Ford Mustang Forum banner
1 - 19 of 19 Posts

·
Registered
Joined
·
20 Posts
Discussion Starter · #1 ·

i started this thread on modded mustangs, but wasn't getting much help so I am pasting it here:

Hi, I have a 1993 2.3L Mustang that is having some behavioral "issues" and I am having a hard time self Diagnosing, so I decided to see if anyone can help.

Basically...

as soon as I start the car it will idle at 1500 RPMs for about 10 seconds, then goes down to 1200 for about 30 seconds, after that it will randomly begin idling pretty erratically anywhere from 900 to about 1200 RPMs. Then after driving it around for 10-15 mins, If I come to a stop (still engaged in drive) it will idle really erratically between 500-900 RPMs. if you shift back into Neutral it revs less erratically generally between 900 and 1200 RPMs again. (Generally for fear of it dying, I lightly rev the engine in neutral at lights)

I'm not really sure what the problem is... A while back (2 years) it had quite the opposite problem with the inability to idle, it would constantly stay between 2000 and 3000 RPMs... but after cleaning the IAC Valve, it stopped and acted normal ever since.
idle.wmv - YouTube Here is a video I took of it idling, kinda tough to capture the idle on video but if you look at the Tensioner pulley, you can see it acting up...

Any help would be greatly appreciated. :D

**Added about a day later**


I have tried resetting the computer on a couple of occasions, it would do a bit better for 10-15 mins until it "relearned" the bad Idle...

I cleaned the IAC again today with little change, and here's a video of the Tachometer after it was warmed up from driving across town to Autozone. It died on me as I was pulling in... so I parked it and took this with my cell... it was freaking out much more severely. (in park and AC/Heat off)After it warmed up[/url


http://www.youtube.com/watch?v=7njIxDIolBE
http://www.youtube.com/watch?v=7njIxDIolBE
 

·
Registered
Joined
·
3,900 Posts
Ok first thing is you have a SES light on and please scan and post the fault numbers. Second an idle issue cant be addressed until you address the SES light. And third get rid of those bogus battery repair ends they SUCK and cause all sorts of issues. Peace Tom:bigthumbsup:bigthumbsup:bigthumbsup
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #3 ·
Thanks for the post...

Well at the direction of someone in another forum I cleared the EEC yesterday after cleaning the IAC so it could re-learn the Idle. :doh: The last time I pulled the codes, about 4 months ago this is what I wrote down. (I know its not Ideal, but until it starts throwing them again its all I have)

116 Coolant Temp outside of self test range
172 Lack of Oxygen Sensor (HEGO) Switches indicates Lean
186 Injector Pulse Width higher than expected
411 Cannot control RPM during KOER low RPM check

What Battery repair ends are you referring to? My terminal connectors? They came on the car when I bought it in 2007. are there any you would suggest to replace them with?
 

·
Registered
Joined
·
263 Posts
i just noticed something on your second video, but first you got to tell me if during the whole vid 1. u werent gassing up, cause i heard some clunks and not sure what they are, and 2. besides the tach, what the other two gauges are there that on left?
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #6 ·
I didn't remember hearing the clunks when I was taking the video, just when I watched it (nor have I ever heard them before). both videos were taken of a straight Idle, never pressed the gas in either video. On the left, the Top is the Battery and the bottom is the Engine Temperature.
 

·
Registered
Joined
·
3,900 Posts
Thank You L my son tom JR made it up. He is the show guy on our team. But at my age it is true. With ford just releasing their new 650HP Mustang i have to put more ponies in our builds. Those Factory Boys are giving me headaches to keep in front of those cars at the RED TRAFFIC LIGHTS!!! Thanks Brother:bigthumbsup:bigthumbsup:bigthumbsup
 

·
Registered
Joined
·
3,900 Posts
Josh what you have to do is replace the IAC and buy a new one. Here is a tip. Disconnect the wire from the IAC and set the idle with the MIN idle screw. It is on the throttle boby arm. If the engine idles correctly and does not surge it will tell you that the ECM is trying to compensate for a defect. But you have to clear those codes. If the CTS is out of range the ECM will not go closed loop. That will screw up everything. You must clear those codes and you have to replace the CTS and make sure the ECM is seeing it's imput. Good luck and keep us informed. Peace Tom:bigthumbsup:bigthumbsup:bigthumbsup
 

·
Registered
Joined
·
263 Posts
No prob Tom. Im impressed how FORD finally coming out of muscle coma, since for long time it was just having low powered cars w high sticker price.
As for the problem w the car JPowel have, what I noticed was that he had a battery gauge fluctuating. I happen to have a bad voltage regulator not a while ago, it was flickering so bad that my car was cutting out at times and had erratic idle. That said why don't u look into that as well while testing and adjusting IAc?
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #10 ·
Josh what you have to do is replace the IAC and buy a new one. Here is a tip. Disconnect the wire from the IAC and set the idle with the MIN idle screw. It is on the throttle body arm. If the engine idles correctly and does not surge it will tell you that the ECM is trying to compensate for a defect. But you have to clear those codes. If the CTS is out of range the ECM will not go closed loop. That will screw up everything. You must clear those codes and you have to replace the CTS and make sure the ECM is seeing it's imput. Good luck and keep us informed. Peace Tom:bigthumbsup:bigthumbsup:bigthumbsup
Attached A Picture of what I think your referring to as the "MIN idle screw" am I correct?
 

Attachments

·
Registered
Joined
·
3,900 Posts
Thats correct as L pointed out. That is the MINIMUM idle screw that must be set correctly. After you fix the ECM codes we can discuss that in detail :bigthumbsup:bigthumbsup:bigthumbsup
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #13 ·
lol, Ok. so where is the CTS located? (the one that speaks to the ECM since I think theres two right?) and whats the difficulty level of replacement? never replaced one before.
 

·
Registered
Joined
·
77 Posts
lol, Ok. so where is the CTS located? (the one that speaks to the ECM since I think theres two right?) and whats the difficulty level of replacement? never replaced one before.
On one of the heater core hoses by the firewall. Hardest part was unscrewing the sensor out of the T. Other than that it is easy. Mine had idle problems and this was one of the codes that popped and this replacement helped.
 

·
Registered
Joined
·
3,900 Posts
Engine Coolant Temperature (ECT) Sensor : RH rear of engine, below throttle body --- C174
 

·
Registered
Joined
·
563 Posts
On one of the heater core hoses by the firewall. Hardest part was unscrewing the sensor out of the T. Other than that it is easy. Mine had idle problems and this was one of the codes that popped and this replacement helped.
this location is only on certain models.
 

·
Registered
Joined
·
563 Posts
Attached A Picture of what I think your referring to as the "MIN idle screw" am I correct?
i also noticed something in this picture is that a vacuum line you have wrapped in electrical tape? if so with a MAF system and a vacuum leak it will cause it to do weird things.
 

·
Registered
Joined
·
20 Posts
Discussion Starter · #18 ·
i also noticed something in this picture is that a vacuum line you have wrapped in electrical tape? if so with a MAF system and a vacuum leak it will cause it to do weird things.
Yeah that pic is about 2 years old, it was a quick fix at the time. But I do know I have vacuum issues going on... tedious job to replace them all so I'm planning on my mechanic doing that. :bigthumbsup
 

·
Registered
Joined
·
3,900 Posts
The heater hose sensor is normally for ATC, Peace tom:bigthumbsup:bigthumbsup:bigthumbsup
 
1 - 19 of 19 Posts
Top