has anyone ever tried.....

dragstang86 · 11-29-2002, 07:42 PM

I was just wondering if anybody ever experimented with unplugging the coolant temperature sensor (for the computer not the gauge) at the track or on the street. By unplugging it the computer will give full timing advancement and it will give it more fuel (as it does when the car is cold). What are your guys thoughts about this?

thanks for the help

ultraflo · 11-29-2002, 07:50 PM

Give 'er a whirl and let us know?

In theory, it sounds like a darn good idea. I'd like to know as well.

I'll shut up now...

HotRoddin · 11-29-2002, 08:45 PM

Quote:

Originally posted by dragstang86
By unplugging it the computer will give full timing advancement and it will give it more fuel (as it does when the car is cold). What are your guys thoughts about this?

Are you sure unplugged (open circuit) tells the computer full cold and not really hot ?? Just a thought

dragstang86 · 11-29-2002, 09:07 PM

I talked to a master technician about that and he was the one who told me that it would think it was cold, which means full timing advancement and more fuel. I just wanted to get your guys input on this.

gin · 11-29-2002, 09:17 PM

The pcm will see an out of range sensor and will ignore it. It will then set a fault code.

Shogun · 11-29-2002, 11:12 PM

YEP gin is right. The PCM will set a "last known" good value. You want to beat the PCM? pull the short plug @ the distributor, set 34-38 TDC and leave out the short plug. However, make sure you have some GOOD gas in the tank! And don't let the RPM's drop to much. This is good for out of the hole grunt, but you invite DETONATION! any internal combustion engines arch enemy. "****DISCLAMER NOTE****" DO NOT TRY THIS AT HOME, if you don't know your doing! You could potentially DESTROY your motor buy doing this.

PKRWUD · 11-30-2002, 12:18 AM

If your cats are gone, you change your oil once a week, and you don't drive it for more than 15 minutes at a time, you'll be fine. Otherwise, DON'T DO IT.

Why would you want to anyway? Are you experiencing an overly lean condition? Hell, if you just want to waste more gas, clog up cats, and dilute your oil, install a set of old O2 sensors. As they go bad, they read lean, and the ECM tries to correct it by adding fuel.

I personally wouldn't do either, but if you feel compelled...

srv1 · 11-30-2002, 12:36 AM

if you unplug the sensor, it may go into a "limp" mode. for performance wise that wouldnt work. if take the spout jumper off, what are you really gaining? i dont think that would work that well at all. if you want to fake out the computer thier is two things you can do. run a resistor(look in book for spec on resistence of coolant temp sensor) in the coolant temp pigtail. Also you can do the same thing, but do it to your intake air temperature sensor. i read but havent tried, relocating the intake sensor from the manifold to the induction tube. i was told this makes the car run a little better. i will try it our for myself.

PKRWUD · 11-30-2002, 01:10 AM

Quote:

Originally posted by srv1
Also you can do the same thing, but do it to your intake air temperature sensor. i read but havent tried, relocating the intake sensor from the manifold to the induction tube. i was told this makes the car run a little better. i will try it our for myself.

I did that to my truck when I changed the clutch (see pic), and it does feel different, but I can't tell if it was just that my clutch was slipping before, and I didn't realize it. Either that, or moving the sensor made it snappier.

Shogun · 11-30-2002, 06:05 AM

Quote:

if take the spout jumper off, what are you really gaining? i dont think that would work that well at all.

Ignition timing, By pulling the "spout" you disconnect the PCM from the distributor, disabling any and all timing curves. Why do think you pull said connector when you set base timing?

srv1 · 11-30-2002, 01:53 PM

Quote:

Originally posted by Shogun
Ignition timing, By pulling the "spout" you disconnect the PCM from the distributor, disabling any and all timing curves. Why do think you pull said connector when you set base timing?

1 puts the computer in base timing. 2. pull the spout so the computer cant adjust through the timing curve. Its like setting minimum air flow. if you dont disconnect the idle speed motor, the computer will keep adjusting idle speed and you will never get a correct setting. same concept.

