How come Backfiring?? :(

[nitrus]

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[Fluffy]

its fuel escaping ur engine thru ur exhaust.

 

[nitrus]

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[vantageX]

? What do u guys think ? Im juz afraid tat it wud damage my engine/muffler .. What do u suggest i do?

Err...don't accelerate to a high rpm and hold it in 3rd gear? Unless you're drag racing, why are you holding high revs in 3rd gear? And even if you are drag racing, you should have a shift point.

Just don't do it too often, it happens and since you're driving a carb engine car (or any car for that matter) its just not advisable to hold your revs high.

As for the cause, well its probably down to timing and unburnt fuel escaping. I mean there's nothing generally wrong with your timing, just that at such high rpm the distributor can 'miss' and not ignite the plugs and allow fuel to escape unburnt. Even more if you have a contact breaker point ignition. No harm done but do try to avoid doing it often.

 

[Fluffy]

avoid revving too high.

 

[BlackSamurai]

check ur tangki got water?

 

[BLaCkHoWLiNG]

running rich?

 

[gohkokeng]

carburetor do not have rev cut and speed cut.

when u rev tooooooo high it will not POP! only

it will sound PPPOOOOOPPPPP!!!!!!!!!!!! then bubye liao

 

[kelvio]

my car like to POP also but when rev high then decell it pop damn loud cos carb kong edi(FC damn high) need carb kit to replace
u might 1 2 check if ur carb is dirty or so

 

[nitrus]

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[gohkokeng]

i think Blacksamurai simply meant.....your FUEL TANK got termasuk air in it?

 

[vantageX]

nitrus: It backfired at 3-4K rpm? I thought it did at a higher rpm like 6-7K. You might have a problem but it can be a number of things. Distributor timing, a hole in the exhaust, a lean mixture of petrol/air escaping left in the combustion chamber post ignition. An engine which isn't tuned to handle aftermarket air-filter or extractors.

Just drive it and see if it happens again but at 3-4K rpm, sounds like a problem there unless you do this often. I mean cars are designed to overtake as well so that kinda RPM range should be ok. You mentioned a burnt exhaust tip so its definitely unburnt fuel. Get your mechanic to check ignition timing and even a small leak in your exhaust though this might be harder to spot especially if its a leaking exhaust gasket.

Most cars over a certain age have some water in the petrol tank, this can't be helped. Question is how much water have you got in your tank.

Lol, as for me? I did automotive engineering at FIT before it closed. Graduated, did a few more courses on EFI but couldn't see a future in Malaysia so went off to start my own internet business. Still do most of the repairs on my own car and diagnose the big problems but let the mechanic's handle it for the big stuff. Easier. Love classic cars and old Japanese cars. Still collect books on automotive repair eventhough am out of the business. :)

 

[BlackSamurai]

nitrus, mind telling us what modification you have done?

 

[nitrus]

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[vantageX]

Aftermarket air-filters and extractors can alter the way a carb engine without an ECU behaves. An EFI set-up will just alter its settings to match the new parts.

Hope your car's fine. Its only 1+ year old so maybe there's nothing wrong and it was a one of incident....or a plastic bag :)

Got future here in Malaysia? Dunno la...maybe, maybe not. As for it being wasted...lol...don't remind me la.