another interupt switch question

[figaro]

1997 mariah 5.7lx 4bl has a tbv ignition system (with knock module & sensor) someone has installed a bravo tbv module that i beleive is the culprit to my interupt switch problem, all wiring tested from distributer to ign module to coil and knock control module to sensor is correct
the engine runs fine , but i canont get the engine to stall by manually activating the interupt switch or even trying to ground the lead from the interupt to the module it will not stumble (difficult shifting in and out of gear)

any thoughts or ideas are greatly apreciated thanks in advance

 

[thumpar]

Re: another interupt switch question

The Bravo drives don't use an interrupt switch so that would explain it.

 

[alldodge]

Re: another interupt switch question

1997 mariah 5.7lx 4bl has a tbv ignition system (with knock module & sensor) someone has installed a bravo tbv module that i beleive is the culprit to my interupt switch problem, all wiring tested from distributer to ign module to coil and knock control module to sensor is correct
the engine runs fine , but i canont get the engine to stall by manually activating the interupt switch or even trying to ground the lead from the interupt to the module it will not stumble (difficult shifting in and out of gear)

any thoughts or ideas are greatly apreciated thanks in advance

The TBV can be used with both drives and I am unsure but I don't remember anything about differences between the two. I'm pretty sure the wiring is there just needs to be connected. Pin E coming from the ignition control module should be Wht/Blk and it goes to the Wht/Grn wire on the interrupt switch. From the other side of the switch it goes to Blk (GRN) of the engine harness .

Tried to upload the manual but iboats won't take a pdf

 

[alldodge]

Re: another interupt switch question

Lets see if this will work


Edit: Way cool this worked

 

[figaro]

Re: another interupt switch question

thanks Alldodge is there a pin letter to wire # correlation ,cut off in the image you posted?
mine does not have a yellow wire or a tan/blu and ive got a white not wht/blk

this wiring diagram year ,engine, drive is for which application ?

thanks

 

[alldodge]

Re: another interupt switch question

This one came from manual No 24 which isn't for you. In manual No 17 it is real hard to get a readable wiring diagram but you are right, the switch is connected to what appears to be the white/(something) wire and the other side of the switch goes to ground. This same wiring is for with or with out a knock sensor.

Boatinfo - Mercruiser Service Manual nr. 17 - 1993-1997 - Engines GM V8 305 & 350 CID (5.0L 1993-1995)

Around page 400 has wiring diagrams for ignition circuits.

Edit: Your solid white wire just may be the white/something I'm seeing, but on page 327 there is no soild white wire. Just not a very good picture.

 

[figaro]

Re: another interupt switch question

i have got the nr 17 service manual and the wiring diagrams are very poor , i also believe the original module (prt #806957t4) has been changed to the new and improved updated design (prt #807264A01) (icm conversion)
, although mine is (prt #861254t1 the incorrect application) which i cannot find a pin out or wiring diagram for

looks like i may have to bite the bullet and buy the correct module or update to a delco est style system

any input pros and cons to this style of system?

thanks again

 

[alldodge]

Re: another interupt switch question

The Delco EST system works very well, and much better then a couple of the other systems out there' I would try to stay with what you have. There is something missing with the wiring or something being missed else where. I'm kind of wondering why others have not entered into this thread but unknown. We are only talking about an interrupter switch with a TB5 ignition system. If it came down to pin outs for the different modules I would go with the new module before I would go with the EST. Something is being missed I just can not put the finger on it

 

[figaro]

Re: another interupt switch question

any reason why i can or cannot reroute the interrupter switch wiring so it grounds out negative (tach) side of coil when actuated

 

[alldodge]

Re: another interupt switch question

any reason why i can or cannot reroute the interrupter switch wiring so it grounds out negative (tach) side of coil when actuated

I cannot say whether that would work or not. Grounding the tech wire will shut the ignition off until the switch is released. The interrupt circuits causes the engine to miss but not on every cylinder. I still don't understand why your wiring doesn't match the year or the boat.

Retraction: After review troubles in another thread I will retract my statement of not going to the Delco EST system. The EST system would be a more cost effective fix then obtaining a new TBV module.

 

[figaro]

update for anyone that may have followed this short thread on interrupt switches for bravo and /or alpha drives
the bravo icm does not have the capabilities of interrupt the alpha icm does ... that being said by changing to the correct icm i have now remedied the problem i have had since owning this boat the last 5 years
anyone in need of a bravo icm for a 5.7 merc :joyous: