How to check ignition timing on -88 vette ?
05-11-2004, 02:19 AM
#1
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How to check ignition timing on -88 vette ?
Please, I feel stupid for asking this but what is the step by step procedure for checking the ignition timing for my vette? Somehow I dont seem to get it how to decipher those timing marks....
:rolleyes:
:rolleyes:
05-11-2004, 08:52 AM
#3
Re: How to check ignition timing on -88 vette ? (jutammel)
hook up your timing light to #1 spark plug and disconnect wire near the brake booster. check timing with light and adjust if necessary by rotating distributor cap. i believe base setting is about 6 degrees but some guys seem to run a bit more. just did it and its a 10 minute job. you will need a special wrench to loosen the bolt that secures the distributor. very inexpensive item. there are many threads on this topic under "timing". good luck.
05-11-2004, 08:43 PM
#4
Le Mans Master
Re: How to check ignition timing on -88 vette ? (merplastic91)
You wanted a step-by-step, okay, here's how I do it.
I start the engine and let it run until it's warmed up.
I then shut it down, and disconnect the EST wire, (it's a SINGLE wire that is tan in color with a black stripe and is located just under the power brake booster/windshield wiper motor area).
I get out my 3/8" ratchet and distributor wrench, adjust the ratchet to the loosening position, and place it on the passenger side tire. The distributor wrench is shaped like an "L" and makes getting to the distributor bolt much easier than using a straight 9/16" open end/box end wrench.
I then connect my timing light to the #1 spark plug wire and the other two clips to the battery; red to positive and black to negative. I don't have a self powered timing light; mine uses battery voltage.
I then start the engine. It may be a little difficult to keep running at first with the EST wire disconnected. That's the reason I let the engine warm up first; makes it a little easier to get it to idle by itself.
Once the engine settles down and idles by itself, I point the timing light at the harmonic damper and see where the groove in the harmonic damper aligns with the timing tab on the timing chain cover.
The stock setting is 6 degrees Before Top Dead Center (BTDC). Each little line on the timing tab should equate to 2 degrees.
If the timing needs adjustment, I walk to the passenger side of the engine and loosen the bolt that secures the distributor to the intake manifold (you have to access it from the passenger side). I loosen the bolt just enough to allow me turn the distributor with my hand.
I adjust the ratchet to the 'tighten' position and leave the ratchet and distributor wrench in place, kind of standing up but still on the head of the bolt.
I then return to the driver's side of the engine, point the timing light at the damper again, pull the trigger and turn the distributor with my hand while watching the groove on the harmonic damper move.
Once the mark on the damper aligns where I want it, I reach over and give the ratched a turn to tighten the distributor hold down bolt.
I then check to see that the timing I'd selected hasn't moved. It will sometimes as you tighten the hold down bolt. If it has moved, I loosen the bolt, make the necessary adjustment by turning the distributor (again) in the required direction. Then I tighten again.
Once I have the timing set to where I want it. I walk over to the passenger side of the engine again and tighten the bolt completely.
I then go back to the driver's side and verify that the timing hasn't moved..
Then, I shut down the engine, re-connect the EST wire, remove the timing light connections and disconnect the battery (just one cable) for about 30 seconds. This clears the code that gets automatically set when the computer detects the engine running with the EST disconnected.
I try to work as fast as I can because with the engine idling with only 6 degrees of timing advance, the headers/exhaust will begin to glow red due to the engine not having enough timing advance.
Once the engine is re-fired with the EST re-connected and code cleared, the timing mark should be just off the scale of the timing chain cover tab. Up near the 12 o'clock position. You can re-connect the timing light if you want to check it.
That's it.
Jake
I start the engine and let it run until it's warmed up.
I then shut it down, and disconnect the EST wire, (it's a SINGLE wire that is tan in color with a black stripe and is located just under the power brake booster/windshield wiper motor area).
I get out my 3/8" ratchet and distributor wrench, adjust the ratchet to the loosening position, and place it on the passenger side tire. The distributor wrench is shaped like an "L" and makes getting to the distributor bolt much easier than using a straight 9/16" open end/box end wrench.
I then connect my timing light to the #1 spark plug wire and the other two clips to the battery; red to positive and black to negative. I don't have a self powered timing light; mine uses battery voltage.
I then start the engine. It may be a little difficult to keep running at first with the EST wire disconnected. That's the reason I let the engine warm up first; makes it a little easier to get it to idle by itself.
Once the engine settles down and idles by itself, I point the timing light at the harmonic damper and see where the groove in the harmonic damper aligns with the timing tab on the timing chain cover.
