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Thunderbolt 1V troubleshooting

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english_man_in_norway

Contributing Member
"Having followed proceedures i

"Having followed proceedures in the flowchart,I arrived at the spark test gap where you strike a ground with the green/white from the distributor whilst watching for a spark from the coil wire,surely the green/white wire needs voltage to cause a reaction? Just that I checked it with a meter & got zero? Does anyone know any differant checks I can do other than this method?"
 
So did you do the test or not?

So did you do the test or not?

Why would a mechanical guy think you need voltage to create a spark? What is needed is a change in the state of the current flow; try the test like the factory service procedure states.
 
Continue w/the same post pleas

Continue w/the same post please. Make sure the ground is bare metal. By striking the ground w/the bare wire you are causing the coil to fire via the amplifier if the amp. is good.
 
"Yeh I'm a Mechanical guy

"Yeh I'm a Mechanical guy 'welding',fabricating,e.t.c,not an 'electrical' guy.
I completed the test with no spark from 2 coils so as usual,its the expensive part that needs replaced the amplifier. Thanks Guy."
 
"That's a bummmer.

Some

"That's a bummmer.

Some of those amplifiers are hard to find, let alone expensive. When mine go belly up, I'm seriously considering swapping in Delco EST systems. (whole new ignition system for about the same $$.)"
 
Bt. Dr.:

Back in the 70&#39

Bt. Dr.:

Back in the 70's I must have filed hundreds of contact points while working on pinball machines and other games. I would watch the stacks of contact points in the dark while the game was played. That would allow me to see the ones that were burning when they would flash brightly. Usually the cause was a cold/loose solder joint. I'd file the points and resolder the wires and that would fix them. Nothing like an electrical part that you can actually see working.

If the spark control amplifiers were not sealed in epoxy they could easily be repaired and sold for less.
 
"Mine are 20 years old this se

"Mine are 20 years old this season and have had a good life. Compared to the time NOT regapping points and the resulting fuel savings, I'd say they were a very cost effective swap.

As Guy noted, the potting makes repairing them a major pain. I've heard of a couple rebuilders but never investigated them further. Based on my experiences, on the boat and in the shop, they are pretty reliable...wonder how much is attributable to the environmental resistance from that potting?"
 
"RE: "wonder how much is a

"RE: "wonder how much is attributable to the environmental resistance from that potting?"

Electronic components need to be protected from high humidity environments ( fungus, corrosion). Potting is one solution. Potting, however also gives protection from vibration which can cause failure of the joints between the component leads and the circuit board, and dependingon the board technology, failure of the copper trace itself (at the lead attachment point)"
 
"Looks like I've started a

"Looks like I've started a debate,very Interesting though,when I unplugged the amplifier there was water seated inside,which probs caused it to packup.I've noticed the newer model amps are now mounted on the distributor,unlike mine which is on the exhaust elbow,Is this to combat previous problems? Guy my engine is a 1991 4.3L OD810854,the number on the amp is 2A09A V6 14. Thanks everyone for their interest,it certainly helps not being alone when you have a 'boat'!"
 
I sent you an email for the on

I sent you an email for the only amp module I found; decent price.

Clean the water out from the harness and module w/some compressed air and WD-40 and try the test again.
 
"Mike:

Are the amps that fa

"Mike:

Are the amps that failed the old style or the new style? I call the Old style the ones about 30cm thick with a rectangular and the new ones are much smaller, the amp itself being mounted on a pentagon shaped plate which bolts to the elbow."
 
"Guy
I did actually try to cl

"Guy
I did actually try to clean it out with an electric oxide cleaning airosol,but to no avail,didn't find your email though?
Mark
As I mentioned in my last mail,I have the older version that mounts on the elbow."
 
"Guy,thanks that is the 1,I&#3

"Guy,thanks that is the 1,I'm returning to 'Blighty' on monday so if nothing turns up cheaper,I will order this one thanks.
Mark,youv'e got a keen eye,It is in fact the newer version,what I didn't realise before is that mercruiser actually upgraded some of the older type modules that is on the exhaust elbow with the new type before they on later models moved it to the distributor.
sorry for the confusion."
 
