Question about 1994 Cadillac DeVille

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No egr flow after reaching operating temp

I have a good egr valve and chged. egr slenoid 2 times.excessive pinging when engine is warm. can run vac. direct stops ping, but is too much egr and idles rough. how do i check to see if getting power to egr soleoid, or signal from ecm

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  • caddy freak Jun 17, 2008

    has no engine codes, even if i unplug egr solenoid, i know these engines are known for carbon buildup, also converter smell is horrible,

  • caddy freak Jul 01, 2008

    do not need obd for caddys, all caddys have on board diagnostics,



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Use an OBD II reader, $60 at Walmart.

Also try cleaning out your air intake. Carbon buildup can cause rough idle and hesitation. Run two or three cans of throttle cleaner through it, clean out the pathways from the EGR to the intake, put two shots of the LUCAS brand fuel system cleaner in it or SEAFOAM.

If it improves then there you go. If not, you may have other issue, take it to a mechanic or have a gearhead friend take a look.

The OBD will tell ou if theres any engine codes going off caused by something wrong.

use the Carb cleaner/Intake cleaner by removing the the air intake hose to the air box, use one hand to increas the throttle whiile spraying the cleaner through it. Make sure to rev it enough to keep it from stalling, bu tnot too much.

If you start seeing smoke come out your tailpipe, then you have carbon buildup.

If unsure about any of this. I suggest you make friends with a guy or gal that knows about cars, buy em a six pack and ask them what they think about it, eventually they wont be able to stop themself from helping you.

Good luck

Posted on Jun 17, 2008


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2 Answers

What is a erg valve

An egr valve is an emmsion component to help lower exhaust also helps with pinging, this is a valve that takes exhuast and recirculates it back into engine to be reburned and is controlled by the computer, the computer with vacuum. the computer sends a signal to the vacuum solenoid to open that allows vacuum to flow through to the egr valve so it can open to allow exhaust back into engine, the computer uses a signal form the egr feedback sensor, this sensor is used so that the computer knows the egr is working correctly by monitoring the exhaust preasure, there are two hoses connected to this sensor and when the egr valve opens the preasure drops a little going to the feedback sensor which changes the signal to computer so that computer knows valve is working. the most common reasons for the system not to work is the vacuum solenoid goes bad and doesnt allow vac to flow to the valve, the next thing that could go is a hose to feedback sensor falls off or breaks causing a leak and then the preasures dont change, the last thing is the egr valve itself. a could way to test the valve is to remove vac hose and connect a vac pump to it and apply vacuum with engine running and you should see idle drop and engine speed lower, this means valve is good, the feedback sensor you would need a scan tool to watch readings or a meter to watch readings and see if they change as you open valve, the last test is the egr vac solenoid, you will need to unplug connector and turn engine on, then test connector you will have power to one wire or ground, lets say you have power to connector but no ground you will mark the power wire so not to mix up wires. next connect connector and apply a ground jumper wire to terminal that has no ground, dont connect to power connector, now see if the egr valve opens, some of these are set up with power and ground already and the computer removes one to open the valve, so first try to test both connectors at the solenoid and if theres power and ground with engine running then all you need to do is check the hose to egr valve for vacuum when you remove the connector from the solenoid. by removing the connector from the solenoid you will be opening it and vac should flow to egr valve, note this is only if when you test the connector theres power on one wire and ground on the other. hope this helps.heres pictures of each component. good day.2_4_2012_7_48_20_pm.jpg2_4_2012_7_48_31_pm.jpg2_4_2012_7_48_41_pm.jpg

Feb 04, 2012 | 2000 Lincoln Town Car

1 Answer

When engin gets hot it starts to **** is the plugs

if it is overheating , ti will ping. do not drive like this. Low on coolant? why getting hot? or do you just mean at operating temp? If yes, your EGR valve is plugged or not opening. EGR reduces ping on warm engine by reburning exhasut gases.

Jan 07, 2011 | Ford Fiesta Cars & Trucks

1 Answer

Check engine light. Code: Exhaust gas

Usually this is due to carbon build up. Fuel injector cleaners will not help. It involves removal of the EGR valve and inspection of the valve for carbon and the passages for carbon. You can also test the valve itself prior to removal if it is vaccuum operated. Unplug the vac hose, plug it and then install a piece of vac hose long enough to reach it without bending over the engine. While the engine is idleing apply vaccuum to the hose via a pump or the old fashioned way via sucking on it and note engine idle change. If none either the baffle is bad inside the valve or it is clogged. Hope this helps.
Also, some EGR valves have a vac control solenoid and those go bad too. If the idle does change via the procedure above then suspect the control vac solenoid.

