DH6twinotter

Hey all,
I haven't figure out what my pinging is comming from yet. I did have a question though. When I was replacing my knock sensor, I noticed that their were 2 white marks (drawn on) next to the stock timing marks (or indentions) on my engine. They are about 1/4 inch next to the stock marks. One of the marks was down above the main pulley (or whatever that's called) and the other was next to the stock timing mark on the passenger side cylinder bank. Do dealers put white timing marks if they advance or retard the timing? When I put every thing back together after my knock sensor replacement, I just lined the timing up with the stock marks. Anyhow, is it common for mechanics to reposition the timing on vehicles with higher miles to help with the pinging? If it makes any difference, my Runner has 163,000 miles on it.

Would there be anything wrong with advancing or retarding the timing that far (the 1/4 inch in either direction)?

Also, when somebody says that thier timing is advanced 10 degrees, what part of the timing mechanism are they measuring? Probably a dumb question, but I though it was worth asking.

Well, I hope that all makes some sense. Thanks in advance for the help.
Have fun all.
DH6twinotter

ravencr

Don't know all your answers, but advancing your timing will induce pinging, which requires that you run higher octane fuel. Retarding timing, to a point, will reduce the pinging, but make sure you don't do it too much, because you will notice a loss in power if you go too far. I don'thave much experience in this, but this is what I've gathered from reading like crazy on the forums. I would choose which octane gas you wanted to run, and then adjust the timing accordingly. Obviously, if you choose to run the highest octane, the less retard you will have to do, and the more power you'll have. You decide!

Chris

Dr. Zhivago

You should probably check your Initial (Idle) Timing. It might be TOO advanced. You'll need a Timing Light, about 30 minutes and a few wrenches. Check out this article for an overview of how to do it. You will need Adobe Acrobat to view it. This is not a vehicle specific article, but it is Toyota specific and it does apply to the type of ignition system you have.

If you need more specific help with your truck, please post back after you read the article.

Hope this helps.
Dr. Z

Victor

A small amount of advance may increase power but your truck will probably start to ping. When I checked my initial timing it was set at 7 BTDC. Now at 10 BTDC the thing idles much smoother and runs great - better fuel economy too. What I'm getting at is that the factory setting is about perfect for these trucks.

DH6twinotter

Hey all. Thanks for all the help. Sorry it's taken me so long to get back to you.

Thanks for that link too, Dr. Z. Some of it was over my head, but what I did understand was really interesting.

What does BTDC mean?

Can somebody explain what the timing light does? The article mentions it, but I'm kinda lost as to what it does.

When I put my timing back together after the knock sensor replacement, I lined the bottom pulley (whatever that's called) up to the 0 mark. Is this where it is suppose to be? It seems like every pic I've seen has it at the 10 mark. Is 10 the factory setting?

A dumb question: If I moved the timing from the 0 to the 10 mark, would this be advancing or would it be retarding the timing?

I've been running 89 grade gas. It helps a bit, but is still really annoying. I'd like to go back down to 87, especially with gas prices the was they are.

Well, thanks again for all the help you all.
Have fun.
DH6twinotter

growinseed

BTDC=before top dead center. The number is degrees. 0 is TDC (top dead center). I think BTDC is retarding the timing.
A timing light has a probe to the #1 spark wire which causes a light to strobe everytime a spark is sent to the cylinder. With the engine at normal op. temp. and the light attached as manufacters instructions, usually the vacuum advance is detached and pluged from distributer, you can 'see' where the timing is set. Its easier if you mark the dent in the main(crankshaft) pulley with white out. This mark should 'flash' on the timing scale, the plate with numbers near the crankshaft pulley. My 22R runs best at factory timing per the sticker on the hood. To change the timing turn the distirbuter, after loosening the adjusting bolt, one direction or the other. These movements are very small i.e. just enough to feel it move. IMO quarter turn adjustments are WAY to much.
With timing correct the engine should start quickly, run smooth, and not diesel at shut down.
Hope this helps

Nathan

Dr. Zhivago

You're welcome. It is a great article.
"Before Top Dead Center" This is in reference to the piston reaching the very top of the compression stroke before plummeting back down on the power stroke. The Degrees refers to Crankshaft Rotation. Since the Crankshaft makes 2 complete revolutions per combustion cycle in a 4-Stroke engine such as ours, there are 720 Total Degrees of Crankshaft rotation to measure.

The 4 Strokes of the piston are:

1. Intake (Piston moves Down)
2. Compression (Piston moves Up)
3. Power (Piston moves Down again)
4. Exhaust (Piston moves up again)

You want your timing to be a little Advanced because it takes a small amount of time to build the spark and then ignite the Air/Fuel mixture. You want the flame front of the combusting mixture to contact the piston face as close to TDC as possible for best power. Too much advance can cause pinging (kinda bad) or detonation (very, very bad).

Read this article to better understand what your ignition system is for and how it works along with a Timing Light's role in adjusting all of it.

The 10* Mark is for setting the Initial Idle Timing which is 10 Degrees BTDC, which is 10 Degrees of Advance and that is the Factory Setting. Without seeing exactly what you did with regards to setting up your Crank Pulley to the Timing Marks on the Cylinder Block, I can't comment on it. However, from the sounds of it, your Timing is too Advanced.

