Popping noise when pressing the gas pedal???

NYC1 · 01-27-2003, 02:40 PM

If I rev real quick and aggressive there's a popping or poofing noise. even sometimes in between shifts. especially when I step on the next gear pretty hard. Not a real loud popping noise like a backfire, but close. Sounds like it's coming from under the car or tailpipes? Anyone know what that can be? This happens with no cats on the car. Plugs and wires were changed less than a year ago.

any input would be appreciated.
Thanks

01-27-2003, 06:45 PM

It may be your valves floating from revving a little too high? What are you shifting at? And does it happen if you shift at a lower RPM, like 5000?

Coupe50h · 01-27-2003, 10:10 PM

Man i have the same problem, but it seems to happen when i let off the clutch, and put a load on the suspension, like a popping noise under my feet? my trans mounts are tight? im thinking loose strut, or brake component.

drtbiker · 01-28-2003, 12:21 AM

popping or thumping??? my guess if it is popping i had the problem of timing too retard... but i could be wrong check the timing. My car was bugging the heck out of me and then i found out it was only the timing...

just my .02

later

B2r3y · 01-28-2003, 12:56 AM

Well im also having the same problem on my 5.0 that i just got yesterday and its like when i shift or like if im crusing in 5th and i just hammer the gas into the ground no it doesnt go fast but this pop like behind the shifter like on the axel or something pops and i dunno what it could be.. anyone any ideas?
Bry

NYC1 · 01-28-2003, 04:42 PM

It sounds like some of us have the same problem. Mine is definitely some sort of air/exhaust pop. It's not a hard mechanical part thump.

It doesn't happen at high rpms. It sounds like B2r3y's description, but it's air. I'll check the timing. I think it's set at stock. I hadn't bumped it up to 14 or anything yet.

Tony Frank · 01-28-2003, 06:20 PM

the popping you are hearing might be an exhaust pop caused by emissions putting gasses and un burned fuel into the exhaust and they are burning in the exhaust.

take off all of the emissions and this wont happen.

crazypete · 01-28-2003, 09:16 PM

Exhaust leak. Just solved the same problem last week. When you decelerate, the extra air gets sucked into the exhaust and makes little doof doof popping sounds. Get down and tighten the header flange bolts and look for obvious things like cracks, etc.

I also had the thump under the car problem. My crossmember was partially rotted out on the passenger side and the "tube" portion of it that accepts the bolt had broken away and the x-member would whap up against the bottom of the car when you did something that would "flex" the drivetrain like punching the gas. Make sure that nut and bolt on the center of the crossmember hasnt broken off. That would also make the transmittion wobble and whack up against the bottom of the car. They break off sometimes. I broke one on my last stang.

The final thing that could cause that is if your dump valve for the airpump is malfuctioning or not opening. That would pump air to the cats fulltime and that would cause some exhaust backfire. Check your EEC for a code.

LayanRubr · 01-28-2003, 11:10 PM

Wow! Those are the 2 same exact probs I've been having with my 5.0, man time to get to work

mustanggt_50 · 01-29-2003, 12:19 AM

Quote:

Originally posted by crazypete
Exhaust leak. Just solved the same problem last week. When you decelerate, the extra air gets sucked into the exhaust and makes little doof doof popping sounds. Get down and tighten the header flange bolts and look for obvious things like cracks, etc.

ive got the same noise happening in my car, same description and everything, i didnt really care to much tho as i figured id find out how to fix somehow, and now that you mentioned an exhaust leak i know i have one on the drivers side header - H-pipe flange, so thats good to know, thanx crazypete!!

drtbiker · 01-29-2003, 12:39 AM

If it is an exaust leak it usually occurs under deaceleration...... That is usually known on a car with no cats infire from the outside air rushing in the pipes... correct me if im wrong... if ur car is under stress when it occurs it seams more of a misfire....

just my 02 tho

later

NYC1 · 01-29-2003, 09:05 AM

It does occur under stress. How do you correct a mis-fire? thanks.

I'll check if they're any exhaust leaks. The whole exhaust sys is new except the headers. I'll see if they have a hole. I recently tightend them down tho.. maybe there's a hole somewhere in them?

