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Backfire/pop When Ignition Turned On

wlspn

By wlspn,
in Engines & Forced Induction

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wlspn Proficient

wlspn

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Have an rb25 in my r32 & recently installed a Haltech ECU & got a tune.

The day after my tune I discovered a hose had come off an intercooler pipe (probably during tune) so I have re-attached that & am fixing up a few little things then I will go for another tune.

Anyway for the last few days when I go to start my car (just to move it around, etc.) as soon as I turn the key to ignition there is a bang from the exhaust, almost like a little backfire... But the engine isn't actually running...

Have never really had or heard about this before & I'm getting really curious as to what it could be

If anyone has experienced this or has any ideas please let me know...

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https://www.sau.com.au/forums/topic/311753-backfirepop-when-ignition-turned-on/
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rob82 Mentor

rob82

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I'd bet the columns for 0RPM in the tuning map have values in them that aren't 0 and the ECU is pulsing ignition and fuel as mention.

Most ECU's still need to see a crank reference (bare minimum) to pulse the injectors and coils - shouldn't matter if you have values in the 0rpm column.

wlspn Proficient

wlspn

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Hope its not CAS. Never had the issue before the haltech went in & was tuned so does that rule that out?

Leaking injector(s) is something I will try to look into, & is quite possible as injectors were recently highflowed. Will also check 0 rpm tables on haltech & cranking rpm too.. Should mention it doesn't happen every time..

Whatever it is I'm guessing it wont cause any major probs?

wlspn Proficient

wlspn

Posted
  • Author
Posted

Hope its not CAS. Never had the issue before the haltech went in & was tuned so does that rule that out?

Leaking injector(s) is something I will try to look into, & is quite possible as injectors were recently highflowed. Will also check 0 rpm tables on haltech & cranking rpm too.. Should mention it doesn't happen every time..

Whatever it is I'm guessing it wont cause any major probs?

rob82 Mentor

rob82

Posted
Posted
Hope its not CAS. Never had the issue before the haltech went in & was tuned so does that rule that out?

Leaking injector(s) is something I will try to look into, & is quite possible as injectors were recently highflowed. Will also check 0 rpm tables on haltech & cranking rpm too.. Should mention it doesn't happen every time..

Whatever it is I'm guessing it wont cause any major probs?

For it to pop out the exhaust there needs to be spark. If the issue was not there b4 the haltech went in - then it must be the haltech. Seen it b4 and there is nothing really to be alarmed with as long as the car drives fine.

tridentt150v Grand Master

tridentt150v

Posted
Posted
For it to pop out the exhaust there needs to be spark. If the issue was not there b4 the haltech went in - then it must be the haltech. Seen it b4 and there is nothing really to be alarmed with as long as the car drives fine.

It also needs fuel, spark alone will not fire a cylinder. Also you say it doesn't happen every time, that is because the spark happens each time, but the firing order means that the cylinder with the fuel only lines up randomly with the spark every now and then.

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