PDA

View Full Version : Back fire in exhuast



Expplucky
04-21-2013, 12:43 PM
99 A4 2.8 30v


-ok so my catalytic converters blew out and forced debree into my muffler, so i had the cats replaced, and had an after market muffler put in to replace to old one, they took out that box looking thing too.

but now when i drive it feels like its missfiring like skipping while i drive and not accelertating properly, and i can hear what sounds like gunshots coming out of the tail pipe and it sounds like a rattle in the muffler, tho when i bang on the muffler i dont hear anything move around.

Also ive replaced the ignition coils, spark plugs, and spark plug wires as well as the maf but anytime i plug the maf in it shuts off as soon as i start driving and gives me random missfire codes coming from only one side of the engine!

PLEASE HELP ive taken it to 4 mechanics each says a different thing! before i shell out $500 for a fix i want to make sure it actually fixes the problem.

157,000 miles!

Tanzimur
04-24-2013, 06:12 PM
99 A4 2.8 30v


-ok so my catalytic converters blew out and forced debree into my muffler, so i had the cats replaced, and had an after market muffler put in to replace to old one, they took out that box looking thing too.

but now when i drive it feels like its missfiring like skipping while i drive and not accelertating properly, and i can hear what sounds like gunshots coming out of the tail pipe and it sounds like a rattle in the muffler, tho when i bang on the muffler i dont hear anything move around.

Also ive replaced the ignition coils, spark plugs, and spark plug wires as well as the maf but anytime i plug the maf in it shuts off as soon as i start driving and gives me random missfire codes coming from only one side of the engine!

PLEASE HELP ive taken it to 4 mechanics each says a different thing! before i shell out $500 for a fix i want to make sure it actually fixes the problem.

157,000 miles!.

Check the coil packs for spark and also check for compression on that side with the codes also make ssure everyground wire is tightened down and not mangled or crushed by somthing else ... happned to me on the 1.8t shorting ground caused the whole engine to mis...

Expplucky
04-27-2013, 02:34 PM
i already ran the compression test and they were all within 20psi of each other, but as far as the ground wires i wouldnt know where to even start looking for those.

demonmk2
04-27-2013, 03:11 PM
Could a bad vacuum leak cause it? Intake manifold leak or a bad injector?
Not very familiar with the 2.8's. Just throwing some ideas out.

Expplucky
05-07-2013, 12:04 AM
no leaks in the manifold....and i literally went through every tube in that car and replaced them....grounds wires look good....well the ones i could find.....and it still sounds like I'm shaking pennies in my muffler when i step on the gas....as of now im assuming its fuel relates,. I'm going to check the injectors tomorrow, I'm also now getting the blinking cel (after i just redid the timing and checked it for over 3 hours) im also getting repeated codes with pd at the end have no idea what that means but i guess ill know more when my vag-com cable gets here.

U_know_me
05-07-2013, 07:12 AM
as well as the maf but anytime i plug the maf in it shuts off as soon as i start driving and gives me random missfire codes coming from only one side of the engine!

I could be reading this wrong but does this mean you have been driving around with out you MAF plugged in?

Also does the car sound like its misfiring at idol, if so be sure to check the connections on your coil packs, I replaced mine over the weekend and one of the wire pins got pushed into the connector and was not making a connection to the coil, it caused that coil not to fire.

csosnowski
05-07-2013, 07:38 AM
Blinking cel is current misfire occurring.

You may have a bad coil, pull each plug wire partially off the misfiring cylinder and listen for the snap of the arc, then pull it farther and see if it affects the way the car idles. This will tell you at least if your coil is providing spark to the cylinder.

This may sound like a silly question but do you have fuel in the vehicle? I had a Passat on the lot with a 2.8l and the gas gauge was off, so when people would run the fuel down to the reserve it would start misfiring and not running properly until we put more fuel in it.

PerryPhilly
05-07-2013, 11:19 AM
Did you gap the plugs properly? I replaced the plugs in my b7 I used to own and before checking for proper gap on my plugs I replaced 4 coil packs. Turns out when I put the stock plugs back in no misfire. Just a thought.

Expplucky
05-08-2013, 06:48 PM
-ya gaped em@ .32
-did the spark test and im getting a voltage white in color
-ya i have fuel in the car a little over a 1/4 tank

so after closer inspection it looks as tho the person who changed my cats did not remove all the shit from the old blown cat, so it pluged up the right banks down pipe somehow or another....anyway im sick and fucking tired of paying welders im already in the hole about $400 for their mistakes so im just guna cut my loses by a mig welder for $109.00 and take it apart and re weld it......

but another question would be that a pluged pipe would cause these issue's right?

Expplucky
05-08-2013, 08:07 PM
yes i have been driving around with un-metered air and my maf was unplugged, at the time i wasnt making enough money to shell out 200 for a MAF

walky_talky20
05-09-2013, 05:35 AM
No wonder the cats fell apart. The car runs extra rich with the MAF unplugged. That leads to death of the cats over the long term.

That said, if you paid for labor and it was not done correctly - you need to take it back there and have them finish the job.

Expplucky
05-09-2013, 10:18 AM
I agree 100% walky_talky only thing is when i go in now suddenly no one speaks english, and the invoice they gave me is not itemised so their is no way to prove they didnt do what i said. I think im just going to suttley steal tire's from them until i get my money back.

walky_talky20
05-09-2013, 11:03 AM
^Sounds like a plan.

Expplucky
05-09-2013, 05:06 PM
im still hoping that this is the reason for the misfire....but what if it isnt
so far ive done the following

-Checked fuses
-changed fuel filter
-changed spark plugs and Gaped @.32
-redid timing belt
-water pump replaced
-thermostat replaced
-new belt tensioner
-new serp belt as well
-changed vavle cover gaskets
-replaced coil pack
-most of the plug wires
-did a spark test getting spark
-checked for the injector pulse (the screw driver method)
-left battery unpluged over night to reset fuel trims
-replaced maf (like 3 times)
-cleaned throtle body and entire intake manifold
-ordered the vag-com cable and got vcds
-ran seafoam through the tank
-and a little in the intake
-changed vac lines (not very well tho i did have to replace that 3way valve with some ghetto hose invention, and replace the braded hose from the vaccum res with a rubber hose)

anything else i can do until the vag cable gets here?