A Word of Caution.... Stuck Throttle Body

[STORMCAT]

Last night at about 12:00 am I had a very interesting moment while taking a friend for I ride. I was wound out in 3rd gear and let off the throttle to let the car slow down on it's own. To my surprise she did slow down.. I did not panic. I applied the brakes but at that speed and with the engine making power. This was not a quick solution. I pushed it the clutch and the motor hit the rev limiter.. I shut of the ignition and coasted about a 1/4 mile to a gas station.

I quickly jumped out and popped the rear deck lid. After a quick inspect of the Throttle Body ( TB ) it was stuck about 1/3 open. I could open it fully but when released it would not return to the normal resting position.

I cycled the TB about 10 times and when released it snapped back but felt weird like it was hitting something soft. After a few more cycles it closed and felt normal. At that time of night and with no tools it was not the best place to start tearing her apart. We started her up and eased her back to the shop.

Today I started to take it her apart. Really curious to what had happed and why Throttle plate freed up again. In the back of my mind I was thinking if I didn't find anything obvious I was going to live in fear that this could happen again anytime which is not a comforting thought.

I first pulled the bellows section out to look directly in the TB and inspect the butterflies. They looked normal and operated smoothly. I than looked inside the bellows section. I have an Accufab stiffener. When the TB was stuck open I was thinking maybe the Accufab stiffener had shifted or part of it broke off and lodged in the TB opening ?? It was fine .. At this point I was not happy about not finding anything obviously wrong.

I than looked into the outlet tube of the air box. With the bellows off you can see the back side of the air filters. Well , well I found a very obvious and unexpected problem. The filters were pushed down in the housing and un seated from the sealing channel. There were two large chunks of the seal laying on top / back side of the filter..
These two chunks were off the long side of the filter. The total length of the long side is about 8 " These two pieces added up to be about 4". I just watched Sherlock Holmes and I quickly concluded that the soft blockage I felt was,,, yes you guessed it was part of the air filter seal stuck in the TB.

I dissembled the air box to look a the air filters and see of some of the seal and fallen to the bottom of the air box. sad to say there was no pieces there so you guessed it... the missing 4" of the air filter seal was sucked into Super Charger and shredded to bits.. And you know where the remains would be resting.. Yes you are correct. They were nicely collected under the Super Charger on top of the Inter cooler.

I vacuumed out all of the large bits and sent a considerable amount of time getting the fine bits out of the small finned openings of the inter cooler.

Tomorrow I'll do some more cleaning and service the SC fluid while she's off.

I'm not sure what to say but I can give you these facts. The rubber seals on these filters was brittle and degraded upon inspection . They both were brittle and cracked. I just installed these new Ford Motor Craft filters before the rally so they have only seen about 500 miles of use.
They fit fine in the housing. The seals were soft and formable upon installation. The housing halves went back together smoothly. I have performed several air filters changes before so I am ruling out any installation issues ??
Maybe it was a bad batch of rubber or not cured properly. I have done a search and have never heard of this problem. I am not trying to cause panic . I just want you to be aware that a stuck throttle could happen to anyone at any moment . Hopefully this is an isolated case. It's a PIA to take apart the SC and clean the IC but I am very thankful nothing else bad happened to the vehicle !!

Bill or Kendal any thoughts on why the filters were pushed down? The natural suction should have drawn them Up not Down ??

 

[STORMCAT]

More photos.
This is the only other thing I could find here discussing a stuck throttle ??
http://www.fordgtforum.com/forums/showthread.php?t=2071&highlight=Throttle+stuck

 

[BlackICE]

Not only are you a Fast Cat, but a Cool Cat as well. You didn't panic and safely stopped your car. Some Toyota owners fail to do the right thing and crash into stuff when the motor goes nuts from "floor mats." A Toyoda with a automatic tranny and keyless access, turning the motor off isn't intuitive. You have to hold the start/stop button down for 3 seconds.

Maybe those record speeds at the TX mile under 110F+ did the seals in.

 

[ChipBeck]

Post of the month.

Stormcat,

That was an outstanding post and photos. I'm glad everything worked out. If this had to happen it's better that it was to one of our more technically astute members who was able to understand it, find it, fix it, document it, and photograph it for the rest of us. It'll be interesting to find out if anyone else has had their air filters come apart in this manner.

Thanks again for a great, great post.

Chip

 

[Fyr-FtrGT]

I wonder how many GTs will have their airbox taken apart and filters inspected tomorrow, (Sunday) morning. There are two in my garage that will be checked post haste.

Thank you Stormcat for the heads up.

Gary T.

