MP3 turbo idle problems!
January-4th-2003, 07:06 PM
#1
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Join Date: Jul 2002
Location: New Hampshire
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MP3 turbo idle problems!
Alright I have been battling this damn idle issue for severa months now. It all started after my turbo install.
Basicly the cars idle when the clutch is pressed in even while driving slow can fall to almost 0 RPM. If I am going 60 and I press and hold the clutch the RPMs will fall to 0 then return up to 800. If I accelerate then immedatly press in the clutch, the car will stall then a second later restart itself. Also the idle is the worst when the head lights are on. When switched on they can drop the idle to about 200 RPM.
So far I have confirmed there are no intake leaks by spraying choke cleaner on all joints, welds and connections after the maf and all over the intercooler to ensure no leaks. I have released the idle screw so far that it is all but come out.
THe VAC on the car is 20-21 PSI is great according to both Flyin miata and BEGI and rules out the possibility of a vacuum leak.
The idle fuel pressure is 35 PSI which is within range.
HELP!!!!!!!!!!!!!!
Basicly the cars idle when the clutch is pressed in even while driving slow can fall to almost 0 RPM. If I am going 60 and I press and hold the clutch the RPMs will fall to 0 then return up to 800. If I accelerate then immedatly press in the clutch, the car will stall then a second later restart itself. Also the idle is the worst when the head lights are on. When switched on they can drop the idle to about 200 RPM.
So far I have confirmed there are no intake leaks by spraying choke cleaner on all joints, welds and connections after the maf and all over the intercooler to ensure no leaks. I have released the idle screw so far that it is all but come out.
THe VAC on the car is 20-21 PSI is great according to both Flyin miata and BEGI and rules out the possibility of a vacuum leak.
The idle fuel pressure is 35 PSI which is within range.
HELP!!!!!!!!!!!!!!
January-4th-2003, 09:38 PM
#5
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Join Date: Jan 2002
Location: Dallas, Texas
Posts: 1,122
Does the car run fine otherwise? Have you checked the OBD-II for codes?
If the answers are (1) yes and (2) there are none, my money is on the IAC (Idle Air Control valve, if you didn't already know that).
It's the big electric-motor shaped thing on top of the throttle body; it will have a vacuum hose leading to the intake manifold.
FSM procedures for checking the IAC:
(1) Warm the car up to normal operating temperature. Unplug electrical connector to IAC. Engine should immediately stall or idle rpms should drop almost to zero (kinda like what your car does with the IAC plugged in).
If engine rpm increases or does not change much, proceed to step 2. [I betcha that unplugging your IAC makes little or no difference.]
(2) Unplug negative battery cable and IAC. Measure the resistance between the 2 eletrical terminals on the IAC. Resistance should be 7.7-9.3 ohms at room temperature. If not as specified, replace IAC.
(3) If step 2 checks out OK, inspect for open or short circuit between the IAC harness connector and terminals 54 and 83 on the ECU.
Good luck!
If the answers are (1) yes and (2) there are none, my money is on the IAC (Idle Air Control valve, if you didn't already know that).
It's the big electric-motor shaped thing on top of the throttle body; it will have a vacuum hose leading to the intake manifold.FSM procedures for checking the IAC:
(1) Warm the car up to normal operating temperature. Unplug electrical connector to IAC. Engine should immediately stall or idle rpms should drop almost to zero (kinda like what your car does with the IAC plugged in).
If engine rpm increases or does not change much, proceed to step 2. [I betcha that unplugging your IAC makes little or no difference.](2) Unplug negative battery cable and IAC. Measure the resistance between the 2 eletrical terminals on the IAC. Resistance should be 7.7-9.3 ohms at room temperature. If not as specified, replace IAC.
(3) If step 2 checks out OK, inspect for open or short circuit between the IAC harness connector and terminals 54 and 83 on the ECU.
Good luck!
January-4th-2003, 10:28 PM
#6
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Join Date: Jul 2002
Location: New Hampshire
Posts: 720
Thanks for the help so far guys, I will do all that was advised tomarrow morining.
2 questions.
