My 1985 Volvo 740 GLE 2.3L Sedan passed the pvc section, air filter is new, passed ERG, O2 sensor passed also. Issue: ( High NOX). If the FEC failed what areas (on my Volvo) cover that section, that can be corrected to pass smog?
How many miles is on the catalytic converter?
120,000+ miles is goner.
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Do the carbon clean up and test again.
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Please post the Nox figure on repost.
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Check for
vacuum leaks on intake manifold,
the air tube between the air filter.
intake manifold vacuum hose.
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clean throttle plate with Berryman carburator cleaner
SEE sample picture HERE
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Also remove carbon built up behind the EGR valve and the EGR passage tube.
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Vacuum leak WILL offset the intended 14.7 to 1 air fuel ratio.
More un-metered air (leaks) will lean out the fuel mixture.
Use small amount of Berryman carb clearer at potential air leak area will help you identify trouble spot.
At idle,just spray and listen for the RPM surge.
The in-rush of carb clearer will increase the RPM on the motor.
Record the problem spot(s) and address it later.
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EGR carbon built up require 2+ hours to clean from start to finish.
You will need a new EGR base gasket before your start.
Locate and remove the EGR valve after the vehicle is cool down.
Carefully record the connector and vacuum line (for older vehicle) location by drawing an easily to follow diagram.
Remove the EGR valve.
Inspect the location of the carbon built-up inside the valve and the EGR passage tube.
SOAK these areas with WD-40 spary.
You will need a small screwdriver,cloth hanger and lot of newspaper and time to get this cleaning done right.
RE-SOAK the carbon and let it sit for over-night will also help.
One the last round,pass a shop vacuum of the EGR valve and the passage pipe.
Install the new EGR gasket and connectors.
Allow the vehicle to warm up outdoor to burn up any remaining WD-40.
Take it for a test drive.
Please rate my answer if it's useful to you.
Cheers,
Mustgo
That is a heat problem there are only two components on the car that effect the NOX and that is the egr system and the catalytic converter. to check the egr valve start the car up let it idle diconnect the egr valve put a hose on it and **** on the hose if the egr is good it will get a erradic idle you will also have to check the egr soloniod to see if it is working you can do this by removing the hose from the egr and reving the engine if it starts to **** when you rev the engine then it is working if all of that is good replace the catalitic converter and it should sail through.
Paul
www.carburetorexchange.com
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