Back-fire

[TOYMOTA]

I've noticed over the last couple of weeks that my Rolla seems to be doing a sort of back-fire/popping noise when I lift off the gas at about 4 - 4500 revs. The question is, is there somthing wrong?

Logical thinking would make me think that it's over fueling, therefore there's too much fuel going in and as a result there's gas flowing out the exhaust and with the heat is exploding, but how, as I haven't changed any of the setup?

Should I get her tuned up on a rolling road, or something else?

I'm at a loose end!!!

[TOYMOTA]

Anyone out there??

[Unity Jon]

if you havent changed anything i doubt its overfuelling, its more than likely you have a cold air leak in your system, check your exhaust out for leaks, check your intake out also your hoses, perhaps they're getting slack when the engine is hot. ?

[System~G]

Mine has a gurgling sort of inhalation type of sound when I lift off juice with a few pops here and there. I put it down to the thruflow exhaust system.

I do sort of like it even if it is a little too loud

[TOYMOTA]

its more than likely you have a cold air leak in your system, check your exhaust out for leaks, check your intake out also your hoses, perhaps they're getting slack when the engine is hot. ?

I know there's a slight leak at the bottom end of the downpipr, where it joins the zorst (dodgy gaskets). I've bandaged and then put some of that zorst cement over it, but I can still hear it blowing slightly.

I do also get a smell of petrol for some reason!!!

[Unity Jon]

if you can smell petrol then its overfuelling, check you return line is not blocked.

[TOYMOTA]

if you can smell petrol then its overfuelling, check you return line is not blocked.

Is the return line on the TVIS part of the car??

[Unity Jon]

the return line is connected to the fuel pressure regulator which is bolted to the end of the fuel rail, also check the regulator, if its not flowing correctly then its creating back pressure in the fuel system and the extra fuel that the car doesnt need is being forced into the chambers doiwn to the exhaust and exploding.

Be carefull when you undo the regulator from the fuel rail as there is 'normally' quite a lot of pressure in the fuel line and it will squirt out, i even think its designed to squirt into your eyes ??

[TOYMOTA]

Thanks for that mate, I will have look when I get home.

Is this likely to damage anything in the engine? or just my wallet as far as fuel is concerned!!

[Unity Jon]

you need to disconnect the return line then at the TANK end blow it through with a air line and get all the crap out of it, it needs to come out the way it went in so blow from the tank end toward the engine.

shouldn't cost anything.... unless you spill all the fuel ??