NEED HELP ASAP!!!!!! please.......

[johnny5]

ok guys theres the thing, my cars not running right and i cant figure out why. now i just put new plugs and wires, car idles fine but it bogs bad and back fires like a mofo. i know im not leaking fuel i already checked that soooo im not understanding whats makin it backfire. now its not like the normal pop pop pop its a loud bang like a shotgun. any and all help would be great ive included a vid so you can hear what im talkin about

http://www.youtube.com/watch?v=fZ0X08Mug-4

im not sure if itll work, i just uploaded it

[ward28465]

possibly an O2 sensor if it only does it when the car is at operation temp. if it does it all the time i would say MAF. to check for a bad MAF unplug your MAf while its running, if there is no defference in the way it runs, its your MAF. hope this helps.

[stb240sx]

It sounds like your timing is off at the distributor. I would put it on a timing light and see if you are running where you are supposed to be. What all exactly did you replace or remove to do the work?

[posh jop 240]

i agree with this guy.. sounds like your running a bit retarded. why i say this is that when the timing is set to retarded, not all of the fuel is "burned" and is thrown out the exhaust, and then fully burning giving you the "poping" you hear

[teamelude]

Do you get any CELs. I would suggest double checking your timing at the distributor as well.

[Klits562]

my car had a bad backfire because of the timing was really off also idk if a clogged catalytic converter would cause backfiring

[johnny5]

ok well ill have to invest in a timing light and i have a test pipe so it cant be a clogged cat, also i was throwing a knock sensor code, not sure if i am anymore, but ill check tomorrow

[kilo g]

What did you do before this started happening? I'm not sure If I got the whole story. perhaps a leaky injector? Do you notice any subtle misses during idle? Just for the heck of it, throw an Ohm meter on each injector. Should be somewhere around 14 ohms cold. Couldn't tell from vid, but you're sure it's coming from the exhaust? Could be a pop back in the intake manifold. This is where an O-scope would be handy, but not many people have one of their own. As far as the bogging... have you ever replaced the fuel filter? Could be clogged.

[kilo g]

Almost forgot. You said you did plugs and wires. Which leads me to believe you left the existing cap and rotor. (Timing would be uneffected) Did you check the gaps on the plugs? I know all parts pushers claim they're pre-gapped but how many time you think that box was dropped during shipment? Look at those plugs carefully. Carbon tracks on the insulation can indicated a short to ground. Also give the tips a little tug to make sure the insulator hasn't broken free from the housing causing the tip to move (seen it happen) Also, make sure you've got the right firing order on those wires 1-3-4-2. Didn't notice if you still have the old looms but crossing wires between cylinders can cause crossfire in cheap wires for instance don't cross wires 1&3 3&4..etc... If you suspect the wires, you can either try the old ones, or ohm'ing out the new ones. not sure what the spec is on the ones you bought.Make sure you added some dielectric grease to those plug boots too.

ABOVE ALL ON S13's. Check for any Vacuum leaks you might have knocked loose. There are soo many.FYI, if you feel like it, you can hook up a pressure gauge and should be I think 43psi at idle to the fuel rail. Good luck!

[oldtown driver]

chain tensioner

[johnny5]

ok well i have msd wires, gaps are good no vacuum leak i checked with some propane, i dont have a light so i cant check timing but my nissan mechanic (moms ex) thinks its a maf sooooo if anyone has one for cheap lmk i think hes gunna come over monday and take a peak at it
Modified by johnny5 at 3:55 PM 9/18/2009