The stock setting is 6 degrees Before Top Dead Center (BTDC). Each little line on the timing tab should equate to 2 degrees.
If the timing needs adjustment, I walk to the passenger side of the engine and loosen the bolt that secures the distributor to the intake manifold (you have to access it from the passenger side). I loosen the bolt just enough to allow me turn the distributor with my hand.
I adjust the ratchet to the 'tighten' position and leave the ratchet and distributor wrench in place, kind of standing up but still on the head of the bolt.
I then return to the driver's side of the engine, point the timing light at the damper again, pull the trigger and turn the distributor with my hand while watching the groove on the harmonic damper move.
Once the mark on the damper aligns where I want it, I reach over and give the ratched a turn to tighten the distributor hold down bolt.
I then check to see that the timing I'd selected hasn't moved. It will sometimes as you tighten the hold down bolt. If it has moved, I loosen the bolt, make the necessary adjustment by turning the distributor (again) in the required direction. Then I tighten again.
Once I have the timing set to where I want it. I walk over to the passenger side of the engine again and tighten the bolt completely.
I then go back to the driver's side and verify that the timing hasn't moved..
Then, I shut down the engine, re-connect the EST wire, remove the timing light connections and disconnect the battery (just one cable) for about 30 seconds. This clears the code that gets automatically set when the computer detects the engine running with the EST disconnected.
I try to work as fast as I can because with the engine idling with only 6 degrees of timing advance, the headers/exhaust will begin to glow red due to the engine not having enough timing advance.
Once the engine is re-fired with the EST re-connected and code cleared, the timing mark should be just off the scale of the timing chain cover tab. Up near the 12 o'clock position. You can re-connect the timing light if you want to check it.
That's it.
Jake
The following 4 users liked this post by JAKE:
05-11-2004, 09:04 PM
#5
Le Mans Master
Re: How to check ignition timing on -88 vette ? (jutammel)
Figuring out the timing marks has tripped up a lot of guys, so don't fret.
Most timing tabs are marked in two degree increments. Each little hash line on the timing tab indicates two degrees difference from the hash line nearest it. You may not see actual numbers, like 2, 4, 6, etc., all you may see are just little lines cut in the timing tab.
Tabs differ, but there is usually ONE spot on the tab that is marked ZERO, has the letter "0", has a deeper notch or longer hash line than the others. Something that makes it different from all the other marks on the timing tab. That's the sucka you have to identify first; all changes are made in direct reference to it.
The damper has a groove cut in it which is 'supposed' to concide with the #1 piston being at TDC (Top Dead Center). This isn't always accurate, but unless you want to go to all the trouble of verifying it, just accept it as being cut in the correct place.
Most guys mark those spots (ZERO on the tab and TDC on the damper) with something that will make them stand out when the timing light is flashed at it. I use red fingernail polish, others use white-out, etc.
The ignition advance is determined by where the groove in the damper aligns with the little hash mark on the timing tab.
If you are standing on the driver's side of the engine, those marks on the timing tab that move away from you, which also causes it to move away from the ZERO mark (in a counter clock-wise direction) are advance marks.
Those that move toward you (in a clock-wise direction from the ZERO mark) are the retard direction.
So, for each little hash mark on the timing tab that you move the damper groove you've changed the timing two degrees. If you move the damper groove counter-clock-wise (away from you) you're advancing the timing and if you move it clock-wise (toward you) you're retarding it.
With the EST disconnect, the engine will idle noticably better as you advance the timing and noticably worse as you retard it. Do be fooled; stick to the stock setting of 6 degrees, or at best 8 degrees. Modified engines may call for more initial advance that 8 degrees, but for a basically stock setup, stick with a max of 8.
Remember, the directional references I listed are with you standing on the driver's side of the engine.
If you can picture yourself standing directly in front of the engine, facing it (which won't do a lot of good since you wouldn't be able to see any of the timing marks from THAT position), clock-wise and counter clock-wise applies.
Hope this helps explain it.
Jake
[Modified by JAKE, 2:41 AM 5/12/2004]
Most timing tabs are marked in two degree increments. Each little hash line on the timing tab indicates two degrees difference from the hash line nearest it. You may not see actual numbers, like 2, 4, 6, etc., all you may see are just little lines cut in the timing tab.
Tabs differ, but there is usually ONE spot on the tab that is marked ZERO, has the letter "0", has a deeper notch or longer hash line than the others. Something that makes it different from all the other marks on the timing tab. That's the sucka you have to identify first; all changes are made in direct reference to it.
The damper has a groove cut in it which is 'supposed' to concide with the #1 piston being at TDC (Top Dead Center). This isn't always accurate, but unless you want to go to all the trouble of verifying it, just accept it as being cut in the correct place.
