2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.
Sponsored by:

Cold Engine Redlining

Thread Tools
 
Search this Thread
 
Old 05-14-15, 09:17 PM
  #1  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Cold Engine Redlining

So need some other ideas, I haven't tried any yet (planned tomorrow) I started the 7 today (been sitting about a week) and it immediately shot up to redline. Got the g/f to help, I popped the hood, made sure the throttle plates were moving freely and not stuck (not) and had her fire it up, same thing, shot right up to redline, so I held the TB shut, had her start it again, same thing. So then I asked her if it was in gear, she said no....ok..maybe the AWS is acting up, put it in gear, turned it over, hit redline again WHILE I held the throttle shut.

Any ideas where to start looking? Last time I drove the car it ran perfect like it always has, steady 750 rpm idle, never missed a beat, ran smooth

My plans tomorrow, weather permitting, is to try unhooking the BAC valve to see if that makes a difference (I wouldn't think it would be able to change the idle that much)

Actually visually see if the throttle plates are closed (fairly certain they are as the linkages are in the closed position)

Other than that I'm stumped

88 S4 stock engine (110K ish miles)
5/6th ports removed/blocked off along with the ACV
Racing Beat Street Header
Minor porting on the lower intake manifold (performed this over a year ago along with everything above)
El cheapo "spectre" cone air filter

Any help and thoughts are appreciated, weird that it happened when its just sat, but weirder things can happen

Last edited by lduley; 05-14-15 at 09:19 PM.
Old 05-14-15, 10:09 PM
  #2  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Make sure the AFM flapper is not stuck open. You might unplug it w/the fuel check connector jumpered to see if it makes a difference.
Old 05-14-15, 10:54 PM
  #3  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Orly? I never would of thought the AFM would have anything to do with engine RPM except airflow measurment.

The AFM could be a good possibility being as i used K&N's cleaning kit on this air filter, and maybe i drenched to much oil on the filter and it made my AFM flapper gummy

Think the AFM may be the first thing i look at if i can tomorrow
Old 05-15-15, 09:49 AM
  #4  
Rotisserie Engine

iTrader: (8)
 
driftxsequence's Avatar
 
Join Date: Jan 2007
Location: Wilmington, DE
Posts: 1,833
Received 48 Likes on 38 Posts
I believe you can unplug the AWS plug. Its on the drivers side attached to the dynamic chamber right near the oil filler neck. One plug is the IAT sensor, the other on the little black thing with 2 hoses is the AWS piece. try unplugging that. However that wouldnt explain why it goes to redline. Does the engine actually sound like its hitting the redline or is the gauge not displaying properly?
Old 05-15-15, 12:02 PM
  #5  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Oh, its hitting redline, the exhaust makes it quite obvious.

Haven't made it to it yet, doing the oh so fun thing of sanding drywall mud right now, will update when i get to it
Old 05-15-15, 04:43 PM
  #6  
I wish I was driving!

 
Join Date: Dec 2001
Location: BC, Canada
Posts: 5,241
Received 84 Likes on 68 Posts
Full face respirator is your friend... That, and having your final coat be as close to perfect as possible. House reno's?

It won't be the afm. Revving the engine requires airflow, and a stuck afm won't provide that.

I don't think is a vacuum leak, as the air would have to be metered to add the extra fuel for the extra air for it to rev like that, and this pulling through the afm.

I think removing the throttle elbow is your best start to take a look at the throttle plates, after that, plug the air feeds to the BAC and AWS with some rubber stoppers.
Old 05-15-15, 04:52 PM
  #7  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Originally Posted by scathcart
Full face respirator is your friend... That, and having your final coat be as close to perfect as possible. House reno's?

It won't be the afm. Revving the engine requires airflow, and a stuck afm won't provide that.

I don't think is a vacuum leak, as the air would have to be metered to add the extra fuel for the extra air for it to rev like that, and this pulling through the afm.

