This is the cats ass! I really really needed this just to be 100% sure I was doing it right, thank you! I also agree that being able to check and adjust timing is a dying art as cars become fully digital. I can't say distributors were any better (probably cheaper) but much like the carburetor their time has come and gone. But I personally prefer distributors

I will add one point. My 93 Corolla says "from the hood sticker" that timing must be checked while the car is in neutral, even if it's automatic. Idk why but I'm guessing because it idles lower in park then neutral? I really did need this thread though, I'm printing it out haha

 

Thanks! Your point made me add an additional point to the checking: turn off all accessories - no AC, radio, etc.

As for that sticker, I bet it's because it's reusable across automatic and manual if it says to keep in in neutral. For automatics I can't see any practical differences between P and N for this - the only difference is engagement of the parking pawl which does not affect idle.

 

Thank you for yet another wonderful contribution 94RollaDad! Added to DIY sticky.

 

...
(The OBD-2 95.5 - 97 vehicles do not have adjustable distributors.)
...

The 4A-FE has adjustable distributors even on OBD-2, 95.5-97 models. This is what my 97 FSM and Chilton says. If in doubt check the emission label on the bottom of the hood. It will say if the timing adjustment is part of the tune-up.

94RollaDad, you might want to update the thread title. 93-95 7A-FE and 4A-FE 93-97 or something like that. Thanks for the thread. :thumbsup:

 

A lot of manuals aren't updated as the cars change. Very few reflect the changes from OBD-1 to OBD-II. Such as migration of ignitor from inside the distributor to strut-tower. Or the movement of NE sensor to the crank. Some of these manuals still have you try to test NE sensor impedance at single-connector distributor on OBD-II cars!

The parts listing will show these changes much more accurately than service manuals. For example:

1993-1995 1.6 4a-fe OBD-1 distributor #19020-16260, adjustable, dual-connectors
1993-1995 1.8 7a-fe OBD-1 distributor #19020-16280, adjustable, dual-connectors

1995.5-1997 1.6 4a-fe and 1.8 7a-fe OBD-II distributor # 19050-16030, non-adjustable, single-connector

Not possible to have same OBD-II distributor be fixed and non-adjustable on the 7a, yet be adjustable on the 4a. That would also violate the OBD-II regulations as well.

 

Yes, you are correct. It's odd that the Toyota repair manual would get it wrong two years after the switch to OBD-II. I guess you can't believe everything you read in the bible. The ignition timing check procedure in the Engine section gives different procedures for 4A-FE and 7A-FE, but in the Ignition section there is no mention of any differences. Just one bolt to remove the distributor in all cases.

I would hope that the emission sticker under the hood would be accurate for anyone that is not sure if their distributor is adjustable (95 or 95.5 model).

 

Here's sticker from OBD-1 4A-FE. It shows ignition-timing specs and how to jumper the DLC port.

And a sticker from 1995.5+ OBD-II car. No mention of ignition-timing as it is no longer user adjustable.

 

Line under "Engine Family" shows emissions equipment.

EGR - exhaust gas recirculation lowers peak combustion temps and lowers NOx emissions significantly, ~3000ppm down to ~1000ppm. Used on all CA cars and all later OBD-II cars.

TWC - three-way catalytic converts NOx, HC and CO into N2, H2O and CO2. Takes ~1000ppm NOx down to ~50-100ppm. Fed/Canada cars have single catalytic.

TWC(2) - twin catalytic converters. CA cars have a primary cat (pre-converter) built into the exhaust headers. This allows for quicker catalytic light-off for cleaner start-up cycle. This reduces overall smog-emissions from the car during its lifetime, even though this isn't part of regular smog check. The start-up emissions is what kept Bill Gates' Porsche 959 quarantined on the docks for 10-years because it couldn't get federalized without passing that test. The secondary cat is in the regular under-body position and further cleans up exhaust. This is how the CA cars have cleanest exhaust out of all models.

O2S - oxygen sensor detects free O2 in exhaust and is a proxy indicator of AFR - air fuel ratio. The ECU uses free O2 to adjust fuel to arrive at optimum 14.7:1 AFR which is good compromise of mileage and smog emissions. The OBD-1 Fed/Canada cars have a single O2S between the exhaust header and catalytic.

O2S(2) - twin O2-sensors on OBD-1 CA cars. The 1st sensor between header & catalytic is used by the ECU for fuel trim. Second sensor is after main catalytic and is only used to monitor cat effectiveness. If signal between the 1st and 2nd O2-sensor is too similar, catalytic isn't working properly and ECU throws a code.

HO2S - heated O2-sensor is used in secondary position on all OBD-II cars. Due to the downstream position, this sensor takes a while to get to operating temperature on earlier cars; heating it electronically has it working sooner. ECU sends a variable PWM signal to heater in sensor to keep it at constant temperature; higher duty-cycle on initial start-up and lower as engine warms up.

MFI - multi-port fuel-injection, individual injector per cylinder

SFI - sequential fuel-injection (MFI implied). Crank-sensor allows ECU to determine if a cylinder is on a compression versus exhaust stroke and each cylinder has its own injector timing. This allows for cleaner emissions at idle. Partial and full-throttle isn't any different than MFI.

