timing 4.3 with thunderbolt ignition

tcline11

Cadet
Joined
Oct 5, 2011
Messages
13
I had to change intake manifolds and now i have to check the timing. Can I simply check the timing at idle or are there different procedures with this ignition. Thanks
 

mpdive

Chief Petty Officer
Joined
Apr 23, 2011
Messages
567
Re: timing 4.3 with thunderbolt ignition

I had to change intake manifolds and now i have to check the timing. Can I simply check the timing at idle or are there different procedures with this ignition. Thanks

If it's the thunderbolt 4 ignition, you have to bypass the computer advance by grounding the purple wire lead at the distributor. Set timing and don't forget to take the grounding wire off.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: timing 4.3 with thunderbolt ignition

If it's the thunderbolt 4 ignition, you have to bypass the computer advance by grounding the purple wire lead at the distributor. Set timing and don't forget to take the grounding wire off.

Ayuh,... With T-Bolt IV, ya just hook up the timing light, 'n shoot....

T-Bolt V needs the jumper wire to set it to base mode, then time it...
 

mpdive

Chief Petty Officer
Joined
Apr 23, 2011
Messages
567
Re: timing 4.3 with thunderbolt ignition

I stand corrected. It,s the ignition amplifier that supplies advance on the 4. The 5 is grounded for base timing. I was confused for a second ,Thanks Bond-o
 

tcline11

Cadet
Joined
Oct 5, 2011
Messages
13
Re: timing 4.3 with thunderbolt ignition

Thanks for the quick response. I have the TB 5 ignition but it doesn,t have a purple wire on the distributor it ha s a black going to ground and 1 white with red stripe and 1 white with green stripe The only purple wire is from the coil. what do i jump and how.

Thanks again
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: timing 4.3 with thunderbolt ignition

It's not on the distributor, look up next to the carb on the starboard side. Why is it newbies never seem to think that a simple think like the year has any impact on their engine? All 4.3's are not created equal.

time.jpg
 

joewithaboat

Lieutenant Junior Grade
Joined
Jul 3, 2011
Messages
1,172
Re: timing 4.3 with thunderbolt ignition

I dont have this ignition, mine is IV, but... Manual says for V there is a purple and white wire in the harness, with a spade conector, between the ICM and KCM. Run to engine ground with jumper and this makes it run on base timing. Start and use timing light as usual.

Note: it also states that the carb shoud be adjusted with the engine runing on base like this as well.
 

tcline11

Cadet
Joined
Oct 5, 2011
Messages
13
Re: timing 4.3 with thunderbolt ignition

I dont have this ignition, mine is IV, but... Manual says for V there is a purple and white wire in the harness, with a spade conector, between the ICM and KCM. Run to engine ground with jumper and this makes it run on base timing. Start and use timing light as usual.

Note: it also states that the carb shoud be adjusted with the engine runing on base like this as well.

Thanks for the info I will try that in the morning
 

tcline11

Cadet
Joined
Oct 5, 2011
Messages
13
Re: timing 4.3 with thunderbolt ignition

It's not on the distributor, look up next to the carb on the starboard side. Why is it newbies never seem to think that a simple think like the year has any impact on their engine? All 4.3's are not created equal.

View attachment 117005

thanks for the info. sorry for being a newbie
 

tcline11

Cadet
Joined
Oct 5, 2011
Messages
13
Re: timing 4.3 with thunderbolt ignition

When I checked the timing when I grounded the purple and white wire and set it at 10 deg as it says to on the top of the carb. when I unhooked the wire and checked the timing again it was still at 10 deg. Is this correct or should it have changed. Also it idles just fine but when it gets to about 1900 rpm it starts to run bad and backfires sometimes. What else could be wrong and what should I check next. I also checked the pos side of the coil with the key on and it has the same voltage as the battery. Thanks
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: timing 4.3 with thunderbolt ignition

Did you set it into timing mode and take it out of timing mode at the right time?
Did you read and follow the procedure I posted earlier?
 

tcline11

Cadet
Joined
Oct 5, 2011
Messages
13
Re: timing 4.3 with thunderbolt ignition

Did you set it into timing mode and take it out of timing mode at the right time?
Did you read and follow the procedure I posted earlier?

I read the instructions and the only thing i couldn't figure out is where it says to remove jumper wire from timing terminal. Is that the same as the purple and white wire for the ground if it's not the instructions never say hook up any jumper wire from the timing terminal. If it's a seperate step to do can you please explain. The engine is a 2003. Thanks
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: timing 4.3 with thunderbolt ignition

Read item 8, especially the bold part that says important.
 

joewithaboat

Lieutenant Junior Grade
Joined
Jul 3, 2011
Messages
1,172
Re: timing 4.3 with thunderbolt ignition

Step 8 seems to restate what the second part of step 7 says. And then again puts it in Bold
Does the timing move as rpm comes up?
Why was this torn apart to begin with?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: timing 4.3 with thunderbolt ignition

I read the instructions and the only thing i couldn't figure out is where it says to remove jumper wire from timing terminal. Is that the same as the purple and white wire for the ground if it's not the instructions never say hook up any jumper wire from the timing terminal. If it's a seperate step to do can you please explain. The engine is a 2003. Thanks

:facepalm: Are literacy rates falling that fast???

Read Item 3...

Jumper wire = short length of wire used to connect one wire to another or to a ground.
Timing lead = Purple/white wire that will put the system into 'Base timing mode' if connected to ground when power is applied to the system.

Always connect or disconnect the timing wire to ground with the ignition key OFF.

Look, it's easy.
1. Engine off. Connect purple/white lead to ground.
2. Start engine and make adjustments where required.
3. Stop engine. Remove purple/white from ground.
4. Have a beer... or 3.
 

joewithaboat

Lieutenant Junior Grade
Joined
Jul 3, 2011
Messages
1,172
Re: timing 4.3 with thunderbolt ignition

Easy for you Chris you already know how to do it :D
That particular set of instuctions is poorly written, 7 and 8 restating the same thing differently make it sound as if there are 2 wires. Am i missing something ?
Maybe i need more beers.:)
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: timing 4.3 with thunderbolt ignition

Always connect or disconnect the timing wire to ground with the ignition key OFF.

Look, it's easy.
1. Engine off. Connect purple/white lead to ground.
2. Start engine and make adjustments where required.
3. Stop engine. Remove purple/white from ground.
4. Have a beer... or 3.

Uhhhhh Chris, you might want to read the manual again.
1. hook up purple/white to ground
2. Start engine.
3. Set timing
4. Remove purple/white from ground.
5. Shut off engine.


attachment.php
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: timing 4.3 with thunderbolt ignition

Uhhhhh Chris, you might want to read the manual again.
1. hook up purple/white to ground
2. Start engine.
3. Set timing
4. Remove purple/white from ground.
5. Shut off engine.

Ok.. so I shut the engine down before removing the grounded wire... I seriously doubt that will make any difference. The important thing is to ground the wire BEFORE starting the engine and time it while in base mode....

My bad.... :)
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: timing 4.3 with thunderbolt ignition

This thread seems to be more about miss-reading and miss-typing than it is about timing.

Sorry about that Chris.
 
Top