 

[fjpikul]

Dear KittyCat, remember when I posted about the strange new filters I got and the poor fit on one side? I had to trim the foam edge aout 1/8 inch to get it to seat correctly. Now I would NEVER doubt your mechanical abilities, but do you think it might have been a poor fitting filter and the excess caused the edge to shear off due to heat? Glad there was no apparent permanent damage. You weren't hot rodding in the tunnel again, were you?

 

[Empty Pockets]

"I pushed it the clutch and the motor hit the rev limiter.. I shut of the ignition and coasted about a 1/4 mile to a gas station"


Doesn't the steering column LOCK when the ign is shut off?????

How the heck did you steer it?:eek

 

[BlackICE]

"I pushed it the clutch and the motor hit the rev limiter.. I shut of the ignition and coasted about a 1/4 mile to a gas station"


Doesn't the steering column LOCK when the ign is shut off?????

How the heck did you steer it?:eek

EP, those of us that actually drive cars, know that the key as two positions with the ignition off, The 1st just shuts the engine off and if you turn the key a little more the steering lock engages. You have to be very careful not to turn the key too far. You can give it a try the next time you sit in one of your cars in your garage with complete safety. :rofl

 

[Empty Pockets]

EP, those of us that actually drive cars, know that the key as two positions with the ignition off, The 1st just shuts the engine off and if you turn the key a little more the steering lock engages. You have to be very careful not to turn the key too far. You can give it a try the next time you sit in one of your cars in your garage with complete safety. :rofl

Thank you, Grand Master Yoda, for my unworthy self has never been privy to this information before...having lead the far too sheltered life I have. I'm am forever in your debt, oh, knowledgable one.:bow:bow:bow



(Actually, that's no bull! I did NOT know that! :frown)

 

[Shadowman]

Last night at about 12:00 am I had a very interesting moment while taking a friend for I ride. I was wound out in 3rd gear and let off the throttle to let the car slow down on it's own. To my surprise she did slow down.. I did not panic. I applied the brakes but at that speed and with the engine making power. This was not a quick solution. I pushed it the clutch and the motor hit the rev limiter.. I shut of the ignition and coasted about a 1/4 mile to a gas station.

I quickly jumped out and popped the rear deck lid. After a quick inspect of the Throttle Body ( TB ) it was stuck about 1/3 open. I could open it fully but when released it would not return to the normal resting position.

I cycled the TB about 10 times and when released it snapped back but felt weird like it was hitting something soft. After a few more cycles it closed and felt normal. At that time of night and with no tools it was not the best place to start tearing her apart. We started her up and eased her back to the shop.

Today I started to take it her apart. Really curious to what had happed and why Throttle plate freed up again. In the back of my mind I was thinking if I didn't find anything obvious I was going to live in fear that this could happen again anytime which is not a comforting thought.

I first pulled the bellows section out to look directly in the TB and inspect the butterflies. They looked normal and operated smoothly. I than looked inside the bellows section. I have an Accufab stiffener. When the TB was stuck open I was thinking maybe the Accufab stiffener had shifted or part of it broke off and lodged in the TB opening ?? It was fine .. At this point I was not happy about not finding anything obviously wrong.

I than looked into the outlet tube of the air box. With the bellows off you can see the back side of the air filters. Well , well I found a very obvious and unexpected problem. The filters were pushed down in the housing and un seated from the sealing channel. There were two large chunks of the seal laying on top / back side of the filter..
These two chunks were off the long side of the filter. The total length of the long side is about 8 " These two pieces added up to be about 4". I just watched Sherlock Holmes and I quickly concluded that the soft blockage I felt was,,, yes you guessed it was part of the air filter seal stuck in the TB.

I dissembled the air box to look a the air filters and see of some of the seal and fallen to the bottom of the air box. sad to say there was no pieces there so you guessed it... the missing 4" of the air filter seal was sucked into Super Charger and shredded to bits.. And you know where the remains would be resting.. Yes you are correct. They were nicely collected under the Super Charger on top of the Inter cooler.

I vacuumed out all of the large bits and sent a considerable amount of time getting the fine bits out of the small finned openings of the inter cooler.

Tomorrow I'll do some more cleaning and service the SC fluid while she's off.

I'm not sure what to say but I can give you these facts. The rubber seals on these filters was brittle and degraded upon inspection . They both were brittle and cracked. I just installed these new Ford Motor Craft filters before the rally so they have only seen about 500 miles of use.
They fit fine in the housing. The seals were soft and formable upon installation. The housing halves went back together smoothly. I have performed several air filters changes before so I am ruling out any installation issues ??
Maybe it was a bad batch of rubber or not cured properly. I have done a search and have never heard of this problem. I am not trying to cause panic . I just want you to be aware that a stuck throttle could happen to anyone at any moment . Hopefully this is an isolated case. It's a PIA to take apart the SC and clean the IC but I am very thankful nothing else bad happened to the vehicle !!

