poping when I down shift
Thread Starter
Pro
Joined: Feb 2001
Posts: 606
Likes: 0
From: FL
Cruise-In II Veteran
poping when I down shift
OK here is the deal.
My car pops out the exhaust and gurgles when I down shift some times. :sad: Not al the time. It seems to be when it is cold or when I am a bit aggressive. Acceleration and up shifting are fine. The car only has 41K on it. So I am not sure why it would be doing this.
Sticky valve? Why?
Also my steering rack makes a noise. I was told it could be the rack its self. Do they make a rebuild kit for the rack? I do not want to replace the rack. I was quoted $500 just for the parts.
Thanx
CJ :flag :chevy
ps I still have more of those borders if anyone is interested. A few people backed out.
My car pops out the exhaust and gurgles when I down shift some times. :sad: Not al the time. It seems to be when it is cold or when I am a bit aggressive. Acceleration and up shifting are fine. The car only has 41K on it. So I am not sure why it would be doing this.
Sticky valve? Why?
Also my steering rack makes a noise. I was told it could be the rack its self. Do they make a rebuild kit for the rack? I do not want to replace the rack. I was quoted $500 just for the parts.
Thanx
CJ :flag :chevy
ps I still have more of those borders if anyone is interested. A few people backed out.
Instructor
Joined: Sep 2000
Posts: 193
Likes: 0
From: Jefferson, GA, USA
Re: poping when I down shift (CJ454)
The popping noise can be anything from wrong timing, wrong fuel mixture to leaky valve. I'd guess one of the first two. Also, if you do not have enough back pressure it may pop. There should be some restriction in the exhaust.
Racer
Joined: Jul 2001
Posts: 253
Likes: 0
Re: poping when I down shift (CJ454)
I'm not sure if this will help or not, but I also have an '83 V65 Magna that pops during deceleration. The consensus on the V4 board is one of 2 things:
1) the pilot screws need to be adjusted a little richer because there's not enough 'fuel to burn completely' being delivered from the carbs
Since you don't have a carb with pilot screws, can your TPS be out of adjustment? (.54 idle and 4.65 WOT) Or do you have an dirty IAC?
2) there's a leak in your exhaust system.
I'm not sure why this would cause popping, but maybe it'll help you out.
Hope this helps.
1) the pilot screws need to be adjusted a little richer because there's not enough 'fuel to burn completely' being delivered from the carbs
Since you don't have a carb with pilot screws, can your TPS be out of adjustment? (.54 idle and 4.65 WOT) Or do you have an dirty IAC?
2) there's a leak in your exhaust system.
I'm not sure why this would cause popping, but maybe it'll help you out.
Hope this helps.
Thread Starter
Pro
Joined: Feb 2001
Posts: 606
Likes: 0
From: FL
Cruise-In II Veteran
Re: poping when I down shift (CJ454)
Thanx for all the ideas. The exhaust is fine. Factory exhaust on the car.
I am not sure how one would adjust the fuel mixture on the car. Any thought on how to adjust/check this?
CJ
:flag :chevy
I am not sure how one would adjust the fuel mixture on the car. Any thought on how to adjust/check this?
CJ
:flag :chevy
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: poping when I down shift (CJ454)
Ahh.. stock exhaust .. that's another story. As said above you shouldn't have any weird noises coming from it. If you had aftermarket exhaust and were getting a few small pops on deceleration and gurgling as well, I'd say it isn't a problem.
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Burning Brakes
Joined: Aug 2000
Posts: 984
Likes: 1
From: Cincinnati OH
Re: poping when I down shift (CJ454)
It's normal, mine did it with the stock exhaust too. Sounds cool to me, don't know why, but it does. I think the ecm cuts off the fuel on overrun, which results in a lean crackle.
Le Mans Master
Joined: Jul 1999
Posts: 8,683
Likes: 6
From: Phoenix AZ
Re: poping when I down shift (CJ454)
I don't think you need to worry, mine did it with the stock exhaust as well...and it does it with the Corsa system too, just a little louder now! And EVERY motorcycle I have ever owned has done it as well and they were all solid as a rock, just like the Vette. Enjoy it, it's a nice sound!