1. Where exactly is the IAC sensor? Is that at the top of the throatle body, since there are several clips on that damn thing? Does anything distiquish it?
2. If I inspect the AIC terminals to the ECU shouldn't each pin show a short circuit, AKA direct connection, to at least one of the ECU pins? I would assume its an open circuit or a short to ground that would be a problem?
Sorry to continue to prod but I am not fmilair under the hood of this car as I should be.
2 questions.
1. Where exactly is the IAC sensor? Is that at the top of the throatle body, since there are several clips on that damn thing? Does anything distiquish it?
2. If I inspect the AIC terminals to the ECU shouldn't each pin show a short circuit, AKA direct connection, to at least one of the ECU pins? I would assume its an open circuit or a short to ground that would be a problem?
Sorry to continue to prod but I am not fmilair under the hood of this car as I should be.
January-5th-2003, 04:01 PM
#7
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Join Date: Jul 2002
Location: New Hampshire
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I pulled the grey clip and nothing happened. It just kept going. I also checked the impedance of the valve and of the grey clip. The grey clip was 11.49 volts dc and the valve was 9.0 volts dc.
I had let the engine warm for about 10 minutes before doing anything but it is 30 degrees out so I don't know if that was long enough.
I took the cylinder part of the IAC valve off and it was covered with black seposites.
I didn't take the peice off the trottle body but I did notice it also had alot of black deposites.
After reinstilation and computer reset the car would not even idle at first and just stalled. I had to hold the gas down and let it rev for 5 minutes then it was able to hold itself. It still idles low and will al but stall if the lights are turned on.
I also check the charging voltage and its at 15 volts, aftermarket alternator, so that OK too.
I had let the engine warm for about 10 minutes before doing anything but it is 30 degrees out so I don't know if that was long enough.
I took the cylinder part of the IAC valve off and it was covered with black seposites.
I didn't take the peice off the trottle body but I did notice it also had alot of black deposites.
After reinstilation and computer reset the car would not even idle at first and just stalled. I had to hold the gas down and let it rev for 5 minutes then it was able to hold itself. It still idles low and will al but stall if the lights are turned on.
I also check the charging voltage and its at 15 volts, aftermarket alternator, so that OK too.
January-6th-2003, 08:23 AM
#8
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Join Date: Jan 2002
Location: Dallas, Texas
Posts: 1,122
Originally posted by 1st MP3 in NH
1. Where exactly is the IAC sensor? Is that at the top of the throatle body, since there are several clips on that damn thing? Does anything distiquish it?
1. Where exactly is the IAC sensor? Is that at the top of the throatle body, since there are several clips on that damn thing? Does anything distiquish it?
To the immediate left of the "Injen" logo in this picture:
http://www.surfergeek.net/protege5/i...take%2019.html
Top dead center of this picture, partially cut off by the edge of the frame. The gray connector at right is the one to unplug to test the IAC:
http://www.surfergeek.net/protege5/i...take%2014.html
Got it?
Last edited by carguycw; January-6th-2003 at 08:28 AM.
January-6th-2003, 08:27 AM
#9
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Join Date: Jan 2002
Location: Dallas, Texas
Posts: 1,122
Originally posted by 1st MP3 in NH
I pulled the grey clip and nothing happened. It just kept going. I also checked the impedance of the valve and of the grey clip. The grey clip was 11.49 volts dc and the valve was 9.0 volts dc.
I pulled the grey clip and nothing happened. It just kept going. I also checked the impedance of the valve and of the grey clip. The grey clip was 11.49 volts dc and the valve was 9.0 volts dc.
If you've got an old-school analog multitester, you may be reading the wrong scale on the meter face.After hearing your description of the problem, if you unplugged the right connector I am almost certain it's the IAC. My car immediatly stalls when I unplug it. If the car's idle behavior doesn't change, the IAC *must* be broken.
Last edited by carguycw; January-6th-2003 at 08:30 AM.
January-6th-2003, 08:41 AM
#10
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Join Date: Sep 2001
Location: Miami, FL
Posts: 116
Re: MP3 turbo idle problems!
Originally posted by 1st MP3 in NH
Alright I have been battling this damn idle issue for severa months now. It all started after my turbo install.
