HELP no spark tried eveything I know

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
hey i've been a lurker for awhile, great info here now I can't figure this one out myself. I've got an older merc 5.7 with a t-bolt 4 ign. i've got no spark.
I've done tests: 12v at coil 6v at dist (red/white) by passed shift switch,
not kill switch, not tach i've put in a new module, new sensor in dist, new coil
I either need help or explosives apreciated either way
my local boat shop is too swamped to help me for weeks and it's 32c
HELP thx
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: HELP no spark tried eveything I know

TB4troubleshooting.png
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

don u r a good man those are the diagnostics I tried still no spark. All new sensors. I had an HEI auto dist in it (i know) it ran fine now that I've switched back it wont run. Thats why I went HEI in the first place (tired of ignition problems) HEI won't allow my boat to shift out of forward. Thats why I went back (and safty issues) I'm stumped
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: HELP no spark tried eveything I know

If everything in that chart checks out, it has to be the cap, rotor, or coil wire.
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

Sorry Don I've done the tests and I have no spark anywhere at all I've replaced the ign module and i still don't have spark at the high tension lead. It is also also a new coil?????????????????????????????
Could it possibly be a faulty new module????
 

marine4003

Lieutenant Junior Grade
Joined
Feb 3, 2008
Messages
1,119
Re: HELP no spark tried eveything I know

Seems you've angered the boat God's,using the automotive part....module..or the HEI fried the t-bolt completely.Very sensitive things,those T-Bolts.theres a small computer pack in there,Toast???
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

I don't know it's all new parts as of this weekend. New module, new coil, new sensor I don't know what to do. I've talked to every boat place in the area and no one seems to have a clue. this problem is why I went to an HEI in the first place. I live in the Okanogan (B.C. Canada) and every boat place is booked solid. Best I can do is a month away, in a town 1 hr away from home
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: HELP no spark tried eveything I know

Have you checked to see if the rotor is actually turning when you try to start the engine?
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

Ya I have you're the third person to ask me that today! I don't know what else to do looks like I better leave the boat till I can get it in a shop:(
I better do some chores around the house anyways before I end up single:)
Thanks guys I don't know what else to do.
Don even if my dist/cam were shot wouldn't I still have spark at my coil?
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,130
Re: HELP no spark tried eveything I know

Don even if my dist/cam were shot wouldn't I still have spark at my coil?

Nope,... The Distributer tells it When to Spark....
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

Ya but by striking the white/green on a ground am I not simulating a spining dist?
 

MikDee

Banned
Joined
Jun 6, 2007
Messages
4,745
Re: HELP no spark tried eveything I know

How about the Dist cap? is the carbon on the inside center terminal there? and touching the rotor? Besides it sounds like you've replaced everything but this? Why not replace this too?

This is of course, that you've already checked or replaced the coil wire? As Don mentioned
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

It's farily new and i polished the contacts, and the tip of the rotor, this morning with a dremel just a touch but it works really well. All ideas help there's got to be something I'm missing. Ya sorry it's a new coil wire yesterday. The cap and rotor were replaced last summer before I went HEI, they have never been used
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

Hey just a thought is there a marine HEI sys that will solve any/everything
My boat ran great last weekend with the HEI, but it won't shift out of forward. Everything else works great. I run a stainless steel prop and I heard that if I went aluminum it might solve my shifting problem(less torque?). But then I will have an automotive dist which I don't want. But I will be on the water.
I just want it working.... safely
 

bjcsc

Lieutenant Commander
Joined
Jun 1, 2006
Messages
1,805
Re: HELP no spark tried eveything I know

Not that it will solve your problem (don't know), but D.U.I. makes a marine HEI. Here's a link..I have one of their distributors in my Jeep. Other than the Weber carb it's one of the best improvements I have ever witnessed...
 

MikDee

Banned
Joined
Jun 6, 2007
Messages
4,745
Re: HELP no spark tried eveything I know

It's farily new and i polished the contacts, and the tip of the rotor, this morning with a dremel just a touch but it works really well. All ideas help there's got to be something I'm missing. Ya sorry it's a new coil wire yesterday. The cap and rotor were replaced last summer before I went HEI, they have never been used

So much for that idea? One more thing, is the wire going into the Dist possibly broken inside? If thats not it I'm done :confused:
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

Sorry which wire? I've got whit/green, white/red and a black ground and all three are in really good shape. My local boat shop ran some continuity tests on it this morning and it all seems good. Trust me I'm about as done with it as you. I'm starting to look for any possible way around it. Even all my local boat shops can't figure it out. Look on the bright side all my buddies with boats, and less toys than me, get to borrow my stuff 'till I get this figured out:rolleyes: I've lent out tubes and skis today already.
 

MikDee

Banned
Joined
Jun 6, 2007
Messages
4,745
Re: HELP no spark tried eveything I know

How may wires have you got going from the coil (negative -) small terminal to the distributor? Not sure about the if the Thunderbolt 4 ignition is setup this way? If it's more then one, then disregard that :redface:
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: HELP no spark tried eveything I know

What year is this 5.7 Thunderbolt IV?
It can't be that hard to figure out. If it passes all the tests in the chart I posted in the beginning, then something is preventing the spark from leaving the distributor.
You can keep saying it's all good, but it's not, or it would run. You are missing something, everytime you check it.
 

Glastron78

Cadet
Joined
May 30, 2008
Messages
16
Re: HELP no spark tried eveything I know

It's in an 89 Glastron futura engine s/n oc664599
it doesn't pass the tests there is no spark at coil after a new module was installed
 
Top