We've got a TS 4cyl auto wagon thats been a pain in the butt of late .. I've replaced the ISC, checked and adjusted the TPS, checked timing, and checked temp sensors , O2 sensor ,etc ,, I get no error codes .. BUT........ when She Who Must Be Obeyed takes off in the mornings , it backfires; pops , sometimes very loud!! through the intake.... Injectors all cause the same rev drop if I disconnect the wiring, so I assume all are working OK ... It starts and idles OK , idles OK in gear when cold too ....

It's great after its driven 1.5-2km though ...

it's really annoying SWMBO, therefore I'm getting annoyed too ..:nuts: :nuts:

Anyone got any ideas ??

let the car warm up before you drive away? like ur supposed to do?
:nuts:

check leads, plugs and dizzy cap/rotor. also let the car warm up for a few mins.

dizzy cap and rotor are next to be replaced ,plugs and leads are new ; few " bubbles " on end of rotor ...... now just have to tell SWMBO to not be so impatient!

I'd check the compression on each cylinder too. Could have a leaking valve.

Also is it petrol or LPG? I've heard often of problems with LPG converted ones...

its petrol .. and I dont even want to think about valves etc...:gtfo:

let the car warm up before you drive away? like ur supposed to do?
:nuts:

You should never have to let a car warm up. You should begin driving immediately after starting the engine

You should never have to let a car warm up. You should begin driving immediately after starting the engine

This is true......it states this in just about every car manual of the last 17 or 18 years. Infact in the new commodores it has a warning saying not to let the car warm up as the motion of the car assists in lubricating the engine.

tis true! You dont have to let it sit there at all, You just shouldn't flog it straight away, while the engine is cold - same theory of metals expanding/contracting with temperatures.

back firing like unburnt fuel getting past the combustion stage. Like running rich while cold like it should?

def seems to be richer than it should, on start up anyway ,

It sounds like it may be your fuel injection temperature sensor. It's usually located where the dash temp sender unit is, and it tells the ECU how hot the coolant is, so the ECU knows how much fuel to inject.

Just a thought though.

Thanks , I'll check/replace it , and see what happens .. Got to keep SWMBO happy......:boohoo:

Infact in the new commodores it has a warning saying not to let the car warm up as the motion of the car assists in lubricating the engine.

that sounds like a load of ****... but you never know...
true that with the newer engines warmup is not a problem (only those with carby/choke) was warmup required...

id rather let my car lubricate itself at 1,000RPM than at 2,000RPM, but thats just me

"Castrol Magnatec - Protection from the moment you turn the key"

lol

id rather let my car lubricate itself at 1,000RPM than at 2,000RPM, but thats just me

oil from the sump reaches the critical components faster if the car is in motion over it being at idle. Oil is forced through the pump at a higher rate when the engine is working.

Is your car running rough.

The reason i ask is it is possible you have high resitatance in one of your ignition leads.

When they are cold, the continutity on the leads have more resistance. In return fuel does not gett burnt.

Youll be supprosed on the amount of crap in a catlytic convertor as a result