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DescriptionHow to check and set the ignition timing on a Mk2. AuthorDateMon Mar 21, 2005 11:50 amTypePicture How-To CategoryEngine Views 12103
Ignition Timing How to check and set the ignition timing on a Mk2.
Setting Ignition Timing on an MR2 Turbo
by Jon Sturgeon
Introduction
The MR2 Turbo has a 'hybrid' ignition system. The car was developed in the mid-1980s and thus benefits from computer-controlled ignition timing; however it still has a mechanical distributor and single coil. More modern cars have mostly moved on to a distributorless ignition system (DIS) and individual coils on each spark plug.
The angle at which the distributor is attached to the head controls the base ignition timing. The computer will vary the exact time at which the spark is fired depending upon engine speed, load etc, but the adjustments that the computer makes are all relative to the base timing set by the alignment of the distributor. If the base timing is out of adjustment then the car will tend to run erratically under boost (if it is advanced too far) or be sluggish (if it is retarded too far).
The correct setting for the base ignition timing on the MR2 Turbo is 10 degrees before top dead center (10' BTDC).
Tools/Parts Required
* Timing Light - I purchased the basic model shown above from Pep-Boys for $30.
* Cross-head screwdriver
* 10mm socket
* 14mm socket & 3-inch extension
* Bent paper clip
* Flashlight
Directions
1. Warm the car up to normal operating temperature.
2. Remove the right-hand engine cover panel by removing two cross-head screws and one 10mm grounding bolt.
3. Unclip the lid of the 'diagnosis' port on the rear of the engine bay and insert the two ends of the bent paper clip into the holes labelled TE1 and E1. This prevents the computer from varying the ignition timing electronically while you are trying to adjust it.
4. Remove the lid of the fusebox in the opposite corner of the engine bay. Connect the positive lead of the timing light to the large power cable in the fusebox. Connect the negative lead to a nearby grounding point; I used one of the bolts holding down my strut tower brace.
5. Connect the timing light pickup over the number 1 spark plug wire. The #1 cylinder is closest to the timing belt end of the engine (passenger side for US-spec cars).
6. Shine a flashlight down between the two intake pipes that lead to and from the intercooler. Below the alternator belt you should be able to make out the timing marks that you will use to set the ignition timing. Use the photo below for reference:
7. Start the engine. Note that the 'check engine' light will flash because the TE1 and E1 terminals are connected.
8. Shine the timing light down between the intercooler pipes and watch as the mark on the crank pulley is illuminated as it passes by the timing marks. If the mark is nowhere to be seen, make sure you have the timing light pickup connected to the #1 spark plug wire.
9. If the mark on the crank pulley does not line up with the 10' BTDC point, then your base ignition timing is set incorrectly.
10. To correct the ignition timing, stop the engine and loosen the two 14mm bolts on the distributor. You'll need a short (3 inch) socket extension to access the bolts. Do not remove the bolts.
11. Restart the engine and rotate the distributor slightly in one direction. You will notice the idle speed of the engine rise or fall as the distributor is rotated.
12. Shine the timing light on the timing marks again to see if you have moved the mark on the crank pulley closer to or further away from the 10' BTDC point. Keep moving the distributor slightly until the mark is aligned exactly on the 10' BTDC point.
13. When the timing is set correctly, tighten the two distributor bolts. Recheck the timing again just to be sure the distributor didn't move.
14. Remove the paperclip from the diagnosis port and disconnect the timing light from the spark plug wire and fusebox.
15. Enjoy the smooth acceleration that correct ignition timing brings!
This article has been copied from Jon's site with permission. He welcomes feedback so feel free to contact him with any corrections or suggestions: [email protected]
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