Idle problem

Gho$t · 12-10-2002, 11:38 PM

Ok fellas please dont get mad if you've seen this thread hundreds of times. I have a '86 Stang w/ gt40 heads, Cobra intake and plenum, E303 cam, MSD 6AL, Edelbrock 70mm throttle body, and it is speed density. Here's my problem.......... My car idles at around 1600 rpm's. I've adjusted the screw on the throttle body and it did absolutley nothing. I know for sure I have no vacuum leaks. How in the hell do you set the idle??? this is truly frustrating and annoying. I have read so many threads bout there must be a vacuum leak BUT trust me I do not have a vacuum leak. What are the ways that you can adjust the idle? Please please somebody help me or guide me in the right direction. Thanks in advance.........

toevil1 · 12-11-2002, 12:15 AM

Did you check your TPS voltage?

Gho$t · 12-11-2002, 12:45 AM

No I haven't and not to sound stupid but I dont know how, I've seen things here and there bout it but not the full procedure. Im a newbie when it comes to fuel injection cars. Your help will be appreciated.

drtbiker · 12-11-2002, 01:23 AM

Ill give it a shot...
First u need to get a multi meter
then turn the iginition on but do not start the car. Then your going to take and find the wiring harness for the tps. Once you find it your going back probe the black probe with the black wire. Then your going to take the red probe and back probe the green wire. You should get a reading anywhere from what i heard of .70v and 1.0v u want it right around .95 and you should be fine. Your going to loosen the two screws on the top of the tps sensor and the turn the tps sensor until u get the reading you want. You may have to enlongate the holes or (make them bigger) If you r not getting a reading there you are going to keep the black back probed to the black wire and touch the red to the orange. If you dont have 5volts there then you have a break in the line somewhere or a fried ecu.. If your wondering why i know this i went through the same bs for a month, i was so angry and then pkrwud saved the day... so i owe my knowledge to pkwud.

my problem was broken wire due to fords wiring setup. The wire broke right where the tps sensor orange wire meets the egr valve harness

hopes this helps later..
oh i also had a lower intake gasket leak that i didnt notice...

Gho$t · 12-11-2002, 03:08 AM

thanks bro..........It should def get me on the way.

Gho$t · 12-11-2002, 10:41 PM

Ok I got it at .95 but it still tachs at 1600 rpm's what now?? Now Im confused again.

Coupe50h · 12-11-2002, 10:49 PM

my car did that, and i replaced the tps and it fixed it, but with .95 on it, it should'nt be bad, im stumped.....

Gho$t · 12-11-2002, 11:00 PM

Damn its a brand new throttle body w/tps on it to..........Now its starting to worry me. Im resetting the ecu hopefully it will help it.

drtbiker · 12-12-2002, 02:00 PM

only one other thing even though you said you dont have a vaccum leak... didd you check the intake gasket the one inbetween the heads and lower intake. Mine stumped me.. no sound or sense of it sucking air but then noticed when it was raining and i was working on my car. Some water leaked right where it meets the heads and it started bubbling. If it wasnt for me being so stupid to set the timing on my car in the rain i would of never noticed

later

raptor · 12-16-2002, 06:48 PM

Dude I know your problem. My ride used to be speed density. I had the same problem. You have come to the end of your ECM's capabilities. In other words you have done the max that you can do with speed density. It's time to upgrade to mass air. Sorry to tell ya. Good Luck.

drtbiker · 12-17-2002, 12:48 AM

i beg to differ look at my mods raptor

Gho$t · 12-17-2002, 01:46 AM

Nope Mass Air is not the answer, problem is in cali if I upgrade to mass air my proble is I cant smog it. I got my problem fixed it was the damn idle air sensor. What really gets me is that I had just gotten it back from my mech and he said it was fine...... Fine taching at 1800rpm's ......? GO figure luckily I kept asking enough questions on how to adjust the Idle. Got the fix for free so I cant complain all in all. Thanks for everyone that had an Idea or 2.

Gho$t

302man · 12-17-2002, 08:40 PM

gho$t, now that you have the high idle fixed, what you need to do is get the car hot, shut ngine off, disconnect IAC, then set base idle with the idle screw. Then check the TPS after you have the idle you want. Turning the idle screw will change the tps voltage. Then plug everything back in and you are good to go.