Jul 15, 2010 | 2000 Honda Passport

1 Answer

I have a 1987 Dodge Dakota the check EGR light went on after that it started running crappy. I changed the valve the light is still on and it still runs crappy. The clerk at the parts store told me to...

that light comes on at 30,000 mile intervals it is a timed thing only and does not indicate a problem
the dealer or a shop with a scan tool can turn it off for you. you have another problem mabee tune up needed. a delay valve wont do anything. if you want to see if egr is a problem just disconnect the vac hose and try it out.if it runs better that dont mean the valve is bad though.
if it has a smog pump make sure that after the engine warms up to normal operating temp, the air flows through the tube that goes down to the exaust just in front of the cat converter.make sure it doesnt blow into the exaust manifold after warmed up because this will cause the 02 sensor readings to be off and it will run bad

Mar 24, 2010 | 1987 Dodge Dakota

1 Answer

I have a 1991 buick regal stalls and shut off after warming up

egr valve is not opening up when the engine reaches it normal operating temperture

Feb 07, 2010 | 1991 Buick Regal

2 Answers

Just changed plugs running well 1 day later service engine soon light appears. Took to parts house code P0401 is what shows cleared code not returned yet

Technical Description

Insufficient EGR Flow

What does that mean?

EGR stands for Exhaust Gas Recirculation. It is part of the vehicle emmissions system, and is used to reduce combustion temperature and pressure to control Oxides of Nitrogen. There are generally three parts to the EGR system: the EGR valve, an actuator solenoid, and a differential pressure sensor EGR (DPFE). These things work together to deliver the correct amount of recirculation based on engine temperature, load, etc. The P0401 code means that OBD detected an insufficient amount of EGR.

You may notice drivability problems such as pinging (a.k.a. pre-ignition knock) when the engine is under load or the vehicle is at higher speeds. There may also be other symptoms.

A code P0401 most likely means one or more of the following has happened:

* The DPFE (differential pressure feedback EGR) sensor is faulty and needs to be replaced
* There is a blockage in the EGR (tube), most likely carbon buildup
* The EGR valve is faulty
* The EGR valve may not be opening due to a lack of vaccuum

Possible Solutions

In fixing this code, it is quite common for people to just replace the EGR valve only to have the OBD code return. The EGR valve is not always the culprit.

* Use a vacuum pump and pull the EGR valve open while monitoring engine RPM's & DPFE voltage. There should be a noticable difference in RPM's with the EGR open
* Clean out the EGR valve and/or tubing to remove deposits
* Check the voltage at the DPFE, compare to specified values (refer to a repair manual for your specific model)
* Replace the DPFE sensor (with a good quality / OEM one)
* Replace the EGR valve

Jan 13, 2010 | 2002 Ford Expedition

1 Answer

1990 Deville 4.5 litre v-8 vacuum present from vacuum line to egr selenoid but no vacuum from egr selenoid to egr valve the car runs fine when cold but runs poorly when warmed to operating temperature.

You will not see any vacuum from the egr solenoid until the engine has reached normal operating temperature and certain other driving conditions have been reached (like throttle position and road speed). If the engine runs rough when warmed up, check the CTS (coolant Temp sensor) when hot and cold and if no fault shows there, start checking input sensors for engine and cam position, engine timing, RPM etc. If the EGR valve was leaking, it is only adding air to the exhaust stream and usually, manually opening the valve and blowing out the seat with compressed air should fix the issue. This can also be an issue with clogged injectors. When the engine is cold, fuel enrichment supplies more then normal fuel amounts to encourage even running. When the engine warms up (normal operating temperature), fuel enrichment mode is turned off. If your injectors are clogged (even if only slightly) fuel starvation will cause rough running. Fuel enrichment overcomes the starvation of clogged injectors. Try adding a propriety injector cleaner to your fuel tank and watch for an improvement. If you do see an improvement, have your injectors cleaned and tested professionally. If you locate any other issues with engine sensors, replace them and ensure the new components are adjusted correctly if required..

Dec 12, 2009 | 1990 Cadillac Deville

2 Answers

Engine run good until warmed up

One runs the gauge (or light), and one is for the computer. You want the one for the computer. You can unplug to see if it's for the guage when warmed up.

Sep 21, 2009 | 1992 Chevrolet Lumina

1 Answer

Manual for replacing a EGR valve.

This is a common problem with the 104 engine. I'm assuming it is a c 280. First you need to check a couple of things. Below your intake manifold there is a source vac. line running to a switchover valve located under the plastic cover on your front cam cover. that switch over valve operates your 2ndary air inj. and egr pipes. The codes you have are saying that these 2 systems are not operating. If the source is good take of the plastic cover on your valve cover(held in by 5mm. allen head bolts). the 2 vac lines running under that trough are running to your egr and your 2ndary inj. the 1st is the air inj. the rear one is your e.g.r. valve. If these systems just plain were not operating it would not cause your car to run poorly cold unless there was a vac. leak. Take a vac. pump and apply press. to your e.g.r. valve with engine running and you should notice a rough run when vac. is applied. The 2ndary air inj. is more complicated to test because there is more involved. Fixing this vac. leak will help get your adaptations under control and your vehicle will run a lot better

May 27, 2009 | 1997 Mercedes-Benz C-Class

1 Answer

Excessive ping after engine is warm

timing is off a bit and you might try running premium gas through it and add a bottle of heet to the tank,

Jun 24, 2008 | 1994 Cadillac DeVille

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