Idle staying at 2,000 RPM

[aete2]

This may sound stupid, but your problem is the same as mine was! I fought with it for years, finally we tried something and it worked. We cleaned the throttle body and no more problem as of yet. Have you tried that? My throttle body really did not look dirty but now i have no more idle issue. I went though all that other stuff and none of it worked. Try it, cheap and easy- it may work.

 

[savegoodautonfg]

Click here http://forums.stangnet.com/showthread.php?t=698148 to find the link to dump the codes.

The ECT is located in the water feed tube for the heater on the passenger side of the car. It is near the front of the engine.

Thank you jritcher, did you see waht i wrote about the MAF, sounds to you like its good right?

SO far, I've cleaned throttle body, MAF, EGR, IAC. Still going thru the checklist by jritcher.

What color are the wires coming off the connector for the ECT. Also i dont get it what do you mean water feed tube?

Anyway you can show me a picture jritcher or anyone else. having trouble finding it still.

i appreciate everyone trying to help me thru this.

this link no longer works... http://www.mustangworks.com/articles/electronics/eec-iv_codes.html

Also, if my fuel pump relay was bad. what would the symptoms be?

 

[savegoodautonfg]

This may sound stupid, but your problem is the same as mine was! I fought with it for years, finally we tried something and it worked. We cleaned the throttle body and no more problem as of yet. Have you tried that? My throttle body really did not look dirty but now i have no more idle issue. I went though all that other stuff and none of it worked. Try it, cheap and easy- it may work.

Did you take the TB off the car to clean it. I cleaned it today but with it still on the car.
We'll see how it works when i'm done doing everything on the Surging Idle Checklist.

 

[aete2]

Did you take the TB off the car to clean it. I cleaned it today but with it still on the car.
We'll see how it works when i'm done doing everything on the Surging Idle Checklist.

Yes right off the car good cleaning, hang in there you will fix it, pain in the back side this problem is i know.

 

[savegoodautonfg]

Just finished going thru the list. all done. set idle set screw and set TPS and reset computer.

something still is'nt right. ill adjust the idle to like 700RPM and then when i drive it it wont get completely stuck like it did before, but whatever rpm it is at, it will go fast down to 1,500rpm and then it will go real slow back down to idle, then it idles at like 1,000 now and i didnt change the idle from when i got it 700rpm. its really strange. i'm going out of my mind.

Jritcher, i went thru your steps. waht else you got in mind?

P.S. don't know if this will help but i got a BBK Throttle Body with EGR Spacer 70mm

ALSO JUST PULLED CODES AGAIN I GOT 63 (tps TOO low but it is at .98volts.) also got 91. now im wondering how the hell my car is running lean after i fixed everything.

 

[savegoodautonfg]

I played with the IAC and the TPS wen it was idling.

heres the deal:

If i rev it up and the TPS and IAC are connected: will go down to idle after a few seconds or so.

If i rev it up and the TPS is connected but IAC is disconnected, will go down to idle a little fast then with both connected.

If i rev it up with IAC and TPS both disconnected, it basically shoots right down to idle.

PLease respond to if this helps my situation or not?

 

[HISSIN50]

Nick, again, you have to have the car acting up in order for testing to be valid. I only say this to try and save you time and frustration. I might have misread your last post but I didnt see where the idle was acting up when you tried each battery of tests.


As a crude example, if a car has vibration at 50 MPH or higher, and someone tries using small counterweights on the DS to fix it but they can only go up to 40 MPH after adding weights, the testing is invalid.

In the above example, the car would need to be driven at 50+ mph after each new weight was added. And in your case, you have to get the car to act up before you can disconnect things and narrow down what's at fault.
Good luck.

 

[savegoodautonfg]

Nick, again, you have to have the car acting up in order for testing to be valid. I only say this to try and save you time and frustration. I might have misread your last post but I didnt see where the idle was acting up when you tried each battery of tests.


As a crude example, if a car has vibration at 50 MPH or higher, and someone tries using small counterweights on the DS to fix it but they can only go up to 40 MPH after adding weights, the testing is invalid.

In the above example, the car would need to be driven at 50+ mph after each new weight was added. And in your case, you have to get the car to act up before you can disconnect things and narrow down what's at fault.
Good luck.

Hissin, what im saying is so far its not sticking like it used to but the only times it seems to go right down to idle is when the IAC and TPS are disconnected?

And also i set it for 700rpm and the RPM when i start the car for like 10 min will go down to 700 but after a while it will stay at 1000rpm for the idle.

Understand what im trying to say?

 

[Luis911]

I have a problem same,
1.- Release IAC and to place it head first (when IAC is bad this stabilize) (later to buy a IAC)
2.- Turn idle set 1/2 or 3/4 less (left) and to readjust TPS at 0.985 V (disconnect computer 20 minutes and to connect)

Note: Maybe the 2 IAC are bad...

 

[HISSIN50]

Hissin, what im saying is so far its not sticking like it used to but the only times it seems to go right down to idle is when the IAC and TPS are disconnected?

And also i set it for 700rpm and the RPM when i start the car for like 10 min will go down to 700 but after a while it will stay at 1000rpm for the idle.

Understand what im trying to say?

