I have a 5.7 Thunderbolt , The Purple and white wire ignition control system timing lead. is is used for performing following tests and procedures..... setting base ignition timing engine idle speed idle mixture also Testing Knock Control Circuit. When this lead is connected to ground - the ignition control module (worth $1000 in Canada) goes into Base Timing Mode. Note the Knock module ($250)
Thank you. I have a 1998 Bravo engine that I was trying to adjust today after having removed the distributor. Your clue that the "Denso unit" tries to adjust the timing if that lead is not ground out just gave me an idea with something I was struggling with. I did not ground out the purple and white lead, and the engine kept surging. Was wonder how in the world the engine can possibly surge without me touching anything. Well, if the TB unit is adjusting timing on the fly, then that would explain it. Will try it again after grounding that lead. Thanks.
If you don’t set the distributor at 15 degree BTDC the density would try and correct causing your engine to surge .. did you mark your distributor before removing so when you reassembled you were so where in the right place. You will need a strobe light and earth the purple lead to reset correctly 👍
@@MrRossYoung44 Unfortunately I did not notch the dizzy before removing. However, local auto shops allow you to borrow timing lights so I will do that and get it properly timed with the lead grounded. Thanks!
Hi Paul - great vid, halleluyah my friend I have been chasing a low end miss in our boat for 4 years now, can you tell me if that wire which needs to be grounded, what does it connect back to at the other end please? So that I can find mine and then set the timing. Thanks, Lyle
@@MrRossYoung44 apologies Ross. Thanks for the info. My mercruiser doesn't have the nice little plug unfortunately. But I have found a bare section to work with. Cheers.
Guys This purple white striped wire should NOT be grounded.....It needs to be connected to the knock sensor at the bottom of the block blue drain plug. Note The Knock sensor should be on the opposite side of the starter as well . This info is on the Mercury document Thunderbolt 5 diagrams. My heads are now at the shop and the fella is a marine electrical engineering dude. I would never know . He told me he did not want to see me bring the heads back in in 2 to 3 years again for another overhaul. Knock sensor issue is my issue or the module it hooks up to . The module runs 250 bucks.
@Great Music Good feel thats a different purple lead. This one is purple with a white stripe. The one you're talking about is purple with a yellow stripe
I have a 5.7 Thunderbolt , The Purple and white wire ignition control system timing lead. is is used for performing following tests and procedures.....
setting base ignition timing
engine idle speed
idle mixture
also Testing Knock Control Circuit.
When this lead is connected to ground - the ignition control module (worth $1000 in Canada) goes into Base Timing Mode. Note the Knock module ($250)
Thank you. I have a 1998 Bravo engine that I was trying to adjust today after having removed the distributor. Your clue that the "Denso unit" tries to adjust the timing if that lead is not ground out just gave me an idea with something I was struggling with. I did not ground out the purple and white lead, and the engine kept surging. Was wonder how in the world the engine can possibly surge without me touching anything. Well, if the TB unit is adjusting timing on the fly, then that would explain it. Will try it again after grounding that lead. Thanks.
If you don’t set the distributor at 15 degree BTDC the density would try and correct causing your engine to surge .. did you mark your distributor before removing so when you reassembled you were so where in the right place. You will need a strobe light and earth the purple lead to reset correctly 👍
Denso not density
@@MrRossYoung44 Unfortunately I did not notch the dizzy before removing. However, local auto shops allow you to borrow timing lights so I will do that and get it properly timed with the lead grounded. Thanks!
is the Mercury 5.0 Thunderbolt V Ignition Mercruiser Carbureted or Fuel Injected or what ?
Thank you in advance for your reply ...
It was a carbureted version with denso unit providing automated electronic ignition (points)
Hi Paul - great vid, halleluyah my friend I have been chasing a low end miss in our boat for 4 years now, can you tell me if that wire which needs to be grounded, what does it connect back to at the other end please? So that I can find mine and then set the timing. Thanks, Lyle
The lead is purple and white and needs to be earthed to the engine mounts or similar...note sure who Paul is??? Lol
@@MrRossYoung44 apologies Ross. Thanks for the info. My mercruiser doesn't have the nice little plug unfortunately. But I have found a bare section to work with. Cheers.
Guys This purple white striped wire should NOT be grounded.....It needs to be connected to the knock sensor at the bottom of the block blue drain plug. Note The Knock sensor should be on the opposite side of the starter as well . This info is on the Mercury document Thunderbolt 5 diagrams. My heads are now at the shop and the fella is a marine electrical engineering dude. I would never know . He told me he did not want to see me bring the heads back in in 2 to 3 years again for another overhaul. Knock sensor issue is my issue or the module it hooks up to . The module runs 250 bucks.
@Great Music Good feel thats a different purple lead. This one is purple with a white stripe. The one you're talking about is purple with a yellow stripe
Where is the oil filter on that engine