Question about 1990 Cadillac Deville

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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.

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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..

Posted on Dec 12, 2009

Testimonial: "Thanks for the advise! I will start with the suggestions you recommend. Thanks again, sjk88"

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1 Answer

What controls the opening and closing of the EGR solenoid?


ECU controls the EGR system. Check for vacuum to the valve with the engine running. There should be no vacuum. If you have vacuum disconnect the electrical to the vacuum control solenoid and see if the vacuum goes away. If it does you have a command or wiring problem and will need to trace the signal wire back to the ECU.

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It's not your battery. It might be your IAC valve (intake air control valve) or an EGR valve, maybe even a vacuum leak. The battery is fine. Your fuel filter is most likely fine. When the fuel filter plugs, the car will usualy idle ok but will lose power during acceleration.

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Got a 2001 Ford Taurus with 128K miles, engine was rebuilt 10 months ago, for the last 4 months it has been chugging or hesitating when I'm stopped at a light, Autozone codes said egr pressure sensor,...


Sounds like the egr solenoid stuck..Not the valve..When you are sitting at idle,,you should be able to take off the vacum line and there should be no vacuum..,If there is back track that line and see if it goes to a solenoid..I bet the vacuum lines are crossed..One should have vacuum,,the other should go to the egr valve..If they are crossed on the egr solenoid,,then you end up with constant vacuum going to your egr valve..Until you figure it out leave the line off the egr valve and block the line..If you are constantly haveing the valve held open,,you killing sparkplugs and the catylitic converter

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I have a 1990 corolla carburettor. When its at normal operating condition the car jumps and runs rough. When you accelerate the car runs well. It only plays up when at idle. But when cold it runs very...


Check for a malfunctioning EGR valve. This valve is only selected to perform when the engine is warm. It has a vacuum diaphragm which can crack and lead to vacuum leaks. This will cause rough running. The EGR valve should be vacuum checked to see if this diaphragm is leaking. This valve can also stick open due to carbon deposits. When the valve sticks open, the fuel/air mixture is leaned out and rough running ensues. This problem is practically expected on a vehicle of that age.

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Your fuel pressure regulator may have failed. See pic below. Find it on top of the engine bolted to the fuel rail. With the engine idling, briefly pull the vacuum hose off the regulator. If gas comes out of the regulator vacuum port, replace the regulator.


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Code 15 ignation output car runs good when cold gets warm check eng light miss.lacks power not hitting on all cyl. suspect bad ignitor..


Check the EGR valve. Look up on the internet where on your car it is located. Find the vacuum line connected to it. Start the engine cold and as it warms up and starts to miss and stumble, pull off the vacuum line from the EGR. If the car idles fine, replace the EGR. Ignition system problems are more likely to occur at idle or lower rpm. Besides, testing the EGR is free, easy and do fail in high mileage vehicles.

Jun 02, 2010 | 1988 Acura Legend

1 Answer

Intermittently won't hold idle and stalls


The symptom you describe can be caused by either a bad or dirty EGR vavle or a broken / defective vacuum line.

Try this
1. disconnect and plug off the EGR vacuum supply line

2. Connect a vacuum hose of equal size to the EGR valve.

3. Start vehicle

4. draw a vacuum on the line orally.

a. the engine should die or run really bad.

5. Restart vehicle and repeat checking for same result.

6. If EGR valve is performing correctly as stated in steps 4 and 5 thern you most likely have a bad / cracked / damaged vacuum line somewhere.

7. Reconnect original vacuum line to the EGR Valve

8. Locate source of Vacuum leak.

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Cold starting problem


How old is your Battery? at the Temp. Stated above an Older Battery even though Good may not have Enough Cold Cranking Amps Left to Kick her Over.

Jan 04, 2009 | 1990 Cadillac Deville

1 Answer

Hard Start with trouble code 32


You should have your battery checked, it may be getting old and doesn;t have as much cold cranking power, I don;t think code 32 has anything to do with the slow cranking when cold.


Trouble Code 32 indicates that the Exhaust Gas Recirculation (EGR) valve diaphragm is not where the ECM expects it to be. The ECM controls the diaphragm with a Pulse-Width Modulated (PWM) waveform. The EGR has a vacuum bleed solenoid that adjusts the vacuum applied to the EGR valve based on this pulse width. If there is sufficient vacuum at the EGR valve, a switch closes to send a signal back to the ECM. The absence of this signal is the bases for code 32.
The conditions for setting this code are:
  • no vacuum to EGR (switch open), and
  • Code 33 or 34 (MAF error) is not present, and
  • engine running and LV8 is less than 100, and
  • coolant temperature is > 118 deg F (48 deg C), and
  • the EGR solenoid duty cycle is < 65%, and
  • the above conditions are met for more than 25 seconds


Typical causes for this code include:
1) Faulty EGR valve-to-ECM connection
2) Plugged EGR passages and/or sticking EGR valve
3) Defective EGR valve
4) Defective ECM

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