The $0.99 mod that works!!!!!

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

Hmmmm, something doesnt sound right to me because I dont think that these cars run right without the IAT plugged in so you gotta have one on there somewhere. I unplugged mine one day while the car was running and the thing died. But like I said I dont know about when you put an aftermarket intake on these things so maybe one of these other guys can help.

Website · Post by **s13sr20chris** » Tue Jun 01, 2004 3:42 am

are you sure thats an iat sensor? does it say jecs on it?

Post by **Toms240420** » Tue Jun 01, 2004 3:42 am

anyone have a pic of the damn IAT sensor, i cannot find mine either, plus i was told that maybe my car doesnt have one. i only see the MAF and those wires

Post by **Toms240420** » Tue Jun 01, 2004 3:42 am

i just read a thread that said that after 91 they did away with the iat sensor. is that true?

Website · Post by **s13sr20chris** » Tue Jun 01, 2004 3:42 am

i think the iat is incorporated into the maf on the sohc 240sx. they may be messing with the a/t dropping resistor.

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

are you talking about a sohc or a dohc 240 chris??? because mine is a sohc and it has the IAT located on the side of the airbox but I have no idea where it would be on a dohc model or if it is incorporated into the MAF like you are talking about

Post by **niznos** » Tue Jun 01, 2004 3:42 am

The SOHC's do have the IAT. I had to transplante it to my K&N FIPK, so I am sure of that. I just looked at my FSM for DOHC's and they don't mention the IAT at all.

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

well then they probably incorporated the IAT into the MAF on the dohc's, I know a lot of car manufacturers did that if that is the case then this mod only applies to sohc 240's but I am sure it will work on a lot more nissans with an IAT because from what I have read they pretty much all have the same resistance values for the IAT's

Post by **Dattebayo** » Tue Jun 01, 2004 3:42 am

I dont mean to inject any hatred in here, but there are plenty of threads that have touched on this subject in the past.I think you should use the search button to se what others have to say about this particular modification and the wiring involved.

Also, i can tell you that what you are doing to your engine can (in the semi long-term) really destroy your engine more than a ecu upgrade OR bigger injectors.

You must remember that this sensor's signal, read along with other inputs to the ecu, decides the whole environment inside your engine. You are not just gunking up the exhaust, but if your EGR is still connected, fuel vapors leak into the intake manifold and cause the internal workings to be attacked by a fine spray of gasoline. If its on a switch, i would say fine but running all the time this way is not very smart at all.

I suggest if you like to drive like this, move to a cooler climate.

Edit: By the way, popping in your exhaust is not a good thing at all...

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

Well, like I have said in the past, all that this sensor does is alter fuel and timing......the same thing that bigger injectors and/or ecu upgrades do so unless it is running overly rich then no it is not going to have any adverse affects v.s. any other mod that does the same and p.s. a nissan tech posted a good point about the ecm being in open loop at WOT so this mod will not effect WOT operation. Also, the exhaust is NOT stock and has a reason to pop e.g. glass packed muffler and no cat so the popping is normal, and if you do your research a popping in the exhaust can be caused by differences in ignition timing. I have tried to stress that this is not a replacement for a remapped ecu or any other REAL mod, it is just a way to squeeze a little more power out of a car cheaply for those like myself who cannot afford expensive parts presently. So, like I had mentioned in my original post about IAT specs, I am not an amateur who hasnt done my homework, I know all the aspects of this mod very clearly and have tried to explain that several times and also have tried to explain that this should only be done by somebody who knows what they are doing. Plainly, I know this is no substitute for doing things the correct way, but little things like this are what win races at the local track..........

Post by **SilviaS14KA24DE** » Tue Jun 01, 2004 3:42 am

the IAT is no longer available in 95< cars. They still have them 94>

Post by **Dattebayo** » Tue Jun 01, 2004 3:42 am

You're talking smack about this real useless mod and saying "things like this are what win races at the local track". This is how you lose at the local track.Yes, one of these resistors will make it sound a little louder, but you will not gain any power at all.

A proper air-fuel mix tuned to the outside temperature is what gives you the most power, tried and true. You get more power from cold air when applyed with an intake system and an exhaust, not by fooling the computer into pumping in more fuel .I didnt go through 3 years at automotive school for nothing, kid.You may go on believing that this is gonna win your next meet at the "local track", but dont come crying to me because you clogged the crap out of your engine and lost to a honda whose owner has more sense than you. Your 240 is rare and you should show it some respect.

Post by **p00t** » Tue Jun 01, 2004 3:42 am

2BN_S13 wrote:You're talking smack about this real useless mod and saying "things like this are what win races at the local track". This is how you lose at the local track.Yes, one of these resistors will make it sound a little louder, but you will not gain any power at all.

A proper air-fuel mix tuned to the outside temperature is what gives you the most power, tried and true. You get more power from cold air when applyed with an intake system and an exhaust, not by fooling the computer into pumping in more fuel .I didnt go through 3 years at automotive school for nothing, kid.You may go on believing that this is gonna win your next meet at the "local track", but dont come crying to me because you clogged the crap out of your engine and lost to a honda whose owner has more sense than you. Your 240 is rare and you should show it some respect.

bit harsh...

but true.