84LX89GT · 12-20-2002, 02:06 AM

You could try cleaning out your Idle air Control valve (Inlet air control valve...same thing). Alot of times carbon will build up inside them and they will stick causing either too much air to be let into the engine or too little. One will cause a low idle, and stalling, the other will cause a high idle. A IAC valve gasket and o-ring will cost less than $5 so it's worth a try. Another trick you could do is try tapping lightly on it with a hammer, you'd be amazed and what a little smack with a blunt instrument can do sometimes

. Unfortunately because of the design the IAC valve sucks in alot of PCV gasses that stick to the valve and then harden on the shaft causing it to stick. Carb cleaner works great to clean them out.
Good luck,

12-10-2002, 11:38 PM	#1
Gho$t Registered Member Join Date: Dec 2002 Location: Granada Hills, Ca Posts: 13	Idle problem Ok fellas please dont get mad if you've seen this thread hundreds of times. I have a '86 Stang w/ gt40 heads, Cobra intake and plenum, E303 cam, MSD 6AL, Edelbrock 70mm throttle body, and it is speed density. Here's my problem.......... My car idles at around 1600 rpm's. I've adjusted the screw on the throttle body and it did absolutley nothing. I know for sure I have no vacuum leaks. How in the hell do you set the idle??? this is truly frustrating and annoying. I have read so many threads bout there must be a vacuum leak BUT trust me I do not have a vacuum leak. What are the ways that you can adjust the idle? Please please somebody help me or guide me in the right direction. Thanks in advance.........

12-11-2002, 01:23 AM	#4
drtbiker Registered Member Join Date: Jan 2002 Location: Mt. Prospect,IL Posts: 474	Ill give it a shot... First u need to get a multi meter then turn the iginition on but do not start the car. Then your going to take and find the wiring harness for the tps. Once you find it your going back probe the black probe with the black wire. Then your going to take the red probe and back probe the green wire. You should get a reading anywhere from what i heard of .70v and 1.0v u want it right around .95 and you should be fine. Your going to loosen the two screws on the top of the tps sensor and the turn the tps sensor until u get the reading you want. You may have to enlongate the holes or (make them bigger) If you r not getting a reading there you are going to keep the black back probed to the black wire and touch the red to the orange. If you dont have 5volts there then you have a break in the line somewhere or a fried ecu.. If your wondering why i know this i went through the same bs for a month, i was so angry and then pkrwud saved the day... so i owe my knowledge to pkwud. my problem was broken wire due to fords wiring setup. The wire broke right where the tps sensor orange wire meets the egr valve harness hopes this helps later.. oh i also had a lower intake gasket leak that i didnt notice... __________________ 87-ford-mustang-SOLD! mods: 3:73's, off road h-pipe, b303 cam in gt- 40 motor w/ Power Plus intake, edelbrock 70mm tb & egr spacer, 72mm C&L, bbk long tubes, tremec tranny, centerforce dual friction clutch, upr and lwr CA's 255lph FP and soon more to come.... when i have money again SOME ADVICE Don't do burn outs in reverse it is very expensive New times with dead hook on dr's 13.27@103 with 2.0 60 foots w/100lb system Fastest time to date: 12.8@113

12-11-2002, 10:49 PM	#7
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	my car did that, and i replaced the tps and it fixed it, but with .95 on it, it should'nt be bad, im stumped..... __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

12-12-2002, 02:00 PM	#9
drtbiker Registered Member Join Date: Jan 2002 Location: Mt. Prospect,IL Posts: 474	only one other thing even though you said you dont have a vaccum leak... didd you check the intake gasket the one inbetween the heads and lower intake. Mine stumped me.. no sound or sense of it sucking air but then noticed when it was raining and i was working on my car. Some water leaked right where it meets the heads and it started bubbling. If it wasnt for me being so stupid to set the timing on my car in the rain i would of never noticed later __________________ 87-ford-mustang-SOLD! mods: 3:73's, off road h-pipe, b303 cam in gt- 40 motor w/ Power Plus intake, edelbrock 70mm tb & egr spacer, 72mm C&L, bbk long tubes, tremec tranny, centerforce dual friction clutch, upr and lwr CA's 255lph FP and soon more to come.... when i have money again SOME ADVICE Don't do burn outs in reverse it is very expensive New times with dead hook on dr's 13.27@103 with 2.0 60 foots w/100lb system Fastest time to date: 12.8@113

12-16-2002, 06:48 PM	#10
raptor Registered Member Join Date: Sep 1999 Location: Dundalk, Ont, Canada Posts: 129	Dude I know your problem. My ride used to be speed density. I had the same problem. You have come to the end of your ECM's capabilities. In other words you have done the max that you can do with speed density. It's time to upgrade to mass air. Sorry to tell ya. Good Luck. __________________ 88GT, 331Stroker,FMS 70mm TB,77mm Pro-M mass air,Ram Air,K&N,GT40/Exployer Intakes,Gasket Matched,FMS 24lb injectors,Crane hi-6 ignition system,B303 cam,Crane 1.6RR,FMS underdrive pullies,351W/heads,port/polish,FMS h/f oil pump,Hedman headers,2 1/2in H pipe Flow Masters,190lph Holley fuel pump,Center Force dual friction,FMS 3.55,Hurst short throw/ trigger T handle,Subframe connectors,Welded torque boxes.