Most guys mark those spots (ZERO on the tab and TDC on the damper) with something that will make them stand out when the timing light is flashed at it. I use red fingernail polish, others use white-out, etc.
The ignition advance is determined by where the groove in the damper aligns with the little hash mark on the timing tab.
If you are standing on the driver's side of the engine, those marks on the timing tab that move away from you, which also causes it to move away from the ZERO mark (in a counter clock-wise direction) are advance marks.
Those that move toward you (in a clock-wise direction from the ZERO mark) are the retard direction.
So, for each little hash mark on the timing tab that you move the damper groove you've changed the timing two degrees. If you move the damper groove counter-clock-wise (away from you) you're advancing the timing and if you move it clock-wise (toward you) you're retarding it.
With the EST disconnect, the engine will idle noticably better as you advance the timing and noticably worse as you retard it. Do be fooled; stick to the stock setting of 6 degrees, or at best 8 degrees. Modified engines may call for more initial advance that 8 degrees, but for a basically stock setup, stick with a max of 8.
Remember, the directional references I listed are with you standing on the driver's side of the engine.
If you can picture yourself standing directly in front of the engine, facing it (which won't do a lot of good since you wouldn't be able to see any of the timing marks from THAT position), clock-wise and counter clock-wise applies.
Hope this helps explain it.
Jake
[Modified by JAKE, 2:41 AM 5/12/2004]
05-11-2004, 11:29 PM
#7
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Location: Summerland B.C. Canada
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Re: How to check ignition timing on -88 vette ? (FlyboyZR1)
:withstupid:
I agree, but not once while you where going back and forth from drivers side to passenger side, did you stop for a gulp of beer :confused:
I agree, but not once while you where going back and forth from drivers side to passenger side, did you stop for a gulp of beer :confused:
05-12-2004, 12:28 AM
#8
Le Mans Master
Re: How to check ignition timing on -88 vette ? (JAKE)
Those that move toward you (in a clock-wise direction from the ZERO mark) are the retard direction.
05-12-2004, 01:39 AM
#10
Le Mans Master
Re: How to check ignition timing on -88 vette ? (jutammel)
[SNIP]Wow, thanks for the great info guys! You're great :hurray: [/SNIP]
I accept PayPal! LOL
Jake
I accept PayPal! LOL
Jake
05-12-2004, 01:46 AM
#11
Le Mans Master
Re: How to check ignition timing on -88 vette ? (AGENT 86)
:withstupid:
I agree, but not once while you where going back and forth from drivers side to passenger side, did you stop for a gulp of beer :confused:
I agree, but not once while you where going back and forth from drivers side to passenger side, did you stop for a gulp of beer :confused:
Jake
05-12-2004, 02:00 AM
#12
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Member Since: Sep 2000
Location: Partying with the Cowboys cheerleaders in Mt. Olive, New Jersey
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Re: How to check ignition timing on -88 vette ? (JAKE)
Wow! That's some write up!
/saving it as a word document as we speak
//hope Jake didn't copyright it
:D :D :D
/saving it as a word document as we speak
//hope Jake didn't copyright it
:D :D :D
05-12-2004, 02:09 AM
#13
Re: How to check ignition timing on -88 vette ? (AGENT 86)
The proper procedure for adjusting the timing always includes a cold Budweiser (beverage of choice) but only after the hood closes! Safety first! This is especially tricky though as one has to repeat the application of beer as necessary to achieve the desired results! :seeya
06-24-2018, 08:47 PM
#14
Advanced
Figuring out the timing marks has tripped up a lot of guys, so don't fret.
Most timing tabs are marked in two degree increments. Each little hash line on the timing tab indicates two degrees difference from the hash line nearest it. You may not see actual numbers, like 2, 4, 6, etc., all you may see are just little lines cut in the timing tab.
Tabs differ, but there is usually ONE spot on the tab that is marked ZERO, has the letter "0", has a deeper notch or longer hash line than the others. Something that makes it different from all the other marks on the timing tab. That's the sucka you have to identify first; all changes are made in direct reference to it.
The damper has a groove cut in it which is 'supposed' to concide with the #1 piston being at TDC (Top Dead Center). This isn't always accurate, but unless you want to go to all the trouble of verifying it, just accept it as being cut in the correct place.
Most guys mark those spots (ZERO on the tab and TDC on the damper) with something that will make them stand out when the timing light is flashed at it. I use red fingernail polish, others use white-out, etc.
The ignition advance is determined by where the groove in the damper aligns with the little hash mark on the timing tab.
