failed Cal smog. need help

6pk2go

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My '85 gn failed and the parameters are listed below. I have since changed the O2 sensor and EGR solonoid. I lost the Turbo a week after the test and I suspect that the seals in the turbo may have been passing oil through though I never saw smoke until the day it failed. I also failed the change back to the stock fuel regulator and had in the 237 TA regulator before the test. Computer chip is stock.

15 mph HC CO NO
129 .71 1765

25 mph 107 .48 1485

Failed HC and NO. I'm having the turbo fitted to a TA33C which flows more. Where am I failing and will the bigger turbo cause a smog failure.
 

gofstbuick

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Jul 20, 2001
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I doubt if the tubo will cause a problem (unless like you said it's leaking oil past the seals). I was wondering about the rest of the readings though (O2 and CO2). But here goes. Since you're failing both at 15 and 25 mph, it is quite possible that your catalyst may be bad. You could try a catalyst test. If you have a pyrometer (or could borrow one), take your car for a freeway blast and get it warm. Then pull over to the next off ramp and test the temp at the front and rear of the cat. It should be warmer (by at leat 100*) at the rear of the cat. You said you changed the EGR solenoid. If you lift the EGR pintle at idle, does the engine stall? Because it should. If not, you're EGR passages may be plugged.
 

6pk2go

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O2 and CO readings

Thanks. When I lifted the EGR the motor stalled but did not die. Since I have the turbo off the passage in the intake is at least partially open I will try to clear it some more. The O2 and CO reading are:

15 MPH O2 CO2
.9 13.7
25 mph .7 13.9
 

gofstbuick

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The EGR passages are probably fine, but the O2 reading s are a little high and the CO2 is a little low. I would try a catalyst test next. Since the readings are close, I would almost be inclined to replace the cat.
 

TurboJim

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I dont know what your cutpoints are in Cali, but in NJ the NOx cutpoint is ~1180 on a 3800# V6 car. Given that, I'd wonder how your EGR was operating. The new solenoid, and the fact the motor reacts when the pintle is lifted doesnt mean it is getting vacuum applied to it or not, nor does it mean the pintle is lifting with vacuum applied. Its quite possible the EGR system isnt working properly. Add to this, the added advance in the chip in anticipation of EGR (The ECM doesnt know the EGR is open or not) I'd venture a guess that the added advance without the exhaust dilution is causing both the NOx and HC failures.

Add to this a non functioning cat as gofast mentioned and the have the recipie for a emissions failure.

Not to go against gofast, but I dont believe a cat will reduce NOx that much if the car is equipped with EGR. I know some cars like Toyota 1.6's and Honda 1.5/1.6's use TWC as a sole NOx reducer, but its been my experience in most other cases, when NOx is more than a couple hujndred points off, the problem is NOT the cat, but a cyl temp problem. Be it EGR, low coolant, radiator fan inop etc. Timing advance will cause HC, which is the reason I suggested the EGR not working properly as at least part of your problem.

Whoops, started rambling.....sorry...