02 Protege 2.0L - will not start
 

Good evening,

I am in a bit of a quandary at the moment. I've got a car that won't start and I'll list the symptoms and what I've looked at thus far.

1) The battery and starter are fine. The engine turns over fine but doesn't fire.

2) Running an OBD scan reveals no fault codes. This is very strange.

3) Car has spark and fuel.

4) Compression reads low. Like 30 psi. I think the gauge is good, but I could be off. But..

5) Timing belt is in tact. I and E marks on the cam pulleys line up appropriately. When they are lined up the mark on the crank pulley lines up with the "T" mark on the crank case. My assumption is that this corresponds to the same mark that would be on the crank timing pulley that corresponds to TDC.

Apparently the car was driving fine, but then exhibited a "loud rattling" and wouldn't accelerate and was pulled over off the freeway. Hell if I know what that means, that's just what my gf that was driving it at the time told me.

If anyone has any ideas, I'm all ears. Thanks in advance.

Get another compression test with a different tester. Compression should be 150-180psi on each cylinder.

a car with low compression won't fire!
Check your clogged catalytic converter which could lead to many other issues like clogged egr valve, bits of catalytic coverter entering your engine and oil causing connecting rod bearing fial, piston ring failure.
The no fault codes is very strange.

I think the compression gauge is suspect.

What would cause all 4 cylinders to read consistently low compression?

It seems highly unlikely that all 4 pistons rings went simultaneously

Exactly!
The timing belt jumped. Anyway that is my guess.
Hopefully this video and will explain what going on:

That was what I had thought as well. But the I and E marks on the cam pulleys line up properly as does the T mark above the crank pulley. I can see thru the spark plug hole that #1 is indeed at TDC when the marks line up.

I wonder if the cog on a cam has moved, or the key of the cog at the crankshaft has sheared off and jammed at a new location.
From what information you give us I think it is necessary to disassemble the timing mechanics.

Does that engine have variable valve timing?

Nope. I can try to get the crank pulley off soon to have a closer look.

What if the tensioner is failing in a way that timing is o.k. when you crank by hand, but gives a little way when under load?
I am thinking if all cylinders have the same amount of too low compression it must mean 2 things: The valves do close and open, but they don't close early enough or open too late in respect to the pistons.

I agree with that. Once I get the crank pulley off I can confirm timing

AARGH

mechanical timing is fine.

I feel your pain. How about a cylinder leak down test? EricTheCarGuy has a good Youtube video on that. It will reveal where the compression gets lost.

That's the next step. But I don't know what it could possibly be

Have you had another compression test?

Yes, do a second compression test with another gauge, even though you are convinced your gauge is fine.
Next step is leak down test. It will reveal where the leak is and thus remove your uncertainty.
Once a friend of mine was asked for help with a motorcycle. It had a 1 cylinder 4 cycle engine. He asked me to ride the bike and then tell him my verdict. I rode the bike, it sounded alright but had no power to speak off, maybe 25 % of what it should have delivered.
He found out that the rod bearing was worn out so much that the compression was gone. Imagine your piston sitting 10mm lower than normal.

I've confirmed the cyl 1 is at TDC when the timing marks say so by sticking a caliper end into the spark plug hole.

what I wonder is if it is possible for the cam to slip relative to the timing pulley.

TO CONFIRM:

With the I mark at 3:00 and the E mark at 9:00 on the two cam pulleys, should the mark on the crank be at T or 10 ?

T

Look at this video at the 37th second. This guy used adjustable wrenches and a vise grip to keep the cam marks aligned. I finagled it by putting the blet on only 1/4 " then I levered a big flat screw diver on on the inlet cam, pulled the belt of that cam and pried the shaft back by one tooth and slipped the belt back on. After that I released a sigh of relieve and wiped the sweat of the forehead.


The tensioning process is not well explained. However, in the comments to the video you find the information needed.
My belt came with instructions and it appears that the Haynes manual copied these instructions: after you have the timing belt on have the tensioner bolt loose. Hand crank the engine almost 2x (if I remember correctly) but stop about 10 degrees before T. My 1.5L engine has a special mark for that. Now the tension has been set and you tighten the bolt on the tensioner wheel.

Is there something on the crank timing pulley that clocks the harmonic balancer/crank pulley in a specific position so the mark on the balancer is always in the right spot?

there is a key way and there is a small notch on the belt guide (sprocket backing plate). The key way positions the sprocket in reference to the crankshaft and the notch is your TDC timing mark.
https://www.mazdaforum.com/forum/dat...oO0UUUBRRRQf/Z

http://www.chiltonpro.com/content/im...s/79235g52.gif

and another picture:
http://www.2carpros.com/forum/automo...800397cc_1.jpg

How likely is the key that positions the harmonic balancer to shear?
I have not been able to take the harmonic balancer off, even with my impact gun. But the mark on the harmonic balancer(not the timing pulley behind it) lines up with the T on the crankcase when the cam pulleys are positioned correctly.

btw, i appreciate your help, tanprotege

The key/key way are not likely to fail. but it has happened before.
I was able to get the harmonic balancer off by the means of gentle persuasion: taps with a 2lbs sledge. A gear puller might work as well.
And you are welcome. I hope together we get you back to zoom -zooming.

