EGR Valve

If the check engine light is on it fails the emission test.The EGR valve controls the amount of exhaust gas routed to the intake manifold. Vacuum is applied to the EGR valve in response to throttle valve opening. The vacuum controls the movement of a taper valve connected to the vacuum diaphragm in the EGR valve.
The main reason for the egr valve is to reduce combustion chamber temperture to reduce nox emission which is when nitrogen and oxygen combine.If you could go to a auto part's store like auto zone and have them scan your car for code's and let me know what the code number's are that would help me a lot to give you more advice on your car.

I will get the code and get right back to you.

Thank you

The code trouble shooting PO4O2 also
oembranddomestic. Is this helpful for you to get an answer for me to be able to get the dealer to fix it!

My 1997 Nissan Altima GLE (Engine KA24DE) misfires on cylidner 4 (P0304 code) when the EGR system is attached. When the vacuum hose to the EGR valve is disconnected, the misfire completely stops. All the EGR components test OK on the bench. The car also seems to be calling for EGR right off of idle (in the 1000-2000 rpm range) as well as during normal operation (2000-4000 rpm range).

I've performed the following work/tests on the vehicle:

Replaced intake manifold gasket (upper and lower plenum)
Replaced spark plugs, wires, distributor cap, distributor rotor
Compression tested - all cylinders at 150 PSI (+/- 2 PSI)
Tested vacuum at intake manifold - meter reads about 18" vacuum and steady - revving the engine causes vacuum to drop slightly and then come back up to normal
Swapped fuel injectors for cylinder 2 and 4 to see if the problem followed the fuel injector and it did not - misfire continued on cylinder 4 even w/cylinder 2's injector installed
Tested resistance across fuel injectors (all injectors are at 12.0 ohms +/- 0.2 ohms)
Listened to injectors - all of them seem to be tapping happily away at idle
Adjusted engine timing to 20-deg BTDC
Adjusted idle speed to 750-rpm

Since the problem seems to be related to the EGR system, I also tested the following:
EGR valve (I applied a vacuum to it and the car began to stumble at idle as it should)
EGR BPT valve (removed from the car and blew into the bottom port while checking for airflow at the top 2 ports - the BPT seemed to function properly)
EGR Solenoid valve (removed from the car and tested the valve according to the service manual - it functioned perfectly)
EGR temperature sensor (appears to function within normal resistance limits)
Checked all hoses for leaks, cracks, etc.

I have seen weak egr return spring's cause the valve to open too far causing the miss fire to happen.It will hold vacuum and all that but with a weak spring it just open's too far too fast.

I have even seen bad electric egr valve do the same thing you unplug them the miss goes away you plug them back in the miss return's.

Should I look to replace the BPT valve or the EGR valve first. A couple of people told me that the BPT valve is probably bad. I pulled vacuum on the EGR valve and it didn't open until at least 5" of vacuum, so I'm wondering if I should start w/the BPT.

Also, do you know if the car is supposed to call for EGR directly off of idle? The misfire usually occurs at or around 1500 rpm.

I posted the description and operation and testing of the bpt valve and the egr valve.The egr valve can open just off of idle as you read what i posted there are different condition's for it to open.I would test the bpt valve like it say's to i would say it's the egr valve that's bad because you said the miss goes away when the egr valve is unhooked and come's back when you hook it back up.Let me know what you find.




SYSTEM DESCRIPTION
The EGRC-BPT valve monitors exhaust pressure to activate the diaphragm, controlling throttle body vacuum applied to the EGR valve. In other words, recirculated exhaust gas is controlled in response to positioning of the EGR valve or to engine operation.


COMPONENT INSPECTION

EGRC-BPT valve

1. Plug one of two ports of EGRC-BPT valve.



2. Vacuum from the other port and check leakage without applying any pressure from under EGR-BPT valve. Leakage should exist.


SYSTEM DESCRIPTION
This system cuts and controls vacuum applied to the EGR valve and EVAP canister to suit engine operating conditions. This cut-and-control operation is accomplished through the ECM and the EGR valve & EVAP canister purge control solenoid valve. When the ECM detects any of the following conditions, current flows through the solenoid valve. This causes the port vacuum to be discharged into the atmosphere. The EGR valve and EVAP canister remain closed.

* Low engine coolant temperature
* Engine starting
* High-speed engine operation
* Engine idling
* Excessively high engine coolant temperature
* Mass air flow sensor malfunction

COMPONENT DESCRIPTION



Exhaust Gas Recirculation (EGR) Valve
The EGR valve controls the amount of exhaust gas routed to the intake manifold. Vacuum is applied to the EGR valve in response to throttle valve opening. The vacuum controls the movement of a taper valve connected to the vacuum diaphragm in the EGR valve.



COMPONENT INSPECTION



Apply vacuum to EGR vacuum port with a hand vacuum pump. EGR valve spring should lift.
If NO, replace EGR valve.

The EGR passages are plugged, very common issue on these cars. Remove the intake manifold and clean the passages and it will cure the misfire issues.

