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I just received and intake sensor modification from e-bay. This is a modification to your Intake Air Temperature sensor that will let your engine breath cooler air and increase the amount of fuel that enters your engine. The increased air/fuel ratio that you recieve will bump up your horsepower significantly over stock cars with a resistor chip. Not only will you feel better acceleration and torque you will feel this through the entire RPM band.

Same Function as ECU Upgrades and Performance Chips Like the Jet V-Chip!

Im tryin to figure out if i should install it or not. Suggestions please.......
 

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Making your air/fuel ratio higher will not in and of itself give you more power (and might give you drivability or emissions problems). If you have an FI Zetec (or highly modified N/A) that runs lean due to the inability of an unmodified stock fuel injection system to supply proper amounts of fuel to such a modified engine, then such a mod, if it worked at all, would help you restore the air/fuel ratio to the proper amount and give you the max power available (and also keep your engine from detonating). Up to a point, more fuel will help keep your engine cool, but that's only compared to an engine that's running lean. Back in the bad old days of carburated emissions controlled engines with things like air pumps, etc(anybody remember them?), the engines were tuned to run very lean and they generally ran like s*** and produced low power. With modern engine management systems you would only gain a benefit from such a mod when your setup pushes fuel demands beyond what your ECU can deliver. That is actually not too hard to do-even the low pressure boost from the JRSC needs a fuel management module to make it work right.
Do you have any mods to the engine that could cause it to run lean? If possible you should find out what kind of A/F ratio you are running and then decide if you need to modify the fuel management system.
 

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What you're risking with this mod is the PCM detecting the IAT sensor as faulty and ignoring it's value all together. At engine start the PCM compares the IAT and CHT or ECT sensors to determine if they are reading within 30 degrees of each other. (this is after a cold soak period) If they are not reading the same value this indicates a possible sensor malfunction.(P0116)

The PCM also does an IAT self test for Low and High input signal. (P0112 and P0113)

In other words, this mod may work for a while, then the PCM will probably work around it.
 

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Aight guys thanx, i just got done tryin to install it. The instructions say its and easy job, but they lie, its almost impossible and im too afraid im gonna brake the stock peice, so im probably just not gonna install it, well there goes a wasted 10 bucks. Haha, i only ordered the piece for kicks to see if it would do nething, but oh well.
 

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I know of a ZX2 that the guy went to radio shack and made a do it yourself chip mod. the directions were put out through his ZX2 forum. all it is is like 3 dollars worth of equipment, and some knobs. it actually works very well on his zx2. you can feel the difference. when you turn the knobs on you're rpms go up right on idle because its spraying more gas on the engine. what do you think about this and could it be done to a focus?
 

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the job i saw had knobs to turn it off or on. he leaves it off while driving around, but in a race turns it on. seems like a nifty idea

Jon
 

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Originally posted by jonszx3:
I know of a ZX2 that the guy went to radio shack and made a do it yourself chip mod. the directions were put out through his ZX2 forum. all it is is like 3 dollars worth of equipment, and some knobs. it actually works very well on his zx2. you can feel the difference. when you turn the knobs on you're rpms go up right on idle because its spraying more gas on the engine. what do you think about this and could it be done to a focus?
<font size="2" face="Verdana, Arial">can i please get a link to this ZX2 mod?? my car runs SOOOO much better when its in cold start mode and the idle is kept higher in cold start mode this would really be a life saver for me!!
 

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well i dont know if it can be done yet on a focus, thats why i was trying to continue this post. to see if anyone knows if it can happen.
 

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Originally posted by jonszx3:
the job i saw had knobs to turn it off or on. he leaves it off while driving around, but in a race turns it on. seems like a nifty idea

Jon
<font size="2" face="Verdana, Arial">Yep, those knobs are pots (variable resistors) used to change the heat readouts...So you can switch between altered and normal readouts whenever you like.

Wheter this can be done to a Focus has been debated some time ago and if I remember correctly, it could not be done for some reason (sorry, I am not very sure about that)
 

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The famous ZX2 mod is for keeping the car in "heat-up" mode, or "cold start" mode if you prefer. With the resistors sensor readouts are altered, the car thinks that the engine is still cold, and keeps up the high fuel profile...

I personally would not do it, as I like the ECU to be in charge of things at all times...
 

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Originally posted by zx3steve14:
can i please get a link to this ZX2 mod?? my car runs SOOOO much better when its in cold start mode and the idle is kept higher in cold start mode this would really be a life saver for me!!
<font size="2" face="Verdana, Arial">http://www.zx2racing.com/mods/mod_pots2.htm

And be sure to read the "Important Notes" on this simpler version:

http://www.zx2racing.com/mods/mods_iatEct.htm

Note: The 'Pots' mod is really only good for drag racing, you should not run them all the time.

Also, the Pin Out for the Focus PCM may not be the same as the ZX2, so if you are going to connect them near the PCM, check a focus wiring diagram. You hook the Pots into the return signal wires for the Intake Air Temperature end Engine Coolant Temperature sensors. Not on the Common Controlled Voltage source. If you hook the Pots into the wires out by the sensor, then it doesn't make a differance which wire you use.

[ 12-20-2002, 08:24 PM: Message edited by: TheReaper ]
 

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Originally posted by MyBlackZX3:
I just received and intake sensor modification from e-bay. This is a modification to your Intake Air Temperature sensor that will let your engine breath cooler air and increase the amount of fuel that enters your engine. The increased air/fuel ratio that you recieve will bump up your horsepower significantly over stock cars with a resistor chip. Not only will you feel better acceleration and torque you will feel this through the entire RPM band.