Thread Starter
Pro
Joined: Feb 2001
Posts: 606
Likes: 0
From: FL
Cruise-In II Veteran
Re: poping when I down shift (CJ454)
Thnax for the help on the exhaust issue. I guess I will wait it out and see what happens.
To the guy who found a reblt rack where did you get it? Where can I get a new one for that price?
CJ:flag :chevy
To the guy who found a reblt rack where did you get it? Where can I get a new one for that price?
CJ:flag :chevy
Instructor
Joined: Sep 2000
Posts: 193
Likes: 0
From: Jefferson, GA, USA
Re: poping when I down shift (CJ454)
86Vette Bill's comments confirm my post as well.
And No, it does not sound "cool". It sounds unhealty and a mechanic would shurly giggle if he saw someone showing-off in a car that made this sound.
BTW, mine DOES NOT do this. Its 100% stock, except for the rims.
And No, it does not sound "cool". It sounds unhealty and a mechanic would shurly giggle if he saw someone showing-off in a car that made this sound.
BTW, mine DOES NOT do this. Its 100% stock, except for the rims.
Melting Slicks
Joined: Apr 2002
Posts: 2,308
Likes: 1
From: Portsmouth VA
Re: poping when I down shift (CJ454)
i have to agree with most of the guys... the gurgling is something that is COOL and lots of people spend lots of money to get it... and is to be expected while decellerating with it still in gear especially at higher RPM's. the popping sound is another story.... you shouldn't be getting a loud "POP" ... maybe just a low gurgle alternating with a little bit louder gurgle. Are you sure it's the stock exhaust?
Pro
Joined: Aug 2000
Posts: 519
Likes: 2
From: South River N.J.
Re: poping when I down shift (CJ454)
CJ454: My bike poped thru the pipes because it was running to rich. I put in a smaller low speed jet and that clered it up. If it spit thru the carb then it would be running to lean and I would have to richen it. The ECM does shut down the ejectors when you decellerate to conserve fuel. I would be supprised if yours wasn't shutting down the ejectors. An air leak such as air leaking into the exhaust manifold or pipes could also cause pops since that air would help ignite any unburned fuel. Let us know what you find. Popping thru the pipes is not normal.
Thread Starter
Pro
Joined: Feb 2001
Posts: 606
Likes: 0
From: FL
Cruise-In II Veteran
Re: poping when I down shift (CJ454)
Thanx for all the good ideas. I hope to take it to the shop this week. Or the first of next week. I hope it is not a $$$$ item...
May be I shold change the exhaust out then I would have an excuse for it poping :D
CJ :flag :chevy
May be I shold change the exhaust out then I would have an excuse for it poping :D
CJ :flag :chevy
Le Mans Master
Joined: Mar 2001
Posts: 8,434
Likes: 3,921
From: Omaha
2020 Corvette of the Year Finalist (performance mods)
C4 of Year Winner (performance mods) 2019
Re: poping when I down shift
It's fairly normal on the 92s when they are cold. As someone else stated it is mostly due to the "batch" fuel delivery system. When you let off the gas there is unburnt fuel making it's way into the exhaust system where it is igniting, thus causing a "pop" or backfire. It's worse when cold because the computer is running "open loop" which doesn't use any sensor feedback, thus it's just dumping a preset rich fuel mixture into the engine. The stock exhaust system will mostly mask this, but not completely. You should hear what mine sounds like with muffler eliminators! I was slowing down under an overpass right after leaving work one day, and the darn thing popped so loud I thought someone had just fired a howitzer next to me. :eek:
Instructor
Joined: Aug 2001
Posts: 138
Likes: 0
From: upatate ny
Re: poping when I down shift (EvanLT1)
Right on!!! Not to worry. Music to the ears!!! Now on the other hand if its signifigant backfire thats another story. The gurgling can also be caused by minor reverse compression upon letoff of gas.. again not normally anything to be concerned with. IMHO
:cheers:
[Modified by daves87, 4:42 AM 4/10/2002]
:cheers:
[Modified by daves87, 4:42 AM 4/10/2002]