 

hi
does anyone have a repair manual for a 1994 4efe engine at all?
i need to figure out where exactly is 10 degrees marked on the plastic cap and what are all of those other lines in here:
preview.ibb.co/iYdhtT/syytenurk1.jpg

i had like emission problems(after replacing piston rings etc) and after some adjustment i managed to get it to ~170(from 550+), but it has to be below 100...(preferably like 50?)
and do i also have to check all of the resistances on the coils also? and the air gap in the distributor somehow?
i dont think it has any vacuum leaks anymore(even bought a brand new plastic valve thing) and i have also welded all of the exhaust leaks now...

 

i need to figure out where exactly is 10 degrees marked on the plastic cap and what are all of those other lines in here:
preview.ibb.co/iYdhtT/syytenurk1.jpg

 

Just a heads up, posting Toyota manual material (full pages or PDFs) is against our rules as it is copyrighted material. But you can usually download the manuals from Toyota directly for a small fee, I forget the link but others have posted it before.

 

Is there a set RPM the car should be idling at in order to check the timing? My timing light does not have a tach and I'm wondering if I need to get one in order to do this properly.

 

No, the only two pre-conditions the FSM outlines are 1) allow the engine to warm up and 2) Bridge TE1 and E1 as described in the DIY above.

 

I believe if the idle is much higher than normal it will affect the base timing. Just grab the throttle while using the timing light and see if the timing changes as you rev the engine a little, but this takes the TPS out of the idle position. Maybe if TE1 & E1 is bridged and TPS is at idle position then the timing shouldn't change. If you suspect you are not at a normal idle, then you might want to check the idle speed.

Does the 93-95 FSM have a troubleshooting section? In my 97 FSM the step before checking the ignition timing is checking the idle speed, but on 96-97 neither is adjustable. This is just to check it.

 

engine has to be @operating temperature, air filter installed and @700+-50rpm with the 2 pins grounded into the body - idle speed can be adjusted with the screw on the air intake (4efe).
altho not really sure how can you actually set it to 700, because sometimes it just drops down/fluctuates itself after just idling too much in the same place...

 

Nothing is grounded to body. TE1 is jumped to E1.

You can't adjust idle speed on 7th gen 93-97 4A-FE and 7A-FE, at least not in North America. Idle speed is all controlled by the computer using the IAC valve. The idle speed can be adjusted on 6th gen 88-92 4A-FE. I'm not sure in other countries around the world.

 

I’m not sure why one would speculate on messing with the idle when the factory service manual pretty clearly outlines how to do this. Why make it harder than it needs to be?

 

It can be problematic when you buy a cheap IAC valve from Ebay. An OEM one costs between 250€ and 500€, which can be a deal breaker for a 25 year old economy car, so there's no shame in buying a cheap one from Ebay, but they're so poorly made most of them just don't work out of the box, however you can unscrew and rotate the solenoid by a fair margin to sort of cheat and set the idle closer to OEM spec. It still won't work quite as good as an OEM part and usually you have to sacrifice your warm or cold rpm a bit so it behaves properly.

 

I don't think anyone suggested messing with the idle. My only suggestion was to check the idle speed because it's the step before checking ignition timing in the troubleshooting section of my repair manual, so having a proper normal idle speed is an implicit requirement before setting the base ignition timing. If for some reason your engine was running at 2000 RPM warmed up when you were trying to set the ignition timing then the problem of high idle should probably be addressed first. Having an idle that high may throw off the timing, so you can't set it correctly.

My repair manual is for 1997 but I still think the general troubleshooting procedure applies. You might as well do all the basic tests while doing a tune-up.

If someone can demonstrate that jumping TE1 & E1 keeps the timing exactly at 10° BTDC no matter what the engine speed then I'll say idle speed doesn't matter when setting the timing.

 

Since manual timing was eliminated in the '95.5 Corolla, I wonder why it is covered in the '97 manual.

 

Checking timing is still a useful diagnostics tool even if the engine has a non-adjustable timing (or to be precise, a computer-controlled timing). It can uncover other issues - if your timing is off then something is off either in the sensors the ECU relies on to adjust timing, or something mechanical (e.g., a timing belt issue).

 

As with many of my DIYs this one originated from having to do the work and deciding to document it along the way. It appears checking and adjusting timing is knowledge that's slowly fading away as modern cars do not have a need for mechanical adjustments of ignition timing. So I figured let's get this one documented as it's a very important and easy item to check for those of us who have the "gen 7.0" Corollas with OBD-1 and adjustable distributors. (The OBD-2 95.5 - 97 vehicles do not have adjustable distributors.)

Tools you need:

• Timing light. I decided to splurge a bit and got an Innova 3568 light - it's very nice and easy to read, and also does RPM/tach. I suspect any cheapo light will work fine, but if the bulb is weak you might have to do this in a pretty dark setting to see properly.
• 17 mm, 12 mm sockets (6 sided preferred); a couple of extensions and a flexible joint; rachet; torque wrench appropriate for 15 ft/lbs torque
• A tiny bit of bright (I used white) paint and something to apply it with (I used a Starbucks coffee stirrer...). Use whatever you have on hand.