Same Function as ECU Upgrades and Performance Chips Like the Jet V-Chip!
<font size="2" face="Verdana, Arial">Simply put, this is a load of bull, and you got taken.

It will mildly modify TIMING (not a/f ratio), but nothing that will net you anything of worth. I had a mod similar to this on my escort.

It does not let your car breathe cooler air. The air it brings in is the same temperature, it just thinks it's colder. And like I said, it doesn't help by adding any more fuel at all. It is effective over the entire RPM band, but take your car to a dyno and with or without this IAT Sensor modification, you won't see any measurable differences.

It definitely doesn't offer the same function as a chip, either. The chip actually advances timing the the point where you need to run high octane fuel. It modifies shift points on the automatic transmissions, and alters the fuel maps (in some cases, a chip does increase the a/f ratio). It can also force the PCM to ignore or be more lenient with values provided by certain sensors, and can tweak the operating parameters of the PCM, including providing odometer/speedometer correction when using a different final drive ratio, increasing the top speed and RPM limiters, de-activate the EGR, etc) The little resistor-on-a-stick that you bought was a nice way for some eBay snake oil salesman to get rid of $0.30 worth of merchandise for $10, and it won't ever live up to the claims you posted.

I'm not saying that it does **nothing** for the car's performance, but it does very little, and the claims made (that you probably cut and pasted out of the auction) are bogus. Simply a lie.
 

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By the way, if you're gonna do this regardless, I'd like you guys to do it CORRECTLY, so here's my tidbit of info for you all:

the IAT sensor uses the 2 middle wires (there's 6 wires total) of the connector that plugs into the MAFS. On a stock focus, it's the harness that plugs into the intake tube right next to the airbox. It's the same for SPI and Zetec Foci.

Most IAT sensor mods require you to cut the wires and connect the resistor in place of the sensor. Depending on the resistance of the device you got in the mail, it may be meant to go "inline" (series) with the sensor. Do NOT hook it up in parellel with the IAT sensor, as that will DECREASE the effective resistance and may cause even more problems than just using this modification alone.

I don't recommend changing the CHT (Cylinder head Temp) Sensor's reading, as you could cause some very serious problems!!! I'm assuming that's what the "water temperature pot" mod is. don't even mess with that.

Personally I think anyone who bought into the resistormod should have saved the $10 and put it towards some other moderately-inexpensive mod like an underdrive pulley or saved it in a bank to go towards a real chip, or at least picked up their own resistor for under a buck at the local radio shack, but what's done is done.

/RANT



[ 12-20-2002, 08:33 PM: Message edited by: ax0n ]
 

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Originally posted by ax0n:
By the way, if you're gonna do this regardless, I'd like you guys to do it CORRECTLY, so here's my tidbit of info for you all:

the IAT sensor uses the 2 middle wires (there's 6 wires total) of the connector that plugs into the MAFS.
<font size="2" face="Verdana, Arial">Almost. I have an MAF connector in my hand that's been modified for an external IAT and the two wires it uses for the IAT are the two OUTSIDE wires. Please don't use the two middle wires. I've been running an external IAT (not a resistor mod) for 2 months now and know that the OUTSIDE wires are the IAT.
 

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Originally posted by ax0n:
...I don't recommend changing the CHT (Cylinder head Temp) Sensor's reading, as you could cause some very serious problems!!! I'm assuming that's what the "water temperature pot" mod is. don't even mess with that...
<font size="2" face="Verdana, Arial">Ah, but that is the one that gives the most gains. It is also why the pots should only be used for a short period of time (like a drag race). If he reads the "Import Notes" like I suggested, he will know that it disables the cooling fan, so his engine could over-heat.

There is one warning I would make, you should know the basic principles of electricity to do this mod. Because if you don't know what you are doing and screw up the wiring, you will never be able to explain what you did over the internet (to get help).

[ 12-20-2002, 10:19 PM: Message edited by: TheReaper ]
 

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Originally posted by Blue01Street:
I have an MAF connector in my hand that's been modified for an external IAT and the two wires it uses for the IAT are the two OUTSIDE wires. Please don't use the two middle wires. I've been running an external IAT (not a resistor mod) for 2 months now and know that the OUTSIDE wires are the IAT.
<font size="2" face="Verdana, Arial">Tell more!!
Using FI I think any engine management system would work better reading the IAT after the IC or turbo.
 

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Hi guys, I want to try this mod in some weeks. I've done research on this and here what I've found. Hope this help.

 

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Originally posted by Leadfoot/S2:
Tell more!!
Using FI I think any engine management system would work better reading the IAT after the IC or turbo.
<font size="2" face="Verdana, Arial">I converted over to a MAF from a F-150 Lightning. It doesn't have a built in IAT sensor for the very reason you mention. In fact the connector on the MAF has only the four middle pins, no outside pins for the IAT. I bought the Ford sensor for the Lightning. It's the same temperature curve as the Focus. I think all Fords use the same thermistor value for the IAT.

Of course I had to get a custom chip for the MAF, but you could use an external sensor with the stock chip. Just splice into the MAF wiring harness on the two outside pins (cut the wires to disable the internal one) and there you have it.

[ 12-21-2002, 11:53 AM: Message edited by: Blue01Street ]
 

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I know this is a rather old topic, but I just wanted to mention that at a recent dyno day (with a bunch of zx2's and foci combines), zonker dyno'd with those resistors on his zx2. He gained 8whp with the resistors enabled. So it does show measureable improvement.

Still not a mod I would do, but they do show gains!
 
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