ignition Amplifier help!!!

[riverman223]

Start by saying i have a 1987 formula223 mercruiser chev 350 mag/alpha.went out boating for the day boat was running great then all of the sudden it backfired and stalled then I had no spark I figured out that it was the ignition amplifier the one I had was thunderbolt IV with the mark 22a. A guy that works for a marina gave ($225)me a replacement one that had denso 131800-7072 stamped on it he said it was for a thunderbolt Vand that it would work I was questionable about weather this was right or not. I wired it into my harness and boat started right up and sounded little different but idled good took it and family to lake and it would barely plane out and when it did I could only reach 4100rpm and 47 mph before I would hit 4600 rpm 55 mph is there a specific replacement amplifier for thunderbolt Iv 22a. Need advice on amplifier.I have made sure my base timing was at 8?btdc. I think the advance in the replacement is wrong I have already thrown 500$ into this issue

 

[Bt Doctur]

Re: ignition Amplifier help!!!

can you wait about a week, working on replacement modules for those.

 

[Fun Times]

Re: ignition Amplifier help!!!

Few questions, Do you have your engine serial number?

Is the module mounted on the exhaust elbow or on the distributor housing?

Are you sure the number is 131800-7072 and not 131800-7071? There is no info to be found online using the denso part number 7072 . Also that is just a denso manufacturer part number and don't mean a whole lot when comparing cross reference numbers to Mercruiser part numbers that I can see at the moment.

When he handed you the new ignition module, Was it in a box with a Mercruiser part number on it?

Saving the link below here as we may need it in a little bit,
http://www.marinemechanic.com/merc/...lder/thnbolt-IV-module-replacements_EN_14.pdf
Page 12 as well,
http://www.boatfix.com/merc/Bullet/95/95_11.pdf
http://www.mercruiserparts.com/selectSerailRange.asp?doc_nbr=350+MAG.+ALPHA+++GM+350+V-8++1987-1995

 

[riverman223]

Re: ignition Amplifier help!!!

My set.# is b605751 the amplifier is mounted on the elbow the part did not come in a box it was used. the guy that I got it from is a friend of mine and he said it came out of a good running boat later I will go and see if there is any other numbers on the new module I don't think there is it has to plugs that go and ithe said it was for a thunderbolt 5 and that it would work with mine you were right I made a mistake the # on the module is 131800-7071thanks for checking this out for me need to get back on water gets cold here in Michigan soonthe new module is not giving me the performance that my 22 a Thunderbolt did

 

[riverman223]

Re: ignition Amplifier help!!!

the module that broke was a thunderbolt 4 second generation 22 a

 

[achris]

Re: ignition Amplifier help!!!

I was going to stay out of this thread (and some of you were hoping that, I can tell ), however, when I saw the engine serial number, and the numbers on the module, I just couldn't help myself (you know me and electronics :facepalm:....) I did some digging...

OK... what have I found?

By the serial number... 1987, 350Magnum Alpha engine.

Original part number for the module originally on the engine, 390-7804A3. That number supersedes to -15248T02, which is a second generation module, with harness. Referencing SB09-14 we see that the module with that number is a V8-24, not a 22A. I also looked at the curves for each of the different modules, and they are quite different...

Now, you have put a Thunderbolt V module on, That should have bought you back closer to the V8-24 curve... But it doesn't have the knock module attached... so it needs to be wired correctly. If it isn't, then the module may be running with maximum retard, believing there is a knock signal...

I have no idea if this helps you or not... Just putting it out there for all to see... (Shoot me later )

Service Bulletin 2009-14

V8-24 timing curve. Which includes the correct number for your original module.

V8-22A timing curve

TB-V timing curve

 

[achris]

Re: ignition Amplifier help!!!

...I have made sure my base timing was at 8?btdc. ...

As you've got a TB-V module in there now, you need to set the module into 'base timing mode', by grounding the the purple/white wire coming out of the new module.... It also needs to be in base mode to set the engine idle speed and mixture. For your engine 8?BTDC at 600 rpm in neutral...

