Timing light flash question
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Joined: Jan 2005
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From: A redder shade of neck on a whiter shade of trash
Timing light flash question
No need for all the "kill 05 members" posts, I've been on here since 2002 but I lost my password and had to make a new acct 
Anyway- When using a timing light aimed at the crank pulley, what does it mean when each flash isn't *exactly* where the previous flash is? Only thing I can think of is a shot distributor cap/rotor...
To better explain the situation, here is a diagram:
| <---Rotation one
*
| <---Two
*
| <---Three
*
| <--Four
*
Each vertical line is 16 deg BTC marks on pulley, the first one is the first revolution, the second is the next, etc. The asterisk is where the flash from the timing light, except it would be like 1 degree or so before or after the previous one.
Any ideas?
Anyway- When using a timing light aimed at the crank pulley, what does it mean when each flash isn't *exactly* where the previous flash is? Only thing I can think of is a shot distributor cap/rotor...
To better explain the situation, here is a diagram:
| <---Rotation one
*
| <---Two
*
| <---Three
*
| <--Four
*
Each vertical line is 16 deg BTC marks on pulley, the first one is the first revolution, the second is the next, etc. The asterisk is where the flash from the timing light, except it would be like 1 degree or so before or after the previous one.
Any ideas?
Honda-Tech Member
Joined: Jan 2003
Posts: 8,132
Likes: 5
Re: Timing light flash question (Dark_Helmet)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Dark_Helmet »</TD></TR><TR><TD CLASS="quote">Any ideas? </TD></TR></TABLE>I think you got owned by the BB software which collapses the white spaces & makes it look like they all line up perfectly... So how far off are they really? As much as 1 or 2 degrees?
If you don't jumper the SCS connector, your ECU is always making little adjustments to timing. Maybe that's part of it?
If the distributor shaft bearing is getting sloppy, or your timing belt is getting loose or sloppy, that can also do it. That means your timing is truly moving around.
Last, if you've got a timing light with a delay/advance control, maybe it's flaky??
</TD></TR></TABLE>I think you got owned by the BB software which collapses the white spaces & makes it look like they all line up perfectly... So how far off are they really? As much as 1 or 2 degrees?If you don't jumper the SCS connector, your ECU is always making little adjustments to timing. Maybe that's part of it?
If the distributor shaft bearing is getting sloppy, or your timing belt is getting loose or sloppy, that can also do it. That means your timing is truly moving around.
Last, if you've got a timing light with a delay/advance control, maybe it's flaky??
Joined: Jan 2002
Posts: 29,969
Likes: 59
From: Nowhere and Everywhere
Re: Timing light flash question (Dark_Helmet)
Always make sure the car is at full operating temperature and the ECU is in diagnostic mode (jump the diagnostic connector w/ a wire or paper clip, same as when checking for trouble codes) before using a timing light. Diagnostic mode keeps the timing fixed so you can check and adjust it. During regular idling or driving the ECU continually adjusts timing slightly so the engine will run its best.
I just bought a timing light last week and adjusted my timing (the distributor had worked its way over to fully advanced over the course of the last 100K miles since it was last checked
) and I had no problems at all getting it set.
I just bought a timing light last week and adjusted my timing (the distributor had worked its way over to fully advanced over the course of the last 100K miles since it was last checked
) and I had no problems at all getting it set.
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