Last night on a 110 mile round trip drive, the SES light was illuminated for the last 15 miles each way. I retrieved a code 32 and a code 53. My scanner book gives multiple code meanings for each code. Code 32 says:
Barometric pressure sensor circuit failure
Or
EGR valve diagnostic switch - closed during engine start up or
when EGR flow requested by ECM.
Or
EGR/EVRV

Code 53 says:
Over voltage condition
Or
EGR - system problems or EGR Solenoid
No. 1 problem
Or
Voltage reference error
Or
VATS problems

Well, I don't have VATS, fo that rules that out. So, do I have a Barometric sensor? Why would GM assign 3 or 4 different meanings for each code? I have read the EGR tech article and I am still stupid about the system. If you have any input, please tell me. I have a 1986 IROC with the LG4. I have just (3 days ago removed the A.I.R., would that have anything to do with it? I didn't think it would since they are two different systems. My mods are as follows: Flowmaster Force2 3" cat-back, 3" Catco catalytic converter, Edelbrock Performer EGR intake manifold (has been on for 7 years), a Hypertech Thermomaster chip (also been on for 7 years), and an L69 Dual Snorkel air cleaner. I have read thru the archives and found some stuff (everybody with a 53 was talking about VATS) and I still don't know exactly what to look for. I can do the diagnostics that I have the tools for, but would like your tips please. I do not have a hand held vacuum pump. I do have a vacuum gage, DMM, compression gage, and an assortment of tools.

thank you for your help!

Mark

 

O.K.,
I have done some testing and this is what I have done. I put full vacuum to the valve itself and it doesn't open, I assume that is bad. Also, there is a vacuum switch that has two wires going to it along with two vacuum hoses, one from the carb and one going to the valve. I get vacuum to the switch but not out of it, is there a way to check the wiring? I assume it is from the computer (at least that is what my chilton manual says). If it is computer controlled, what inputs to the computer tell it to open the valve by opening the switch and letting the vacuum pass?

Thanks!

Mark

 

I checked the wiring to the switch, it is getting 14.15 volts. It will not let vacuum pass when it has voltage, is this correct? Is the voltage too high? According to GMTech's writeup, when the conditions are right, the ECM grounds out the switch. Is this saying that the voltage will go away when conditions are right? According to the Chilton's manual when the engine is at normal operating tempuratureI can bring up the RPM's andthe vacuum should go to 5", it doesn't. I am lost.

Mark