See the answer above.

Once you read the Ignition Article and get your Timing Adjusted properly, you can go back to using 87.

Good Luck and you're welcome!
Dr. Z

AgRunner06

Dr. Z,

Thats one of the best replys I've read.
Keep up the good work.

Good Job.

DH6twinotter

Wow. Thanks for explaining all that stuff to me! You're awesome Dr. Z! That web site was sweet! Never seen it before.

I'm going to try and pull the timing cover off today. It may rain for the next few days, so it may rain before I get a chance. Maybe I'll take a few pics.

I'll get back with what I find out (if I don't get rained out).

Thanks again all. Especially you Dr. Z.
Have fun.
DH6twinotter

DH6twinotter

Ahhhhh! I forgot they put the retarded coolant hose through the center of the timing cover. I aint about to drain the coolant for the 3rd time this month. :mad: So, I guess I'll try the timing light idea. My mom just told me that my dad has a timing light. Never been used. He got it back in the 80's though. Would it still be ok to use it on my '90? If I can figure out where to stick all the wires I'll give it a try. :eek: kinda scared when it comes to wiring. :eek:

Thanks again all.
Have fun.
DH6twinotter

Dr. Zhivago

Yeah, that Timing Light of your Dad's should be just fine.

Good luck and let us know how it goes!
Dr. Z

DH6twinotter

Well, my radiator went bad, so I just pulled it out yesterday. I decided to check the timing now that I have the coolant drained (getting good at that ).

I have the timing cover off now, and my Haynes manual says,

Remove distributor cap and turn crankshaft until line on vibration damper is aligned with zero mark on the timing plate. The rotor should now be pointing directly at the mark on the distributor. To get piston to TDC on the compression stroke, turn the crankshaft one complete turn clockwise. The rotor should be pointed at the mark." (condensed version)

Why do I need to do anything to my distributor? Do I only need to do that if I was doing a major rebuild or something? Also, it says to take off the wire connector at the distributor. I don't really get why I should have to do anything to my distributor. Any help? Is there a way of adjusting the timing with the distributor?

Is the mark on the crankshaft for TDC or BTDC? The sticker under the hood says to have BTDC at 10*. How would I find that? There is a whiteout mark on 10* line on the crank. Looks like the previous owners may have moved the timing a bit. I dunno. There is also a white out mark about ¼ inch (maybe 10*) to the left of the original timing mark on the passenger side cam. No whiteout mark on the driver’s side cam. Would it hurt anything if I moved the timing so it lines up with these white marks? Appears like they are there for a reason.

Sorry about all the questions. Maybe I should just have a pro do this.
Thanks all.
DH6twinotter

BTW, I'll try and have some pics up Sunday, so you all can have a better idea of what I'm talking about.

DH6twinotter

Hey all,
I checked the cam and crank timing (or whatever the technical term for that is). I put the #1 cylinder at TDC and the crank is 5* off. Not sure if it's 5* advanced or rertarded. It's 5* in the direction of the ac compressor. So, whatever that would be. Would that cause any spark knock being off by only 5*?

I'm going to go out and put the timing back at 0*. I just hope that the timing being off is what caused the spark knock. Also, my engine has been running hot. Would 5* off also cause this?

Thanks all.
Have fun.
DH6twinotter

DH6twinotter

I was just outside piddling around with the timing. If I jump the belt 1 tooth on each of the cams, it makes my crank go to the OTHER 5* mark. So it's changing it by 10*. How in the world do I get it to only move 5*??? I hope that makes some sense. It's like I need to adjust it by 1/2 tooth.

Well, have fun all.
DH6twinotter

Victor

I think you've confused cam timing with ignition timing. You don't have to have the front cover off. Return everything the way you found it.

Now go over to the passenger side of the engine. You will find a small covered object next to the fuse box. You need to insert a wire into two of the metal connectors - on mine there is a label that said which two to short. If yours doesn't have it let us know.

Ok - connect your timing light to the battery and then place the inductive pickup on sparkplug wire #1. Toyota was nice enough to number them right on the wires.

With the jumper on, the light ready, you need to mark the timing mark. There is a timing mark down by your lower pulley. You should look for a notch on the pulley and mark it with white-out or chalk.

Now start the truck. Where is it showing? Loosen the bolt by the base of the distributor and set the timing to 10 degrees btdc. Make sure you double check it is right after you retighten the distributor.

When you are done remove your jumper wire. Check your idle speed. It should be at about 750 on your tach. There is an adjustment screw on the front of the intake manifold. Clockwise lowers the RPM and anticlockwise raises the idle. Hope this all helps.

DH6twinotter

Thanks for the reply. I was a bit confused about the TDC and BTDC thing at first. I wasn't sure what they applied too. I think I got that figured out. My problem is that the cam timing was 5* off. I think it's been off the mark since the timing belt was replaced last time. Once I do correct it, I'll check the distributer. Thanks for the little write up on that!

Have fun.
DH6twinotter

Bumpin' Yota

just thought I'd bringthis one back since it deals with advancing the timing and a lot of how to's I was looking up....