Question about 1999 Chevrolet Malibu
vacuum leaks on intake manifold,
the air tube between the air filter.
intake manifold vacuum hose.
clean throttle plate with Berryman carburator cleaner
SEE sample picture HERE
Also remove carbon built up behind the EGR valve and the EGR passage tube.
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.
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.
Posted on Dec 19, 2009
More than likley has a bad egr valve.
Posted on Sep 27, 2009
Remove egr valve, and clean out carbon from valve and engine where it mounts,
Posted on Sep 25, 2009
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Posted on Jan 02, 2017
You probably pulled a code p0401, insufficient egr flow. Your DPFE sensor is more than likely at fault. There has been a lot of trouble with these sensors. Then reset CEL or disconnect battery for 5 minutes.
Posted on Aug 17, 2008
Can you give me a code number. Also the egr ports plug in the elbow the valve is bolted to. Remove the elbow and clean the ports.
Posted on Mar 15, 2009
SOURCE: Insufficient EGR Flow problem
Specifically DTC P0401 is "Exhaust Gas Recirculation (EGR) Insufficient Flow". Now this is where we have to be careful when we read a code. In this case it is not saying the EGR valve is bad, it's saying the EGR flow is too low. Now it could be because the EGR valve is bad. Or it could be a clogged EGR tube or a broken vacuum line. This is why you have to be careful and check the whole system before you go changing parts.
The PCM tests the EGR system during deceleration by momentarily commanding the EGR valve to open while monitoring the Manifold Absolute Pressure (MAP) sensor signal. When the EGR valve is opened, the PCM should see a proportional increase in MAP. If the expected increase in MAP is not seen, the PCM notes the amount of error that was detected and adjusts an internal fail counter towards a fail threshold level. When the fail counter exceeds the fail threshold level, the PCM will set DTC P0401. The number of test samples required to accomplish this may vary according to the amount of detected flow error.
Normally, the PCM will only allow one EGR flow test sample to be taken during an ignition cycle. To aid in verifying a repair, the PCM allows twelve test samples during the first ignition cycle following a scan tool Clear Info or a battery disconnect. Between nine and twelve samples should be sufficient for the PCM to determine adequate EGR flow and pass the EGR test.
To check the system first you need to remove the EGR valve and if it is clogged or broken. If it is, clean or replace it. If it is okay, then remove the EGR inlet tube from the exhaust manifold and the EGR outlet tube from the intake manifold. If either or both are clogged, clean them out or replace them. Then check the ports in the manifolds themselves to see if they are clogged. If so, clean them out.
When you are done, disconnect the battery for about 30 seconds to clear the code and drive the car to see if the light comes back.
This should take care of the problem. If not, then you will need to put a scan tool on the car and see what the EGR control system is doing wrong and correct it.
The Valve on this car is electronic, so, unfortunately a vacuum pump will not work for testing.
If you have a scan tool, you can command the pcm to open the valve to see if the valve itself is working.There are really only4 things to go wrong with these things, PCM, wiring,the valve itself, or plugged passages. I have never seen the pcm cause this problem, or the wiring for that matter. If you say you have pulled the EGR and checked the intake passages, then I would be pretty confident in saying the the egr valve itself is bad.
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Posted on Mar 18, 2009
You need to reset the cars cpu,..you can do this by unhooking the negative side of the battery for about 10 minuts,then if the light comes on again,run the obd2 reader again,because there is another problem.
Posted on Apr 13, 2009
SOURCE: 1996 Mercury Sable with a
Before replacing anything else, it's important to clear the code before determining any more repairs are necessary. You can take the car to an autoparts store that features free diagnostic tests or you can disconnect the negative battery cable for 10 minutes to clear it. If after clearing the code P0401 still appears, then it comes down to 1 of 2 problems:
The DPFE is located at #1
The EGR is #2
Best of luck with your Sable.
Posted on Jun 12, 2009
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