'93 Geo Prizm (Toyota 1.6l) emissions... High NOx and EGR valve?

I figure I'll update this now that the car passed inspection in case anyone else may benefit from the information...

As I suspected the car does not have an EGR valve. I searched more and could not find anything on the underside of the intake as some people mentioned that it was placed on some model years of this engine. The timing was way advanced , nearly 20*. I set it to 6* and it passed emissions. The car was completely lacking in power after that though, so after getting the sticker I put it at 14* and the car is now at least reasonably safe. It still can't get out of it's own way if it's life depended on it (or my life, for that matter), but at least it's a little better now.

Cory

Jeez Cory, you need to find out the proper amount of advance for your car...not much wonder it's gutless at 14 or so...20 - 22 is likely a much better pick, but 'find out'...you can damage your engine if you get it too far advanced (especially as it's an older car)

And as I suspected......

Why not try setting it to specs? (10 degrees) They're on the VECI sticker under the hood. Did you jumper TE1 to E1 in the diagnostic connector first? Otherwise you won't set base timing correctly.

Toyota MDT in MO

Cripes. is that all it is?...10 deg?...I'm surprised that it's that low...

That's only the /base/ timing - the computer can fiddle with the advance quite a bit from there, if the starting point is right.

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I did not see any sticker under the hood. I tried disconnecting the large plug from the distributor, but that made the car not run. I don't know these silly foreign or modern cars. I know on modern Fords you disconnect the SPOUT plug from the distributor to set base timing, so that's why I tried disconnecting the plug on the distributor. I'm not gonna worry about it, it's my dads car and he's trying to sell it. The base timing is probably more advanced than the factory specs anyhow, so that's a good thing since it isn't pinging. That tiny little engine needs all the help it can get, especially with that automatic transmission. I never understood the point of a torque converter when there isn't any torque to convert...

Cory

Yes I suppose...we used to disconnect the vacuum to set it years ago ISTR...I think you short something to something to do that now?...

On race engines often times people will lock in the timing at the total advance they want, 36* for example is in the ballpark of waht most motors like for max advance. A race motor with that much advance locked in will have a retard for starting to bring teh timing back to a more reasonable setting generally in the 10*-20* range. Even as you near 20* most engines will become hard to start. An engine with locked timing will only see high RPM. Such an engine may have a transmission with a 4500 RPM stall converter, or launch at a similar RPM. The point is that the engine will never be under load at a low RPM. With a 4500 RPM stall converter at no point after leaving the line will the engine drop more than a couple hundred RPM below that point.

I'm imagine total timing on the Geo is somewhere in the 30*-40* range. Actually it may very well be less to reduce NOX, with the unfortunate side-effect of increasing HC and particulate output and reducing gas mileage.

Cory