Bill or Kendal any thoughts on why the filters were pushed down? The natural suction should have drawn them Up not Down ??

First and foremost I am glad that you are alright and that your gal weathered the storm

Now having shared this; the post was excellent and a reason that like clockwork I inspect the filters even though IMO the process is needlessly complicated.

I have thoughts on what took place however want to look at a few things first nonetheless the debris as traveled through her should be of no concern as it was injested and then promptly spit out with no harm caused; on this can assure you. Then add to this your removing the supercharger and vacuuming the charge cooler was “perfect”.

I will make another comment in a couple days

Takes care

Shadowman

 

[RALPHIE]

...Bill or Kendal any thoughts on why the filters were pushed down? The natural suction should have drawn them Up not Down ??

Brian - it would appear that deformation in that direction would only be caused by a pressure surge from the engine side of the filter, such as would occur if the engine backfired. Does this car have a standard factory tune since the filters were changed? Or do you run a modified tuning program?

 

[Pete S.]

I am certain the correct inspection of these filters has been made, I just want to add I have, in the past, found evidence of mice/rodents in that area of the car, as well as others. Just want you to check for "bite" marks. Great job staying relaxed. I had the same issue one day at a 1/4 mile drag strip and simply reached over and hit the kill button, as even with a strap around the accelerator over my toes for "lifting" the throttle back up failed. I suppose it might present a big problem in a high speed turn, but on straights, not so much. Either way: great post.

Pete S.

 

[Hydra GT]

Brian,
Very nice post and pictures! So many little things that can cause a major problem. I have the K&N filters and will look at them this week. I bet it was tough to get some sleep after this happened. Glad you, your passenger and Helenor are safe!

 

[Shadowman]

Brian - it would appear that deformation in that direction would only be caused by a pressure surge from the engine side of the filter, such as would occur if the engine backfired. Does this car have a standard factory tune since the filters were changed? Or do you run a modified tuning program?

RALPHIE; I agree that mechanically this is the most plausible explanation because it is only under this time that the throttle blade would be likely at WOT.

Takes care

Shadowman

 

[pauleddy]

Brian,
An excellent post and thanks for the pic's. I'm assuming that your filters were the recommended FORD. Have you considered using K&N's. I've had no problems with K&N what so ever, (I change them out regularly) have noticed a slight gain in power by using them vs FORD's and I've 9K+ miles on #1049.
Any Forum Members welcome to chime in with opinions FORD vs K&N.
Best,
Paul

 

[tmcphail]

Brian is using one of my calibrations

 

[soroush]

glad you are alright Brian.

I have the K&N's I like them ok, you may want to get a set and compare the two.

 

[PL510*Jeff]

AnalogueDesigner posted this in 2006:

I think that another one of my original concerns about air filter performance and quality revolved around overall engine life. If a K & N air filter allows more dirt particles (almost 10 times more) into you intake system, how will this affect overall engine life? (Refer to the "Accumulative Gain" graph) at: http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
This whole K & N "thing" started with me about 15-20 years ago when professional race car drivers that I knew quit using them. This was because near the ending of the race, they were losing too much horsepower due to the higher restriction once the filter had accumulated too much airborne dirt from the track. At first, I was skeptical about their claims. Now after close analysis of that excellent filter test, it completely validates their claims.

The only claims that I could find about K & N's air filtering tests, is that they use the easier (my opinion only, since the ISO 5011 is much more "bastard" of a test) "SAE J726 procedure, which uses dirt particle sizes from 5.5 microns to 176 microns." They claim that the majority of engine wear is caused by dirt particles ranging from 10 to 20 microns in size. (I cannot locate any data proving this as perhaps larger sized dirt particles may eventually get picked up by the oil filter).

So, as I mentioned earlier, it could boil down to engine life.

Now, what I feel really matters is a new product that I have designed and have been testing for quite a while which minimizes the collapsing of the flexible air inlet coupling hose. At high engine RPM's, this should provide more flow improvement than any aftermarket air filter. Please note image below of what can occur at high RPM's with a very warm (heat soaked) engine compartment. I will have more on this later in the week as right now ..... Jay

 

[ViperJoe]

Please note image below of what can occur at high RPM's with a very warm (heat soaked) engine compartment.[/FONT][/FONT]

Please post image.

 

[PL510*Jeff]

Please post image.

I haven't a clue as how to do that.

Jay's coment was regarding the air inlet tube. I did a search "Air Filters", and found this on page #7, Titled Inlet Sleeve, dated 5/8/2006 and is item #18.

Hope this helps

Jeff