Failsafe mode after throttle body cleaning.

[Hunter.shawnRN]

We normally replaced the unit as a whole. Also to the OP. What year is the car? Send me the VIN I want to look at something for you

Will do.. Stand by. Okay guys I'm getting codes and copy cat codes for the the throttle actuator control system. Also when I turn the key and the engine rolls over there is NO throttle response. Furthermore, the pedal is sending a reading so it's not a pedal sensor. I think I'm looking at a faulty throttle body. It's the only variable I can come up with. Again all of the codes are pointing to the throttle control system.

Never heard of killing a TB by actuating the blades manually. I've sat around while my car was in pieces just dickin with the T-body blades. Usually I clean the T-body any time I've had it off the car, which is quite a few times, and when I clean it I get after it with the same CRC MAF cleaner and a toothbrush, pushing the blades open and cleaning around the blade shaft. I've never had issues with my T-body other than replacing a TPS once. You probably could damage the gearing if you were rough enough about it, or fighting the motor while it was online. But moving the blades while the T-body is unpowered will damage it? GTFO and leave the crack pipe behind. Someone lied to you.

OP, any harness or wire you touched needs to be closely inspected. Particularly any harnesses that you removed, such as MAF and TPS/Motor harness. Make sure you look at the pin side and make sure no pins both at the harness and the connector were damaged/bent/loose. Also to verify the TB is actuating properly, as stated above you'll need a helper to turn the car to "on" without starting. While you look at the throttle blades, no intake tube, just exposed. If the T-body opens and shuts, it's prepped for startup. With the key "on" you should have them push the gas pedal slowly, and make sure the throttle blades open accordingly. If all of that works, you need to either sit down with a meter and test your TPS sensor, or just replace it. When having sluggish throttle or bad throttle response, along with other throttle errors, it's a 50/50 bet as to it being a dirty throttle body or a failing/failed TPS sensor. I've never had issues with the T-body being dirty, but I have had to replace the TPS sensor before. It randomly would throw the wrench light at me, I'd shut the car down and restart and it would go away. Days later, it would throw the wrench again. Replaced the TPS and never had a wrench light again. Though I didn't notice bad throttle response before the wrench light.

If you go through the wiring, checking the T-body, checking the TPS, the only other place to look would be the gears. OEM gears don't have a reputation for being faulty, but it could be possible. There is a procedure to servicing them and keeping them clean, but it's important to inspect the gears to make sure none have stripped, in your case. I could see if a gear had stripped a portion of its teeth in the right spot would give you the issues you're describing.

I'm gonna pull this throttle body apart. Gonna take a couple days to get a new one anyhow. Will update on what I find in this thing. Was going to take the car through the mountains this weekend...

 

[Dino Dino Bambino]

Pretty simple... Cleaned the Maf, cleaned the throttle body. Disconnected the battery for 20 minutes to reset the codes.

Now it either won't turn over.. Or turns over and skyrockets to 5k rpm. Then immediately stalls and dies. Absolutely no throttle response. Should I leave the battery unhooked longer? Am I gonna have to tow the car to get it reflashed? 05 mustang gt. K/N air filter. No other mods. Car was running okay before this. Just sluggish throttle response.

You shouldn't need to reflash the ECU. I reckon the problem's something very simple to rectify and you've missed something during the procedure. I suggest you retrace your steps.

 

[Bingo]

Let us know the codes. A dead TB motor will act in this manner.

 

[redfirepearlgt]

You shouldn't need to reflash the ECU. I reckon the problem's something very simple to rectify and you've missed something during the procedure. I suggest you retrace your steps.

This. If the pedal is providing output to the PCM, then the nexrt question is whether the PCM is providing output to the TB motor. Therefore you can also rule out the TPS. So you need to focus on the TB motor and the wiring harness between the motor and the PCM.
The orange /yellow wire is the motor + direction wire.
The Dark Blue/Yellow is the motor - direction wire.