I admit that I don't follow everything, and I know my posts themselves are hard to decipher.

Right now, how is your cold idle? Does it start out at like 1000+ RPM for some seconds, then kick down a hundred or two RPM for a minute, and then drop once again (to around 750 RPM) after that? On my 88, it's 1100 RPM for 5 seconds, 900 RPM for about 45 seconds and then 800 RPM or so till it's warmed up (I'm driving by then so I dont know for sure).

The point was that if your cold idle sucks (it's 700-900 RPM) and your warm idle is doing all this BS too, that is helpful. To me, if it was like clockwork, I'd still think IAC. And if it's erratic or sporadic, a vac leak can cause just that kind of inconsistancy.

 

[savegoodautonfg]

I admit that I don't follow everything, and I know my posts themselves are hard to decipher.

Right now, how is your cold idle? Does it start out at like 1000+ RPM for some seconds, then kick down a hundred or two RPM for a minute, and then drop once again (to around 750 RPM) after that? On my 88, it's 1100 RPM for 5 seconds, 900 RPM for about 45 seconds and then 800 RPM or so till it's warmed up (I'm driving by then so I dont know for sure).

The point was that if your cold idle sucks (it's 700-900 RPM) and your warm idle is doing all this BS too, that is helpful. To me, if it was like clockwork, I'd still think IAC. And if it's erratic or sporadic, a vac leak can cause just that kind of inconsistancy.

WHen i first start it up at cold idle, it seems to idle fine at like 650-750, idle sounds great. after a little while car likes to idle at 1000 rpm.

What do you think about the whole IAC and TPS thing i wrote in the post before?

 

[Luis911]

When RPM is High, to measure voltage in TPS, maybe TPS~1.2 or more V.

 

[HISSIN50]

WHen i first start it up at cold idle, it seems to idle fine at like 650-750, idle sounds great. after a little while car likes to idle at 1000 rpm.

What do you think about the whole IAC and TPS thing i wrote in the post before?

See now, that's not right. Your cold idle should be higher. Your idle function is backasswards of how it should be (it should be high when cold, low when warm. Yours is low when cold and high when warm).

I now understand what you meant in the post before this last one. Simply stated, in general your idle gets higher the warmer the engine is.

I know it had to be measured before but check the IAC wiring. Disco' the connector and prepare to test at the IAC itself. Put your meter's positive lead on the Vpower terminal of the IAC and the neg lead on the ISC lead. Look for 7-13 ohms.

 

[savegoodautonfg]

disconnect the connector going to iac and the what color for what do you want me to do? v-power? neg lead is black right?

 

[jrichker]

disconnect the connector going to iac and the what color for what do you want me to do? v-power? neg lead is black right?

Computer controlled ground for the IAB is white/lt blue.

Diagram courtesy of Tmoss & Stang&2birds

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

 

[savegoodautonfg]

Very helpful digaram jritcher.

anyways, i got my dad to get me an IAC at his cost.

KEM brand only $38.00 with tax. I love having my dad be a manager at an autoparts store. saves me so much f'n money..

THe IAC seems like it change the idle a little bit. At first the car starts up and idles at about 1000rpm then slowly goes down after about 15 seconds. when you rev it up it go fast to about 1,000rpm then down to regular idle after about 2-5 seconds.

is this normal?

Haven't took it for a ride yet, but ill reply again after i take it for a ride.

 

[HISSIN50]

THe IAC seems like it change the idle a little bit. At first the car starts up and idles at about 1000rpm then slowly goes down after about 15 seconds. when you rev it up it go fast to about 1,000rpm then down to regular idle after about 2-5 seconds.

is this normal?

Haven't took it for a ride yet, but ill reply again after i take it for a ride.

That's how it should be in my experience for a coldish motor. Once you're up to temp (160*+), it should return to 700 RPM (ish) sooner. This will be altered by any changes that have been made in the base idle setting.

Good luck.

 

[savegoodautonfg]

Just took it for a ride.

But should it still be sticking like it is for a few seconds or so at 1,500 rpm before it goes back to idle (700-800rpm)?

 

[HISSIN50]

Just took it for a ride.

But should it still be sticking like it is for a few seconds or so at 1,500 rpm before it goes back to idle (700-800rpm)?

If it happens between shifts (dashpot) or while rolling, yes, it's normal and good.

If it happens while stationary it might not be, depending upon how bad it is. While stopped, my '88 hangs for just a tick at about 1500 and I like it. It's always been like that. Jrichker and the others can offer experience with how exactly their engines return to idle. I don't often find two cars that act just the same, often dependant upon mods and state of tune.

 

[savegoodautonfg]

Well ill go with what your saying about the slight sticking at 1,500 rpms. its kind of annoying but it'll work not the worst thing the car could be doing.

I'm just confused cause sometimes after it sticks at 1,500 for a few seconds it goes down to 1,000rpm and sometimes it will go to 700-800 which is idle. it doesnt always go down to 700-800 (idle).

Also, when i start the car after it sat for hours, engine is cold, the car wants to die unless i keep giving it gas, but i think that means the IAC is bad, but the IAC is brand new just got it yesterday.

Thanks again for all you guys help so far.