Can't pass emission - EGR Problem - Please Help??

[schlick]

Having trouble passing emissions, the 25 MPH test failed on HC, CO% and NO PPM. My HC was 150, CO% was .64 and NO ppm was 1813. Car idles like crap. Have mostly stock setup, only Walbro 340 and AFR adjusted to 38 PSI. When the car is idling and I press the EGR diaphram there is no change in the idle. I thought that it was supposed to get really rough and almost stall? Would this indicate a bad EGR? It does hold vacuum. Also, T-link codes an error 44. Could this be caused by a faulty EGR? T-link also shows at idle BLMs at steady 150 and Integrator fluctuating mostly from 140 to 145. Used carb cleaner to check for vacuum leaks and couldn't seem to find any. Has a new MAF, fairly new plugs and wires.

Any ideas?

Thanks,

Ralph

 

[scgnx]

Been down this road last summer..Egr valve went south..it was acting up for a week before it finally through a code. I would just replace the thing. Also, exhaust leaks act similair to vacum leaks. Check the headers,etc. If you have a re-manufactured MAF, many of those are not correctly calibrated. You might want to swap with someone's good one to check it. Good luck!!

 

[Ken Cunningham]

If you're really lucky, the EGR valve is bad. Pull it off, clean it up or replace it, and you're good to go.

What I have seen, though, is too many TR's with totally clogged egr passages through the intake. Carbon builds up and no gas can pass even with a good EGR valve. Short of removing the intake manifold, I don't know a good fix for this condition.

 

[Jeff]

Just went throught this last week...

High BLMs, crappy idle, failed the emissions test, and was throwing and EGR code (I think it was 31?).

Checked the EGR valve, it was good, held vacuum, diaphragm moved nicely, etc.

Checked the EGR solenoid, which is adjacent to the EGR valve, and it was bad. It's hard to check it, because it's not supposed to hold full vacuum. If I recall correctly I capped one port and applied vacuum to the other. With the little filter removed from the backside it should lose vacuum at a slight drawdown, but not immediate drawdown. If you suspect yours go to AutoZone and compare the characteristics of yours with their new one. That's what I did. Then bought and installed it and passed emissions with no problem.

Also, remove the EGR valve and clean the passages, and install a new gasket with it. Mine appeared to have been leaking at the base.

Jeff

 

[TurboDave]

Your numbers are ALL high! Indicates a bad/missing cat converter, and a non functioning EGR.

Cat?

EGR passages in the intake blocked for any reason? Power Plate, etc.?

With your BLM's and INT's running so high, you'd never make it through even with good functioning parts. Sounds as though you've got a vacuum leak, or pretty bad exhaust leak (pre turbo).

You've got to get those BLM's down out of the stratosphere before you try again.

 

[gofstbuick]

What is the oxygen content out of the exhaust?, Anything over 0.3%, you should check your CAT (just like Turbo Dave says). I don't know what the NOx cutpoint is, but a properly functioning three-way-cat (TWC) can clean up as much as 1500ppm of NOx. Also, if the your cat is dead and you install a good cat, you could probably bring your FP up a little and the slightly richer mixture will further reduce NOx. If you have a contact or non-contact pyrometer, measure the temp in front of and behind the cat, and it should be at least 100* hotter at the back.

 

[schlick]

Thanks for the replies. I'll pull the EGR and check the passages. What is the best way to clean them? The EGR selenoid is pretty new also. I don't have a power plate and do have a cat. It doesn't sound loud like I have an exhaust leak, the O2 sensor is new also. Is there a good way to check for exhaust leaks short of taking things apart?

 

[gofstbuick]

You may try a speedometer cable attached to the end if a drill. But you may encounter higher HC after the passages are cleared, as the functioning EGR will allow spent exhaust gases to take up space in the combustion chamber and reduce combustion (with the same amount of HC/fuel). You still may end up changing the cat.

 

[Jeff]

Exhaust leaks should be audible, a "ticking noise" usually easier to hear at idle. Also, attach a vacuum gauge to any source of manifold vacuum, if the needle jumps back and forth that's a sign of vacuum or exhaust leaks.
Jeff