pinging GRRRRRRRRRR.

[oregonloyale]

Alright about 2 weeks ago I replaced my timing belts .

I checked and adjusted my timing via timing light after doing so and it ran great.

I have a check engine light that says its the EGR needing attention.

Well today my car started pinging really bad on acceleration and at a consant 55 mph.

The idle is also alittle rough.

Is this all caused by the EGR or is there a problem with my T-belts?

[GLCraig]

I would say it's tied into your EGR not being functional. One of the functions of EGR is to help cool the combustion chamber temp which helps reduce pinging.

[oregonloyale]

that may explain why the car smells hot but the temp gauge is reading normal?!

[archemitis]

dunno... my subaru runs great with no egr.

[ByTheSea]

You might try backing down your timing a couple of degrees till you get the EGR straightened out. Also you might benefit from routing your crankcase and valve cover breathers into a dump can and plugging the intake ports they would normally be in. This reduces the intake temp if you have any ring blow-by(like on older high mileage motors)

[asavage]

The EGR valve admits exhaust gas into the intake manifold. It's designed to displace some air, and since exhaust gas does not contribute to combustion, it has the effect of lowering peak combustion pressure, which reduces formation of oxides of nitrogen, a source of photochemical smog and ground level ozone -- which is bad for your respiratory health.

 

The spark advance curve is calibrated on the assumption that the EGR system is functioning, ie there is more spark advance dialed in than you'd use for a non-EGR-equipped car. So, when the EGR system becomes inop, the engine detonates.

 

The EGR system is only enabled for certain driving modes and conditions (generally, part-throttle only and only with a normal-temp engine. Cold engine, overheated engine, ful-throttle, or idle: these modes = no EGR).

 

The EGR solenoid turns the EGR system "active" or "inactive", and port(s) on the throttle body provide vacuum to operate the EGR valve at the correct time and engine load -- I am simplifying here.

 

Because the Purge Control Solenoid and the EGR solenoid are identical units (except the electrical connector), and the PCS solenoid is notorious for dying, I'd be looking hard at the EGR solenoid first. If you have access to a DMM, use it on the EGR solenoid's connector. It should read about 36 ohms with it disconnected. Mine was open (infinite ohms).

 

Ref http://usmb.ultimatesubaru.org/forum/showthread.php?s=&threadid=3953

[oregonloyale]

Im am going to pull the egr valve out and take a physical look at it .

What should I look for toi find out if the egr is in need of repair or replacement?

I know the Timing is dead on since I have checked and redone it 3-5 times now 20 degrees =-2 degrees. with test connectors connected. 92 ea82 spfi wagon

[asavage]

You usually test the EGR valve on the car, not by removing it.

 

Use a vacuum pump, and with the engine idling, apply vacuum to the valve's port. Engine dies = valve opens OK & EGR ports are not plugged totally.

 

Somewhat common is EGR valve that won't close, you get hard start, bad idle, surging. If idle quality is good, you don't have this problem.

 

You'll want to test that the EGR is actually getting signal vacuum, by teeing the vacuum line to it, connecting a vac gauge with a 6' hose, and taping the gauge to the windshield, then drive it. You can't usually get the EGR valve to open in the driveway, you have to load the engine.

 

It seems like the EGR solenoid is a higher failure item than the valve itself, from what I can see.

 

What's the code number?

[Skip]

I have a question for you Oregon.

You say you adjusted the timing after the belt change.

 

Did it need very much adjustment?

 

If the driverside belt was off by a tooth the ignition timing would need reset

 

Changing the belts should not effect ignition timing

 

 

 

You can also test the EGR for proper sealing as Al says, by gently pushing the diapragm open at idle with a small stick, if the idle stumbles and changes - the EGR valve is sealing and the passage is clear. Like the man says. No need to remove it, yet.

 

If the solenoid were electricly open you would get a CEL

 

If it were plumbed wrong - that could cause some pinging, sounds to severe to be this.

 

Tell me about the ignition timing please.

[oregonloyale]

Well I bought this car w/92k on it from a gypsy car lot for $700.

It ran really rough and it had bad vavle clatter , but drove great and didnt die at stop lights.The check engine light was on when purchased.

I did a complete tune up on it and checked and adjusted the timing during tune up , maybe a degree or 2.

that was 2 months ago .

labor day weekend , replaced t-belts .

This was a B*&%h as the haynes manual left out the procedure for rotating the cam gears when going from one to the other.I had installed and uninstalled the t-belt 5 times before a member on this board informed me of what I needed to do , and wala golden!

check engine light still on.

Checked and minor adjustment of timing , degreee or tow , and no pinging.

Now a 2 weeks later the pinging is quite moderate and the check engine light code is flashing the signal, still, for the EGR.

Im sorry I cant remeber off the top of my head the actual numbers , but it was the EGR code.

Any ideas?

I am also using regular unleaded 87 octane and no fuel additive.

oh yeah and before I did the t-belts I couldnt adjust the timing anymore as I was hitting the dist stops .

After t-belt change the dist rotation is in between the stops giving me alot more room for adjustment.

Thanx

luv this board!

[asavage]

Originally posted by oregonloyale

Now a 2 weeks later the pinging is quite moderate and the check engine light code is flashing the signal, still, for the EGR.

Im sorry I cant remeber off the top of my head the actual numbers , but it was the EGR code.

If it's 34, that's the EGR solenoid, and the solenoid's coil is likely open, but like Skip says, it'll also trigger the CEL staying on beyond key on engine off.

 

If, OTOH, it's a code 55 (for a car built for California only), then it's a EGR flow issue, and you'll need to do the vacuum test I described earlier, followed by pulling the valve and checking for obstructions. The 55 code says that the EGR temperature sensor (on CA cars ONLY!) is not reading hot enough gas when the EGR solenoid is triggered, so either the valve ain't opening, or the passage is obstructed. But this only applies to CA cars; the rest of us don't have an EGR temp sensor, and will never see a code 55.

 

(Here's the article that Skip posted on checking codes and code meanings.)

 

(Sunday, I'm going to solder in a remote LED for that damned O2 LED on the ECU, so I can put the knee bolster cover back in place, but still be able to read codes.)

 

I'd put my money on code 34 and a bad EGR solenoid. One bolt and one connector to replace, unless it's a turbo model. Mine cost $60 from a local supplier. What year is your rig?