Nissan Forum banner

1 - 6 of 6 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I Have a 1987 Sentra SE 4dr with E16S carbed engine (and death to the engineers of the mess). I VERY carefully fixed all the vacuum lines and leaks that were obvious. It runs well now but failed emissions here in Colorado (5000 ft altitude) and is running a bit rich.

I have been working with the 87 factory manual to run though the tests and adjustments. Currently, I discovered that both T.V.V. (thermal vacuum valve) appear bad.... but there's a little confusion. I'll describe where I am here:

Both TVV's appear identical and are original to the car. They have 2 vacuum ports and screw into the water passage of the intake manifold on the driver's side of the carb. They are grey/white in color and both have K6J08 stamped on. There's also a "VT 1 3" on one and "VT 0 4" on the other (the numbers are near microscopic and each are in an individual round recess). I removed these TVV for cleaning and inspection and found they just open and close the vacuum access due to water temp. No direct connection to the intake at all. That comes from 2 other manifold lines that connect to the TVV.

1st TVV on pages "EF & EC-159" and "EF & EC-162" works with the idle controls and failsafe system. The spec says the valve is "off" below 30 C or 86 F. I assume this means the valve should pass no air at 70 F room temp. By sucking and blowing either port, it easily passes air, so it's bad. This accounts for the 3000 RPM cold idle and maybe 1600 RPM warm idle if the vac lines are attached.

2nd TVV is more involved. The vacuum diagram on "EF & EC-132" shows it allows the EGR vacuum and Air Injection vacuum. Obviously, this involves a rich condition if not right. On "EF & EC-181" there's also a TVV allowed connection to the air cleaner that states "TVV lets vacuum leak during cold condition (below 140 F), so that the opening of secondary throttle valve may delay, and thus improve driveability." Now this TVV is working exactly as the 1st with no air stoppage at all at the ports. So, is it supposed to be "off" at room temp like the 1st and open above 86 F to satisfy the 140 F spec??? :confused:

OK, one last wrinkle. The replacements are supposed to be Nissan numbers 14890R and 14890M (this last one now 14890-V0500) in the parts book diagram. They are not to be found as NOS that I can see online (though maybe at dealers). I can find an identical appearing "Ported Vacuum Switch" as Duralast E988 and Standard PVS90. I have no idea if these have right operation for me. :confused:

Now, as emissions only require a warm engine for tests, I could disable a lot of this vacuum spaghetti and just hope to make it work "looking" right. But I'd like to do a proper job if I can. ;)
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
Thank you!! I have just looked into this on your suggestion and Auto Zone has them cheapest for ~15 clams (likely need to wait for them to be delivered though). Duralast E988 is also the right (and only) critter.... still don't know why there's a 14890R and 14890M, though. Hope some one will tell us soon.:nerd:

I have also confirmed that a TVV is indeed equivalent to a Ported Vacuum Switch (PVS), thanks to Rock Auto. Now I can get this show on the road... maybe. ;)

Well, I hope all the past months sleuthing helps more than you and me.0:)
 

·
Registered
Joined
·
357 Posts
Are you still looking for confirmation of these 2 E16S TVVs? I think I have both new ones (OEM) and could try to find them and check their operation out-of-the-boxes.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #5
Thanks for letting me know you have the sensors. I bought the TVV/PVS's mentioned last December. They fit perfectly. There are other fish to fry on this car but they seemed to improve things. Now making sure air and coolant temp sensors work right. Then need to clean the carb and adjust by the book.
 

·
Registered
Joined
·
357 Posts
<... need to clean the carb>

Will you be disassembling all 3 sections of the carb? Carb-cleaner-spraying and then blowing out all the passages? And same for the jets? And replacing the upper and middle gaskets? You're familiar with the mixture heater (base) (electrical grid) that sits below the carb on the I.M.? There is a gasket there also - top and bottom. Maybe 2 on the bottom - very thin ones. Coolant directly underneath them. You're familiar with the richer solenoid (for cold start-up)? And, the AFR solenoid - has o-rings top and bottom (critical)? And there's a small fuel filter at the top pass's rear corner of the carb for fuel inlet? And, then there's the accelerator pump with its spring and link arm/rod. Also, there is the secondary diaphragm (pass's side of carb) for secondary barrel high-speed operation. And, of course the ISCA. There also are ports that would be wise to carb-spray-clean out, IF the above is what you meant by cleaning the carb.

Good luck. Let us know how you make out.
 
1 - 6 of 6 Posts
Top