On the whole IAT sensor deal from what ive seen... 89.5 - 91 had this unit. 92-94 did not (i have a 93, and I have the harness +connector for it, but nothing is plugged in). 95/96-98 had this unit but it is or use in diagnostics only... as i believe one can be plugged into the 92-94's harness for diagnostic as well but didnt come with the car.

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

2BNS13, you can think whatever you want, however I should tell you that I have all of the same qualifications. I am an ASE and GM certified technician with 8 years experience on the job and I reside at a local Cadillac dealer as an Electronics technician, and I can show you all of the papers you wanna see my friend to prove it. YOU are the only one talking smack here because I have only been friendly to EVERYONE in this post reguardless of their response. I have told EVERYONE here that they can believe what they wish about this. AND for your info it IS things like this that win races at the local track, just ask any Buick GN owner about jumping 2 wires together on the ALDL to get the torque converter to lock up in 2nd, 3rd, and 4th gear to shave a couple tenths off of their 1/4 mile times. So dont tell me about backyard engineering because how do you think all of these motorsports came to be in the first place??? It was by people toying with anyhting possible to get a couple more ponies from their ride !

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

and P.S., if the factory fuel mapping is so "correct" then how do you think that a re-mapped ecm will help it make more power?????

Post by **Dattebayo** » Tue Jun 01, 2004 3:42 am

i never said the factory fuel mapping was correct for racing. However, it does do its job for around town. The KA in the 240SX was never meant to be a race engine. You can improve on the factory design with a re-mapped fuel curve for higher RPM and hard throttle, but the fuel curve for everything else basicly remains the same. And it is better (and more reliable) to have a re-map than to put a chincy resistor inline with a sensor.

I wouldnt want you working on my car if you run around telling people its OK to do this, with or without your papers and certs. Who around here wants to trade a .99 cent mod for a pain in the a$$ clean up later on?

Another thing, im sorry to have pissed you off.

I just can not believe that you would honestly tell people to do this without warning them of the consequences.

Post by **SilviaS14KA24DE** » Tue Jun 01, 2004 3:42 am

damn 2bn you start fights in almost every thread. at least be suttle or more nice about it.

Website · Post by **s13sr20chris** » Tue Jun 01, 2004 3:42 am

man i have got to remember to whip out the service manual when i go to work. i know for a fact that all obdII nissans use the iat only for diag of the ect sensor. maybe the older nissans actually used the darn thing for fuel mapping, but i will need to see that in the fsm. i dont however agree that it will win races. with all due respect races are usually run at wot. that would preclude any benifit derived from open loop fuel dump. as long as we are mentioning "papers"...i am an ase certified master tech and a nissan certified engine specialist. i also think a little refinement is lost by sacrificing the dynamic nature of iat to the set value of a resistor.i dont want to argue about it though.

Website · Post by **s13sr20chris** » Tue Jun 01, 2004 3:42 am

pmkls2 wrote: First the IAT DOES affect fuel and timing on ALL autos reguardless of make and model.

i think you should retract that statement. it may affect a/f on the older obd I nissans, but the newer ones use it only for diag. it has absolutely no effect on fuel or ign on an obdII compliant vehicle. it is in fact absent from some.

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

well, 2bn ,I didnt actually warn about any consequences but I did say in my first thread that you shouldnt do this if you do not know what you are doing e.g. experienced mechanic. And most of the people I have met on this forum are competent enough to know if something is wrong. And I actually know quite a few who are "chincy". Like I said before this isnt a substitue for the real deal, rather it is an "option" for those with small budgets. so far I have been keeping a real close eye on fuel economy and looking for an overly rich condition and have seen no "noticeable" differences as of yet. And if you really do some searching you will find some people who have used performance chips in their cars and have had such a rich running car that it would black up the rear bumper. My original thread covered some of the aspects of running overly rich and that if you find the correct resistance value it will richen the fuel without giving it too much. The disbelief doesnt bother me at all because I could care less what anybody thinks but I dont take kindly to insults because I treat everyone in this forum with respect even if I disagree with them. And chris you are correct I need to retract my statement about the IAT. I was actually referring to obd1 vehicles but failed to mention that little fact. I am however quite sure my statement does apply to pretty much all obd1 vehicles that are in fact equipped with an IAT sensor separate from the MAF. I dont know about newer obd2 nissans but most GM cars I see do not have an IAT at all, it is incorporated into the MAF. And by the way I had a little chat with nistech in another thread and he backed up your statement about nissan saying that the IAT was for diagnostics, but he did however point out that the engineers have been wrong in the past ( as I have witnessed with GM engineers MANY times as well ) and that it is quite possible that my mod may actually work. And I will again mention the fact that I have only tried one resistor here and had said that I was going to test a few different setups out to find the best configuration so that it works best at all temperatures and doesnt adversely effect the vehicle.

