More EGR BS

[Skidzz]

So today my check engine light came on. I took it to autozone and it came up as "EGR - Excessive flow". The guy tells me that it could either be that the EGR valve needs replaced OR the pressure sensor. He said if the pressure sensor is bad it can give an incorrect EGR reading. The sensor is $70! and the valve is $45. I'm not buying both if I don't need them both. Is there any way to tell which part is bad? They told me that the only way to pin point it is with the type of diagnostic machine that dealerships and what-not have.

 

[46gtsblown]

try removing the vac line to the egr valve, if you are still flowing exaust gass into the motor you will know because your idle will be poor.
Try taking the valve off and cleaning the carbon out of it to see if that helps.
The sensor is known to go bad so therre is a good chance that is your prob.
You will just have to trouble shoot the system to isolate the cause, If you have a junk yard nearby get the sensor from there to see if it fixes your problem
Dwayne

 

[Skidzz]

try removing the vac line to the egr valve, if you are still flowing exaust gass into the motor you will know because your idle will be poor.
Try taking the valve off and cleaning the carbon out of it to see if that helps.
The sensor is known to go bad so therre is a good chance that is your prob.
You will just have to trouble shoot the system to isolate the cause, If you have a junk yard nearby get the sensor from there to see if it fixes your problem
Dwayne

So if I remove the vac line and my idle is poor, does that mean that the valve is working properly? I've already cleaned it twice so I know it's not carbon build up. So I'll try removing the line, but if the idle goes poor after that, does that mean the sensor is bad?

 

[85 Coupe 5.0]

As stated above, the Transducer is a VERY common problem.

my suggestions,

1. Start car and observe idle, then remove the vac line on the EGR valve, if the idle smooths out, you have a problem with the EGR vacuum solenoid applying vacuum when it should not. there should be VERY little to no vacuum on that line going to the EGR valve at idle. if there is the problem is with the EGR vacuum solenoid or the vac lines aren't on correctly which is impossible unless someone has modified them.

2. You CAN test the transducer if you have a hand held vacuum pump and a digital volt meter. My opinion, just replace the transducer, they are usually the culprit as they go bad alllll the time, although I have seen a few EGR valves and transducers at the same time. The transducer is basically a MAP sensor in disguise. take off the lines going to the transducer, but leave it plugged in. use your volt meter to find the signal return circuit, usually the middle wire. then, use the vac pump to apply vacuum to the upstream port on the transducer. as you apply vacuum the voltage on the meter should change. quickly release the vacuum, the voltage should immediately drop back to what is was when you first started.

I'm sorry, i can't remeber voltage specs for this test. I DO know that when these sensors fail, they usually produce a voltage reading on the signal return of less than 1 volt and won't change no matter how much vacuum you apply, this is a perfect sign that it's bad.

anyone else got some ideas??

 

[Skidzz]

Ok, so when he told me the "pressure sensor", was he talking about the transducer? Just want to make sure it's the same thing. Where exactly is the transducer located? A picture would help, if anyone has one. I'm sure it's easy to find, but I haven't worked with it yet, so I'm not sure where it is.

 

[Skidzz]

No one knows?