CorradoZilla

Hello,


A little long but please help, getting a little frustrated, thinking movie type explosion would be good about now.

Trying to pass an '86 CGT (Stock 2.2) and again and again it fails NO every time; here's what's new/been checked:

Cap, Rotor, Wires, Plugs, Computer, Fuel Distributor, fuel pressure regulator, fuel filters, fuel lines and injectors, O2, catalytic convert, temp sensors, are all new with NEW parts (not scavanged).

Fuel pressure and flow, compression, the 10ma, electrical signals etc have been checked.

At Idle Readings:

Limit HC 300 - CGT 29
Limit CO 1.5 - CGT 0.00

At speed:

Limit HC 112 - CGT 24
Limit CO .63 - CGT 0.01
**Limit NO 1252 - CGT 1713**

Nothing I have done to date has moved the NO whatsoever. The car used to run like crap, now it runs great, used to take 15-20 cranks to start now starts everytime, but no matter what has been done it's still getting high NO.

Any suggestions (interesting death methods now being accepted) please let me know!!

Thanks a lot

Adrian

Cdn Blue Coupe

your CO will go up a bit but you have room to spare there. The retarded timing will result in less pressure during the burn and hence lower NOx

CorradoZilla

Doi! Wha I'm a quick one these days. I do all my work myself, you'd think that'd come to mind eh? :Þ

I'll have to play around with that and hope i can reduce NO by enough before the other numbers get too high, but I do have quite a bit of room to play around with things.

Thanks for hint,

Adrian

Cdn Blue Coupe

let us know how it comes out

mt6127

the quick fix is to retard the timing, the permanent fix is to check/fix for any vacuum leaks (ie boot cracks/bad hoses'bad injector seals), test the O2 sensor, check the temp sensor, cleaning your ISV may also help

CorradoZilla

Vacuum and injector seals have been checked and in the case of the seals replaced as have the temp sensors aroudn tee engine, and my O2 is brand new as of 2 days agoas well.

Timing will be changed a bit and I forgot to post dilution figures:

14.31 @ Speed
12.7 @ Idle

*edit*
I was stating Stoichio values backwards (always get these turned around). So right now my car is running fairly ritch at idle and slightly ritch at speed (Stoichio is 14.7) For best performance it's considered good to run about 12-13 so I might try to get my car there not really for performance but that's where it will have to be to pass E-test! (Works for me ^.^)

So far I'm just going to drop the timing and run a few passes to see if I can get it to work out right.

As a last ditch effort I was thinking of putting a potentiometer inline with the O2 so that i could "trick" the car into thinking it's lean and therefore dump the fuel in to bring down the NO but that is a last ditch attempt.

Thanks for the input,

Adrian

mt6127

re my lean comment, NOs are actually a by-product of a hot combustion chamber - which is generally associated with lean mixtures. So assuming you are in a good state of tune, the choices are retarding the spark as noted, or you may want to consider a colder plug...Do they look to be a normal color? Does the car run in the normal temp range (ie good thermostat/pressure cap)? Then again if your state's test equipment is like that in Connecticut, it may be the tester who's hosed :-)

quattro v1.0

First of all, start the car and get it up to temperature.

With the engine running, take off the oil cap. The engine should die immediately.

If it does not, you have a vacuum leak somewhere in the system and the fuel injection is compensating for it.

CorradoZilla

So I cranked the timing back about 6 degrees. That did a whole lotta nothing.

I talked to a friend whos been testing for years and he said to turn it back so that it sputters, and generally runs like crap and when you drive is absolutely gutless etc. So I cranked it back so that I was retarded about 22-25 degrees, and it passes, better than a low emissions vehicle.

At speed and Idle HCs were <30 and CO was 0.01 and at speed NO (my huge freakin prob) was **drum role** 45!!!! the limit is 1200 and I got a measly 45!! not even worth testing!

Mind you I'm not going to be running like that becuase it's dangerous, put your foot down and the car almost stalls and the whole bit....but it some how passed it with flying colours.

Thanks again for the inputs,

Adrian