280z vacuum delay (part#)

[SteveJ]

I would think that with the improper function of the vacuum delay valve, you may not get the full effect of the EGR.

The EGR helps to control NOx emissions by injecting some exhaust gasses into the intake to reduce the cylinder temperatures. 

In addition to the visual inspection, there is tailpipe monitoring. The test will look at hydrocarbon (HC), carbon monoxide (CO), and NOx.

Typically HC is from the timing not being right or improper valve lash. You might want to read up on setting the valve lash to make sure it is correct. Heck, the correct valve lash will also give better performance.

CO is from being rich.

NOx tends to come from being lean or hot.

Read through the EC section of the FSM and test/repair what you can. Make sure you have fresh oil and a full tank of gas when you test. Check your vacuum lines, especially for the carbon cannister.

And as I said before, if you're in doubt, get a pre-test. If it doesn't pass, post the results if you need some guidance on repairs.

As for the 76 year of manufacture, check the build date on the plate in the door jamb. If it's missing or illegible, check your VIN against the VIN range for 77. It could be that it was an 8/76 or 9/76 build. There are 3 years (sometimes 4) associated with a car: model year (sometimes the title may have a different year if a car was sold after its current model year), safety year, and emissions year. You would have to do some research to find out if the model year and emissions year differed in that timeframe.

[SteveJ]

Interesting reading on the subject: https://ratsun.net/topic/67533-vacuum-problem/

 

[Av8ferg]

I have one of these. My car was a CA car and when I did an engine rebuild I removed it. I never throw old parts away so I have one.
I’m never moving back to CA. I never say never but this “never” I’m sure of.
I can test with my vac pump. Where are you in CA?

[MH77280Z]

2 hours ago, Av8ferg said:

I have one of these. My car was a CA car and when I did an engine rebuild I removed it. I never throw old parts away so I have one.
I’m never moving back to CA. I never say never but this “never” I’m sure of.
I can test with my vac pump. Where are you in CA?

Near San Francisco

[Av8ferg]

I grew up up 20 miles south of SF in a city called Belmont. Went to HS in San Mateo.
I was asking because I’m flying into Sacrament next week for work and if you were near there I could hand the part off to you.

[MH77280Z]

1 hour ago, Av8ferg said:

I grew up up 20 miles south of SF in a city called Belmont. Went to HS in San Mateo.
I was asking because I’m flying into Sacrament next week for work and if you were near there I could hand the part off to you.

pm'd you. I appreciate your offer.