Nixon1 · 01-29-2003, 11:15 AM

I've got the described doof doof doof noises during deceleration....I just assumed it was normal since the car's got a very low-restriction exhaust system and no cats!

drtbiker · 01-29-2003, 12:51 PM

yeah like nixon said "under deceleration" and that is what occurs when u have no cats because of the exaust being so free flowing

later

mtn302 · 01-29-2003, 01:14 PM

i had the same problem with my 95 after heads and cam were installed. problem is lean mixture on thottle tip in. and timing retard on tip in. i owned a mustang shop at the time and corrected my problem with a custom chip

Hethj7 · 01-29-2003, 01:50 PM

I had this problem to, and as stated above, it was a problem with the mixture being lean. A flow test on my injectors found that one was not up to par. I replaced it with a good injector and have not had a problem since.

NYC1 · 01-29-2003, 03:22 PM

Quote:

Originally posted by Hethj7
I had this problem to, and as stated above, it was a problem with the mixture being lean. A flow test on my injectors found that one was not up to par. I replaced it with a good injector and have not had a problem since.

hmmmm.... so you mean I might have a 12 sec car if it's an injector problem?

Hethj7 · 01-29-2003, 04:47 PM

Quote:

Originally posted by NYC1
hmmmm.... so you mean I might have a 12 sec car if it's an injector problem?

Well, how good of a driver are you?

When I had this problem, I took my car to a dealer. They pulled computer codes and did the flow test (which I am not sure how that is done) and just charged me an hour's worth of labor. They provided me with a print out of the flow results for each individual injector. I don't know....this may or may not be your problem, but it certainly was mine. I just bought a set of 8 new injectors and replaced them all when I did it. I haven't had a problem since.

B2r3y · 01-29-2003, 05:52 PM

OK well today when i was driving around its more of a thumping sound hitting somewhere in the drive train i beilve, or thats where it sounds like its coming from. i usually like to do work on my car rather than take to a mechanic but got a old friend who know alot about cars he siad he would put it on a lift in the morn and see what it is. said it might be a transmission mount or something. see sometimes i hear it right by the shifter and back some and sometimes it sounds like its coming from somewhere near the back.

also has anyone noticed say when your going over 30mph and no radio on, have you noticed a constant squeeky sound coming from somewhere that sounds like its in your dash? if anyone has had this problem or knows what im talking about any help would be appreciated becuz its really annoying.
thanks
bry

TwiLighTBluEGT · 01-30-2003, 01:20 AM

I had the same problem when i installed my MAC 2-cat h-pipe on my 91GT last year. My car is an AOD, and for a while whenever I accelerated from a stop, I would get this popping sound. It also occured under WOT at times. It went away once I put my off-road on.

01-27-2003, 02:40 PM	#1
NYC1 Registered Member Join Date: Jun 2001 Location: Maryland, USA Posts: 169	Popping noise when pressing the gas pedal??? If I rev real quick and aggressive there's a popping or poofing noise. even sometimes in between shifts. especially when I step on the next gear pretty hard. Not a real loud popping noise like a backfire, but close. Sounds like it's coming from under the car or tailpipes? Anyone know what that can be? This happens with no cats on the car. Plugs and wires were changed less than a year ago. any input would be appreciated. Thanks __________________ 94GT 5spd Coupe 1/4 = 13.6@103 60ft = 2.0315 on Michelin Pilots GT 40 Intake GT 40Y Aluminum heads 1.7 rockers, BBK Cold air Fluidyne, BBK long tubes & H-Pipe 65mm TB Al Driveshaft Hurst Shifter Cobra R hood HPM Subframes Control Arms Future mods = Procharger and/or 331/347 Stroker, Turbo? Rice Haters Club Member #77 FOR SALE: Strut Tower Brace $30

01-27-2003, 06:45 PM	#2
Simi Stang Guest Posts: n/a	Valves floating? It may be your valves floating from revving a little too high? What are you shifting at? And does it happen if you shift at a lower RPM, like 5000?

