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Old 06-10-2011, 09:06 PM   #1 (permalink)
Cyborg ECU
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Black and Green - '98 Honda Civic DX Coupe
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How to advance ignition timing on a '98 Civic for ecomodders

I read about advancing timing and talked about it with a retired diy dragster friend. Convinced it is worth a try, I researched it online, read the Honda service manual for my 1998 Civic, did the adjustment, and came up with this approach for a mechanically inexperienced ecomodder (like myself). The only thing that makes this post special to "ecomodders" is the fact ecomodders often have gauges that monitor the car's ECU (computer). My gauge gave confusingly factory ignition timing readings after the mod, so included here is how I resolved that confusion. Therefore, you'll be saved some hassle if you read all the way through this post before you attempt anything.

If I have made mistakes please correct me and I will edit this post so it is correct. Thanks to "cbaber" for this correction. I have edited the steps below.

A ratchet
A socket extender (preferably a flexing or knuckle joint extender)
12mm socket
A timing light/gun
(see pic 1)
... you'll also need a metal paper clip (not in pic):

Optionally, you might also like work gloves to protect against hot parts.

1) Warm the engine up until the fan comes and the engine runs at normal idle speed. (BTW, if you have installed an alternator cut-off switch, it seems to affect idle speed, so have the alt "on" when you want to set back to *stock* timing.)

2) While the car starts warming up, "jump" the ECU by inserting the paperclip into the 2P (meaning "two-pin") connector. You'll find the connector under the passenger side of the dashboard. It will have brown and possibly white wires running into it. It may be housed in a green rubber/plastic thing, see pic:

3) Remove the blue 2P connector from the green holder and jump it, see pic: If your check engine light comes on as a result of this procedure you have done it right. If the check engine light does not come on you have probably inserted the paperclip incorrectly. Do it again. This has to be correct because the ECU will undo any changes you make if you don't jump it.

4) After the car has fully warmed up to the point where the fan comes on, leave it running. You are ready to begin checking and adjusting the timing. Attach the timing light to the battery (red cable to positive and black cable to negative). Also attach the rectangular end to the number one spark plug wire. On Hondas the #1 is closest to the crank, on the driver's side of the engine. If your light has an arrow on its rectangular ended cable, attach it to the spark plug wire with the arrow pointing to the spark plugs. (see two following pics):

5) Loosen the distributor. There are three bolts that will take your 12mm socket. Loosen them just enough to put some play into the distributor, so it can twist forward and backward (see pic):

For reference, here is a pic from the Honda Service Manual showing which way is "advance" and which way it "retard."

7) Turn on the light. If it creates a strobe effect, it is working, detecting each spark through the spark plug wire.

8) Find the timing belt pulley on the right side of the engine block. It is the largest pulley of the three or four you'll see. Find the small "V" shaped marker tab protruding from the block just above the pulley. Now find the thorn-shaped marker below it and find a way to see the thorn straight down through the V. The marker tabs are awkwardly placed beneath an engine mount on my car. Be patient. Clean the marks with carb cleaner, if you have it, to make them easier to read (see pic, but notice that I could not get a good angle for flash that would show the lower "thorn" tab too):

For further reference, here is the pic from the Honda Service Manual:

9) Your patience may really be tested as you try to read the timing off the pulley because of the awkward placement. Keep trying angles. Point the light down at the pulley and the marker tabs. Small color-coded lines on the pulley will occasionally flicker through the lighted area as the pulley turns (if yours are hard to see clearly, stop the engine and spray them with some carb cleaner so the colors become brighter). There is a group of three close together and then a single white mark out on its own. The lone mark is for Top Dead Center. You are interested in the three that are clustered together. Factory timing will be in place when the red line in the middle of the three lines up with the tabs (it is about 12* BTDC on the 1998 Civic). You want to line-up to the mark to the left of factory (the marker nearest the front of the car). That is about a 2* advanced. Use carb cleaner and patience to improve the readability of the lines.

10) Advance the timing by taping the distributor TOWARD the passenger compartment. Moving it toward the front bumper will RETARD timing. Check the results with the timing light. You will know you have done it correctly when you line up your vision so you can see the thorn through the V and through the strobe of the timing light see the left mark lined up with it as it flickers through the lighted area. This was a pain given the awkward placement and dirt on the marks.

11) When you have your result carefully tighten the distributor. If you have loosened the distributor too much it might move and mess up the timing adjustment when you try to tighten it back down.

12) Take the paper clip out of the ECU port.

13) Check to see that your timing is where you want it ON THE PULLEY and not on your aftermarket gauge. My Ultra Gauge continued to show stock timing even after I have changed it because it continues to go off the ECU's assumptions. BTW, that's another reason not to greedily advance timing much: the ECU will increasingly be operating upon assumed parameters that you have deliberately made wrong).


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See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.

Last edited by California98Civic; 07-24-2012 at 03:39 PM..
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