Could you guys tell me what this sensor is? I found it unplugged before and plugged it in but not sure if it is plugged in upside down. Plugged in or not the car still runs shitty the same.

 

Air temp sensor. The plug can go either way.

 

Would it have any effect not being plugged in ie. making the card hard to cold start?

 

I don't think it would have an effect. The training manual makes it sound like the intake air temp sensor is used to detect hot start conditions. And I know the ECU uses coolant temp data to adjust startup fuel.

 

It won't affect starting at all. The clip broke on mine and I haven't ran one for like 10,000 miles. Only used for gas mileage I believe.

 

It will affect your AFR under load. I wouldn't leave it broken if it's a turbo car.

 

plug it in and reset ur ecu by disconnecting the neg bat cable for a while...

 

Thats interesting. How did you confirm this?

 

^ After looking through the factory training manual again, I have concluded that it is only the air temperature sensor in the AFM that affects load calculations. The sensor in the manifold/TB elbow is used mostly for idle control (BAC valve, fuel pressure regulator solenoid). It is on the 3rd gen cars (speed density therefore no AFM) where the IAT plays a huge role.

So I stand corrected and withdraw my objection.

 

Mine throws the check engine light without it. The clip broke but I just hooked up a couple spade connectors to it instead and it works fine.

 

I noticed this same thing in the training manual. The AFM temp sensor seems to be the one that matters. The IAT sensor looks to be of limited use, so it's not surprising that it can be unplugged with no noticeable affect.

 

thanks guys. This thing is still having cold start issues. I am going to light it on fire.

 

would a CAS going bad cause my issues?

 

What was your original problem again? Just cold starting problems? Does it ever run, so you can shut it down & see how it hot starts? I know you had some threads asking about the AFMs and other sensors; are those all related?

If you haven't done it already, pull codes and go through the FSM tests at the ECU. Check that the voltage matches on all the pins. You can check the CAS signal while you're there.

 

This thread: https://www.rx7club.com/showthread.p...&highlight=AIT

AND post #8 by HENRIK

 

ok. But since that sensor isnt really all the important would it be retarding my timing? Even after I have plugged it back in?

And yes Rocket this is all related to my cold start issue. Runs great once I get it started and immediately after I get it started. I can shut it off and turn it right back on again. It is that first start.

 

Has zip to do with your starting. I just saw this thread and some remarks and remembered something written by HENRIK and threw it in. You can trust anything HENRIK or TURBO2LTR say on the ECU side of things.

 

I've attached a page out of the training manual. It calls both of the temp sensors "Intake Air Temp (IAT) Sensor", and shows the one in the AFM to be the input used for fuel injection corrections. It's possible Henrik was refering to this sensor input, and not the one on the manifold / compression tube. They both have the same name according to Mazda, so it would be easy to mix up. Anyway, it's not really relevant, but still something to know.

Dltreezan, do you still have thermowax & the BAC, or did you remove those?

 

I still have those and think that maybe that is related somehow.

 

Its very unlikely that you have a bad CAS, stuff like that just doesn't go bad in these cars usually. To make sure you can check the resistance values on it, more info in the FSM.

Thats good to hear you kind had me scared for a sec.

 

Well, the thread https://www.rx7club.com/showthread.p...&highlight=AIT talks about the intake manifold and how this guy used a ?? third gen sensor and wanted to know if this was Kosher or not.

And he talks about plugging it in which means it can't be the afm air intake sensor. And HENRIK knows which sensor because he says you can't connect it wrong.

Either HENRIK or Trubo2LTR also mention this sensor in another thread out there in regards to retardation of timing. I'm pretty sure of that. About 80% sure.

EDIT: Post #19 here: https://www.rx7club.com/showthread.p...ghlight=timing

 

so hailers what you are telling me is that if that sensor is screwed up it will retard my timing?

 

Yeah, that 2nd post is much more clear. He definitely meant the IAT sensor in the compression tube. It looks like it may have just been left out of the training manual diagram. I'll unplug it and compare the timing w/ & w/out once I get my Rtek 2.1 next week. You're making me wonder about its function now.

 

If it was screwed up to show a real, real high temp, then it would retard the timing. What that figure is, is a unknown to me. Leaving it disconnected would make it default to a certain figure, but I doubt that figure would retard the timing. Well I do know that figure. It defaults to 68*F, hardly a retard figure.

But if the sensor was mangled up real bad and put out a resistance that was something like 300*F, then it would retard the timing....I reckon. Guessing.

So here's what you do. YOU go buy a variable resistor and connect it to the wiring for the sensor. Then go for a ride with something like a RTEK2.1 and drive along and turn the pot to output a higher temp/resistace and watch the timing on your Palm. Let us know what happens.

 

even if my timing was retarted, wouldnt cranking it over and over cause me to get flooded? Which is not the case. So that would point to not enough fuel on start up. I am wondering if I should straight wire my fuel pump.