Auto Parts: 88chevy, nox emissions, vacuum diagrams

Question
where can i get a diagram for egr vacuum line  the dealer tells me that they cant get them  thanks

Answer
Hi Jason,

Your local auto parts supplier (New parts) should have comprehensive books on wiring and vacuum diagrams. I deal with used parts and have no sources to help you find the diagram you are looking for.

EGR vacuum USUALLY is pretty simple and straight-forward. The run starts with MANIFOLD vacuum, NOT ported, that line will run to a temperature sensor in the coolant usually right on the intake manifold. The sensor is designed to OPEN when the engine reaches a specific temperature and the line on THAT side of the sensor will go to the EGR valve to operate it once the specified temperature is reached. Typically there is one vacuum source TO the sensor and TWO coming off of it, the second one goes to the AIR-pump purge valve to allow the AIR-pump to oxygenate the exhaust before it reaches the cat-converter to reduce NoX emissions. If there ARE two nipples on the sensor for out, they will probably be staggered. The upper one will be for the EGR and the lower one will be for the AIR pump. If the three nipples are all in-line with each other, the BOTTOM should be the inlet, the second one up will be the AIR and the top one will go to the EGR valve.

I don't have one of these things in front of me right now, so I may not be describing what you are seeing. I'm assuming you are talking about an '88 Chevy TRUCK equipped with a SBC. Cars used a VERY wide range of different vacuum routing because of the vast amount of different drivetrain configurations.

Thanks for the question, I hope this information is helpful to you.
Fred
www.knucklebusters.us
570-453-0910