operation air intake complete

[heirfaus]

Somebody woke up on the wrong side of the bed!

 

If it's like early Nissan EFI, there's most likely an IAT in either the AFM, or it has a MAF sensor that could calculate air density since it measures temperature drop between heated wires.

 

It's also very likely that the other airtemp sensor is purely for emissions which is why it's by itself because it was probably not necessary to meet the same emissions everywhere in the world.

 

My bad. I didn't mean to sound like an asshole. And it was like 1:30 in the morning. 1000 apologies for my previous curt response:o

 

I wasn't refering to you Luke. I just get so frusterated by the Datsun guys who just take stuff off and don't know why they do it.

 

I'm not a KA guy I was just putting up the info for general knowledge so people would know what the dillio is.

 

Mafoose is probably correct. If there is a MAF, then there is usually an air temp sensor in it if there isn't one elsewhere. BUT in any case there is still an air temp sensor in the MAF(and it is important). AND you still need it. I remember two of years ago I had two cars come in to the dealership in the same month that had failed air temp sensors in the MAF and they ran like shit. Kinda rare occurrence, especially two in one month, BUT it's info you need to be sure about when modifying cars. If your drivability sucks you need to be able to find out why.

 

The obd 1 ka24e relies on the coolant temp sensor, the maf sensor, tps sensor, and the cas sensor in the distributor to meter fuel and timing. You guys are making such a big deal on a sensor the single cam obd1 ecu does not need. As far as I know the early 89 ka had no iat sensor, high compression pistons, diffrent injectors, and better fuel and timing maps.the late 89 to 90 had to better meet the emission laws of the time. The main thing jebus has to worry about is, getting a new coolant sensor , new o2 sensor, properly adjusting the tps, correctly set the timing, and give the maf a bath.

 

This is almost the whole story. The change wasn't for emissions it was for drivabiliy. If there is an air temp senor in the MAF it needs to be working. If there is an external one it needs to be in place.

 

From when I went to college to be an Auto Tech:

Advanced Engine Performance Diagnosis

Chapter 8: Advanced Computer Sensor Diagnosis

 

"The Air temp sensor is a low authority sensor and is used by the computer to modify the amount of fuel and ignition timing as determined by the engine coolant temperature sensor....the ECT may be near normal operating temperature, such as 200F (93C), yet the air temperature could be -20F (-30C). In this case the engine requires a richer mixture due to the cold air than the ECT would seem to indicate."

 

 

 

 

Factory TSB

Technical Information

Compression Ratio Change for 1989-90 S13's

 

According to Nissan Technical Bulletin TS89-072:

 

KA24E ENGINE CHANGE

 

APPLIED MODEL: 1989 240SX (S13) from engine number KA24-012039*

 

SERVICE INFORMATION

 

To improve driveability the KA24E engine on the applied model has been changed as follows:

 

Compression ratio has been changed (9.1 to 8.6).

Air temperature sensor has been added.

E.C.U. has been changed.

Idle speed.

Self-diagnosis for E.G.R. "

 

Apparently Nissan thinks the air temp sensor is important for driviability:)

Edited February 15, 2009 by heirfaus

[philcas1987]

Thanks for that info fox. I have read that before but wasn't jebus wanting ro run bare minimun?

[heirfaus]

Hey Luke,

 

Sorry I got so caught up in the technical crap I forgot to say congrats on a nice looking intake pipe!! That thing is cool:cool: I would recommend acquiring or making a heat shield. If I remember correctly every 10 degree drop in air charge temperature is equal to 1 hp. So the 60 degree air outside is better than the 150 degree air next to your manifold.

 

 

Thanks for that info fox. I have read that before but wasn't jebus wanting ro run bare minimun?

 

Naw, the first post asks about install. Hey it's Phil in south east!!:) You finally got online huh? I didn't even realize it was you:D

 

 

I kinda figured it needed to be their. Nissan didn't put it their just for looks. I didn't know the whole story behind it like chris mentioned, I just know the ecu has to have some kinda of knowledge of in coming air temp. The exhaust gets hot way before say a gallon or gallon 1/2 of water gets hot. Could explain why I have read people complaing of terrible gas milage and poor running?? Even with the air temp sensor hooked up does not mean it is doing its job and working corectley anyone know how to test that sensor?

 

Most coolant temp and air temp sensors are "negative coefficient thermistors" fancy words that simply means as the temp goes up the resistance of the sensor goes down.

 

Looking at your temp sensor, I'm not sure whether yours is like that or whether it is a hot wire like the MAF. But I'm almost positive it is the NCT type. Which means it's readings will look similar to this:

 

32F (0C)-- about 6000 ohms within a range of +/- 10%

68F(20C) -- about 2300 ohms "

104F(40C) -- about 1300 ohms "

140F(60C) -- about 600 ohms "

176F(80C) -- about 300 ohms "

212F -- about 190 ohms "

 

Your readings will look somewhat like this but will obviously have different #'s, these are from a coolant sensor from some other car. I just posted them to give you an idea what your looking at. Your best bet is to invest in a Chilton manual. It should have the specs in it and test is SIMPLE once you know the specs.

[jesusno2]

I got a manual but I don't recall seeing info on how to check it, but I'll look again I haven't messed with it much been workin on my other goon!