the only setup using this manor of ignition.

Maybe Fun Times can provide some insight further.

Does the 12V stay at the coil when the motor is cranking?

 

[Jeffv321]

Wow, MEFI-3 = Expensive!

Did Fun Times get linked to this thread via your post or do I need to reach out to him?

Thanks for your time, Jeff

 

[alldodge]

Fun Times would be notified with my post

 

[thumpar]

Since it is MEFI 3 you can use the LED and paperclip to check for codes in the computer.

 

[Fun Times]

Since you have no movement on your tachometer, no fuel pulses at the throttle body fuel injectors and possibly no signal coming out of the distributor ignition sensor mounted under the distributor cap, it indicates you may have a bad/failed ignition sensor as that is the starting point off all the components listed not working to make them work...Some EFI / MPI models have a pick-up coil mounted to the distributor shaft found under the rotor.... Yours being a thunderbolt 5 ignition system uses a sensor to trigger the ignition firing system is all.

Item number 6 in the following link below is where you want to start and to be honest, you (and all boaters that like to be prepared) should always have an extra one for your engine model onboard along with the tools to change it out as sometimes you may never know when it may fail on you....But you have to be careful with the rotor wheel as if it gets bent during removal, it will hit/damage the sensor, so a new rotor is usually advised when changing the sensor. https://www.perfprotech.com/mercury...tion-components/assembly/4856/80?umodel=17383
^ May as well order a new OEM cap and rotor too while you're in there. Item 2 and 5. If the sensor is not the problem then it could be a wiring problem and hopefully not a problem within the MEFI 3 ECM.

Here's your OEM parts guide through iboats,
http://www.iboats.com/5-0L-EFI-GM-305-V-8-1999-2001-0L331631-THRU-0M299999/dm/view_id.1683216

V6 and V8 305/350 cid Engines with MEFI-3
While this next link shouldn't be within your serial number it should help give the idea of what could happen...
Delco EST ignition system. SITUATION Service Bulletin

Let us know, good luck.

 

[Jeffv321]

Fun Times,

Thanks for your response. I really appreciate everyone's help. A bad MEFI 3 sounds, well, really bad! I will continue checking wires and replace items 2,5, and 6 as you described. I will post back with results.

Thank you all for your time and knowledge, Jeff.

 

[alldodge]

Your wiring diagram

 

[CaptainMak]

JeffV, I would suggest that you tested the ignition sensor incorrectly. It has to be checked for RESISTANCE values, not VOLTAGE. Here's what manual #24 says regarding the test: (book 24, page 306)

Sensor
Testing
1. Disconnect the two sensor wires from the wiring harness.
2. Using an Ohmmeter, check for an ohm reading between the two sensor wires. If reading
is less than 100 ohms, replace sensor.


And inspection:
Cleaning and Inspection
1. Use a magnifying glass and light to inspect the two metal “jumper leads” for cracks. If
a crack is found in either metal “jumper lead,” install a new sensor.

Don't go throwing parts at it just trying to guess what's wrong. You have to find out why you're not getting spark.
I have the same MEFI-3 setup and it's really a PIA to diagnose sometimes.

 

[Jeffv321]

CaptainMak,

Thanks for the insight. I'll let everyone know where I'm at in a couple of days when I'm able to get back to working on the boat.

Thank you,

 

[Jeffv321]

Ok, had some time to work on the boat. How hard is it to remove the entire distributor?! (Read below paragraph if you want some entertainment, or skip to the bottom)

One of the bolts holding the ignition sensor down was completely frozen in place. After trying break free, stripping it, cutting new groove for slot screwdriver and then stripping that, more break free, cutting head of screw off, removing sensor in pieces leaving only the headless screw in the distributor, stripping that with a vice grips and finally breaking it off flush with the base of distributor, drilling several consecutively bigger holes threw the screw to try and tap it out or just drill it out all the way....... I broke a drill bit off flush.w Crap...

Pretty sure I need to remove the distributor now to drill it out from the bottom, I hope.

Any advise on distributor removal and re-install ? It's new to me.

Again, thanks for your time and knowledge.

 

[alldodge]

Any advise on distributor removal and re-install ?

Wow, you sure had a time with it.
Put the rotor button on the distributor and then mark the rim of the distributor where it is pointing. Also mark where at the base of the distributor to the intake housing. Now remove the bolt which holds the distributor in place. Grab it and pull up, the rotor will turn slightly as it comes out.

To re-install drop the distributor back in so marks align, If the rotor button does not align, remember it rotates slightly when installing. Just pick it back up, rotate one way or the other until it aligns.

The distributor just needs to be close, because you will set timing once restarted

 

[Jeffv321]

Ok, had some time to work on the boat today. Distributor did have to come out to fix my sensor mess. Distributor of course wouldn't go back down in the same position. The rotor was off the mark clockwise a bit. I did some reading and think I learned that the oil pump gear turns or shifts a bit when you remove the distributor not allowing it to go back in the same position. My solution was to take it in and out numerous, numerous times advancing a gear at a time untilfull makeing a full rotation and finally arriving back at the rotors original position mark. The good, the boat started! I however only ran it for maybe a second as I didn't have water hooked up and it was getting dark. (hopefully my distributor re-install procedure above is proper, and if so might help someone else out)

1) Do I have to time this thing now, or is it still in time as it went back together in the same position without the motor being disturbed. I haven't really ran it so I have no idea where I'm at for performance. Just glad it fired.

2) If it needs to be timed, can a shade tree mechanic such as myself accomplish it?

3) If anyone else is following this thread with similar issues with their TB-V and MEFI-3 and are stumped with the trouble shooting, see below links to a couple service bulletins I found that stray a bit from what I call the standard/popular trouble shooting guides I had originally found.

http://www.boatfix.com/merc/bullet/99/99_04.PDF

http://www.boatfix.com/merc/bullet/99/99_02.PDF

Thanks again for your help and time and I hope I'm on the road to more trouble free boating!

Jeff

 

[thumpar]

It needs to be timed. If you don't have a timing light they are cheap. It is pretty straight forward.