EGR Information
12-18-2004, 09:22 PM
#1
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Thread Starter
Join Date: Dec 2004
Location: Chico, CA
Posts: 13
EGR Information
Hi guys, couple of easy questions for ya all, I searched the forums but could not come up with anything on EGR.
My question is if the small vacuum line coming from the unit on the battery (passenger side), going to the fuel damper (???), if that was not connected what consequences would that have?
Second question, how in the hell do you check that, and if it is "sticky" is possible to fix? Or do I replace? This question is coming from a failed smog that I just had the pleasure to pay for, one that found my HC almost 4 times that of a passable vehicle. EGR???
All cylinders firing, I adjusted the idle down to 750, it was at 1050. I have not timed it but I am going to put it on the timing light once I figure out what is going on with the EGR.
My question is if the small vacuum line coming from the unit on the battery (passenger side), going to the fuel damper (???), if that was not connected what consequences would that have?
Second question, how in the hell do you check that, and if it is "sticky" is possible to fix? Or do I replace? This question is coming from a failed smog that I just had the pleasure to pay for, one that found my HC almost 4 times that of a passable vehicle. EGR???
All cylinders firing, I adjusted the idle down to 750, it was at 1050. I have not timed it but I am going to put it on the timing light once I figure out what is going on with the EGR.
12-18-2004, 10:47 PM
#2
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Thread Starter
Join Date: Dec 2004
Location: Chico, CA
Posts: 13
I actually managed to track down the testng procedures, sorry about that part of the post, however if the vacuum line to the solinoid was not connected, could that in fact cause an influx in the HC levels? I am going to put it back together, and see if I see a difference in performance, but before I take her back to the smog dude, I want to do my best to have addressed the HC level before I pay another $50 on another run.
12-19-2004, 08:38 AM
#6
Jack Of All Trades
Join Date: Jun 2004
Location: Acton, California
Posts: 2,296
For CA smog there should be no vaccum lines disconnected. I heard of a trick regarding creating a vaccum leak to help it pass but if it's running correctly there should be no tricks required.
The EGR has been discussed here recently. so search a little more. The egr opens at around 2500 - 3000 rpm and stays open above there. A problem with the egr valve will not show up as an ecu error code.
First thing to check for is ecu codes. Then vaccum leaks. Manifold vaccum @ idle should be around 20 hg. The egr vaccum line and valve have to be checked independently because the egr solenoid doesn't open and allow a vaccum flow to the valve until the above rpm.
Even if the egr system is working properly, it's common to find what 91zxtt found (search) when he tore into his, ie: the passages in the manifold are clogged with oily carbon residue.
The EGR has been discussed here recently. so search a little more. The egr opens at around 2500 - 3000 rpm and stays open above there. A problem with the egr valve will not show up as an ecu error code.
First thing to check for is ecu codes. Then vaccum leaks. Manifold vaccum @ idle should be around 20 hg. The egr vaccum line and valve have to be checked independently because the egr solenoid doesn't open and allow a vaccum flow to the valve until the above rpm.
Even if the egr system is working properly, it's common to find what 91zxtt found (search) when he tore into his, ie: the passages in the manifold are clogged with oily carbon residue.
12-19-2004, 03:49 PM
#7
Banned
Join Date: Jun 2002
Posts: 143
Originally Posted by CanyonCarver
For CA smog there should be no vaccum lines disconnected. I heard of a trick regarding creating a vaccum leak to help it pass but if it's running correctly there should be no tricks required.
The EGR has been discussed here recently. so search a little more. The egr opens at around 2500 - 3000 rpm and stays open above there. A problem with the egr valve will not show up as an ecu error code.
First thing to check for is ecu codes. Then vaccum leaks. Manifold vaccum @ idle should be around 20 hg. The egr vaccum line and valve have to be checked independently because the egr solenoid doesn't open and allow a vaccum flow to the valve until the above rpm.
Even if the egr system is working properly, it's common to find what 91zxtt found (search) when he tore into his, ie: the passages in the manifold are clogged with oily carbon residue.
The EGR has been discussed here recently. so search a little more. The egr opens at around 2500 - 3000 rpm and stays open above there. A problem with the egr valve will not show up as an ecu error code.
