How To Test EGR Solenoid (Andy’s Garage: Episode - 87) 

Kaden T thanks, I appreciate the feedback

Thanks for the feedback

Gary McAleer yes, there is a good chance that is the problem, could also be the Idle Air Control Valve.

It may be easier for us beginners it you would have a clear close up of the valve so we have a clear idea of what you are explaining. The black valve against your black shirt makes it difficult for newbies like me to figure out what you mean. I think my EGR solenoid may be causing me troubles so I'll check into it. Thank you.

Correct, they were reversed. The other two should be for the vacuum switch and signal

@@PhillipsVision Thanks, I did find a schematic drawing of the solenoid. Pin A is Ignition 12V, B is the Solenoid Activate signal (Open Inactive/Gnd Active). C is the feedback signal (Open No Vacuum to EGR/Gnd Vaccum is applied to EGR), D is Gnd. There is a diode inside between pins A and B. It is reversed biased. This is called a Flyback Diode. When the signal on pin B goes to Gnd, current passes through the solenod coil - the diode does not conduct. When the signal on pin B opens, the coil is shut off and it's magnetic field collapses - this induces a voltage spike in the coil but this spike is negative with respect to 12V. The diode conducts in this case and "absorbs" the spike so it does not damage other circuits in the car. The solenoid will work if the diode is blown (open) but it is not good for the car - you may hear noise on an AM radio. Check the diode on pins A and B with an Ohmmeter. You should get high resistance one way, and low resistance with the leads switched. I didn't say which way the meter leads should go because some Ohmeters put out a negative voltage on the red lead (most properly put a positive voltage on the red lead and this helps identify proper polarity of diodes). In this case we are sure the diode was built into the solenoid assembly properly - you just need to make sure you see different resistance readings with the leads applied both ways to make sure that "protection" diode is still functioning properly. Fieros use a Pulse Width Modulated (PWM) signal to activate the solenoid to allow vacuum to open the EGR. Quick pulses in rapid sucession cause a little bit of exhaust to be pulled into the intake manifold via the EGR, while longer pulses allow more exhaust gas into the manifold. One hose on the Solenoid comes from the intake manifold (this is the source of the vacuum for the EGR). One hose/tube goes to the EGR (the vacuum switched on/off via the solenoid). One hose goes to the air intake cleaner (some kind of venting but not sure why). And finally another hose/tube that connects to the same hose/tube that goes to the EGR. This allows the solenoid unit to confirm (send feedback to the ECM) that vacuum is being applied to the EGR when the solenoid is activated. Another note: Make sure you don't apply 12V to the wrong pin on the Solenoid, you may blow out the diode. The diode is there to absorb the brief spike when the solenoid is deactivated, it is not designed to take a contant negative 12V (power reversed). Doing so will blow out the diode in seconds. The EGR will still work with a blown diode, but now the solenoid with put negative voltage spikes on the Ignition 12V signal and that could damage other circuits in the car over time. Reversing the leads with an Ohmeter is fine because it uses milliamps to make a diode measurement, but reversed power leads can supply many amps that the diode can't handle when reversed.

First thing you need to do is connect a scanning tool to you vehicle so you can get the actual engine codes, that will tell you exactly where to look. If not, you’re going to be replacing things that are not needed.

jennifer campbell you’ll need to find a wiring diagram for your car and determine your wiring

He had the + connected to the negative on the port side, that is why it was reading _ 11.98, also the blowing part was totally out of focus on the two other ports, in my opinion it was an ok video.

Did you test the harness to make sure power it getting to the solenoid?

@@PhillipsVision Yep and hooked to a 12 volt battery no click.

@@snowman307 solenoid might be bad

@@PhillipsVision I was thinking that.Thanks for the help.

checho hermandez High RPMs At Idle and/or racing engine

Thank God you pointed it out keyboard warrior

@@vicferrarisgarage firing a solenoid the wrong way, is not good for it.

You can as well

@@PhillipsVision ok, thks

@@PhillipsVision Forgot to ask. What value would I be looking to see....thks jc

@@Samson-EC 32 to 35 ohms is average for an EGR Solenoid

@@PhillipsVision Thanks very much Andy. Nice to ask a question and someone, such as yourself, takes the time to answer it. Appreciate it very much...jc

greg spight engine racing, high RPMs at idle. This could also be caused by a cracked EGR Tube, so you’ll need to do a process of elimination

@@PhillipsVision mine is running rich,bad fumes smell,replaced just about everything except oxygen sensor and egr valve solenoid

greg spight is your engine sputtering or racing? Is is generating any error codes?

@@PhillipsVision no sputtering,idle is fine just strong exhaust smell.connection port to read codes is broke,but it use to read 32,35 I had something's fixed codes went away,but smell didn't an now can't read codes

greg spight normally, a Damaged EGR will cause high idle like a Vacuum Leak. A bad O2 sensor can cause this or a failing MAF Sensor.

Thanks, that’s an older video of mine and has already been addressed👍

@@PhillipsVision I've watched all of your Fiero videos, and most of them had it, didn't know it was addressed, but glad it was... Thanks again for the very helpful videos!