EGR flow malfunction help - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

shayrgob240 · 08-03-2006, 03:56 PM

hey, what's up guys? I'm trying to diagnose my problem but I'm relatively unexperienced when it comes to diagnosing engine probs. Well, the FSM says to check the EGR lifting and releasing when increasing engine speed from 2k to 3.5k. How exactly do u know or see that the EGR valve is doing so? Isn't everything inside the EGR Valve so u can't really see what's happening? lol

thanks for the help.

*ManoNegra* · 08-03-2006, 04:25 PM

What is it you're trying to fix that makes you think the EGR is bad?
The Exhaust Gas Recirculation valve is primarly used for emission purposes. Did your car fail smog?

The valve is located on the intake manifold, and opens a small passageway between the exhaust and intake manifold to allow a metered amount of exhaust to flow back into the engine. This reduces combustion temperatures and helps control the formation of oxides of nitrogen. The EGR valve is opened by the application of vacuum to its control diaphragm. Some also require a certain amount of exhaust back pressure before they'll open. On newer vehicles, the valve is electronic and uses one or more solenoids or a small stepper motor. The valve should remain closed while the engine is cold and at idle. It should only open once the engine has warmed up and is running at part-throttle. If the valve sticks shut (or is disconnected), NOX emissions will soar and detonation will often result (See Detonation and Spark Knock). If it sticks in the open position or fails to close all the way, it acts like a vacuum leak resulting in a rough idle, hesitation and possible stalling.

Many people get rid of it. But if you're trying to pass smog, then that's a different case.

shayrgob240 · 08-03-2006, 04:31 PM

CEL - P0400

EGR FLOW Malfunction

I would much rather fix the problem for a couple reasons
1) I like the environment
2) I sort of want to learn how to fix the prob.

thanks

*ManoNegra* · 08-03-2006, 04:38 PM

Gotcha.
Change the vaccum hoses attached to it. You can get a pressure tester kit to see it fuctions properly. They usually have sensitive springs that actuate the diaphram and those get stuck/worn when they get old. You may need to get a new one. What year car is it? KA?

shayrgob240 · 08-03-2006, 04:48 PM

Quote:

Originally Posted by ManoNegra

Gotcha.
Change the vaccum hoses attached to it. You can get a pressure tester kit to see it fuctions properly. They usually have sensitive springs that actuate the diaphram and those get stuck/worn when they get old. You may need to get a new one. What year car is it? KA?

It's a 95 and it's a KA. I did one of the tests where I took the vaccum line off the EGR and put my thumb over it. I then increased the engine speed and didn't feel vaccum at all from the EGR control valve.

*ManoNegra* · 08-03-2006, 07:47 PM

Sounds like it's time to replace.

08-03-2006, 03:56 PM	#1
shayrgob240 Zilvia Junkie Join Date: Jul 2003 Location: gurnee, IL Age: 40 Posts: 441 Trader Rating: (0) Feedback Score: 0 reviews	EGR flow malfunction help hey, what's up guys? I'm trying to diagnose my problem but I'm relatively unexperienced when it comes to diagnosing engine probs. Well, the FSM says to check the EGR lifting and releasing when increasing engine speed from 2k to 3.5k. How exactly do u know or see that the EGR valve is doing so? Isn't everything inside the EGR Valve so u can't really see what's happening? lol thanks for the help.

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08-03-2006, 04:25 PM	#2
ManoNegra Guild of Skullduggerous Intent Join Date: Jan 2004 Location: Socal Posts: 7,841 Trader Rating: (48) Feedback Score: 48 reviews	What is it you're trying to fix that makes you think the EGR is bad? The Exhaust Gas Recirculation valve is primarly used for emission purposes. Did your car fail smog? The valve is located on the intake manifold, and opens a small passageway between the exhaust and intake manifold to allow a metered amount of exhaust to flow back into the engine. This reduces combustion temperatures and helps control the formation of oxides of nitrogen. The EGR valve is opened by the application of vacuum to its control diaphragm. Some also require a certain amount of exhaust back pressure before they'll open. On newer vehicles, the valve is electronic and uses one or more solenoids or a small stepper motor. The valve should remain closed while the engine is cold and at idle. It should only open once the engine has warmed up and is running at part-throttle. If the valve sticks shut (or is disconnected), NOX emissions will soar and detonation will often result (See Detonation and Spark Knock). If it sticks in the open position or fails to close all the way, it acts like a vacuum leak resulting in a rough idle, hesitation and possible stalling. Many people get rid of it. But if you're trying to pass smog, then that's a different case.

08-03-2006, 04:31 PM	#3
shayrgob240 Zilvia Junkie Join Date: Jul 2003 Location: gurnee, IL Age: 40 Posts: 441 Trader Rating: (0) Feedback Score: 0 reviews	CEL - P0400 EGR FLOW Malfunction I would much rather fix the problem for a couple reasons 1) I like the environment 2) I sort of want to learn how to fix the prob. thanks

08-03-2006, 04:38 PM	#4
ManoNegra Guild of Skullduggerous Intent Join Date: Jan 2004 Location: Socal Posts: 7,841 Trader Rating: (48) Feedback Score: 48 reviews	Gotcha. Change the vaccum hoses attached to it. You can get a pressure tester kit to see it fuctions properly. They usually have sensitive springs that actuate the diaphram and those get stuck/worn when they get old. You may need to get a new one. What year car is it? KA?

08-03-2006, 07:47 PM	#6
ManoNegra Guild of Skullduggerous Intent Join Date: Jan 2004 Location: Socal Posts: 7,841 Trader Rating: (48) Feedback Score: 48 reviews	Sounds like it's time to replace.