Cold Engine Redlining
#1
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
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.
#3
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
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
#4
Rotisserie Engine
iTrader: (8)
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?
#6
I wish I was driving!
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.
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.
#7
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.
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 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
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#8
I wish I was driving!
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.
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.
#9
Moderator
iTrader: (1)
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.
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.
#10
I wish I was driving!
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.
#11
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.
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.
I also got the room sanded and primered today, time for many colds ones
#12
Moderator
iTrader: (1)
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 also got the room sanded and primered today, time for many colds ones
#15
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GL Rikk
#16
Cold Engine Redlining
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
#23
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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.
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.
#24
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!
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!
#25
MECP Certified Installer
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!
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!
btw, 70 psi means rebuild time.