Exhaust popping

Lethal5Oh · 04-16-2003, 02:19 PM

Now that the temperatures are getting warmer here ive noticed that when the car warms up and then is allowed to sit only a few minutes and restarted theres a popping sound the climbs with RPM and gets worse when i let off the gas. My previous car did this too. Is there something with the 95's that they just do this or what? I know none of my plug wires are crossed, my fuel pressure is low but holding 30 psi. Wires, cap, rotor, plugs, and fuel filter are all new.what would cause this? its really nice and lound now with the american thunder exhaust. thanks

P.S. only 55K miles

cyberstang5.0 · 04-17-2003, 06:57 AM

First of all, you need to un-cross your plug wires.. That is killing performance! Double check to make sure your running at the timing your suppose to (about 14 deg..... + or - 2). Your fuel pressure is ok. I would set set it somewhere between 30 and 35. Stock injectors don't need large amount of pressure. It can even hurt performance it there is too much pressure. Do the above first and then see if it fixes your problem....

95/GT/5.0 · 04-18-2003, 10:53 PM

I see you installed some new exh. Did you remove your catalytic converters?If you did and you still have the smog pump and air tube connected.This is your popping from the exh.The smog pump, pumps vented vapor from the fuel tank,etc. and burns it in the passenger side cat which have probably been removed.You are actually simulating an exh. leak,the smog pump is pumping cool air into the exh. pipe.What happens when you have an exh. leak.It pops back thru the exh. pipe.You can buy a idler pulley to put in place of the smog pump and use all your oem's or you can get creative as I did and re-routed my belt eliminating 14 inches of belt and the smog pump( w/ slight modifications).My 1995 5.0 popped thru the ehx. after installing an offroad H-pipe and flowmasters.Eliminating the smog pump and air tube was my fix.My smog pump and solenoids are still connected,just the belt doesn't go around it anymore and I removed the air tube and capped both ends.I assume you don't have to pass an emissions test where you live.Just my 2 cents.

Lethal5Oh · 04-19-2003, 11:05 AM

Thanks for the replies. First off none of the plug wires are crossed. I made sure when i put on the new LIVEWIRES. Second, the stock Hpipe is still on the car unmodified. I forgot to mention that the idle hunts when its doing this popping. It goes from like 500 RPM to around 800-900 RPM and drops again. As of now i cant do anything with my fuel pressure because my AFPR got messed up thanks to Aeromotives great design with the placement of the vacuum fitting. They want me to send in my AFPR with 77 bucks to get their newly redisgned AFPR thats compatible with the new fuels. Also, i forgot to mention that the car "pops" like this when its below 40 degrees on cold start up. thanks

04-16-2003, 02:19 PM	#1
Lethal5Oh Registered Member Join Date: Jun 2002 Location: Portage Posts: 239	Exhaust popping Now that the temperatures are getting warmer here ive noticed that when the car warms up and then is allowed to sit only a few minutes and restarted theres a popping sound the climbs with RPM and gets worse when i let off the gas. My previous car did this too. Is there something with the 95's that they just do this or what? I know none of my plug wires are crossed, my fuel pressure is low but holding 30 psi. Wires, cap, rotor, plugs, and fuel filter are all new.what would cause this? its really nice and lound now with the american thunder exhaust. thanks P.S. only 55K miles __________________ '95 GT convert. K&N, C&L mass air meter, Performance distributors sreamin demon coil, dyna mod, live wires, king cobra clutch, flowmaster american thunder exhaust, UPR billet adjustable shift handle, Crane Cams Fireball HI-6 box,underdrive pullies, 255lph fuel pump, UPr short throw shifter, caster camber plates, 03 cobra lower A arms, bullit suspension, cobra front brakes

04-18-2003, 10:53 PM	#3
95/GT/5.0 Registered Member Join Date: Dec 2002 Location: Biloxi.Mississippi Posts: 49	I see you installed some new exh. Did you remove your catalytic converters?If you did and you still have the smog pump and air tube connected.This is your popping from the exh.The smog pump, pumps vented vapor from the fuel tank,etc. and burns it in the passenger side cat which have probably been removed.You are actually simulating an exh. leak,the smog pump is pumping cool air into the exh. pipe.What happens when you have an exh. leak.It pops back thru the exh. pipe.You can buy a idler pulley to put in place of the smog pump and use all your oem's or you can get creative as I did and re-routed my belt eliminating 14 inches of belt and the smog pump( w/ slight modifications).My 1995 5.0 popped thru the ehx. after installing an offroad H-pipe and flowmasters.Eliminating the smog pump and air tube was my fix.My smog pump and solenoids are still connected,just the belt doesn't go around it anymore and I removed the air tube and capped both ends.I assume you don't have to pass an emissions test where you live.Just my 2 cents. __________________ 1995/GT/5.0 Last edited by 95/GT/5.0; 04-18-2003 at 11:09 PM..

04-19-2003, 11:05 AM	#4
Lethal5Oh Registered Member Join Date: Jun 2002 Location: Portage Posts: 239	Thanks for the replies. First off none of the plug wires are crossed. I made sure when i put on the new LIVEWIRES. Second, the stock Hpipe is still on the car unmodified. I forgot to mention that the idle hunts when its doing this popping. It goes from like 500 RPM to around 800-900 RPM and drops again. As of now i cant do anything with my fuel pressure because my AFPR got messed up thanks to Aeromotives great design with the placement of the vacuum fitting. They want me to send in my AFPR with 77 bucks to get their newly redisgned AFPR thats compatible with the new fuels. Also, i forgot to mention that the car "pops" like this when its below 40 degrees on cold start up. thanks __________________ '95 GT convert. K&N, C&L mass air meter, Performance distributors sreamin demon coil, dyna mod, live wires, king cobra clutch, flowmaster american thunder exhaust, UPR billet adjustable shift handle, Crane Cams Fireball HI-6 box,underdrive pullies, 255lph fuel pump, UPr short throw shifter, caster camber plates, 03 cobra lower A arms, bullit suspension, cobra front brakes

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Speed Secret # 4	jim_howard_pdx	Windsor Power	13	11-10-2002 03:42 PM
Header gaskets	Stang951	Windsor Power	18	11-01-2002 05:57 PM
Popping exhaust: Short	SCOTTLT79	Windsor Power	4	09-03-2002 01:48 PM
exhaust crackling, popping noises	7000rpmisheaven	Windsor Power	11	02-01-2002 06:50 PM
Exhaust POPPING! HELP!	King Snake	Modular Madness	1	08-07-2001 05:45 PM

04-17-2003, 06:57 AM	#2
cyberstang5.0 347ci of HORSE POWER!!! Join Date: Jul 2001 Location: Houston, TX Posts: 1,416	First of all, you need to un-cross your plug wires.. That is killing performance! Double check to make sure your running at the timing your suppose to (about 14 deg..... + or - 2). Your fuel pressure is ok. I would set set it somewhere between 30 and 35. Stock injectors don't need large amount of pressure. It can even hurt performance it there is too much pressure. Do the above first and then see if it fixes your problem....