'86 300zx didn't pass smog... help!

[xxVERITASxx]

I'm in CA trying to get my '86 Z31 non-turbo M/T to pass smog.

So at 15mpg:

Gas------Reading---LimitHC:--------155-------128CO:-------0.80-------0.80NOx:-----2593------1106

I'm sure it's the EGR (at least for the NOx) because we did the hand pump and ran the test and the NOx passed. Does this mean it's the entire EGR system or just the valve. I'm also wondering if any EGR Valve is interchangeable with the Z31. i.e. can a Z32 EGR Valve work? Can a Z31 Turbo EGR Valve work? Does transmission matter?

Input please and thank you!

[S133P3R]

$300 and ill get that s*** passed for you...

[evildky]

the Z32 egr valve is completely different, it is remotely mounted and has 2 outlets for the dual tb plenum

and the egr isn't really sa system it's just a valve and a tube

most emmissions failure are due to incomplete burnign of fuel, the egr can be a contributor and can sometimes be cleaned, the cat can also fail

or all your problem could be caused by a single bad spark plug or plug wire, it's a good diea to replace your plugs and have a good look at the wires and verify yout ignition timing

[xxVERITASxx]

I just changed the spark plugs and ignition wires, distributor cap and rotor a couple weeks ago... and changed the oil. Part of the problem could definitely be the cat, but I know a good chunk of it is the EGR.

Would the EGR affect HC and CO?

[xxVERITASxx]

So i took out the egr valve to clean it and jacked up the diaphragm by dunking it in Chem Dip. Now I need a new one and I'm pissed. anyone know where i can get a used Z31 egr valve non-turbo, manual transmission?

Also, is the egr valve specific to transmission and turbo/NA?

Thanks.

[evildky]

um, i think they are al the ame on the Z31, I have a man trans 5 speed engine I just pulled complete with egr, $20 shipped if you want it

[xxVERITASxx]

Yeah, I'll take it. PayPal work?

and what's it say on the top letters and numbers EVK......?

[xxVERITASxx]

Still want to sell that EGR valve? Also can you tell me what it says on the top? EVK something... Thanks.

[evildky]

yeha it's got something written on top, I'll get a pic today hopefully

[70 Cam Guy]

inop EGR can cause smog failure with high NOx emissions. The exhaust recirculation lowers peak flame temperature, which keeps the NOx emissions down.

I'm more familiar with Toyota EGR but Toyota's have an EGR solenoid (and a temperature switch) to actuate the EGR valve. Does the Z31 have a control like this? If replacing the valve doesn't fix this, look into that. If it passed when he manually opened the valve, that tells me the passages probably aren't clogged completely... still a good idea to clean what you can while the valve is off.

[BadQ45t]

I have an 84' and over the last 10 years I have had to replace the EGR, Cata Converter, 02 sensor and a few other things. CA is a PITA, I was so looking forward to having my car turn 25 so I was exempt but they change the law and now smog forever.

Hey S133P3R, you work at a Smog shop or something? I might look you up sometime, the new laws in the Bay Area include a test of your fuel system to make sure there are no leaks, if there is one it could cost 1k to find the problem!! I have January smog test heading my way and I'm not looking forward to it. Seems like every smog test is costing me $200-$500 every two years for something new, and my Z in is very good shape!!

[70 Cam Guy]

If you have a failure from your EVAP system due to a small leak, a test and repair station, Gold Shield station, or good diagnostic shop will have a smoke machine that pressurizes your fuel tank and EVAP system and injects a benign smoke into the system. This makes finding an EVAP leak, or any vacuum leak, much more manageable.

The last smog on my pickup with a test only. They hooked it up to the nitrogen tank and did the EVAP test on it. I was lucky and mine passed.

If you know a test is coming up, maybe getting a shop to do a pre test would be a good idea so you have time to do any necessary repairs