bad back fire

[jamie_supra]

any ideas what happened?
has driving the car. so far have not taken it past 50 mph and have not had the boost over 0.5 bar.
was driving down a road at no more than 30 mph on none or little boost. accellerated slowly and the car sounded like a shot gun. let off and thn accelerated very slowly and it kept sounding like shot guns. on low revs it seemed ok but anything over 3k and it had no power / this back fireing. I crawled to a car park and sat there. it idled fine. eventually turned it off. but it wouldnt start up again and if it tried it would miss fire. the oil was ok and the temp was ok.
any ideas??

[BlitzBoy]

Check normal stuff like plugs,leads etc. Then check the vacuum pipe to the MAP sensor is not split or come off.
What ECU is it running? if Apexi you can check via the commander the sensor check to switch if a sensor is not working.
Also check intercooler pipes and couplers for air leaks

[jamie_supra]

its a power fc with commander. knock is showing really really high!!.  where abouts is the map sensor? would that stop it wanting to fire?
could a plug / lead break down suddenly? they are HKS irridiums and have done less than 1000 miles.
 
i am worried i have broken / thrown a tip... but when i have done that in the past it happened on boost and on higher revs it got better - this is the opposite!

[AshRX]

Map sensor is on the bulk head just to the let of the inlet pipe.

Its a little black box with a vacum coming out and a electrical connector. Should have Denso or something written on it

[jamie_supra]

and would the map sensor prevent it from starting?

[BlitzBoy]

sometimes, I couldnt start mine when mine split two years ago as it chucked a load of fuel in and flooded the engine, plus you normally can start the car with a broken tip on one rotor

[nikp]

Mine wouldn\'t idle when the pipe popped off my MAP sensor. But it is a logical place to start. Also, check places that Blitz spoke of, as these are a good source of problems. Doesn\'t sound like tip to me.

[jamie_supra]

cheers. well i have had it trailered over to RGS.  Fingers crossed its something minor . iv just called them and told them to check the map sensor / connection and the plugs and leads.  
 
the odd thing its that it idled relatively well ............... just a lot less power esp up the rev range and then the back fireing.

[jamie_supra]

Mine wouldn\'t idle when the pipe popped off my MAP sensor. But it is a logical place to start. Also, check places that Blitz spoke of, as these are a good source of problems. Doesn\'t sound like tip to me.

cheers mate.  it does sound a possibility!

[nikp]

I should clarify: mine would idle at 1000rpm. It would idle when i turned the idle screw up so that it idled at 1600rpm.

[jamie_supra]

interesting point.............. 2 days ago whaile at RGs it didnt idle and would just cut out. they upped the idle and it was fine. does sound more and more like what you said............... as in a crack in the pipe that split totally yesterday!!

[Bobbit]

Mine did this 2 days ago, started it up and it went bang, just like a gun shot. Then it idled ok, so left it ideling and it seemed fine. Started it up yesterday and went bang again then the idle went up and down, then just kept going down until it died then it would not start at all. Got me a bit worried so took the 2 leading plugs out as i thought i\'d flooded the engine(left the trailing as it was getting dark), I\'ve just had to change the clutch hose as the old one split and I got brake fluid all over the hoses, oil filter and map sensor also. How would i check the leads as less than a month ago I changed for some new magnicor ones? Also if there are no splits on the hose to the map sensor how can i check if the unit is knacker without starting the car (dont have a PFC). Sorry for hijack but there\'s no point starting a new thread for this same issue.

[DR SCHNITZEL]

My car did this for a year until i removed the air pump now i have no problems at all, with pops and bangs at low revs just the occasional huge flame when i change gear off the redline.

[Bobbit]

My air pump has been disconnected as its catless

[jamie_supra]

did you say you have magnacor leads..... so do i. possibly its them. im pretty sure i stil have the air pump attached.  well RGS are looking at it monday now.  iv forwarded on all the points suggested on here. if you have the same symptoms its possible its a similar thing...............
 
hope its done by thursday as i have a photoshoot organised for redline magazine