I suggest metering for DC on the motor + wire with respect to ground and see if you get a rising signal with keyon/engine off and someone pressing the foot pedal down. Then do the same thing with the other wire reading the voltage as the pedal is released. If you get no reading try placing the red probe of the meter on the motor + and the black probe on motor - and check that way. Hope this helps. My suspicion is that you have pushed a pin on the motor connector or damaged the mechanical innards while handling the TB during cleaning. I concur with what was written earlier in that simply opening and closing the TB with key off and cleaning it won' t hurt anything, if it gets roughly forced to far open or allowed to just snap closed without showing some caution while cleaning things can get damaged.

Schematic attached - http://iihs.net/fsm/?d=40&f=Electronic Engine Controls - 4.6L.pdf&p=3

Page 3 of 9 BTW.

 

[Hunter.shawnRN]

This. If the pedal is providing output to the PCM, then the nexrt question is whether the PCM is providing output to the TB motor. Therefore you can also rule out the TPS. So you need to focus on the TB motor and the wiring harness between the motor and the PCM.
The orange /yellow wire is the motor + direction wire.
The Dark Blue/Yellow is the motor - direction wire.



I suggest metering for DC on the motor + wire with respect to ground and see if you get a rising signal with keyon/engine off and someone pressing the foot pedal down. Then do the same thing with the other wire reading the voltage as the pedal is released. If you get no reading try placing the red probe of the meter on the motor + and the black probe on motor - and check that way. Hope this helps. My suspicion is that you have pushed a pin on the motor connector or damaged the mechanical innards while handling the TB during cleaning. I concur with what was written earlier in that simply opening and closing the TB with key off and cleaning it won' t hurt anything, if it gets roughly forced to far open or allowed to just snap closed without showing some caution while cleaning things can get damaged.

Schematic attached - http://iihs.net/fsm/?d=40&f=Electronic Engine Controls - 4.6L.pdf&p=3

Page 3 of 9 BTW.

I'll check the wires! I've got the TB off. How should it feel on these? Again, coming from someone who has always had vehicles with mechanical throttles.. This one sticks where I leave it.. No feeling of springyness.. Is that a word??... It stays exactly where it's left.. It also will not open at all under any amount of pedal manipulation.

 

[Bingo]

I'll check the wires! I've got the TB off. How should it feel on these? Again, coming from someone who has always had vehicles with mechanical throttles.. This one sticks where I leave it.. No feeling of springyness.. Is that a word??... It stays exactly where it's left.. It also will not open at all under any amount of pedal manipulation.

The spring should snap it back to the closed position. I'd take the cover off and make sure the spring is seated properly and the gears are OK. If still no joy, my money is on the motor.

 

[rickf]

It should be fairly hard to open, in fact they are a real pain in the ass to clean for that very reason. They can cut your finger tip off if they catch the joint just right with the blade so you have an issue there. It is best to just get a new one. Don't fall for the hype on the big bore throttle bodies, you don't need it. The stock throttle body will support up to 500 plus HP.

This. If the pedal is providing output to the PCM, then the nexrt question is whether the PCM is providing output to the TB motor. Therefore you can also rule out the TPS. So you need to focus on the TB motor and the wiring harness between the motor and the PCM.
The orange /yellow wire is the motor + direction wire.
The Dark Blue/Yellow is the motor - direction wire.



I suggest metering for DC on the motor + wire with respect to ground and see if you get a rising signal with keyon/engine off and someone pressing the foot pedal down. Then do the same thing with the other wire reading the voltage as the pedal is released. If you get no reading try placing the red probe of the meter on the motor + and the black probe on motor - and check that way. Hope this helps. My suspicion is that you have pushed a pin on the motor connector or damaged the mechanical innards while handling the TB during cleaning. I concur with what was written earlier in that simply opening and closing the TB with key off and cleaning it won' t hurt anything, if it gets roughly forced to far open or allowed to just snap closed without showing some caution while cleaning things can get damaged.

Schematic attached - http://iihs.net/fsm/?d=40&f=Electronic Engine Controls - 4.6L.pdf&p=3

Page 3 of 9 BTW.

