1982 Datsun 720 z22 ATC sensor and AB sensor location

[Ratsuninja]

Hello,I was wondering if someone can show me a picture where the ATC (automatic temperature control) sensor and the AB (anti backfire) valve located on a 1982 Datsun 720 pickup 2.2 liter with mechanical fuel pump? In addition, does anyone have a AB sensor that I may buy off you? I am willing to cover all costs. Thank you for the support.

[datzenmike]

The ATC sensor in riveted to the bottom inside of the air filter housing, literally inside the round filter so it can sense the air temperature and adjust the vacuum to the servo motor inside the snorkel which mixes warm and cold air.

 

The Anti Backfire valve on the California model is located on top of the intake manifold directly in front of the carburetor. The AB has no sensor for it.

[Ratsuninja]

Thank you so much for your help Datzenmike. So is the vaccuum line connected directly to the ATC or to the bottom of the air cleaner so it can activate the ATC? Sorry about all these questions. I am piecing this truck together to make it pass smog. Is the junkyard the only place I can get a AB valve for this truck?

[datzenmike]

The servo motor inside the air filter snorkel is normally held open by a spring to allow in cold air from in front of the radiator. Intake vacuum from a running engine, passing through the sensor pulls it closed so that only warmed air from the hot exhaust is drawn into the carburetor. When the entering air reaches 100F the sensor begins to close off the vacuum and the servo begins to close from spring pressure and cooler outside air is mixed keeping the intake air closely regulates at or near 100F. If maximum power is needed the floored accelerator results in very low intake vacuum and the servo closes off the warmed air and only allows cool air from in front of the radiator in.

 

An engine will run more predictably if the inlet air is at a constant temperature. During warm up the warmed air will vaporize the fuel more efficiently and frost causing carburetor icing is eliminated.

[Ratsuninja]

Can another AB sensor from another car be retrofitted?

[datzenmike]

They aren't a 'sensor' they are a valve that opens when the intake vacuum goes over a set limit such as deceleration at high RPMs. The valve opens and lets filtered air into the intake to lower the vacuum and then closes to keep it regulated at or above that point.

 

I'm sure they can. Most if not all '70s L20B had them and the 1980 720. Note that in some descriptions it may be referred to as 'secondary air control'. On the L20B it was behind the carburetor.

[Ratsuninja]

Does the AB valve have its own mount that attaches to the intake manifold or the AB valve itself is attached to the intake manifold? Thank you so much Datzenmike. You are truly a blessing.

[datzenmike]

 

On the L20B engines there is a clip that holds it in place. I haven't seen many Z22 engines I imagine it's similar. There is a large hose to the air filter. A slightly smaller diameter hose to the intake and a much smaller hose to the intake for the vacuum signal.

 

Do you have a Z22 but the AB is missing? Emissions deleted?

 

 

[Ratsuninja]

Yes that's exactly what's going on. I'm piecing the whole truck together to make it pass smog and put it under my name. It's missing the AB valve and that's the last piece to my puzzle. It was missing the high altitude compensator but I got lucky by finding a truck in the junkyard and it had it. Now I'm looking for a AB valve and I'm set.

[datzenmike]

When you find one get the hoses that go with it. Good luck

[720trail4x4]

Not sure if you're still looking for emissions stuff but I e got everything that came off a 1982 z22 motor. Not sure if it's what you need but I'm willing to help.