01-27-2003, 10:10 PM	#3
Coupe50h Registered Member Join Date: Aug 2002 Location: SanAntonio, Tx Posts: 957	Man i have the same problem, but it seems to happen when i let off the clutch, and put a load on the suspension, like a popping noise under my feet? my trans mounts are tight? im thinking loose strut, or brake component. __________________ X-Texas highway patrol ssp 1990 coupe - exploder Gt-40 iron heads, Explorer intake, 19 lber's. E-cam. crane 1.7 rollers. 190fp. 75mm maf. 65mm tb, tubular subframe connectors, mac cai, Asp crank pulley, T-5, king cobra clutch, flowtech 1-5/8 unequals, mac X-pipe Frpp driveshaft, lakewood Lca's. race weight 3,160 12.69 @ 107.35, 1.71 60' 26x8.5 drag's 3.90 gear 13.20 @ 106.91 - 235/60/15 firestones 2.3 60' 3.27 gear

01-28-2003, 12:21 AM	#4
drtbiker Registered Member Join Date: Jan 2002 Location: Mt. Prospect,IL Posts: 474	popping or thumping??? my guess if it is popping i had the problem of timing too retard... but i could be wrong check the timing. My car was bugging the heck out of me and then i found out it was only the timing... just my .02 later __________________ 87-ford-mustang-SOLD! mods: 3:73's, off road h-pipe, b303 cam in gt- 40 motor w/ Power Plus intake, edelbrock 70mm tb & egr spacer, 72mm C&L, bbk long tubes, tremec tranny, centerforce dual friction clutch, upr and lwr CA's 255lph FP and soon more to come.... when i have money again SOME ADVICE Don't do burn outs in reverse it is very expensive New times with dead hook on dr's 13.27@103 with 2.0 60 foots w/100lb system Fastest time to date: 12.8@113

01-28-2003, 04:42 PM	#6
NYC1 Registered Member Join Date: Jun 2001 Location: Maryland, USA Posts: 169	It sounds like some of us have the same problem. Mine is definitely some sort of air/exhaust pop. It's not a hard mechanical part thump. It doesn't happen at high rpms. It sounds like B2r3y's description, but it's air. I'll check the timing. I think it's set at stock. I hadn't bumped it up to 14 or anything yet. __________________ 94GT 5spd Coupe 1/4 = 13.6@103 60ft = 2.0315 on Michelin Pilots GT 40 Intake GT 40Y Aluminum heads 1.7 rockers, BBK Cold air Fluidyne, BBK long tubes & H-Pipe 65mm TB Al Driveshaft Hurst Shifter Cobra R hood HPM Subframes Control Arms Future mods = Procharger and/or 331/347 Stroker, Turbo? Rice Haters Club Member #77 FOR SALE: Strut Tower Brace $30

01-28-2003, 12:56 AM	#5
B2r3y Registered Member Join Date: Jan 2003 Location: Htown tx Posts: 70	Well im also having the same problem on my 5.0 that i just got yesterday and its like when i shift or like if im crusing in 5th and i just hammer the gas into the ground no it doesnt go fast but this pop like behind the shifter like on the axel or something pops and i dunno what it could be.. anyone any ideas? Bry

01-28-2003, 06:20 PM	#7
Tony Frank Registered Member Join Date: Feb 2001 Location: Brooklyn originally, but Grand Rapids now Posts: 309	the popping you are hearing might be an exhaust pop caused by emissions putting gasses and un burned fuel into the exhaust and they are burning in the exhaust. take off all of the emissions and this wont happen. __________________ Grand Valley State University Senior Accounting and Finance Major 1985 Mustang GT 19,000 ORIGINAL miles, E-303 cam, edelbrock performer RPM intake, holley 600 cfm carb, MAC headers, windage tray, 8.8 rear end with 4.10 gears, 4"cowl hood, 5lug conversion, 04 Mach1 wheels. http://www.mustangworks.com/cgi-bin/moi-display.cgi?1501