"If I am not mistaken, when th

"If I am not mistaken, when they moved the ignition module to the Distributor they also installed a knock sensor on the starter side of the engine????

Besides there is no mounting bracket to mount the newer style on the dist.

As someone who fixes others I have never realy had the need to dig into one and see what it is made of or what is inside that goop. It would be interesting though, maybe one of these days,.

Typically when I find a failed part I replace it with new. Also I have several spares for ME that I never give away......."
 
"Don't know about the knoc

"Don't know about the knock sensor Kghost,as Ive got the newer type amplifier,but Its still exhaust elbow mounted,so when I replace It I'l stick it back on the elbow,but yeh I'm gona rip inside that goop & see how come It costs all them 'bucks'!!"
 
"I think the knock sensor was

"I think the knock sensor was added with theintroduction of the TB-V distributor.

All of the IV systems I've seen had the module on the elbow. They were in two different packages, older and newer. the newer versions are MUCH smaller and appear like the one in the link guy posted. I can trace them back as far as 84 but can't verify anything but the older, thicker ones before that."
 
"I had the same problem, thoug

"I had the same problem, thought amp was bad, but turns out it was good, it was the contacts in the harness plug werent makin properly.
I fixed it by playing with contacts inside the plug, slip off the orange seal, and look into the contacts. You can give em a bit of a crimp with long nose pliers to make a better contact.
After i did this still changed it, cost about $45... didnt trust the orginal after that. worth checking b4 you spend big bucks..JM2cW..Mark."
 
"Mark,Thanks for the interest,

"Mark,Thanks for the interest,Yeh I'd strangely enough done that,as I've bin determined not to spend 'big bucks' & also found it strange that on all the forum sites I'd looked 'no-one' seems to have changed an amplifier! So I've bin double checking 'everything',the amp harness is fine but
I frustratingly found 12volts showing on the negative coil terminal,with the grey wires even off!
So looks like I've bin checking the system with two 'duff' coils,'embarasing' or what!!"
 
"Mike:

If you have the lead

"Mike:

If you have the leads off the neg post of the coil and the + post has +12V applied, it is normal to see +12V on the negative post. There's no current flowing thru the coil so no voltage drop is created."
 
"Like I suggested earlier, you

"Like I suggested earlier, you may want to check out the delco EST kits. Last time I looked you got a whole distributor kit for about the same $$ as a TB-IV module. If that module goes, it's cheap, relatively speaking."
 
"Will check that option out Ma

"Will check that option out Mark,Its just that I've just purchased & fit new rotor-arm,sensor wheel,distributor sensor & new dist cap.
Thanks."
 
"Makomark is spot on..
With t

"Makomark is spot on..
With the grey wires off the coil -ve, and 12v on the pos side, you will also get 12 v on the negative side, as its not yet grounded, which would complete the circuit and produce a spark. You can try it if you like to test the coil, with 12v on the pos side of the coil (ignition on)(disconnect other wiring from coil to dissy etc), jump the neg side to ground, each time you will get a spark from HV output from coil..

BE CAFEFULL, 15KV hurts, (helps to have 3 hands to do this).

My money is still on the harness between amp and dissy.... never seen a bad amp. Mark."
 
"Mark
Thanks for that,yeh som

"Mark
Thanks for that,yeh something In the back of my mind says Its not the Amp,I'm brand new to this electrical 'malarky' & bought a volt-meter for the 1st time only 2weeks ago,I also got the same readings with the grey wires on. I'm back in England at mo,but will be returning to Norway in 4weeks time,to fit new head gaskets on the boat. I'l then re-check the harness.With it unplugged I can remember there was 12v to 3 of the wires in the harness."
 
mikeday:

Use the 1K OHMS se

mikeday:

Use the 1K OHMS setting and check the continuity of each wire; both ends disconnected. They should all read "0" ohms. Wiggle the wires while checking. Look for light corrosion on the male/female contactors.
 
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