USER NOTE: If EGR is causing misfire, flow is excessive. The passages can't be plugged. Don't tell someone to take off the intake manifold if you don't know that's the problem. Not an easy job, and not necessary.

I would say the egr port wasn't clogged because there was a miss fire with the egr hooked up and went away when you disconnected.If the port was clogged that wouldn't be possible.

Computer problem
2000 Nissan Altima 4 cyl Front Wheel Drive Automatic

I replaced my egr on my can then I cleared all codes I ran it for a while about 100 miles check engine didn't come on but when I turn car off check engine comes back for same code then I disconnected battery for 10 min to erace ECM but still can't solve problem can someone help me e mail me at josephlety00@ yahoo.com

What EGR code did you came up with-between P0400-P0409?? If you cleaned the passages thoroughly, check and test the wiring for short and open back to the computer if okay-have the computer tested.

Yes I got code P1400 MOD $10 egr valve position control and the second one P1400pd MOD $10

Where is the EGR valve located and how do you replace it?

There will will a couple lines and bolts that need to be removed, should be obvious when you look at it.

I have had problems with my car not wanting to accelerate. I got a mechanic to hook up the computer to my car and it said EGR system problem. We changed everything to do with the EGR system and it drove perfect for 2 days. Now it is acting up again. The check engine light went off and everything but now its back on. My car acts like it doesn't want to go at times and you have to stomp the gas to get it to go.

Is it the same code if so make sure the EGR passages are cleaned out and make sure its getting vacuum thru the solenoid

[quote:ab6dc61cbc="rasmataz"]Is it the same code if so make sure the EGR passages are cleaned out and make sure its getting vacuum thru the solenoid[/quote:ab6dc61cbc]


I havn't checked to see if its the same code yet. This just happened again. I will check it and do what you said and see if that works. Thanks.

I have a 1993 nissan altima gxe - 2.4 ltr engine with 85,000 and have been having problem passing the nox emmisson part of my inspection. I have changed the egr valve, vaccum solonoid switch, bpt valve , oxygen sensor and all of the vaccum hoses. Everytime I fail the shop keeps saying its my catalytic converter (its only two years old) , my question is how can you tell if I have a 2-way converter or a 3-way converter because its my understanding is that if its 2-ways it only takes care of HC's and the CO"s which it passes. What would you recommend?

Thank you

The EGR passages could be plugged with carbon. Manually pull on the EGR valve at idle, car should come very close to stalling, if not actually stalling. If littel or no change is seen then the passages must be cleaned out.

I did test the egr valvle at idle and engine stalled. I am starting to think I have a defective catalytic converter even though its two years old. I even put in BlueSky (6oz) twice ran the gas down to practically empty followed all the directions and still failed (the readings did come down a bit from 3.23 to 2.89 and the limiit is 250 this is why I and now thinking the converter is somehow defective. Have you ever heard of such a problem with a converter?

yes, but it isnt real common. If you have a vacuum tester, hook a long piece of vacuum line to it and use the tester in place of the EGR valve and drive it with the tester where you can see it.This will tell you if the system that controls it is applying vacuum to the valve when driving

I performed the test you suggested, by teeing in a vaccum gauge between the bpt and the egr valve. I am getting 3 inches of vaccum at the egr valve on accelleration with the rpm at 2000 to 2500 rmps. When I deaccelerate the vaccum falls off and turns back on when I accelerate. I would like to know if I should take a chance and retest, this would be my fourth time at $29.00 a pop. I am still leary of the converter. I ran this test for 26 miles and it was consistant. I also contacted the manufacturer of the converter and explained the problem. He concurred with me that is possible that the converter could be bad and is covered under warranty. What do you think should I get the new converter then retest?

If it is free, go for it. Not sure 3 inches of vacuum is enough to activate the egr valve.

Would the converter cause me to get low vaccum as you suggest? According to all the manuals (Haynes - Shop Manual for 1993 manual) they said 3 inches was enough what should it be - because I'm going for the converter and I going to try your test again.

Computer problem
2000 Nissan Altima 4 cyl Front Wheel Drive Automatic

Where is the EGR valve located on a 2000 Altima? Engine check light is on?

MIL on. Give us the code numbers. Don't have them? Go to the nearest Autozone and have them scan the ECM.

The code is P1400 per Autozone, EGRC solenoid Valve?

1. Disconnect the solenoid valve electrical harness and vacuum lines. 2. Air should pass between Ports A and B freely. 3. Apply battery voltage and ground to the solenoid terminals. 4. Air should NOT pass through Ports A and B freely. 5. Air should now pass through Ports A and C freely. Discard the valve if it does not respond as indicated. If the valve does responds as indicated then check for problems in the power and ground circuits to the valve. BTW, this is a dealer part only.

What do you use for air flow? Do this with the engine running? Use an external power source of 12Volts?
Please clarify/Thanks!

Use engine vacuum when the engine is running. You can use jumper wires from the fuse block, not from the battery directly.