Chris....

 

[riverman223]

Re: ignition Amplifier help!!!

Do you think the thunderbolt v module that I installed will work and give me the same performance that I was getting with the 22a? I wonder why it had a 22a in it if it was supposed to have a 24? The boat ran great before this all happened other than it would stall and not start back up for few min after running for and hour or so (figured that was the amplifier going bad. The guy gave me a whole wire harness with this and told me I had to install it not only would it not reach my starter and other stuff but the plug s would not match up so I cut the pig tail off the harness that go to the module and wired it into my harrness witch left me with few extra wires left over in the pig tail is this OK? I have spent two weeks trying to figure this out on my own have learned a lot just want to get it back to normal!

 

[achris]

Re: ignition Amplifier help!!!

Bit confused... Not reach your starter... ???

To convert a TB-IV system to a TB-V system, no wires would need to go anywhere near the starter....

The TB-IV would have had a purple (Ignition ON power and coil+), a gray (tacho signal and coil-), a Wht/red and wht/grn (both to the dissy sensor). Also a black (ground).

The TB-V should be looking for the same wires, but would have an additional Purple/wht (base timing mode wire. Leave that loose and not touching anything)... and a Tan/blu (alarm system wire. Fold that back and insulate it)...

If you have anything different, could you post up a photo?

Chris.......

 

[riverman223]

Re: ignition Amplifier help!!!

He give me a whole wire harness for the motor. I meant to say it would not reach the alternator and that the main plugs what a match up so I wired it directly to my existing wire harness from the sounds of it from what you said I did it right. are there different replacement modules for example one to match up to a 22a or a 24 or do you have to reset your advance.this is all new learning experience for me so sorry for the ignorance.

 

[riverman223]

Re: ignition Amplifier help!!!

There was also a yellow wire and a white one I just looked at the picture I took don't know how to post it

 

[achris]

Re: ignition Amplifier help!!!

Yellow wire??? Shouldn't be any yellow wires....

How to Post Pictures - The Basics

Yes, different TB-V modules for different engines... (just like TB-IV) And yes, you'd have to reset the timing. And for that you MUST ground the pur/wht wire coming from the TB-V module... And you MUST use an accurate tacho...

Chris.....

 

[riverman223]

Re: ignition Amplifier help!!!

I will post the pic from my computer when I get home. Yes there is a purple,a purple with white stripe,gray,brown with blue stripe,and a yellow also a black ground.I understand you have to ground purple/white to set timing. What I'm wondering is if I have the right module for my motor.thanks for your help!

 

[Fun Times]

Re: ignition Amplifier help!!!

As you've got a TB-V module in there now, you need to set the module into 'base timing mode', by grounding the the purple/white wire coming out of the new module.... It also needs to be in base mode to set the engine idle speed and mixture. For your engine 8?BTDC at 600 rpm in neutral...

Now that he went from TB 4 to 5, I do believe he should now set his timing to 10*BTDC with his idle speed preferably set between 642 & 648 RPM for best results with this system. There is typically a small fluctuation between 642 & 648 RPM seen on a meter when properly adjusted.
If you look through the newer small block service manuals (I could only look at #24 for the moment) you will see the carbed engines say 10 while efi says 8. Also bulletin #94-2 backs that info up. http://www.boatfix.com/merc/Bullet/94/94_02.pdf .

Do you think the thunderbolt v module that I installed will work and give me the same performance that I was getting with the 22a?

What I'm wondering is if I have the right module for my motor.thanks for your help!

Kind of hard to say without knowing exactly what model ICU you have along with what wire harness you now have. There is an important difference to know between having an alpha wire harness and a bravo harness and the way it hooks up.

The guy gave me a whole wire harness with this and told me I had to install it not only would it not reach my starter and other stuff but the plugs would not match up so I cut the pig tail off the harness that go to the module and wired it into my harrness witch left me with few extra wires left over in the pig tail is this OK?