Basicly the cars idle when the clutch is pressed in even while driving slow can fall to almost 0 RPM. If I am going 60 and I press and hold the clutch the RPMs will fall to 0 then return up to 800. If I accelerate then immedatly press in the clutch, the car will stall then a second later restart itself. Also the idle is the worst when the head lights are on. When switched on they can drop the idle to about 200 RPM.
So far I have confirmed there are no intake leaks by spraying choke cleaner on all joints, welds and connections after the maf and all over the intercooler to ensure no leaks. I have released the idle screw so far that it is all but come out.
THe VAC on the car is 20-21 PSI is great according to both Flyin miata and BEGI and rules out the possibility of a vacuum leak.
The idle fuel pressure is 35 PSI which is within range.
HELP!!!!!!!!!!!!!!
Alright I have been battling this damn idle issue for severa months now. It all started after my turbo install.
Basicly the cars idle when the clutch is pressed in even while driving slow can fall to almost 0 RPM. If I am going 60 and I press and hold the clutch the RPMs will fall to 0 then return up to 800. If I accelerate then immedatly press in the clutch, the car will stall then a second later restart itself. Also the idle is the worst when the head lights are on. When switched on they can drop the idle to about 200 RPM.
So far I have confirmed there are no intake leaks by spraying choke cleaner on all joints, welds and connections after the maf and all over the intercooler to ensure no leaks. I have released the idle screw so far that it is all but come out.
THe VAC on the car is 20-21 PSI is great according to both Flyin miata and BEGI and rules out the possibility of a vacuum leak.
The idle fuel pressure is 35 PSI which is within range.
HELP!!!!!!!!!!!!!!
I feel ya brotha!! I've got the same exact problem... It's your blow off valve... close that thing and you won't have much of a problem. Me? I deal with it and open it as little as possible. Let me know if you come across another solution!
January-11th-2003, 04:06 PM
#13
Protege Owner
Thread Starter
Join Date: Jul 2002
Location: New Hampshire
Posts: 720
Originally posted by carguycw
Courtesy of a little creative thread searching:
To the immediate left of the "Injen" logo in this picture:
http://www.surfergeek.net/protege5/i...take%2019.html
Top dead center of this picture, partially cut off by the edge of the frame. The gray connector at right is the one to unplug to test the IAC:
http://www.surfergeek.net/protege5/i...take%2014.html
Got it?
Courtesy of a little creative thread searching:
To the immediate left of the "Injen" logo in this picture:
http://www.surfergeek.net/protege5/i...take%2019.html
Top dead center of this picture, partially cut off by the edge of the frame. The gray connector at right is the one to unplug to test the IAC:
http://www.surfergeek.net/protege5/i...take%2014.html
Got it?
January-11th-2003, 04:11 PM
#14
Protege Owner
Thread Starter
Join Date: Jul 2002
Location: New Hampshire
Posts: 720
Originally posted by carguycw
You should double check what you're measuring. Resistance is measured in ohms, not volts (the little horseshoe-shaped sign, for the electrically impaired.). If you've got an old-school analog multitester, you may be reading the wrong scale on the meter face.
After hearing your description of the problem, if you unplugged the right connector I am almost certain it's the IAC. My car immediatly stalls when I unplug it. If the car's idle behavior doesn't change, the IAC *must* be broken.
You should double check what you're measuring. Resistance is measured in ohms, not volts (the little horseshoe-shaped sign, for the electrically impaired.).
If you've got an old-school analog multitester, you may be reading the wrong scale on the meter face.After hearing your description of the problem, if you unplugged the right connector I am almost certain it's the IAC. My car immediatly stalls when I unplug it. If the car's idle behavior doesn't change, the IAC *must* be broken.
January-11th-2003, 04:12 PM
#15
Protege Owner
Thread Starter
Join Date: Jul 2002
Location: New Hampshire
Posts: 720
Originally posted by Linuxninja
I do remember replacing my BOV after the side port came completely off and the idle got better for a time being. Hmmm....could history be repeating for me...
I do remember replacing my BOV after the side port came completely off and the idle got better for a time being. Hmmm....could history be repeating for me...