Word of caution:

• You are responsible for your own work, I am just documenting what worked for me. Work responsibly, and the biggest caution on this work is focused on the fact that you'll have to start your engine a lot and switch back and forth between having a running engine and working on that engine. Double check before starting the engine, e.g. stuff like REMOVE the ratchet you'll use on the crank pulley BEFORE starting the car. Don't be dumb.

Prep work:

• Before doing this, you MAY be lucky and have the crank pulley at top dead center (TDC) already. Use a flash light and look down the passenger side of the engine bay. The bottom pulley is the crank pulley (a.k.a. harmonic balancer). There's a slight notch in the pulley to indicate TDC. If you see this notch and can access it to fill it with a droplet of paint, you can skip through the next few steps.
• If you have a manual car you need to make sure the gear shifter is in neutral (hand brake applied, please!). If you have an automatic just leave it in P.
• Turn the steering wheel all the way to the right. Alternatively you'll need to jack the front passenger side up and remove that wheel but it's not needed as long as you just turn the wheel.
• Ignition OFF and keys OUT of the ignition. If you want to be extra sure you can disconnect the negative battery terminal.
• Look in the front passenger side wheel well. You'll discover there's a cover that covers up the crank pulley bolt access. Pop that cover off - it should come off pretty easily. This is what you're looking at once it's off:

Close-up:

• Now, get your ratchet and extension and the 17 mm socket. Put it through the access hole and on the crank pulley bolt.

(Yes I know, tiny ratchet for a big job. Should have pulled out the bigger one but this seemed to work.)

• The pulley should only be turned clockwise. Use the ratchet and slowly turn the pulley clockwise. If it's too hard to pull you can make it easier by disconnecting the spark plug wires and loosening the spark plugs, but to be honest that should not be necessary. If you do, remember to torque them back to spec after.
• Alternate between slow turns and then inspecting the top looking for the notch in the pulley. Once you find it, find the best position for applying paint and stop turning. If you turn too far do NOT turn counter clockwise, but just complete another full turn.
• Get some paint out and apply to the notch. Also apply to the timing cover line that indicates the number "10" (which means 10 degrees before top dead center). Some photos to help:

In this photo you can see the 10 degree mark painted (indicated by the arrow) and you can also see the groove having a tiny bit of paint (slightly above the 10 degree mark on the outer rim of the pulley).

• Let the paint briefly air dry as you don't want to sling it around wet.
• Remember to put the crank pulley cover back.
• While you're waiting for the paint instead of watching paint dry... be productive! Hook up the timing light. Whatever light you get should come with instructions but essentially you hook up three cables:
  • Inductive pickup clip - clamps around the #1 spark plug cable (the passenger side one). Mine had an arrow indicating the direction vs. the spark plug.
  • Positive battery cable (I like to always connect positive first)
  • Negative battery cable
  • Here's what mine looked like all hooked up:

• Start the car and let it warm up fully (if you prefer to do that before hooking up the timing light that's fine too).
• Once warmed up, turn the engine off.
• Open the diagnostic tower on the driver side of the engine bay. You'll see the inside of the lid has terminal IDs. Connect TE1 and E1 like this - I used a paper clip:

Check timing:

• Start the engine again. TURN OFF ALL ACCESSORIES (AC, Radio, headlights, defoggers, etc). The idea is to have no accessory load on the alternator or the AC compressor.
• Aim the timing light at the crank pulley area:

• If your timing is aligned according to spec the groove and the 10 degree mark should perfectly align when the timing light illuminates. If not, take note at how much retarded or advanced the groove is relative to the 10 degree mark (every line is 5 degrees).
• If everything aligns congrats - you're done! If not, keep going for the next section. Also you may want to check out how to adjust timing if you want to experiment with different settings.

Adjusting timing

• If timing needs to be adjusted you'll need access to the two bolts attaching the distributor. You'll need to remove the intake hose and air filter. It should look something like this when removed:

• The bolts are not easily accessible. I used a few extensions and joints to get there. Here are some pictures:

Right bolt:

Left bolt:

My extensions put together for the torque wrench:

• Loosen both 12 mm bolts. To further advance timing, rotate clockwise. To retard timing, rotate counter clockwise. Note that you only need to move a tiny bit to shift even as much as 5 degrees. So do this in small adjustments and retest.
• Slightly tighten the left bolt for retesting. Refer to previous section to check timing.
• Once you have obtained desired timing, tighten both bolts with a torque wrench to 15 ft/lbs.

To recap on the factory spec - it's 10 degrees BTDC. I drove around with mine at 15 degrees BTDC for the longest time and it seemed fine. Some claim that (especially in combination with higher octane gas) gives more power and MPG, but so far my butt dyno seems to like the 10 degree setting better in terms of torque.

Enjoy!

January 2022 ....1993 paseo coupe , bought in 2001 with 190k and 55k on engine due to previous owner low IQ complete rebuild on almost every part . Only negative is we need a company who provides parts no longer available window rain seals and wipers and a few items I didn't purchase before out of stock.