I think removing the throttle elbow is your best start to take a look at the throttle plates, after that, plug the air feeds to the BAC and AWS with some rubber stoppers.
No, just a bedroom that i've gutted and redid since january, not the handiest when it comes to this stuff, so its takeing me awhile

I also agree with you about the AFM, because when i was under the hood when it was shut off, i heard the flap pop shut

My biggest thing is how could it be the throttle plates? Last time i drove it, i let it idle for a moment than shut it off, now bam, redline. Also, even if the plates are closed (forced or not) how the hell is it getting enough air to go that high? Seems like it would be getting choked out with them closed, which made me wonder about the BAC, but i can't see that letting enough air in for what minimal it changes when idling
Old 05-15-15, 06:00 PM
  #8  
I wish I was driving!

 
Join Date: Dec 2001
Location: BC, Canada
Posts: 5,241
Received 84 Likes on 68 Posts
When was the last time you drove it?
Hard to recall I'm sure, but perhaps you tapped the gas climbing into the car/when you went to start it, and something has stuck open... Throttle cable, etc.
Testing the AWS and BAC is easy, just detach their metered air feeds, and plug both ends. Electrical tape would work well enough for a test.
Old 05-15-15, 06:10 PM
  #9  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Originally Posted by scathcart
Full face respirator is your friend... That, and having your final coat be as close to perfect as possible. House reno's?

It won't be the afm. Revving the engine requires airflow, and a stuck afm won't provide that.

I don't think is a vacuum leak, as the air would have to be metered to add the extra fuel for the extra air for it to rev like that, and this pulling through the afm.

I think removing the throttle elbow is your best start to take a look at the throttle plates, after that, plug the air feeds to the BAC and AWS with some rubber stoppers.
I was referring to an AFM which has the flapper stuck open and not closed.
Old 05-15-15, 06:49 PM
  #10  
I wish I was driving!

 
Join Date: Dec 2001
Location: BC, Canada
Posts: 5,241
Received 84 Likes on 68 Posts
Stuck open AFM doesn't allow extra air into the engine though. Stuck open AFM would tell the ecu to inject more fuel, which would cause the engine to bog if the throttle plates are closed.
Old 05-15-15, 07:53 PM
  #11  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Originally Posted by scathcart
When was the last time you drove it?
Hard to recall I'm sure, but perhaps you tapped the gas climbing into the car/when you went to start it, and something has stuck open... Throttle cable, etc.
Testing the AWS and BAC is easy, just detach their metered air feeds, and plug both ends. Electrical tape would work well enough for a test.
You hit it on the head. I checked the AFM flap, moved freely, wasn't stuck open, closed normal. Couldn't unplug the BAC valve because i didn't have anything small enough to undo the clip, but knew that wasn't it anyways. So i took off the snorkel to the TB, nothing stuck, but it looked like the primaries were open farthur than usual. So i moved the butterflies by hand and noticed the throttle wire move up, so i had a HMMMM moment, somehow, the throttle cable that is exposed came out of its "guide" and jammed the TB half way open, so i obviously had too much slack in the cable, so tightened the cable up a little bit so it hopefully won't happen again, thanks for the ideas everyone

I also got the room sanded and primered today, time for many colds ones
Old 05-15-15, 09:20 PM
  #12  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Originally Posted by lduley
You hit it on the head. I checked the AFM flap, moved freely, wasn't stuck open, closed normal. Couldn't unplug the BAC valve because i didn't have anything small enough to undo the clip, but knew that wasn't it anyways. So i took off the snorkel to the TB, nothing stuck, but it looked like the primaries were open farthur than usual. So i moved the butterflies by hand and noticed the throttle wire move up, so i had a HMMMM moment, somehow, the throttle cable that is exposed came out of its "guide" and jammed the TB half way open, so i obviously had too much slack in the cable, so tightened the cable up a little bit so it hopefully won't happen again, thanks for the ideas everyone