You are missing a key component in the mix here. The throttle pedal sensors send their signal to the throttle pedal module which compares all three signals from the pedal and also compares those with the two signals from the two TPS's on the throttle body and then all of that is in turn sent to the PCM. It is the throttle pedal module that determines whether the pedal signals are sent or if codes are set. In this case he is getting codes since the TPS's are not seeing the right movement of the blades compared to the pedal sensors.

 

[Hunter.shawnRN]

It should be fairly hard to open, in fact they are a real pain in the ass to clean for that very reason. They can cut your finger tip off if they catch the joint just right with the blade so you have an issue there. It is best to just get a new one. Don't fall for the hype on the big bore throttle bodies, you don't need it. The stock throttle body will support up to 500 plus HP.



You are missing a key component in the mix here. The throttle pedal sensors send their signal to the throttle pedal module which compares all three signals from the pedal and also compares those with the two signals from the two TPS's on the throttle body and then all of that is in turn sent to the PCM. It is the throttle pedal module that determines whether the pedal signals are sent or if codes are set. In this case he is getting codes since the TPS's are not seeing the right movement of the blades compared to the pedal sensors.

But would that really cause engine failsafe? Would make sense but there's no feedback from the throttle body whatsoever.

 

[rickf]

You said you have codes from the throttle actuator control system, That is what tells the throttle to work through the PCM. Once you open it up you are going to find something broken in there, It was probably on it's way out before you started with the cleaning. That was probably the original problem all along. Once you replace the throttle body you will probably find the problems are solved. Just a hint here, once it starts just let it idle for ten minutes or so to establish the idle strategy. So many people want to romp right into it and that just screws with the PCM and makes for a long idle learn process.

 

[stkjock]

A bad stepper motor will 100% cause failsafe. I know from experience 2x

 

[Brandon08GT]

It should be fairly hard to open, in fact they are a real pain in the ass to clean for that very reason. They can cut your finger tip off if they catch the joint just right with the blade so you have an issue there. It is best to just get a new one. Don't fall for the hype on the big bore throttle bodies, you don't need it. The stock throttle body will support up to 500 plus HP.

Is it really that difficult to clean? I just cleaned mine last week because I had been having an issue as well. It didn't seem like it was that difficult to open the blades to be able to clean all the junk. I still havent found exactly whats wrong so this has me thinking that maybe the motor is going out? I will occasionally have a hanging throttle and it seems somewhat sluggish after I try to accelerate.

Didnt mean to thread jack. Really curious as to what OP finds when he opens it up.

 

[redfirepearlgt]

I'll check the wires! I've got the TB off. How should it feel on these? Again, coming from someone who has always had vehicles with mechanical throttles.. This one sticks where I leave it.. No feeling of springyness.. Is that a word??... It stays exactly where it's left.. It also will not open at all under any amount of pedal manipulation.

That would be a bad thing. The spring is there to assist the return of the blade to the idle position along with the feedback signal reversing to drive the motor back closed. So it sounds like you do have a damaged motor assembly IMHO.

All the documentation I have read on advanced tuning states that the 2005 Mustang GT uses torque based TB position control vice the "pedal follower" style of control rickf has described, which predates Torue-based control. The process is very complex and I admit after reading the vague theory of operation on it in Greg Banishes book(Engine Management:advanced tuning - chapter 5 page 42,43) twice I am still somewhat dizzied by it beyound the surface level. The schematics for the 2005 indicate that the accel pedal sensor, TB motor, and TPS sensor each feed directly back to the PCM and never directly to each other in the system. That means that the PCM controls the TB position from data provided by the accel pedal as well as other data such as torque demand, etc.

schematics for reference -
http://iihs.net/fsm/?d=40&f=Electronic%20Engine%20Controls%20-%204.6L.pdf&p=3
http://iihs.net/fsm/?d=40&f=Electronic Engine Controls - 4.6L.pdf&p=8

 

[Hunter.shawnRN]

Picking up a throttle body today. Will update you guys. Didn't get into the old TB today.. Football this weekend lol.

 

[Hunter.shawnRN]

The spring should snap it back to the closed position. I'd take the cover off and make sure the spring is seated properly and the gears are OK. If still no joy, my money is on the motor.

