4.3 No Start - Thunderbolt V

[ajnader]

I have a Searay 2002 Sundancer with twins 4.3L engines, I know they have the Thunderbolt V ignition system, they should be year 2001 or 2002. Yesterday one of the engines did not wanted to start, it did crancked but no start, I didn't have much tools so could not do much of diagnose. I did inspected the wiring around the distributor and the ECM and everything looked good. You can hear the fuel pump running for few seconds after turning the ignition to the on position. I did disconnect the 2 plugs from the ECM and connected them back, tried to start the engine and it did started, aran it for about 1 minute and it died. Try to restarted again and it didn't start. Did the same with the ECM connectors and engine started but died after few seconds. After that I was not able to start the engine anymore.
I noticed when you crank the engine the RPM on the tachometer dont move at all, as per the service book it could be the crankshaft sensor that is bad. Does somebody know where this sensor is located? Does this engine have one? Could this be the cause of failure?
I have a friend that has a scan tool for automobiles, can I use this tool to connect my engine and maybe find the problem?
Any help will be appreciated.

 

[Don S]

Re: 4.3 No Start - Thunderbolt V

Is the engine fuel injected? If not, then you don't have TB5 ignition, if it is carbed, you don't have an ECM.
Do you have a Mercruiser serial number for your engine handy?

 

[zbnutcase]

Re: 4.3 No Start - Thunderbolt V

And no, automotive scan tool (most of which DIYers have are merely code readers anyway) wont work. 'nutcase

 

[ajnader]

Re: 4.3 No Start - Thunderbolt V

Is the engine fuel injected? If not, then you don't have TB5 ignition, if it is carbed, you don't have an ECM.
Do you have a Mercruiser serial number for your engine handy?

It is fuel injection, the serial number is 0M092192. I know is TB V because last year I replaced the sensor underneath the rotor.

 

[ajnader]

Re: 4.3 No Start - Thunderbolt V

And no, automotive scan tool (most of which DIYers have are merely code readers anyway) wont work. 'nutcase

Which one will work? Where can I buy one?

 

[Don S]

Re: 4.3 No Start - Thunderbolt V

Your engine is a 2000 model TBI used up to 2001, which did use the TB5 distributor.
In 2001 and 2002, Mercruiser switched over to the MPI engines and didn't use the TB5 distributor any longer for EFI engines.

As far as scan tool,
http://216.230.203.183/marine/mtspec.htm
You can get a code reader for less, but they usually don't tell you much. I have had most problems with EFI engines never set trouble codes.

If you go up to the Adults only sticky, you can download the OEM service manual for your engine. You want #25.

 

[havasuboatman]

Re: 4.3 No Start - Thunderbolt V

Do me a favor, disconnect the grey tach wire from your coil and try to start your engine again. If your Tachometer is fried and grounding under the helm, ain't nothing you do going start that boat until you fix or disconnect it.
A grounded coil wont charg.

 

[Fun Times]

Re: 4.3 No Start - Thunderbolt V

I have a Searay 2002 Sundancer with twins 4.3L engines, I know they have the Thunderbolt V ignition system, they should be year 2001 or 2002. Yesterday one of the engines did not wanted to start, it did crancked but no start, I didn't have much tools so could not do much of diagnose. I did inspected the wiring around the distributor and the ECM and everything looked good. You can hear the fuel pump running for few seconds after turning the ignition to the on position. I did disconnect the 2 plugs from the ECM and connected them back, tried to start the engine and it did started, aran it for about 1 minute and it died. Try to restarted again and it didn't start. Did the same with the ECM connectors and engine started but died after few seconds. After that I was not able to start the engine anymore.
I noticed when you crank the engine the RPM on the tachometer dont move at all, as per the service book it could be the crankshaft sensor that is bad. Does somebody know where this sensor is located? Does this engine have one? Could this be the cause of failure?
I have a friend that has a scan tool for automobiles, can I use this tool to connect my engine and maybe find the problem?
Any help will be appreciated.

Just so you know your engine does not have a crankshaft sensor You have a Distributor sensor that is under the Distributor cap. See #6 in this link. http://www.mercruiserparts.com/Show...12973.png&inbr=5388&bnbr=50&bdesc=Distributor.

Because you do not see any movement with RPM gauge havasuboatman is right on when he said to unhook the gray wire from your coil Or from the back of the RPM gauge, What ever is easier to get at. And if that does not keep it running then you may have another bad Distributor sensor like you had back on 05/20/2002 [FAIL: DIST SENSR/OBDM ALARM] If this is it you will want to order a new distributor rotor also because you will need to pry it off to install a new sensor. And do not forget the blue locktite to hold down the new rotor. I hope it's not the ECM.

You might want to read this link even though your engine is not within the serial number range it will give you an idea. http://www.boatfix.com/merc/Bullet/00/00_14.pdf

Did you do anything different that may have created a voltage spike? I ask because it's in the Bulletin If not then it could still be the RPM gauge doing this.


Here is your engine history.
Product
ENG: 0M092192 4231077N1 1998M MERCRUISER 4.3L ALPHA EFI 3" RISERS 4.3L ALPHA EFI

DRV: 0M400146 5111300LS MERCRUISER ALPHA 1.62:1
TRN: 0M277143 6111001LS MERCRUISER ALPHA TRANSOM
Warranty Period: 12/07/2001 - 12/07/2002
Product Protection Period: NONE
Manufacture Date: 07/10/2001
Date Type Dealer Information Misc. Information
05/20/2002 WHAT HAS FAILED FAIL: DIST SENSR/OBDM ALARM
05/14/2002 WHAT HAS FAILED FAIL: PUMP-BOOST/VAPOR LOCK
12/07/2001 REGISTERED EXP : 12/07/2002
07/10/2001 INVOICED

 

[Don S]

Re: 4.3 No Start - Thunderbolt V