Need help!

[4eyedperson]

Hey guys,

Basically here is my problem.... I got a VN V6 stocker. And when im accelerating hard the car backfires and pops in the exhaust when the revvs reach about 4500rpm. But this only happens when the peddle is on the floor. If its not flat to the floor it cruises through happily.

Now the things i've changed....

fuel pump
injectors
leads
plugs
computer
coil pack
MAP sensor

these have all been changed from what people think it might be.... And now im outta ideas.

Oh and all other sensors have been changed in the last 3 months... So i dont tinhk i would be any of them.

Any help would be greatly appreiciated. Cheers all

[Not_An_Abba_Fan]

Fuel filter?

Is it actually backfiring or is it noisy in the exhaust? Check the cat, if the guts have been knocked out it will sound crackly up high in the revs. Undo the exhaust off the back of the cat and have a look inside, it should be a ceramic honeycomb looking brick in there, if it is hollow that could be your problem.

[4eyedperson]

Thanks heaps ill chek em both out this arvo. Any other ideas would be great.

Thanks again

[samuels]

Thanks heaps ill chek em both out this arvo. Any other ideas would be great.

Thanks again

other serious problem is valves,but to me,if it's popping up in the revs,it comes back to electrical,but you have covered that section.....

[4eyedperson]

Checked the fuel filter and the CAT. No problems there. So think it has to be the valves or valve springs. Best i start saving. Thanks for everyones help.

Cheers

[nolim8ts]

I had the same problem on a VN that I was selling. It would rev out out to around 4000RPM and then a pop could be heard from the engine bay. The only other difference was that mine had a rough idle and no power when putting it into gear. It turned out to the DFI module so I replaced it with a second hand one including coils and all was good. I now have a whole spare unit as the person buying the car used there own.

[spacattack]

checked the throttle body yet ? TB elbow? fuel vally? could be a serious case of carbon build up :S other than that got me stuffed lol

[4eyedperson]

Hey thanks guys.... Couple more things to check. I'll give them a whirl.

Thanks again

[vncruzr]

check your spark plugs mate. are they the right ones? check the gap to. if in doubt go to holden for some genuine ones, cheap as dirt.

[Full Spectrum]

Check your 02 sensor and fuel regulator could be running to rich and flooding chocking it in high rpm.

Also have you washed the engine of late??? Sometimes they play up after a wash and spit a little when you wont that power.