1985 Nissan 720 MT Federal emissions?

[stingraylx1]

Can a NOS Hitachi DFP 384 carb install without issues or limitations on a 1985 Federal emissions.truck?

 

How to identify Federal emissions versus California emissions, truck is in a different state. Can I identify using the VIN?
 

 

[datzenmike]

California carbs are 6 pin connector ECC Electronic Controlled Carburetors and will have an O² sensor in the exhaust manifold. Federal emissions carburetors only has a 2 pin connector for the idle cut and the choke heater.

[stingraylx1]

Thanks Mike, any limitations if installed on a Federal emissions vehicle.

 

I have the VIN, did Nissan identify emissions  on the VIN number?

 

[datzenmike]

The DFP 384 IS a California ECC carburetor and will have the 6 pin round connector to the engine harness. It has a solenoid that is operated by a separate ECU under the driver's? seat to regulate the primary jet very close to stoichiometric mixture using feed back from an O² sensor. A federal emissions tuck won't have the wiring, the ECU nor the O² sensor. 

 

Federal emissions trucks use a DCR 384 carburetor than only has a two wire plug. If you use a California ECC carburetor on a federal emissions application because you can't wire it up it will revert to a fail safe 'limp home' mode that is extremely rich to preclude any chance of a super lean condition that might harm the engine. You could use a federal on a California emissions engine but not the other way round.

 

 

 

 

VIN or Chassis numbers don't specify federal or California emissions but the MODEL just below, does....

 

KNLY 720 TNF

 

K......... King Cab 

N........ Z24 engine. F....Z20. J.... SD25

(G)...... Long wheel base

L......... Left Hand Drive

Y......... 4X4

 

720

 

( )...... If blank DX model. S... Standard model, J.... GL model. W.... Dual wheel.

T........ Manual Transmission. K.... Automatic

N........ Canada model. U.... non California. V.... California model

F........ Five speed.

[Thomas Perkins]

Wow Mike,you taught me something today.I live in Georgia,bought my 720 here in 93,and changed the carb. to a Weber which has the 6 pin and now use two wires,one to the idle cut off solenoid and other to the blue wire from the choke and have the co2 sensor.So mine is a Cali truck.Does that mean since I have converted to a Weber and got rid of the cat,do I need or use the co2 that is in the exhaust manifold.As we speak,I am having a new exhaust manifold and a egr installed,The exhaust manifold has a 4 inch crack in it,I put a Nissan one in it back in 95 cause it was cracked.Let me know about the co2 sensor.The cat got clogged 5 years ago and caused the head gasket to blow between cylinder 3 and 4 and Jack said to get rid of it,when I bought truck,it didn't have one,dummy me had one put one on it,what a costly mistake.

Edited November 2, 2021 by Thomas Perkins

[datzenmike]

O² sensor has no possible use now that you have converted to a Weber.

 

Clogged catalytic converter is unlikely to have caused the blown head gasket. That is a very common problem with the Z24 engine and happens roughly every 100k. The preventative measure is to simply re-torque the head bolts once a year. On a cold engine, loosen ONE bolt and torque to 60 ft lbs. Once tight, go to the next bolt and do the same. You can do in any order you like but only ONE bolt at a time is to be loosened and then tightened. This keeps the head evenly clamped to the block as the head gasket ages.

[Thomas Perkins]

When the cat was clogged Mike,it caused the exhaust to back up into engine and blow the head gasket.You should of seen the cat,the inside came apart and was not letting exhaust go thru.That was the problem.The only way to know if the cat is blocking the flow is to take the cat off and look at it.

[datzenmike]

With enough blockage the engine simply would lose power and not run. 

[Thomas Perkins]

It caused mine to blow....And it ran,it blew between cylinder 3 and 4 and make them plugs bad.Cause if blockage Happens,and it backs up,the head gaskets will give.The head gaskets blew,the head was sent out to a machine shop and checked for cracks and milled,Valves were done. Then it was reinstalled and it was still making that noise.Jack took the Cat off and seen that it came apart on the inside and was blocking the flow,but not completely.He showed it to me and he removed it,then put a straight pipe in,no more cat.Jack is a Jasper engine installer.He put mine in back in 2009,have over 90,000 miles on it.He is a certified ASE mechanic.He also gutted my Heating and Air out and now I have a custom made one.He is the best...

Edited November 6, 2021 by Thomas Perkins