12-11-2002, 12:15 AM	#2
toevil1 Registered Member Join Date: Sep 2002 Location: Los Angeles Posts: 39	Did you check your TPS voltage?

12-11-2002, 12:45 AM	#3
Gho$t Registered Member Join Date: Dec 2002 Location: Granada Hills, Ca Posts: 13	No I haven't and not to sound stupid but I dont know how, I've seen things here and there bout it but not the full procedure. Im a newbie when it comes to fuel injection cars. Your help will be appreciated.

12-11-2002, 03:08 AM	#5
Gho$t Registered Member Join Date: Dec 2002 Location: Granada Hills, Ca Posts: 13	thanks bro..........It should def get me on the way.

12-11-2002, 10:41 PM	#6
Gho$t Registered Member Join Date: Dec 2002 Location: Granada Hills, Ca Posts: 13	Ok I got it at .95 but it still tachs at 1600 rpm's what now?? Now Im confused again.

12-11-2002, 11:00 PM	#8
Gho$t Registered Member Join Date: Dec 2002 Location: Granada Hills, Ca Posts: 13	Damn its a brand new throttle body w/tps on it to..........Now its starting to worry me. Im resetting the ecu hopefully it will help it.

12-17-2002, 12:48 AM	#11
drtbiker Registered Member Join Date: Jan 2002 Location: Mt. Prospect,IL Posts: 474	i beg to differ look at my mods raptor __________________ 87-ford-mustang-SOLD! mods: 3:73's, off road h-pipe, b303 cam in gt- 40 motor w/ Power Plus intake, edelbrock 70mm tb & egr spacer, 72mm C&L, bbk long tubes, tremec tranny, centerforce dual friction clutch, upr and lwr CA's 255lph FP and soon more to come.... when i have money again SOME ADVICE Don't do burn outs in reverse it is very expensive New times with dead hook on dr's 13.27@103 with 2.0 60 foots w/100lb system Fastest time to date: 12.8@113

12-17-2002, 01:46 AM	#12
Gho$t Registered Member Join Date: Dec 2002 Location: Granada Hills, Ca Posts: 13	Nope Mass Air is not the answer, problem is in cali if I upgrade to mass air my proble is I cant smog it. I got my problem fixed it was the damn idle air sensor. What really gets me is that I had just gotten it back from my mech and he said it was fine...... Fine taching at 1800rpm's ......? GO figure luckily I kept asking enough questions on how to adjust the Idle. Got the fix for free so I cant complain all in all. Thanks for everyone that had an Idea or 2. Gho$t

12-17-2002, 08:40 PM	#13
302man Registered Member Join Date: Jul 1999 Location: INDIANAPOLIS Posts: 404	gho$t, now that you have the high idle fixed, what you need to do is get the car hot, shut ngine off, disconnect IAC, then set base idle with the idle screw. Then check the TPS after you have the idle you want. Turning the idle screw will change the tps voltage. Then plug everything back in and you are good to go. __________________ old S trim combo 10.13@ 135 New YS combo = 680RWHP (no times)

12-20-2002, 02:06 AM	#14
84LX89GT Mustangs Join Date: Jul 2000 Posts: 1,938	You could try cleaning out your Idle air Control valve (Inlet air control valve...same thing). Alot of times carbon will build up inside them and they will stick causing either too much air to be let into the engine or too little. One will cause a low idle, and stalling, the other will cause a high idle. A IAC valve gasket and o-ring will cost less than $5 so it's worth a try. Another trick you could do is try tapping lightly on it with a hammer, you'd be amazed and what a little smack with a blunt instrument can do sometimes . Unfortunately because of the design the IAC valve sucks in alot of PCV gasses that stick to the valve and then harden on the shaft causing it to stick. Carb cleaner works great to clean them out. Good luck, __________________ 2005 Suzuki Hayabusa GSX1300-R 1980 Ford Thunderbird - 255 V8 ported heads, 5.0L ported stock headers, O.R. H-pipe and Flowmaster 2-chambers, dual roller timing chain hi-po Mack Truck hood emblem 1985 Mustang GT 5.0L T5, F-303, GT40p, headers, off-road h, flowmasters, MSD stuff, etc. Sold 02/06/04 1989 Mustang GT ET: 13.304@102.29 mph (5-24-03) Sold - 1998 Mustang Cobra coupe, 1/4 mile - street tires: 13.843@103.41 (bone stock)

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