EGR Valve & TVS

[drew666]

Failed hydrocarbon part of emissions test. HighSpeed: HC=152 CO=.62 CO2=14.1 O2=1 NOx=268 Dilution=14.7 #'s for low speed are:185, .67, 14, 1, 418, 14.7
Received a Recall information form saying the PROM had to be replaced. Dated 06-01-1992. Am not getting EGR operation because there is no vacuum from the TVS (or what AutoZone calls an EGR Vacuum Solenoid). I thought the EGR valve was for NOx emissions? If I get the EGR valve working(it is good, just no vacuum)will the hydrocarbons go down? Engine is stock with K&N air filter and Flowmaster exhaust. Vacuum hoses are good and plugs and wires are new. TPS voltage is .47 at idle and 4.67 at WOT. Do I need a new chip (would Mini Mag 3 work?) or is this the EGR valve? Friend just passed emissions with a Mini Mag 3, but has other mods. Thanks in advance-when figured out I will post results. Drew

 

[gofstbuick]

Originally posted by drew666
Failed hydrocarbon part of emissions test. HighSpeed: HC=152 CO=.62 CO2=14.1 O2=1 NOx=268 Dilution=14.7 #'s for low speed are:185, .67, 14, 1, 418, 14.7
Received a Recall information form saying the PROM had to be replaced. Dated 06-01-1992. Am not getting EGR operation because there is no vacuum from the TVS (or what AutoZone calls an EGR Vacuum Solenoid). I thought the EGR valve was for NOx emissions? If I get the EGR valve working(it is good, just no vacuum)will the hydrocarbons go down? Engine is stock with K&N air filter and Flowmaster exhaust. Vacuum hoses are good and plugs and wires are new. TPS voltage is .47 at idle and 4.67 at WOT. Do I need a new chip (would Mini Mag 3 work?) or is this the EGR valve? Friend just passed emissions with a Mini Mag 3, but has other mods. Thanks in advance-when figured out I will post results. Drew

Lets address the EGR issue first. There should be manifold vacuum on one port of the EGR solenoid. When the coolant reaches the correct temp, the fuel management is in closed loop, the computer senses speed (vss signal), trans is not in park or neutral, TPS is not at idle or WOT, then there will be vacuum on the other port of the EGR solenoid (leading up to the EGR valve). If you mannually lift the EGR pintle at idle, the engine should stumble or die. Another method to check if you have vacuum to the EGR solenoid and test the EGR passages simutaneously is to remove the round cover from the EGR solenoid, remove the round filter and put your finger over the hole (with the engine running at idle) and the engine should stumble or die.
Now the other issues, 1% of O2 is a little high, the catalyst should be burning almost all the emission byproducts up, so O2 content should be near 0-0.3% for an new cat. How old is your O2 sensor and how old is your cat? I assume the plugs, air filter, compression, spark plug wires etc.,, are in good shape.
You're close to passing, just check the basics. Nothing against knowledgeable parts guys, but I wouldn't let a parts junkie try to diagnose my car without a scantool or checking the basics. Would you let an Autozone counter person try to diagnose your transmission if it began to slip? Then why would you let that same person try to diagnose your emissions problems on a computer controlled vehicle without any diagnostic equipment?

 

[drew666]

gofstbuick: Thanks for your response on my problem. Am going to go step by step on your recommendation and then go from there.
I know about the parts people. Just trying to get the right parts for the job. Most of the time I have to go to a dealer for parts. With the good people at turbo regal I can now find parts cheaper I hope. With your recommendations, maybe I won't even need parts. Drew