I also got the room sanded and primered today, time for many colds ones
I hope you cleaned up the dust created from sanding. I do a fair amount of renovating and I cannot stand sanding stuff which wants to travel anywhere and everywhere and than some.
Old 05-16-15, 06:11 AM
  #13  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Cold Engine Redlining

Originally Posted by satch
I hope you cleaned up the dust created from sanding. I do a fair amount of renovating and I cannot stand sanding stuff which wants to travel anywhere and everywhere and than some.
oh yes, i've been sanding/mudding/shop vac'in for weeks, sadly found spots that missed sanding, but they are in a closet, debating if i'm that worried about them
Old 05-16-15, 07:10 AM
  #14  
My job is to blow **** up

iTrader: (8)
 
lastphaseofthis's Avatar
 
Join Date: Jan 2005
Location: palmyra Indiana
Posts: 2,900
Received 3 Likes on 3 Posts
Originally Posted by scathcart
Stuck open AFM doesn't allow extra air into the engine though. Stuck open AFM would tell the ecu to inject more fuel, which would cause the engine to bog if the throttle plates are closed.
maybe on paper. in the real word.. i have had an engine to go 6k and hold itself there because a AFM door was stuck open. i didn't know it was 'only' 6k i thought it was revving to redline. but i would start it and it would take off for the moon...
Old 05-16-15, 08:47 AM
  #15  
Rotary Porn Addict

iTrader: (2)
 
Rikk's Avatar
 
Join Date: Jul 2014
Location: Charleston SC
Posts: 299
Likes: 0
Received 0 Likes on 0 Posts
Originally Posted by lduley
oh yes, i've been sanding/mudding/shop vac'in for weeks, sadly found spots that missed sanding, but they are in a closet, debating if i'm that worried about them
A box fan in the window facing outwards will reduce a lot of that dust that's floating in the air and save a lot of cleanup time also a easy way to look for imperfections is to run a light along the wall rather than at the wall
GL Rikk
Old 05-16-15, 09:19 AM
  #16  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Cold Engine Redlining

Originally Posted by badsvt1
A box fan in the window facing outwards will reduce a lot of that dust that's floating in the air and save a lot of cleanup time also a easy way to look for imperfections is to run a light along the wall rather than at the wall
GL Rikk
ya i did the fan thing, i'm sure it helped, but there was still a ton of dust

also have done the light trick, just apparantly missed a couple spots, all well, i'll just sand through the primer, only 1 coat on it so it shouldn't be too bad
Old 05-16-15, 10:43 AM
  #17  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Originally Posted by lduley
ya i did the fan thing, i'm sure it helped, but there was still a ton of dust

also have done the light trick, just apparantly missed a couple spots, all well, i'll just sand through the primer, only 1 coat on it so it shouldn't be too bad
Did you use a sealer over the sheetrock/mud first before using a paint primer?

Last edited by satch; 05-16-15 at 10:52 AM.
Old 05-16-15, 10:44 AM
  #18  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Cold Engine Redlining

Originally Posted by satch
Did you use a sealer over the sheetrock/mud first before using a primer?
yes, i was actually sanding the top skim coat yesterday
Old 05-16-15, 11:38 AM
  #19  
Moderator

iTrader: (1)
 
satch's Avatar
 
Join Date: Jun 2005
Location: tulsa,ok.
Posts: 11,738
Received 12 Likes on 11 Posts
Originally Posted by lduley
yes, i was actually sanding the top skim coat
yesterday
Do you remember the name of the sealer you used. I've used a drywall repair type sealer made by Zinsser and was wondering if others had used this product, and if so, did they like it.
Old 05-16-15, 11:57 AM
  #20  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
Cold Engine Redlining

i honestly don't remember. its one that i've always seen used, i believe its sheetrock brand, it was the blue lid, stuff has the consistitancy of baby poop, got more on the floor i think
Old 05-16-15, 12:11 PM
  #21  
Retired Moderator, RIP

iTrader: (142)
 
