Question about EGR valve
Thread Starter
Advanced
Joined: Jan 2001
Posts: 51
Likes: 0
From: Gadsden AL
Question about EGR valve
My 1986 has been running rough, especially at idle and low speed. I had a tune up - first one in 81,000 miles and that didn't fix the problem. My mechanic plugged off the EGR valve and that helped a lot, although I still have some roughness at idle and low speed. Two questions: Does it hurt anything for the EGR to be plugged? and any suggestions as to clear up the remaing rough idling/low speed running?
Thanks!
Thanks!
Racer
Joined: Aug 2002
Posts: 386
Likes: 0
From: Lancaster Lancashire
Re: Question about EGR valve (NightRyder)
When you say your mechanic plugged up the EGR, do you mean the vacuum line, or do you mean removed the EGR valve and blanked the manifold port as well?
If your EGR is passing (ie not sealing exhaust gasses) it will flow some exhaust whether or not the vacuum line is connected or not!
If the diaphragm is OK, you can actually remove, disassemble, clean and lap an EGR valve to make it seal again. However I use a very fine diamond lapping paste if I do it and although not difficult, I would'nt recommend a novice do it, you need to stake it to prevent it coming apart in service.
You might want to check your vacuum lines for cracking. and also your manifold, runner and throttle body gaskets for tightness. Another favorite one is the PCV valve gummed up. :steering:
If your EGR is passing (ie not sealing exhaust gasses) it will flow some exhaust whether or not the vacuum line is connected or not!
If the diaphragm is OK, you can actually remove, disassemble, clean and lap an EGR valve to make it seal again. However I use a very fine diamond lapping paste if I do it and although not difficult, I would'nt recommend a novice do it, you need to stake it to prevent it coming apart in service.
You might want to check your vacuum lines for cracking. and also your manifold, runner and throttle body gaskets for tightness. Another favorite one is the PCV valve gummed up. :steering:
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Re: Question about EGR valve (goodson)
The only "harm" is that some emissions (NOx,I think) will be higher with an inorerative EGR system.
First fix the EGR issue; there is a test method on my site that can be rather easily done.
Then clean the TB and the IAC under the TB and check for vacuum leaks.
Since the mechanic did a "tune up" I assume that plugs, wires, ignition and such are fine.
First fix the EGR issue; there is a test method on my site that can be rather easily done.
Then clean the TB and the IAC under the TB and check for vacuum leaks.
Since the mechanic did a "tune up" I assume that plugs, wires, ignition and such are fine.
Racer
Joined: Apr 2003
Posts: 280
Likes: 0
From: edmonton ab
Re: Question about EGR valve (65Z01)
heres what i did:
removed vacuum lines to egr..it should seal and not allow any bypass.
it was the cause of my aceleration, seemed like a miss at mid range throttle..
do you have any codes? if so is it code 32?..then check egr senor switch..replace..
one other problem i found ..fuel pump..works good now..good luck :cheers:
removed vacuum lines to egr..it should seal and not allow any bypass.
it was the cause of my aceleration, seemed like a miss at mid range throttle..
do you have any codes? if so is it code 32?..then check egr senor switch..replace..
one other problem i found ..fuel pump..works good now..good luck :cheers:
Burning Brakes
Joined: Nov 2000
Posts: 855
Likes: 0
Re: Question about EGR valve (Daniel DK)
You might experience engine knock with the EGR removed. The EGR dumps exhaust into the combustion champer to cool the cc and lower NoX. If you get engine knock you could try retarting the timing.
Racer
Joined: Apr 2003
Posts: 280
Likes: 0
From: edmonton ab
Re: Question about EGR valve (Daniel DK)
What was wrong with your fuel pump - if you don't mind me asking...
:cheers:
Daniel
:cheers:
Daniel
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Racer
Joined: Jan 2002
Posts: 473
Likes: 8
From: Shreveport LA
Re: Question about EGR valve (goodson)
Here's a question. ALL of my emmissions have been removed for some time now. I get the impression that the EGR goodies are completely worthless at this point. Am I right?
Thread Starter
Advanced
Joined: Jan 2001
Posts: 51
Likes: 0
From: Gadsden AL
Re: Question about EGR valve (Davemc1963-87conv)
He plugged the vacuum hose that connects to the EGR valve. Does that mean that the problem is the EGR valve and plugging the vacuum hose was only partially sucessful? I mentioned the PCV valve to him but he didn't think it could be that. He's of the old (very) school, and I don't think he understands emission controls very well. Initially, I had him replace the spark plugs, wires, rotor, and fuel filter thinking the skip was probably due to never having a tune up after 81,000 miles. All that probably was due anyway, so I don't feel too stupid. One other question: could water in the gas cause the skip at low speed? or would it be more of a sputter, backfire type thing? I have had problems with the drain hose in the gas filler cavity stopping up. We had heavy rains just prior to this problem. The filler cavity wasn't holding water but, when I opened the cap, water dripped of the inside of the cap. I did add the additive to get rid of water but no change in idle/low spped skip. Thanks for all you help!
Instructor
Joined: Jun 2003
Posts: 176
Likes: 0
From: Columbia SC
Re: Question about EGR valve (goodson)
Plugging your vacuum line maintained the integrity of your vacuum system. It will not deactivate your EGR. Is the EGR stuck open? This will create a rich condition and you will notice a little smoke on first start up. It will idle unevenly and may cause fouling of the plugs after a while. The real fix is to make sure that you have good vacuum, make sure that the relay and electrical signals are correct. Check for mechanical functioning of the diaphragm. If the diaphragm doesn't move up and down easily, the the valve itself is at fault. Either replace it (recommended) or remove it completely and seal a plate over the hole. If you remove it then you need to make sure vacuum is sealed and fake out the computer with some fancy inline diode wiring. Check the post above and test all these things and fix it right. Remember, if you work on the valve itself, the plenum must come off.