Idel goes Up as the motor Warms up...????

Stang Runner · 04-02-2002, 12:30 PM

I Have Instaled many new Parts look at the sig I have not Cats on the car and Remove the Other Crap that goes with them I have No Vac leaks that I know of I have looked and fixed one it is a 1988 using the Stock Ecu thats a S.D. if the Motor is Cold I start it up Runs nice right at 1000-850 and as it get Warmer the Idel goes up to like 1700-1500 after like 3-5Min. I have a new Idel Air Bypass on the car. I still have the ECU coolent temp from 1988 on there might that be going bad????? I remove my MAP with the car on and the Idel drops down to about where it should be a ruff 1000-800.

O I have the staock Cam with 1.72 as well.
Any have any idea what might be doing it?

87 GT MUSTANG · 04-02-2002, 01:06 PM

the problem with your car could be the throttle position sensor, i just had the same thing as you described wrong with my car since i bought it and i recently ripped apart the top half of the engine and cleaned it up and put it all back on and it turned out to be my throttle position sensor, but before you go pulling it off first check the adjustments, place two pins in the wires one in black being negative and the other in green and get a volt meter and check that it is at .980-.990 for best performance and if you cant adjust it to that drill or file out the holes on the tps. Hope this helps you a little

Stang Runner · 04-02-2002, 01:28 PM

Ok mine is at a .084 Wich I know is low But Dont that make the Idel lower??????? Was yours lower than that and you had to Move it up???

Stang Runner · 04-02-2002, 03:00 PM

ok I just got a new ACT sensor did not help. I really think it is the Idel air adjuster might it not work right with the mods I have Might I need to geta Manual one I think I have hear of them before...or something like that.

PKRWUD · 04-02-2002, 03:26 PM

To check the IAC (IAB), unplug it while the engine is running. If the idle remains the same, there is a problem with either the valve, the wiring to the valve, or the passeges in the TB where it mounts. If the idle drops, the IAC is fine.

The TPS voltage has a tendancy to rise as the engine warms up. You said yours was at .084. That is way too low. Did you mean .84? Was this with the engine warmed up, or cold?

Try disconnecting the ECT sensor, and see if that makes a difference. If it runs better, replace it.

If you have a hand vacuum pump, try applying 15" of vacuum to your MAP sensor, and see if it holds the vacuum. If it doesn't stay at 15", replace the MAP sensor.

Take care,
-Chris

Stang Runner · 04-02-2002, 05:29 PM

Ok I have unhooked the IBC with it Running if I do it when the Motor is warm it Just dies the motor If I do it when it is cold it will stay running..... I tested the Vac and the Car is 17.5 I tested it on the Vac tree thing that the Brakes Hook up to I have one more ?? where should I be getting the Vac for the MAP. that was .84 too. I need Help Thx PKRWUD

Stang Runner · 04-02-2002, 05:35 PM

I tested the MAP sensor no leaks on it

Stang Runner · 04-02-2002, 05:47 PM

Ok I will tell you how I have the vac setup on the car I have one Hose from the Intake to the fuel reg thats only thing on it. Next I have a hose to the PVC Valve and thats the only thing On it. next I have One hose going to the Vac Tree thing right by the Brakes I have 1 Hose going to the Brakes and one going to the MAP off that same tree so the Brakes and the Map Run off of it that is all the VAC Lines I have that are on the car. Should I move the MAP to have its owne Hose off the Intake?
the .84v was cold or very close to it.

PKRWUD · 04-03-2002, 06:11 AM

Your vacuum hose routing is fine.

Your TPS is probably fine, but I'd like to know what the voltage is at idle when it warms up, and the idle increases. I'd also like to know what the voltage is at WOT.

Have you tried unplugging the ECT sensor?

The IAC usually will kill the engine when it's unplugged if the engine is cold. Once warmed up, it doesn't usually have as dramatic an effect. Yours is operating the opposite. When warm, and the idle is high, unplugging the IAC kills the engine, but cold, when the idle speed is normal, unplugging it doesn't effect the idle, right? That means the engine is getting air from another source when cold, but that source closes, and the engine relies on the IAC when warm, and it's allowing too much air. Hmmm.

Is the EGR valve still in place?

gtsr515 · 04-03-2002, 04:12 PM

Sounds like 02 sensors are "out of range", in other words....toast.

Also, is the air box sealed up good, and with a clean filter?

Stang Runner · 04-03-2002, 10:07 PM

well might be a O2 I have a few more things to try the stock Fuel reg back on and the stock Injectors after that if that dont help.

I will keep you posted on what I do.....

Hozer 88GTConv · 04-03-2002, 10:21 PM

I have to agree with regards to O2 sensors. Especially since you stated that the problem becomes noticeable so soon as the engine and exhaust heats up.
I will try to find some more detailed info.
http://www.pro-flow.com/t-car.html#instability

04-02-2002, 12:30 PM	#1
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	Idel goes Up as the motor Warms up...???? I Have Instaled many new Parts look at the sig I have not Cats on the car and Remove the Other Crap that goes with them I have No Vac leaks that I know of I have looked and fixed one it is a 1988 using the Stock Ecu thats a S.D. if the Motor is Cold I start it up Runs nice right at 1000-850 and as it get Warmer the Idel goes up to like 1700-1500 after like 3-5Min. I have a new Idel Air Bypass on the car. I still have the ECU coolent temp from 1988 on there might that be going bad????? I remove my MAP with the car on and the Idel drops down to about where it should be a ruff 1000-800. O I have the staock Cam with 1.72 as well. Any have any idea what might be doing it? __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