Sure seems like the hard way to install this, there are now new kit's available to make this a little easier along with you know what your getting/buying. He should have gave you a small wire harness adapter that would have just plugged into the ICU while the other end of the harness has all the connections to make insulation a bit easier.

B.T Doctur has another good idea in the works to make this same type of project more affordable.

There was also a yellow wire and a white one.

Yellow wire??? Shouldn't be any yellow wires....

With the newer system, The yellow wire goes from the water temp switch into the ICU as part of the audio warning components seen on page 4E-2 & 4 of S.M #24.

Now the white wire "i believe" was mainly used for the bravo set up. But S.M 24 shows it could be either white with black or green depending on what engine model it is. 5.0 or 5.7l carbed. S.M #17 may show a difference? Bearing in mind that there is a jumper diode for bravo's while the alpha's use shift interrupter switch. That could hold timing back some if not set up right.

Yes, different TB-V modules for different engines.

+1, Things like bravo and alpha & model engine sizes.

 

[achris]

Re: ignition Amplifier help!!!

Now that he went from TB 4 to 5, I do believe he should now set his timing to 10*BTDC with his idle speed preferably set between 642 & 648 RPM for best results with this system. There is typically a small fluctuation between 642 & 648 RPM seen on a meter when properly adjusted.
If you look through the newer small block service manuals (I could only look at #24 for the moment) you will see the carbed engines say 10 while efi says 8. Also bulletin #94-2 backs that info up. http://www.boatfix.com/merc/Bullet/94/94_02.pdf .

I see where you're coming from on that, and 94-02 definitely backs that. I was basing my spec on manual 17, page 1B-10 for Gen+ engines with a TB-V system... Doesn't really matter. I doubt 2 degrees would make the sort of difference the OP is seeing....

Kind of hard to say without knowing exactly what model ICU you have along with what wire harness you now have. There is an important difference to know between having an alpha wire harness and a bravo harness and the way it hooks up.

Exactly!

OP, is there ANY markings on the module that might give us a clue to the model application? I've seen modules with their model sort of melted into the plastic. I know you quoted a number in the first post, but we have no way of matching that up with any of the Mercruiser numbers. The sort of numbers we're looking for could be something like 'V8-24' or V8-22 Bravo'... Anything really. Close up photos could be helpful (if they're in focus )....

Chris........
(Still trying to stay out of at least one thread this week... :facepalm: and failing....)

 

[Fun Times]

Re: ignition Amplifier help!!!

I was basing my spec on manual 17, page 1B-10 for Gen+ engines with a TB-V system... (Still trying to stay out of at least one thread this week... :facepalm: and failing....)

? Does manual 17 say 8 or 10 for the TB-5?

Lol, Yeah right, And is your wife aware of the fact that while you're out having a nice dinner with her, your thinking of your mistress iboats ? Oh and Bond-o you're probably floating in the same boat as Chris and i.:lol:

 

[achris]

Re: ignition Amplifier help!!!

? Does manual 17 say 8 or 10 for the TB-5?

Manual 17 says 8?BTDC for TB-V....

Lol, Yeah right, And is your wife aware of the fact that while you're out having a nice dinner with her, your thinking of your mistress iboats ? Oh and Bond-o you're probably floating in the same boat as Chris and i.:lol:

I'm still breathing....

 

[riverman223]

Re: ignition Amplifier help!!!

hey thanks guys I am going to talk to the guy that I got it from today and see if I can find out the part number and what exactly it came off fromI appreciate your thoughts I've been tearing my hair out over this for 2 weeks I wonder if it could have anything to do with the shift interrupter being it is of a thunderbolt 5 with the white wire with a black stripe as mentioned earlier in a post I have the old style shift interrupter for TD IV still hooked up I don't have anything hooked up to the white wire with black stripe coming from the new Thunderbolt 5 module?

 

[achris]

Re: ignition Amplifier help!!!

I'll look into that too... In the meantime, photos? Please....

 

[riverman223]

Re: ignition Amplifier help!!!

Soon as I can I will post those pics did not get home tell late last night sorry.can you post pics from a smart phone?