MyMiatas
MyMiatas Reader
2/18/23 12:00 p.m.

Last Sunday I was investigating my lifted Miata. "New" catalytic converter installed

It is running like Keith's a little high on idle. I checked all the items, sprayed all the things with carb cleaner. I decided to check the timing with the light. I have set it in the past. Bought the light and set it early last year. So it should have stayed right where it was. But this is what I found.

You can make out the little white dot at about 3:00.??? WTF?? So last Sunday I manually set the timing by ear and lowered the idle. Now at this point I am thinking that I have a pin that is funky. This morning I pulled the lifted Miata inside. Disasembled it so I can see if it is a torn pin. Along the way I checked to see if maybe the A/C or power steering was the cause. They both turn freely. I have them disconnected, power steering was dumping "sealing" oil. I now have it all apart. And Tada! No problem??

Now the picture with the white timing mark is at TDC.

Can my belt pully slip?

I do not know the cause of how a timing mark can change location and the engine seems to run fine. I am asking The GRM Hive for its information on the possible causes. 

Keith Tanner
Keith Tanner MegaDork
2/18/23 2:37 p.m.

Was the first picture at TDC or some random engine position? You can't check timing unless the engine is running. A photo of the pulley with the engine stopped doesn't tell you anything unless you've put the engine at TDC.

The accessory pulley - which has the timing mark on it - is made of two pieces of steel joined by rubber. It's possible for the rubber bond to fail and the outer piece to rotate relative to the inner one. The way to check that is to set the engine to TDC using the dipstick and then look at the timing mark. It should be lined up with the T mark on the engine. It will NOT line up with the 10 that you use for setting timing, as that's 10 degrees off TDC.

The car will run just fine if the pulley outer ring slips, as the actual timing signal comes from the CAS on the back of a camshaft. Where you get into trouble is if you try to use a slipped pulley to set the timing.

So:

Put everything back together. Set the engine to TDC using the dipstick or some other measure. Check that the mark is at T - you'll need to clean the crud off the front of your engine to see it. Only if it is not at T should you start thinking about replacing things.

The woodruff key ("pin") only fails if you have a loose crank bolt.

Keith Tanner
Keith Tanner MegaDork
2/18/23 2:38 p.m.

Note that the high idle problems I was dealing with were not ones you'd find by looking for an external air leak with carb cleaner. But first, set your timing and idle speed. If the car cannot maintain it, then you start looking for a source of air.

MyMiatas
MyMiatas Reader
2/18/23 7:20 p.m.

The picture with the white timing mark at 3:00 is at TDC of the first Cylinder as shown in the picture with the SS ziptie sticking out. I have ordered a new Harmonic Balancer for it from Treasure Coast Miata. The idle screw is turned all the way down. I have removed the throttle control part and examined and cleaned it all. I didn't find any build up of coolant/lime or extra carbon on anything. It all looked fine. I did have that funky welded area on the mass airflow detector.  I have the feeling I will be buying more items to weed out this high idle and it running rich.  The parts on it have over 114000 miles on them. No check engine lights. Make me wonder why it has a diagnosis plug on it?? Oh wait. That so you can buy pass something so you can set the timing with a timing light. ;0) 

Keith Tanner
Keith Tanner MegaDork
2/18/23 7:32 p.m.

You can put the car into a mode where it displays error codes on the dash with coded flashes. The diagnostic port actually does a few different things other than the ignition timing mode.  

High idle means extra air. The air valve on a 1.6 can leak internally, if you have another known good unit on another car they're pretty easy to swap. Make sure the IAC valve moves freely as well.  Once that's been checked out, you can keep looking for leaks. 

MyMiatas
MyMiatas Reader
2/19/23 5:04 p.m.

Today I checked the codes it flashes. It came up with 8 and 12. Parts are on there way. I purchased a O2 sensor just in case from FM. They have some others do not.

MyMiatas
MyMiatas Reader
2/25/23 9:44 p.m.

Well today I was ment to repair the lifted Miata. But the parts I ordered last weekend didn't show up yet. The two sensors were ment to be here today but there must have been snow/weather causing delays.  The harmonic balancer that I ordered from Treasure Coast Miata hasn't even been mailed yet. I even called them and was told. " I will mail it today(friday) and email you the  tracking number." No email, no tracking number either.   :0P   but on the positive side I did receive one of the books I ordered on the same day.

That is reading material.  :0D

MyMiatas
MyMiatas Reader
3/12/23 12:57 a.m.