04-02-2002, 01:06 PM	#2
87 GT MUSTANG Registered Member Join Date: Mar 2002 Location: Oshawa,Ontario Posts: 46	high idle the problem with your car could be the throttle position sensor, i just had the same thing as you described wrong with my car since i bought it and i recently ripped apart the top half of the engine and cleaned it up and put it all back on and it turned out to be my throttle position sensor, but before you go pulling it off first check the adjustments, place two pins in the wires one in black being negative and the other in green and get a volt meter and check that it is at .980-.990 for best performance and if you cant adjust it to that drill or file out the holes on the tps. Hope this helps you a little __________________ Adam pennington

04-02-2002, 01:28 PM	#3
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	Ok mine is at a .084 Wich I know is low But Dont that make the Idel lower??????? Was yours lower than that and you had to Move it up??? __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

04-02-2002, 03:00 PM	#4
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	ok I just got a new ACT sensor did not help. I really think it is the Idel air adjuster might it not work right with the mods I have Might I need to geta Manual one I think I have hear of them before...or something like that. __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

04-02-2002, 03:26 PM	#5
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	To check the IAC (IAB), unplug it while the engine is running. If the idle remains the same, there is a problem with either the valve, the wiring to the valve, or the passeges in the TB where it mounts. If the idle drops, the IAC is fine. The TPS voltage has a tendancy to rise as the engine warms up. You said yours was at .084. That is way too low. Did you mean .84? Was this with the engine warmed up, or cold? Try disconnecting the ECT sensor, and see if that makes a difference. If it runs better, replace it. If you have a hand vacuum pump, try applying 15" of vacuum to your MAP sensor, and see if it holds the vacuum. If it doesn't stay at 15", replace the MAP sensor. Take care, -Chris __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

04-02-2002, 05:29 PM	#6
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	Ok I have unhooked the IBC with it Running if I do it when the Motor is warm it Just dies the motor If I do it when it is cold it will stay running..... I tested the Vac and the Car is 17.5 I tested it on the Vac tree thing that the Brakes Hook up to I have one more ?? where should I be getting the Vac for the MAP. that was .84 too. I need Help Thx PKRWUD __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

04-02-2002, 05:35 PM	#7
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	I tested the MAP sensor no leaks on it __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

04-02-2002, 05:47 PM	#8
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	Ok I will tell you how I have the vac setup on the car I have one Hose from the Intake to the fuel reg thats only thing on it. Next I have a hose to the PVC Valve and thats the only thing On it. next I have One hose going to the Vac Tree thing right by the Brakes I have 1 Hose going to the Brakes and one going to the MAP off that same tree so the Brakes and the Map Run off of it that is all the VAC Lines I have that are on the car. Should I move the MAP to have its owne Hose off the Intake? the .84v was cold or very close to it. __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

04-03-2002, 06:11 AM	#9
PKRWUD Junior Member Join Date: Mar 1999 Location: Ventura, California Posts: 8,981	Your vacuum hose routing is fine. Your TPS is probably fine, but I'd like to know what the voltage is at idle when it warms up, and the idle increases. I'd also like to know what the voltage is at WOT. Have you tried unplugging the ECT sensor? The IAC usually will kill the engine when it's unplugged if the engine is cold. Once warmed up, it doesn't usually have as dramatic an effect. Yours is operating the opposite. When warm, and the idle is high, unplugging the IAC kills the engine, but cold, when the idle speed is normal, unplugging it doesn't effect the idle, right? That means the engine is getting air from another source when cold, but that source closes, and the engine relies on the IAC when warm, and it's allowing too much air. Hmmm. Is the EGR valve still in place? __________________ Webmaster: Rice Haters Club Jim Porter Racing Peckerwoods Pit Stop Support Your Local RED & WHITE!

04-03-2002, 04:12 PM	#10
gtsr515 Registered Member Join Date: Nov 2001 Location: Sunny, Hot, Sebring, Florida Posts: 725	Sounds like 02 sensors are "out of range", in other words....toast. Also, is the air box sealed up good, and with a clean filter? __________________ Remember...2nd place is 1st place for losers!

04-03-2002, 10:07 PM	#11
Stang Runner Registered Member Join Date: Jun 1999 Location: Walker, MI, USA Posts: 1,202	well might be a O2 I have a few more things to try the stock Fuel reg back on and the stock Injectors after that if that dont help. I will keep you posted on what I do..... __________________ Engine: steel mounts, Under drive pulleys, K&N, GT-40 Intake ported Lower, No power steering, No A/C, Mac cold intake, 65MM TB, 255 Fuel pump, 24's, AFR 165 58cc, Rocker Arms 1.7with the stock Cam, 1 5/8 short headers, offRoad X-pipe Drive Train: 3.55, T-5 with a Pro 5.0 shifter 12.656@107.71MPH See It at www.T-racing.com/mustang.htm

04-03-2002, 10:21 PM	#12
Hozer 88GTConv Registered Member Join Date: Feb 2002 Location: Jacksonville, FL Posts: 706	O2 sensors... I have to agree with regards to O2 sensors. Especially since you stated that the problem becomes noticeable so soon as the engine and exhaust heats up. I will try to find some more detailed info. http://www.pro-flow.com/t-car.html#instability __________________ 1988 GT Convertible 331 10:1 TW heads, GT-40 intake, MSD, TRW flattops, B Cam w/ 1.7's, MAC exhaust, 24's, 70 TB, 76 MAF, 3.73's, Pro 5.0, Koni's, Anderson PMS, Wideband 02, yatta, yatta... One week with new motor, two speeding tickets...joy Last edited by Hozer 88GTConv; 04-03-2002 at 10:33 PM..

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