misterstyx69's Avatar
 
Join Date: Sep 2005
Location: Smiths Falls.(near Ottawa!.Mapquest IT!)
Posts: 25,581
Likes: 0
Received 131 Likes on 114 Posts
Originally Posted by lduley
i honestly don't remember. its one that i've always seen used, i believe its sheetrock brand, it was the blue lid, stuff has the consistitancy of baby poop, got more on the floor i think
sand da floor..wax on,wax off!..lol..
Old 05-16-15, 07:59 PM
  #22  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
no, its going to be carpet, doing it for my g/f's daughter so she has a nice room to herself when she attends college so she can do her studiezz

got it all primered today, hope to paint tomorrow
Old 05-16-15, 09:45 PM
  #23  
Rotary Enthusiast
iTrader: (1)
 
archaphil's Avatar
 
Join Date: Nov 2012
Location: bloomington, mn
Posts: 1,100
Likes: 0
Received 0 Likes on 0 Posts
Having recently sheet rocked and mudded/sanded my garage, I feel your pain. No 2 ways about it, it is a mess with dust. I am now back to the priming stage.

Neighbors did not like it, but fired up the leaf blower to get the excess dust off after hand sanding. Was quite the spectacle. I emerged from the garage in a face mask and goggles after the dust cloud revving that leaf blower to high hell. Good times.
Old 05-17-15, 08:28 PM
  #24  
roTAR needz fundZ

Thread Starter
iTrader: (1)
 
Join Date: Aug 2002
Location: Freeland, MI
Posts: 2,614
Likes: 0
Received 31 Likes on 31 Posts
actually, since I have this thread going, theres actually another question I would like to ask

My oil always REEKS of gas, I know its fairly common for a n/a to do that, but its enough of a smell that it worries me. I have gone through the idle relearn according to the FSM many times, and my TPS is dead on. A few weeks ago I changed the oil (didn't even have 1.5K on it) and replaced the water thermosensor behind the water pump just to see if that would cure it, I checked it recently and it still stinks of gas and it doesn't have 1K miles on this oil change. I'm stumped, I haven't replaced the o2 sensor yet, but the car runs so smooth and idles so damn well I can't see it being a faulty o2

Another tid bit, last year I compression tested the front rotor and I got 70psi on all 3 faces, I didn't check the rear, but I'm fairly confident that its lower (since it usually always is)

So I guess my 2 main questions are, what else could I look at? Or are my side seals just getting that bad and I need to hurry and rebuild my spare?


P.S got the room completely painted today, I am so happy, next step, carpet!
Old 05-18-15, 08:54 AM
  #25  
MECP Certified Installer

 
jjwalker's Avatar
 
Join Date: Feb 2009
Location: Mesquite, TX-DFW
Posts: 3,176
Likes: 0
Received 2 Likes on 2 Posts
Originally Posted by lduley
actually, since I have this thread going, theres actually another question I would like to ask

My oil always REEKS of gas, I know its fairly common for a n/a to do that, but its enough of a smell that it worries me. I have gone through the idle relearn according to the FSM many times, and my TPS is dead on. A few weeks ago I changed the oil (didn't even have 1.5K on it) and replaced the water thermosensor behind the water pump just to see if that would cure it, I checked it recently and it still stinks of gas and it doesn't have 1K miles on this oil change. I'm stumped, I haven't replaced the o2 sensor yet, but the car runs so smooth and idles so damn well I can't see it being a faulty o2

Another tid bit, last year I compression tested the front rotor and I got 70psi on all 3 faces, I didn't check the rear, but I'm fairly confident that its lower (since it usually always is)

So I guess my 2 main questions are, what else could I look at? Or are my side seals just getting that bad and I need to hurry and rebuild my spare?


P.S got the room completely painted today, I am so happy, next step, carpet!
That gasoline smell is completely normal. If you go for a good long drive most of it will go away. Even if the engine reaches operating temperature, short trips will make your oil reek of gasoline.

btw, 70 psi means rebuild time.


Quick Reply: Cold Engine Redlining



All times are GMT -5. The time now is 07:46 PM.