Looking at this random Mazda DOHC diagram,http://cdn.2carpros.com/diagrams/1327/large.gif
With number 1 cylinder at TDC, the I on the Inlet cam should be at 12 o'clock & the E on the Exhaust cam should be at 12 o'clock.

But this one http://i.fixya.net/uploads/images/daves944.jpg shows the timing marks at 90 degrees.

Grim:
that's why it is so important to know the difference between 'precise' and 'accurate' even if you are neither.:D:D;)

We try to figure out the '02 2.0 liter engine.
Unfortunately my Haynes manual covers only the years '90 to 2000.

Accidetalprotege has not been able to remove the harmonic balancer. Given how difficult it is the get a straight-on view of the affairs and the fact that all 4 cylinders lack compression to the same degree I am sure that the crank timing cog is off TDC by 1 or 2 teeth.

This guy also had difficulty lining everything up correctly and succeeded in the end:
Mazda Protege 2002 Timing Belt | Getting back into it

service manual ive got says the marks face inward

Weekend update:

First, I got hold of a second compression tester and recorded the results:

1) 45 psi
2) 20 psi
3) 15 psi
4) 35 psi

Second, I got myself a Harbor Freight leakdown test kit and did some testing. After going back to HF to get another set of pneumatic fittings because the ones that came with the kit were **** and didn't fit my lines.

I measured 5 times for each cyl at TDC, here are the averages:

1) 65%
2) 69%
3) 71%
4) 68%

All to be expected.

I removed the intake boot and noticed that on 2 of the cylinders air was coming out through the throttle body(cyls at TDC for each of my tests..). I can't quantify how much air was leaking through the valves but I assume it is not unreasonable for a cold engine with 150k miles to not have perfectly seated valves.

I tried connecting my compression gauge to the cylinder adjacent the cylinder being pressurized for each of my tests but never registered a reading. Which makes sense now that I think about it since the valves would just be open anyway.

What's most interesting is: On all 4 cylinders when the air was turned on the coolant level in the radiator bubbled or raised. !!!

.....which means you were blowing the air into the cooling system.
Your head gasket is shot.


I hate being the bearer of bad news.

I'm hoping that's all it is. Hopefully the heads still straight

Accidentialprotege: Now and then I need to get my head straightened too, if you know what I mean.;)

After removing the head take it to a machinist. He should resurface the head and check it for cracks.

Remove all carbon deposits and replace the valve guide seals.

Also, make sure to absolutly clean the studs and chase the threads with a special chasing die. I believe you need to lube the threads as well. The reason is that the nuts and threads are so closely matched that any gunk will increase the torque needed to turn them. That would mess up the reading of the torque when you button up the engine.

Head gasket failure is not that common on these engines. I would try to find out why it happened. Possibly the engine was overheating once. Possibly the engine was running on 3 cylinders for awhile which causes thermal stress. Possibly the engine coolant was not changed often enough.

All the best!

the car did have a heater hose burst a couple months back and overheated. No immediate issues after that, but this must somehow be related..

Coolant in the catalytics aren't good. Need to be inspected.
Hope your rod bearings are Ok, coolant mixing with oil is not good for them.
Check your oil for coolant.

Oil or Antifreeze Entering Exhaust affect on Catalytic:
Oil or Antifreeze entering the exhaust system can block the air passages by creating heavy carbon soot that coats the ceramic catalyst. These heavy Carbon Deposits create two problems. First, the carbon deposits prevent the catalytic converter from reducing harmful emission in the exhaust flow. And second, the carbon deposits clog the pores in the ceramic catalyst and block exhaust flow, increasing backpressure and causing heat and exhaust to back up into the engine compartment. Your engine may actually draw burnt exhaust gasses back into the combustion chamber and dilute the efficiency of the next burn cycle. The result is a loss of power and overheated engine components.
Possible causes are worn piston rings, faulty valve seals, failed gaskets or warped engine components, cracked head, block.

https://encrypted-tbn1.gstatic.com/i...HdC33iXTdtCmp4http://autorepairinbirmingham.com/wp...er-Failure.jpg
http://radiorestorer.com/camrycat.jpghttp://image.highperformancepontiac....il-fouling.jpg

yikes

luckily, it looks like coolant didnt enter the oil. oil is dark and clean

what do ya reckon book time is for a head gasket change ?

Sorry, I don't know.

moot point, as i got the head off myself this afternoon. see attached

i didnt look too indepth at anything. but the head gasket didnt look destroyed and the valves closed fine. i didnt see any cracks anywhere

? the black coating is gone between most the cyls

Your camera sucks. All of Images very blurry.
Can't see color differences very good, although some coolant seems apparent. Can't really see. Can't see if passages blocked, where coolant air leaking.
It may be machine shop time, making sure surface is straight, not warped, they can also test your cylinder head for cracks, leaks.
The area between cylinders could mean air/coolant leaking from one cylinder to another causing your poor compression test. Coolant could be travelling from nearby jackets/holes and migrating between cylinders.