01-28-2003, 09:16 PM	#8
crazypete Registered Member Join Date: Sep 2002 Location: Boston Posts: 592	Exhaust leak. Just solved the same problem last week. When you decelerate, the extra air gets sucked into the exhaust and makes little doof doof popping sounds. Get down and tighten the header flange bolts and look for obvious things like cracks, etc. I also had the thump under the car problem. My crossmember was partially rotted out on the passenger side and the "tube" portion of it that accepts the bolt had broken away and the x-member would whap up against the bottom of the car when you did something that would "flex" the drivetrain like punching the gas. Make sure that nut and bolt on the center of the crossmember hasnt broken off. That would also make the transmittion wobble and whack up against the bottom of the car. They break off sometimes. I broke one on my last stang. The final thing that could cause that is if your dump valve for the airpump is malfuctioning or not opening. That would pump air to the cats fulltime and that would cause some exhaust backfire. Check your EEC for a code. __________________ 91 GT Carb conversion, holley 600 double pumper, edelbrock performer intake, FMS "C" drop springs, march 1000 underdrive pullies, crane 1.7 roller rockers, GT-40P headers, bassani x pipe, american thunder catback, FMS 4.56's, msd aL6, trunkmount battery, A/C eliminator kit, 3000 stall tci streetfighter, AOD with transgo kit, A+ servo, 300M hardened lockup shaft, kevlar bands and 28,000 gvw trans cooler, 3 core radiator, 300 lbs stripped with a full interior

01-28-2003, 11:10 PM	#9
LayanRubr Registered Member Join Date: Feb 2002 Location: Aggieland, Texas Posts: 297	Wow! Those are the 2 same exact probs I've been having with my 5.0, man time to get to work __________________ 87 Mustang 5.0 (308) Notchback - The Blue Baron Rice Hater's Club member #20

01-29-2003, 12:39 AM	#11
drtbiker Registered Member Join Date: Jan 2002 Location: Mt. Prospect,IL Posts: 474	If it is an exaust leak it usually occurs under deaceleration...... That is usually known on a car with no cats infire from the outside air rushing in the pipes... correct me if im wrong... if ur car is under stress when it occurs it seams more of a misfire.... just my 02 tho later __________________ 87-ford-mustang-SOLD! mods: 3:73's, off road h-pipe, b303 cam in gt- 40 motor w/ Power Plus intake, edelbrock 70mm tb & egr spacer, 72mm C&L, bbk long tubes, tremec tranny, centerforce dual friction clutch, upr and lwr CA's 255lph FP and soon more to come.... when i have money again SOME ADVICE Don't do burn outs in reverse it is very expensive New times with dead hook on dr's 13.27@103 with 2.0 60 foots w/100lb system Fastest time to date: 12.8@113

01-29-2003, 09:05 AM	#12
NYC1 Registered Member Join Date: Jun 2001 Location: Maryland, USA Posts: 169	It does occur under stress. How do you correct a mis-fire? thanks. I'll check if they're any exhaust leaks. The whole exhaust sys is new except the headers. I'll see if they have a hole. I recently tightend them down tho.. maybe there's a hole somewhere in them? __________________ 94GT 5spd Coupe 1/4 = 13.6@103 60ft = 2.0315 on Michelin Pilots GT 40 Intake GT 40Y Aluminum heads 1.7 rockers, BBK Cold air Fluidyne, BBK long tubes & H-Pipe 65mm TB Al Driveshaft Hurst Shifter Cobra R hood HPM Subframes Control Arms Future mods = Procharger and/or 331/347 Stroker, Turbo? Rice Haters Club Member #77 FOR SALE: Strut Tower Brace $30

01-29-2003, 11:15 AM	#13
Nixon1 Registered Member Join Date: Jan 2003 Location: Palm Bay, FL Posts: 432	I've got the described doof doof doof noises during deceleration....I just assumed it was normal since the car's got a very low-restriction exhaust system and no cats! __________________ '91 Mustang GT 5.0 AOD Daily Driver Current stats: NEW 302 short block, E-303 cam (@.050, 220/220, .498/.498, 110 degrees), 1.6 roller rockers, Performer RPM heads (aluminum, 1.9/1.6, 60cc chambers), Cobra intake, Granatelli 75mm MAF, Billet AFPR, Equal-Length Shorty Headers, Off-Road X Pipe, Flowmasters, 4.10 POSI 13.73 at 103.8, ~2.2 60'