You were right! That throttle body was shot. The spring no longer pulled closed.

Car now runs. Still runs like shit. I'm getting some codes off my reader. P0
174 (system too lean Bank 2) p0011 (A camshaft positioning.. Timing over advanced) p0171(system too lean Bank 1).

Car had Zero codes at startup with new TB.. Let idle for 15 minutes.. Cruised down the street.. In second gear about 30mph it started to stumble all over itself and would not accelerate until I dropped the pedal harder.. Codes came up and then it grabbed and launched.. On its own sweet time. Car also feels like it's hesitating at cruising speeds on the highway.. Most noticeable on low acceleration with cruise control engaged.

Any input is appreciated

 

[Hunter.shawnRN]

Car is also dumping fuel.. Maybe 10mpg

 

[rickf]

You dropped the pedal with cam timing codes!!!!!!!

Have you wiped the KAM since all of this started? I would strongly suggest you do it now and then start it again and if you get the cam code investigate it. Check the plugs on the VCT solenoids. Check the cam position sensor plugs.

 

[Hunter.shawnRN]

You dropped the pedal with cam timing codes!!!!!!!

Have you wiped the KAM since all of this started? I would strongly suggest you do it now and then start it again and if you get the cam code investigate it. Check the plugs on the VCT solenoids. Check the cam position sensor plugs.

You mean by letting it sit with the battery disconnected?.. Yes I have.

There were not any codes when I dropped the pedal.. It hesitated and would not accelerate.. Like someone was choking the engine. I nudged the pedal along and it eventually evened our and accelerated like there was too much gas in the ignition chamber. Then it lit up the CEL

 

[702GT]

Pretty simple... Cleaned the Maf, cleaned the throttle body. Disconnected the battery for 20 minutes to reset the codes.

Now it either won't turn over.. Or turns over and skyrockets to 5k rpm. Then immediately stalls and dies. Absolutely no throttle response. Should I leave the battery unhooked longer? Am I gonna have to tow the car to get it reflashed? 05 mustang gt. K/N air filter. No other mods. Car was running okay before this. Just sluggish throttle response.

You were right! That throttle body was shot. The spring no longer pulled closed.

Car now runs. Still runs like shit. I'm getting some codes off my reader. P0
174 (system too lean Bank 2) p0011 (A camshaft positioning.. Timing over advanced) p0171(system too lean Bank 1).

Car had Zero codes at startup with new TB.. Let idle for 15 minutes.. Cruised down the street.. In second gear about 30mph it started to stumble all over itself and would not accelerate until I dropped the pedal harder.. Codes came up and then it grabbed and launched.. On its own sweet time. Car also feels like it's hesitating at cruising speeds on the highway.. Most noticeable on low acceleration with cruise control engaged.

Any input is appreciated

This all started from cleaning the TB & MAF? You didn't by chance hose the whole motor with a pressure washer?

When you decided to clean the TB/MAF, what troubles were you having with the car exactly? Were they the same issues as described above?

 

[Hunter.shawnRN]

This all started from cleaning the TB & MAF? You didn't by chance hose the whole motor with a pressure washer?

When you decided to clean the TB/MAF, what troubles were you having with the car exactly? Were they the same issues as described above?

No sir I did not pressure wash it... I know better haha.. And pretty similar issues.. Just terrible mpg and overall bad drivability... Sometimes it seems to run allot better than others. By that I mean it won't studder and my mpg is decent... Other times it sucks gas like nothing I've ever drove and just drives rough. The throttle response is better now.. But, the other issues remain.

 

[Juice]

No sir I did not pressure wash it... I know better haha.. And pretty similar issues.. Just terrible mpg and overall bad drivability... Sometimes it seems to run allot better than others. By that I mean it won't studder and my mpg is decent... Other times it sucks gas like nothing I've ever drove and just drives rough. The throttle response is better now.. But, the other issues remain.

Since your lean codes point to bank 1, I would check the 02 sensor. Easiest thing to do is swap the left and right 02 sensors and see if the lean codes move to bank 2 after sensor swap.