Jump to content
SAU Community

Car Back Firing?

ginger

By ginger,
in Engines & Forced Induction

 Share

Recommended Posts

Eug Grand Master

Eug

Posted
Posted

has it just started doing it?

have you done any mods recently to cause it? i.e. spark plugs, exhaust, timing, etc?

it's not exactly normal, but also not surprising.

the fuel mixture does normally run rich in the high rpm range.

Link to comment
https://www.sau.com.au/forums/topic/202039-car-back-firing/#findComment-3588962
Share on other sites
inthisglass Grand Master

inthisglass

Posted
Posted

mine does it aswell, nearly all the time in 3rd.

its just because the fuel runs rich then when you put your clutch in all the unburnt fuel thats left sitting around pops.

its not a bad thing.. i personally like it as mine sometimes makes a tiney flame :(

when i get my safc2 and get the air/fuel mixture tuned it will stop this..

Link to comment
https://www.sau.com.au/forums/topic/202039-car-back-firing/#findComment-3590386
Share on other sites
r33cruiser Grand Master

r33cruiser

Posted
Posted

check the forced induction section man there was a technical write up about it..

basically your car is running rich.. when the fuel comes into contact with oxygen it creates a popping noise.

thats about all i can remember. but it is in the FORCED INDUCTION section.

Link to comment
https://www.sau.com.au/forums/topic/202039-car-back-firing/#findComment-3592569
Share on other sites
342Four Grand Master

342Four

Posted
Posted

thats called overrun

thats different to backfiring cause the engine is at high-ish revs, but there is no real load on the engine, and so it revs without using the accelerator

there is an excess of fuel in the burnt mixture because of the closed throttle, and when it hit the cat converter it mixes with a bit of oxygen and self ignites

thus the pop/gurgle/burping noise

backfiring is like a full on ignition of fuel/air mixture partially in the engine and in the exhaust - thats why its loud and bad for your engine

Link to comment
https://www.sau.com.au/forums/topic/202039-car-back-firing/#findComment-3592934
Share on other sites
ignuz Mentor

ignuz

Posted
Posted
I love my NA,

Going threw shopping centres as your slowing down, makes all the burping and dull popping noises.

Every one looks :(

grrrr lol while I sit at home on Fridays when I don't feel like spending cash going out bored out of my mind hahaha

edit: Yea the only part of the exhaust that was still stock was the cat. So in the future if you ever wanted to upgrade something I'd look at getting a high-flow cat maybe, but yea it sounded and went nice anyway =P

Also have you done anything new to it?

Link to comment
https://www.sau.com.au/forums/topic/202039-car-back-firing/#findComment-3597699
Share on other sites
ginger Collaborator

ginger

Posted
  • Author
Posted
grrrr lol while I sit at home on Fridays when I don't feel like spending cash going out bored out of my mind hahaha

edit: Yea the only part of the exhaust that was still stock was the cat. So in the future if you ever wanted to upgrade something I'd look at getting a high-flow cat maybe, but yea it sounded and went nice anyway =P

Also have you done anything new to it?

Just a few little things here and there.

Changed the gear knob pretty much straight away, has a gt nismo titanium on there now, lining up a new clutch soon, and also suspension. but besides that, shes still the same from the day i drove away.

Hows your legs going for transport?

Link to comment
https://www.sau.com.au/forums/topic/202039-car-back-firing/#findComment-3599594
Share on other sites
ignuz Mentor

ignuz

Posted
Posted
Just a few little things here and there.

Changed the gear knob pretty much straight away, has a gt nismo titanium on there now, lining up a new clutch soon, and also suspension. but besides that, shes still the same from the day i drove away.

Hows your legs going for transport?

Ahhh they go ok, thinking of lowering them a little and putting some 18's on there :laughing-smiley-014:

Link to comment
https://www.sau.com.au/forums/topic/202039-car-back-firing/#findComment-3600946
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • 25zenki
      S1 rb25/s14 starting problem

      By 25zenki · Posted

      Harness is for a s1 Rb25det, and it is engine and lower harness.  the old harness had broken off plugs and was in very rough condition/exposed wires and splices etc. it is not able to be put back on the car, I could visually inspect to see if they had rewired any pins on the ecu plug. The fuel pump definitly isn’t turning off it’s an external pump and very loud you can hear it. Will look at the other harness tonight, am also going to pull the fuel rail and watch the injectors spray, will update here with what I find. Pretty sure at this point it has to be something to do with injectors because car will fire up on starting fluid and cas is clicking the Injectors. Fuel pressure is steady 43psi 
    • Waders360
      M35 Brake caliper replacement

      By Waders360 · Posted

      Sorry. Front brake calipers
    • MBS206
      S1 rb25/s14 starting problem

      By MBS206 · Posted

      Check the injectors flow evenly, and are actually flowing what you and the ECU think they should be flowing. If it's starting up on starter fluid, you have a fuel issue. Is it possible under cranking your fuel pump is turning off?   The harness you replaced, is that the whole engine harness? Do yourself a test, and drop the old harness on and plug it into the Z32 ECU. It's possible they've wired things different. From memory S1 to S2 is different in RB25 and you may have a wrong loom
    • 25zenki
      S1 rb25/s14 starting problem

      By 25zenki · Posted

      I haven’t pulled the injectors to watch them spray yet but they are clicking from the cas and all of the spark plugs are wet with fuel. I’ve thought the cylinders were being flooded from the beginning and was hoping fuel pressure would fix it. Tonight I am going to pull the rail and watch the injectors spray. Don’t know how to test/diagnose if the plugs are firing in correct sequence but that should be a timing thing and as far as timing goes my car still has the half moon for the cas can only install it 1 way. And my mechanical timing is 100% correct I posted photos above. Confirmed with the balancer on and off. 
    • 25zenki
      S1 rb25/s14 starting problem

      By 25zenki · Posted

      I checked spark on all cylinders and they all visually have spark with the plug pulled and grounded, but plug 1 is the only one that fouled. This was a running swap that blew up and was rebuilt by a machine shop, put a new wiring specialties harness and did all gaskets, studs, and bolts while it was out.  compression is 135-150 across all cylinders. Aside from that from my understanding with the z32 ecu and maf the car should start regardless. The wiring for TPS and the dual 02 sensor/ dual knock sensor stuff shouldn’t actually stop the car from starting or even running well, (just slightly rich)  they just give fault codes. Car supposedly is supposed to start as long as you have z32 afm and ecu with the nistune base map and that’s info coming from a well known and trusted tuner who does a lot with SR/RB (Rsenthalpy). After more trouble shooting today where I’m at right now is that the cas is sending signal to the injectors they click while spinning the rotor, Fuel pressure is now set at 43psi, all cylinders have good compression and all of the plugs looked great (just wet with fuel) except for cylinder 1 which was very black (cylinder 1 has 150psi compression). all of the coils generate spark if pulled out and grounded out on the head. On the fuel pump car just pops into the exhaust. On starting fluid car will fire off. Hard to tell if all cylinders are firing off but definitley a couple. sounds like all of them but it’s only for 3-5 seconds hard to tell. 
×
×
  • Create New...