If you are standing on the driver's side of the engine, those marks on the timing tab that move away from you, which also causes it to move away from the ZERO mark (in a counter clock-wise direction) are advance marks.
Those that move toward you (in a clock-wise direction from the ZERO mark) are the retard direction.
So, for each little hash mark on the timing tab that you move the damper groove you've changed the timing two degrees. If you move the damper groove counter-clock-wise (away from you) you're advancing the timing and if you move it clock-wise (toward you) you're retarding it.
With the EST disconnect, the engine will idle noticably better as you advance the timing and noticably worse as you retard it. Do be fooled; stick to the stock setting of 6 degrees, or at best 8 degrees. Modified engines may call for more initial advance that 8 degrees, but for a basically stock setup, stick with a max of 8.
Remember, the directional references I listed are with you standing on the driver's side of the engine.
If you can picture yourself standing directly in front of the engine, facing it (which won't do a lot of good since you wouldn't be able to see any of the timing marks from THAT position), clock-wise and counter clock-wise applies.
Hope this helps explain it.
Jake
[Modified by JAKE, 2:41 AM 5/12/2004]
Most timing tabs are marked in two degree increments. Each little hash line on the timing tab indicates two degrees difference from the hash line nearest it. You may not see actual numbers, like 2, 4, 6, etc., all you may see are just little lines cut in the timing tab.
Tabs differ, but there is usually ONE spot on the tab that is marked ZERO, has the letter "0", has a deeper notch or longer hash line than the others. Something that makes it different from all the other marks on the timing tab. That's the sucka you have to identify first; all changes are made in direct reference to it.
The damper has a groove cut in it which is 'supposed' to concide with the #1 piston being at TDC (Top Dead Center). This isn't always accurate, but unless you want to go to all the trouble of verifying it, just accept it as being cut in the correct place.
Most guys mark those spots (ZERO on the tab and TDC on the damper) with something that will make them stand out when the timing light is flashed at it. I use red fingernail polish, others use white-out, etc.
The ignition advance is determined by where the groove in the damper aligns with the little hash mark on the timing tab.
If you are standing on the driver's side of the engine, those marks on the timing tab that move away from you, which also causes it to move away from the ZERO mark (in a counter clock-wise direction) are advance marks.
Those that move toward you (in a clock-wise direction from the ZERO mark) are the retard direction.
So, for each little hash mark on the timing tab that you move the damper groove you've changed the timing two degrees. If you move the damper groove counter-clock-wise (away from you) you're advancing the timing and if you move it clock-wise (toward you) you're retarding it.
With the EST disconnect, the engine will idle noticably better as you advance the timing and noticably worse as you retard it. Do be fooled; stick to the stock setting of 6 degrees, or at best 8 degrees. Modified engines may call for more initial advance that 8 degrees, but for a basically stock setup, stick with a max of 8.
Remember, the directional references I listed are with you standing on the driver's side of the engine.
If you can picture yourself standing directly in front of the engine, facing it (which won't do a lot of good since you wouldn't be able to see any of the timing marks from THAT position), clock-wise and counter clock-wise applies.
Hope this helps explain it.
Jake
[Modified by JAKE, 2:41 AM 5/12/2004]
02-02-2019, 09:20 PM
#15
Hi you did a great job of explaining the step by step engine timimg
Im still having a problem it stars fine but at low rpm it stalls out
dont think it's the pump because it runs fine at hi rpm
i just had shut it down to fix a intake leak which I just finished
and now have this running problem
before I tore it apart it ran great
there is 1 small connector two pin white I can't find where it goes
dont know if that could be a problem
thanks gasandvetteman
Im still having a problem it stars fine but at low rpm it stalls out
dont think it's the pump because it runs fine at hi rpm
i just had shut it down to fix a intake leak which I just finished
and now have this running problem
before I tore it apart it ran great
there is 1 small connector two pin white I can't find where it goes
dont know if that could be a problem
thanks gasandvetteman
02-02-2019, 11:45 PM
#16
Take a few pics, and post them. I redid my intake and one of my fuel injector plugs did not seat properly, so I had a bad idle for a month before I finally figured it out.
I sprayed each cyl with a stream of water to find number 4 cyl was cold . fiddled around and found the plug loose. Try to go over things.
Good Luck
I sprayed each cyl with a stream of water to find number 4 cyl was cold . fiddled around and found the plug loose. Try to go over things.
Good Luck
02-04-2019, 03:29 PM
#17
Starts but wont idle
take a few pics, and post them. I redid my intake and one of my fuel injector plugs did not seat properly, so i had a bad idle for a month before i finally figured it out.