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

oh, by the way if anybody would like I am willing to let anybody drive my car just to let someone see for themselves the difference it actually makes. because we can discuss this all day long but nothing can argue with real-world conditions. It has been proven many times in the past that what looks good on the drawing board doesnt always work in the real world (and vice versa) and that you can look at a fsm all day long and sometimes it doesnt mean $h!t. Anybody who has enough wrench time in can agree with that fact

Website · Post by **s13sr20chris** » Tue Jun 01, 2004 3:42 am

certainly cant be too terrible. some aftermarket chips and "ecm retunes" are just adjustments to the iat and thats it. pretty sorry if you ask me(in the case of paying big bucks for that). anyway, im glad we arent all irate then, eh?

Post by **proimport17** » Tue Jun 01, 2004 3:42 am

This thread seems like much ado about nothing. I have worked on nissans for over 20 years and what we used to do on the 280's was to go to radio shack and purchase a potentiometer of the correct ohm rating and wire it in line with the coolant temp sensor so that you could adjust the amount of resistence and fool the ecu into thinking it needed to supply more fuel, but as was soon realized this mod is neither efficient or very helpful and if used improperly can lead to engine damage. Just my 2 cents

Post by **gyfer** » Tue Jun 01, 2004 3:42 am

Not to be a a$$ here. Being a ASE, GM certified technician, and 8 years experiece doesn't mean you know how KA ECU programming algorithm work...

I am very skeptic about this. If this really work, why no performance company like Apexi, HKS or Greddy design a device for this purpose? Imagine a $29 device with 15-20hp boost ... it will be a BIG hit !!

To be "politically" correct, there're 10 input signals that will alter the injectors output. Which are:1. Crank angle sensor2. Air Flow meter3. Engine temerature sensor4. Exhaust gas sensor5. Throttle sensor6. Idle Switch7. Neutral switch (Gear Position)8. Vehicle Speed sensor9 Ignition switch10. Battery.

From here, you can clearly see that there's no way a 4.7k ohms transistor can alter your fuel map. Neither it does anything to "performance"

And quite frankly, if you are an electrical technician, you should able to get the actual resistance reading from IAT sensor by bringing the room temperature to 40F and measure yourself... you do not need to wait someone to tell you that.Wonder who gave you and certified you as an elec tech....

Post by **Twiztid_S13** » Tue Jun 01, 2004 3:42 am

well this was interesting .. heh

Post by **SilviaS14KA24DE** » Tue Jun 01, 2004 3:42 am

pmkls2 wrote:oh, by the way if anybody would like I am willing to let anybody drive my car just to let someone see for themselves the difference it actually makes. because we can discuss this all day long but nothing can argue with real-world conditions. It has been proven many times in the past that what looks good on the drawing board doesnt always work in the real world (and vice versa) and that you can look at a fsm all day long and sometimes it doesnt mean $h!t. Anybody who has enough wrench time in can agree with that fact

i want to test drive it! Bring it to so cali

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

Well, gyfer obviously you are not listening very well. First of all the IAT does affect fuel map and timing because as temperature changes so does air density so small adjustments in both help engine performance because obviously fuel doesnt ignite as easily in 40 degree air as it does in 90 degree air, and if I just dreamed it up then what purpose does it serve? If you would like you can come a nd drive the car yourself, I'll even warm it up for ya and get the A/C blowing cold.And the whole big deal here with the aftermarket companies not having this available is they acutally do by way of remapping the ecm because like I have said repeatedly now it is not a replacement for a remap but rather a low cost alternative. And if you do your checking with JET technologies they sell a plug in module that serves basically the same purpose and costs $200 as an alternative to sending your ecm in for a remap for $300. And I actually wasnt asking for specs at 40 degrees rather I asked for the specified range that the IAT is supposed to function within as I wanted to have a minimum and maximum working range you smarta$$. I really dont know why some people are so closed minded and so touchy about this subject because I have yet to say to somebody in here that I am either smarter, better, faster, or doing something more "correct" than them. And I have up until this point refrained from name-calling as well, but quite frankly I am getting sick of the verbal abuse here. If you dont believe me then fine but dont insult my intelligence, come meet me and I'll gladly show you indesputable proof..........

Post by **gyfer** » Tue Jun 01, 2004 3:42 am

If you are smart, congratulation.

But our ECU (KD24E, OEM programming) don't make any injection adjustment because of IATS. period.

Remap the ECU, which probably reprogram the coding, and make use of the IAT is different. That's why JET have the plug in module because the programming has change.

Guess you are not so smart afterall.... too bad

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

Ok, I am tired of arguing this point so I will just say this..... Unplug the IAT and drive the car around the block to see how it runs........ if you can keep it running. If you unplug the IAT the engine wont even idle so if it has no effect on engine performance then how do you explain that one einstein ????

Post by **pmkls2** » Tue Jun 01, 2004 3:42 am

and the plug in module cannot alter the internal workings of the factory ecu, all it does is alter the signal going to the ecu e.g IAT......

The $0.99 mod that works!!!!!

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