01-29-2003, 12:51 PM	#14
drtbiker Registered Member Join Date: Jan 2002 Location: Mt. Prospect,IL Posts: 474	yeah like nixon said "under deceleration" and that is what occurs when u have no cats because of the exaust being so free flowing later __________________ 87-ford-mustang-SOLD! mods: 3:73's, off road h-pipe, b303 cam in gt- 40 motor w/ Power Plus intake, edelbrock 70mm tb & egr spacer, 72mm C&L, bbk long tubes, tremec tranny, centerforce dual friction clutch, upr and lwr CA's 255lph FP and soon more to come.... when i have money again SOME ADVICE Don't do burn outs in reverse it is very expensive New times with dead hook on dr's 13.27@103 with 2.0 60 foots w/100lb system Fastest time to date: 12.8@113

01-29-2003, 01:14 PM	#15
mtn302 Registered Member Join Date: Jan 2003 Location: gatlinburg tn Posts: 2	i had the same problem with my 95 after heads and cam were installed. problem is lean mixture on thottle tip in. and timing retard on tip in. i owned a mustang shop at the time and corrected my problem with a custom chip __________________ supercharged 95 478 rwhp its red

01-29-2003, 01:50 PM	#16
Hethj7 Mizzou Tigers Join Date: Apr 1999 Location: weston, MO United States Posts: 1,455	I had this problem to, and as stated above, it was a problem with the mixture being lean. A flow test on my injectors found that one was not up to par. I replaced it with a good injector and have not had a problem since. __________________ 2006 Mustang GT 1990 LX GT-40 motor 262 horsepower, 307ft-lbs (sold but forever loved) 1998 Contour SVT Rice Haters Club Member #244

01-29-2003, 05:52 PM	#19
B2r3y Registered Member Join Date: Jan 2003 Location: Htown tx Posts: 70	OK well today when i was driving around its more of a thumping sound hitting somewhere in the drive train i beilve, or thats where it sounds like its coming from. i usually like to do work on my car rather than take to a mechanic but got a old friend who know alot about cars he siad he would put it on a lift in the morn and see what it is. said it might be a transmission mount or something. see sometimes i hear it right by the shifter and back some and sometimes it sounds like its coming from somewhere near the back. also has anyone noticed say when your going over 30mph and no radio on, have you noticed a constant squeeky sound coming from somewhere that sounds like its in your dash? if anyone has had this problem or knows what im talking about any help would be appreciated becuz its really annoying. thanks bry

01-30-2003, 01:20 AM	#20
TwiLighTBluEGT Registered Member Join Date: Jun 2002 Location: Massachusetts Posts: 157	I had the same problem when i installed my MAC 2-cat h-pipe on my 91GT last year. My car is an AOD, and for a while whenever I accelerated from a stop, I would get this popping sound. It also occured under WOT at times. It went away once I put my off-road on. __________________ 1991 Mustang GT Conv: 58,000 original miles, 2nd owner. Engine: FMS 65mm tb/spacer, C&L 73mm maf, MAC cai. Drivetrain: Built AOD w/ Edge 2800rpm lockup converter, hardened 3-4 inner shaft, Trans-Go shift kit, B&M supercooler, FMS 3.73 gears & aluminum d/s, rebuilt traction lock. Exhaust: BBK unequal length shorty headers, BBK o/r h-pipe, Flowmaster 2 chamber mufflers. Chassis/suspension/brakes: Kenny Brown supersubs. The rest is stock.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
popping noise	93GTDIN	Windsor Power	12	10-15-2004 08:28 PM
popping noise	jinx6570	Modular Madness	2	02-09-2003 08:37 AM
Motor back together - strange noise????	DZEE'S LX	Windsor Power	13	03-15-2002 12:46 AM
4cyl clutch pedal vs 5.0 pedal?	WADS56	Windsor Power	5	02-05-2002 02:27 AM
Air Intake Whistling Noise?!	sgrn	Modular Madness	4	10-25-2000 09:46 AM