11-29-2002, 07:42 PM	#1
dragstang86 Registered Member Join Date: Sep 2002 Location: baltimore, md Posts: 220	has anyone ever tried..... I was just wondering if anybody ever experimented with unplugging the coolant temperature sensor (for the computer not the gauge) at the track or on the street. By unplugging it the computer will give full timing advancement and it will give it more fuel (as it does when the car is cold). What are your guys thoughts about this? thanks for the help __________________ 90 LX Hatchback 306, AFR 165's 58cc, E303, 1.6 roller rockers, 70mm throttle body, cobra intake, bbk fenderwell, bbk longtubes, x-pipe, flowmasters, pullies, msd 6a, crane ps-92, stock MAF sensor, electric fan, No AC, No air pump, flaming river quick ratio rack C-4, 3500 stall, 373's, aluminum driveshaft SSM Lift bars, , sub frame connectors, strut tower brace 12.57 @105.12mph w/ 1.686 60ft before bbk longtubes (with equal shorties) ----------------------------------------- 86 tube chassis coupe - the trailor queen

11-29-2002, 07:50 PM	#2
ultraflo NX dealer-man Join Date: Sep 1998 Location: Peoria, Illinois Posts: 977	Give 'er a whirl and let us know? In theory, it sounds like a darn good idea. I'd like to know as well. I'll shut up now... __________________ RLS Racing! 93 LX 9.20 @ 147mph 03 Mach 1 12.39 @ 116mph

11-29-2002, 09:07 PM	#4
dragstang86 Registered Member Join Date: Sep 2002 Location: baltimore, md Posts: 220	I talked to a master technician about that and he was the one who told me that it would think it was cold, which means full timing advancement and more fuel. I just wanted to get your guys input on this. __________________ 90 LX Hatchback 306, AFR 165's 58cc, E303, 1.6 roller rockers, 70mm throttle body, cobra intake, bbk fenderwell, bbk longtubes, x-pipe, flowmasters, pullies, msd 6a, crane ps-92, stock MAF sensor, electric fan, No AC, No air pump, flaming river quick ratio rack C-4, 3500 stall, 373's, aluminum driveshaft SSM Lift bars, , sub frame connectors, strut tower brace 12.57 @105.12mph w/ 1.686 60ft before bbk longtubes (with equal shorties) ----------------------------------------- 86 tube chassis coupe - the trailor queen

11-29-2002, 11:12 PM	#6
Shogun Registered Member Join Date: Feb 2002 Location: Nebraska Posts: 86	YEP gin is right. The PCM will set a "last known" good value. You want to beat the PCM? pull the short plug @ the distributor, set 34-38 TDC and leave out the short plug. However, make sure you have some GOOD gas in the tank! And don't let the RPM's drop to much. This is good for out of the hole grunt, but you invite DETONATION! any internal combustion engines arch enemy. "**DISCLAMER NOTE**" DO NOT TRY THIS AT HOME, if you don't know your doing! You could potentially DESTROY your motor buy doing this. __________________ Proud RHC member #99 1990 Mustang GT Trick Flow heads,F303,Mac cold air,FMS 65mm tb,73mm ma,FMS 1.6,GT-40 intake,MSD igintion,NOS Big Shot@150,Mac equal shorties,Mac h-pipe,American Thunder flows,Centerforce dual friction,TTC 3550,alm drive shaft, 3.73's, HPM subframes, k-member brace, strut tower brace.. amongst others.

11-30-2002, 12:18 AM	#7
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	If your cats are gone, you change your oil once a week, and you don't drive it for more than 15 minutes at a time, you'll be fine. Otherwise, DON'T DO IT. Why would you want to anyway? Are you experiencing an overly lean condition? Hell, if you just want to waste more gas, clog up cats, and dilute your oil, install a set of old O2 sensors. As they go bad, they read lean, and the ECM tries to correct it by adding fuel. I personally wouldn't do either, but if you feel compelled... __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

11-29-2002, 09:17 PM	#5
gin Registered Member Join Date: Dec 2001 Location: Jersey Posts: 7	The pcm will see an out of range sensor and will ignore it. It will then set a fault code.

11-30-2002, 12:36 AM	#8
srv1 Get down..... Join Date: Apr 2001 Location: Room 103 Posts: 2,095	if you unplug the sensor, it may go into a "limp" mode. for performance wise that wouldnt work. if take the spout jumper off, what are you really gaining? i dont think that would work that well at all. if you want to fake out the computer thier is two things you can do. run a resistor(look in book for spec on resistence of coolant temp sensor) in the coolant temp pigtail. Also you can do the same thing, but do it to your intake air temperature sensor. i read but havent tried, relocating the intake sensor from the manifold to the induction tube. i was told this makes the car run a little better. i will try it our for myself. __________________ Cobra brakes are on! Finally..... ------------------------------------------------