Thread: how much vacuum needed to the egr/bpt?

Hey guys I'm having some smog troubles right now, heres what I replaced.

New spark plugs
New 02 sensor
New CARB 3 way cat
No exhaust leaks
cleaned and tested AIV (sucks in air to the exhaust well and gets 15-20in vacuum)
flowtested fuel injectors
retarded timing to 13deg, used 91 and put a little alcohol in my tank
took apart egr manifold and poked out the pinhole, my egr now works when free revving and driving under light load, however I'm only seeing 5in vacuum from the egr control solenoid going to the bpt and same only 5in vac from bpt to egr valve. I'm thinking this is not enough to open the egr as much as it should be? Whats the spec on this? Can I hook the egr valve to an alternate vacuum source so that it stays open when doing smog check?

This engine is 100% stock, no check engine light. Runs and idles well, has decent power. Yet I am failing cali smog with 1000 NOx out of a max of 550

Anyone got any ideas? because I'm out of em and if I can't get this car to pass I'll need to sell it which is stupid after I've put all this new shit on it.

You could try and run the 91 octane through and then add a half tank of 87 octane with some methyl hydrate to it. I haven't used it but have heard of others having success with this fuel tank additive and passing emissions testing. The 91 octane with your lowered timing might possibly cause higher emissions readings. Higher octane gas is MORE resistant to detonation, you want your gas to burn up inside your engine before it hits the cat so a lower octane gas will help a bit. Also, make sure your engine is kept running before the test so your cat is nice and hot.

Your Nox reading is very high if you have a properly working EGR. You might be right about the EGR not opening all the way as the EGR helps in lowering Nox readings.

I'm getting a pretty complete burn of my fuel as my hydrocarbons are very very low, and with about 14-15% CO and 1% oxygen is telling me the combustion mixtures are pretty good. I was told the high nox is caused by high combustion temps thats why i retarded my timing and put alcohol and 91 octane, i smog it after ive been drivin around at high revs with low load (i feel like if the car just sits and idles the engine will get hot and the cat will not be). I feel like I have a decent understanding of how the emissions equipment works on these cars so the only thing i can think of checking is how much vacuum should there be do the egr?

can anyone here check for me how much vac the egr valve gets on their car? would be easy to check if you had a vac/boost gauge laying around

isn't the vacuum variable depending on your throttle?

sort of, my point though is that it only gets a max of 5in of vacuum, where other solenoids like my AIV valve get 15-20in of vacuum upon activation. I'm not sure if this is by design?

If your lines are clear and sealed, then you're good. Past that there really wouldn't be much you could do about it anyway if you wanted to up it.

What about the solenoid not opening completly?? Did you already rule that out?