First thing to check for is ecu codes. Then vaccum leaks. Manifold vaccum @ idle should be around 20 hg. The egr vaccum line and valve have to be checked independently because the egr solenoid doesn't open and allow a vaccum flow to the valve until the above rpm.
Even if the egr system is working properly, it's common to find what 91zxtt found (search) when he tore into his, ie: the passages in the manifold are clogged with oily carbon residue.
EGR isnt RPM based alone..
And oily residue in the manifold is from the PCV system and blow by.
12-19-2004, 06:22 PM
#8
Registered User
Join Date: Nov 2003
Location: Gerber, CA
Posts: 3,672
The vacuum line from the EGR connects to a vacuum galey that runs under the upper plenum. If that vacuum line is disconnected, then you will have problems with a high idle. By adjusting the idle screw, you are only masking a problem. 1050 RPM is fine for passing smog. It needs to be below 1200 RPM. Plug the EGR hose back in, take it back to the shop that failed you and ask if they can give you a reading. They can't re-test you, but they can tell you what the HC levels are at. When you take your car to a referee to pass it, they will test it 1st before doing any repairs. If it passes, then you're done.
If it passes, then we'll be trouble shooting a high idle problem. not a smog problem.
It looks like you have already read the saga of my problems, so you probably saw this link. If you dind't here it is again....
http://www.300zxclub.com/showthread.php?t=15586
What did carbon monoxide check at on your test?
If it was high, then the car is running rich, if it's low, then the car is running lean.
To recap,...these are the problems that I've found on my car.
1) TPS out of adjustment.
2) Injector #6 failed (but not enough to detect a misfire audibly).
3) Partially plugged EGR return tubes.
4) Bad connections at the fuel injectors.
I tested the EGR, it's fine. O2 sensors are new. Eliminated precats. Installed test pipes w/hi-flow cats. With any luck, I'll have the car back together in January, so cross your fingers.
If it passes, then we'll be trouble shooting a high idle problem. not a smog problem.
It looks like you have already read the saga of my problems, so you probably saw this link. If you dind't here it is again....
http://www.300zxclub.com/showthread.php?t=15586
What did carbon monoxide check at on your test?
If it was high, then the car is running rich, if it's low, then the car is running lean.
To recap,...these are the problems that I've found on my car.
1) TPS out of adjustment.
2) Injector #6 failed (but not enough to detect a misfire audibly).
3) Partially plugged EGR return tubes.
4) Bad connections at the fuel injectors.
I tested the EGR, it's fine. O2 sensors are new. Eliminated precats. Installed test pipes w/hi-flow cats. With any luck, I'll have the car back together in January, so cross your fingers.
Last edited by 91zxtt; 12-19-2004 at 06:30 PM.
12-19-2004, 07:25 PM
#9
Southern Speedster
Join Date: Aug 2004
Posts: 179
Originally Posted by 00Evan
False, EGR is 90% of the time closed..
By "normally open" I mean that without vacuum, the valve would be in the open position. This presents a negative logic problem -- I am using the term technicall as an ex-controls/automation guy.
If the valve is normally open and vacuum applied typically, hence the valve would be be in the closed position as you indicated. When monitoring my EGR with NDS, I agree it is closed most of the time.
I think that the question related to the impact of having the actuator's vacuum hose disconnected. If it is normally open, then it presents a rather significant impact. Thoughts?
12-19-2004, 08:36 PM
#11
Jack Of All Trades
Join Date: Jun 2004
Location: Acton, California
Posts: 2,296
Here's some basics on the egr system:
http://www.autoshop101.com/forms/h61.pdf
Keep in mind, most of our cars are not odbII, so all is not applicable.
Also the pcv system dumps into the intake tract and not the exhaust tract. that way most oil residue from the pcv system is burnt off thru the combustion process.
http://www.autoshop101.com/forms/h61.pdf
Keep in mind, most of our cars are not odbII, so all is not applicable.
Also the pcv system dumps into the intake tract and not the exhaust tract. that way most oil residue from the pcv system is burnt off thru the combustion process.
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