I sprayed each cyl with a stream of water to find number 4 cyl was cold . Fiddled around and found the plug loose. Try to go over things.
Good luck
I sprayed each cyl with a stream of water to find number 4 cyl was cold . Fiddled around and found the plug loose. Try to go over things.
Good luck
it ran fine before i messed with it so its something that i changed
probably somthing simple but i cant pinpoint it
thanks all.
11-17-2021, 05:48 PM
#19
Timing?
Figuring out the timing marks has tripped up a lot of guys, so don't fret.
Most timing tabs are marked in two degree increments. Each little hash line on the timing tab indicates two degrees difference from the hash line nearest it. You may not see actual numbers, like 2, 4, 6, etc., all you may see are just little lines cut in the timing tab.
Tabs differ, but there is usually ONE spot on the tab that is marked ZERO, has the letter "0", has a deeper notch or longer hash line than the others. Something that makes it different from all the other marks on the timing tab. That's the sucka you have to identify first; all changes are made in direct reference to it.
The damper has a groove cut in it which is 'supposed' to concide with the #1 piston being at TDC (Top Dead Center). This isn't always accurate, but unless you want to go to all the trouble of verifying it, just accept it as being cut in the correct place.
Most guys mark those spots (ZERO on the tab and TDC on the damper) with something that will make them stand out when the timing light is flashed at it. I use red fingernail polish, others use white-out, etc.
The ignition advance is determined by where the groove in the damper aligns with the little hash mark on the timing tab.
If you are standing on the driver's side of the engine, those marks on the timing tab that move away from you, which also causes it to move away from the ZERO mark (in a counter clock-wise direction) are advance marks.
Those that move toward you (in a clock-wise direction from the ZERO mark) are the retard direction.
So, for each little hash mark on the timing tab that you move the damper groove you've changed the timing two degrees. If you move the damper groove counter-clock-wise (away from you) you're advancing the timing and if you move it clock-wise (toward you) you're retarding it.
With the EST disconnect, the engine will idle noticably better as you advance the timing and noticably worse as you retard it. Do be fooled; stick to the stock setting of 6 degrees, or at best 8 degrees. Modified engines may call for more initial advance that 8 degrees, but for a basically stock setup, stick with a max of 8.
Remember, the directional references I listed are with you standing on the driver's side of the engine.
If you can picture yourself standing directly in front of the engine, facing it (which won't do a lot of good since you wouldn't be able to see any of the timing marks from THAT position), clock-wise and counter clock-wise applies.
Hope this helps explain it.
Jake
[Modified by JAKE, 2:41 AM 5/12/2004]
Most timing tabs are marked in two degree increments. Each little hash line on the timing tab indicates two degrees difference from the hash line nearest it. You may not see actual numbers, like 2, 4, 6, etc., all you may see are just little lines cut in the timing tab.
Tabs differ, but there is usually ONE spot on the tab that is marked ZERO, has the letter "0", has a deeper notch or longer hash line than the others. Something that makes it different from all the other marks on the timing tab. That's the sucka you have to identify first; all changes are made in direct reference to it.
The damper has a groove cut in it which is 'supposed' to concide with the #1 piston being at TDC (Top Dead Center). This isn't always accurate, but unless you want to go to all the trouble of verifying it, just accept it as being cut in the correct place.
Most guys mark those spots (ZERO on the tab and TDC on the damper) with something that will make them stand out when the timing light is flashed at it. I use red fingernail polish, others use white-out, etc.
The ignition advance is determined by where the groove in the damper aligns with the little hash mark on the timing tab.
If you are standing on the driver's side of the engine, those marks on the timing tab that move away from you, which also causes it to move away from the ZERO mark (in a counter clock-wise direction) are advance marks.
Those that move toward you (in a clock-wise direction from the ZERO mark) are the retard direction.
So, for each little hash mark on the timing tab that you move the damper groove you've changed the timing two degrees. If you move the damper groove counter-clock-wise (away from you) you're advancing the timing and if you move it clock-wise (toward you) you're retarding it.
With the EST disconnect, the engine will idle noticably better as you advance the timing and noticably worse as you retard it. Do be fooled; stick to the stock setting of 6 degrees, or at best 8 degrees. Modified engines may call for more initial advance that 8 degrees, but for a basically stock setup, stick with a max of 8.
Remember, the directional references I listed are with you standing on the driver's side of the engine.
If you can picture yourself standing directly in front of the engine, facing it (which won't do a lot of good since you wouldn't be able to see any of the timing marks from THAT position), clock-wise and counter clock-wise applies.
Hope this helps explain it.
Jake
[Modified by JAKE, 2:41 AM 5/12/2004]