I did make some improvements to my Miata. The Harmonic Balancer appeared recently so it has been installed. But during the setting of the timing with the light. This did not fully repair the problem. It was still to far off.  So I disassembled it again. Removed all the covers and Harmonic Balancer so I could see the timing belt. When looking at where the E's and the I's were located it all looked fine. I whipped out all the books I have about it.  All the books I have that have articles about timing belts read that it was right. But the count of humps was off by one (20). And the location of the E and I were ment to be a little bit below the marks not dead on. ( why have marks to line it up if they don't work??) So moved the first cylinder to TDC and removed the belt. Adjustable wrenches and FM gear holding device in place. I reassembled the belt back in place. Keeping an eye on the count and the lower mark on the main gear. I learned that if it goes on easy it is off on the count.

When I compared the new Harmonic Balancer to the old one. The timing mark on the old one was at 4:00 and the new one was at 1:00. Having a A/C pump and power steering pump not working up to par can cause a 32 year old Harmonic Balancer to slip.

It is running better but it still needs some sorting.

Keith Tanner
Keith Tanner MegaDork
3/12/23 1:46 a.m.

Glad you're making progress!

The marks on the front of the timing cover won't line up until you have tensioned the belt. Once you tension it, they'll be dead on or off by a full tooth. And unless you lock that intake cam into the proper position somehow, you'll be off by a tooth. There are marks on the FM ninja tool that line up with the marks on the cam gears as well if you don't want to use the ones on the timing cover for some reason. 

I've never counted teeth :) I use the I and E at 12 o'clock instead of the E and I on the timing cover because it's really easy to eyeball.

Note that in the picture of the pulley, you're not at TDC.

 

MyMiatas
MyMiatas Reader
3/12/23 12:24 p.m.

The unusual thing about this is that the cams before I redid the belt were all lined up the E's and the I's in both places. But the lower gear was just a smidge off. When I installed the harmonic balancer the first time I had to move it all the way toward you(which would be all the way down) to get the timing in the ballpark.  Now it is in the middle area instead of all the way down. I did confirm a leaky fuel injector on it with some glass cleaner. Does FM have a kit lying around for replacing the gaskets? 

MyMiatas
MyMiatas Reader
3/12/23 12:26 p.m.

The picture of the harmonic balancer was to show that a new one was installed. It may have moved a bit due to tightening things down. 

Keith Tanner
Keith Tanner MegaDork
3/12/23 3:22 p.m.

The only way you can be a smidge off on a timing belt is if the tension isn't set. You can only be off by a full tooth once it's tensioned. 

FM does sell various gaskets, including injector seals.

MyMiatas
MyMiatas HalfDork
3/25/23 9:49 p.m.

The last pick is how they looked before cleaning. The hard part is removing the tan end cap and installing the new one. I used my heat gun to warm them and they pulled off. I did the same to install the new ones plus a little oil. If your Miata will not start after it is all assembled and your scratching your head. You have the gas lines backwards.

 It is running better now. She gets up and goes alot better too!  It is still running high with the idle but that seems to come and go....

MyMiatas
MyMiatas HalfDork
3/25/23 9:54 p.m.
Keith Tanner said:

The only way you can be a smidge off on a timing belt is if the tension isn't set. You can only be off by a full tooth once it's tensioned. 

FM does sell various gaskets, including injector seals.

Flyin Miata should sell these kits.

AnthonyGS (Forum Supporter)
AnthonyGS (Forum Supporter) UberDork
4/4/23 9:38 p.m.

I need to do the timing belt on my 2000.  After reading all about the one tooth off problems in many different sources and seeing this post, I ordered the ninja tool.  I like simple elegant solutions.  I also don't like fussing with things that can invoke Murphy's law or gremlins when the problem has been solved.  The tool will likely pay for itself in headache prevention.  

MyMiatas
MyMiatas HalfDork
6/13/23 11:58 p.m.

I had to do a repair this past weekend. This Miata was "when it wanted too" running too hot. Like pegged needle hot. The weekend before I removed the thermostat and made sure it was working and made sure it was full of antifreeze. But on Saturday it would randomly heat up. So I let it could down and removed the radiator. And installed a new one. Apparently one of the PO had used just water in it .judging by the calcium in the fins

MyMiatas
MyMiatas HalfDork
6/22/23 8:48 p.m.

Today I received an email from TCM. I never canceled the order and as you have read it is already installed?? You can not cancel order 3 months later! >:0P

MyMiatas
MyMiatas HalfDork
6/28/23 2:26 p.m.

So I received a phone call and some more email exchanges and....

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