VY LS1 Runnning rough, Backfiring. What is wrong?

[crazzy-johno]

My car all of a sudden (ls1 vy2 Calais) when you start her up for the first time.. it runs like a dream! Perfect! Get to where your goin turn it off, sweet as! If you leave the car sit off for about half hour. Then turn it on. It coughs, chokes, splutters, backfires, feels like 5 cylinders have just shut down.. That happens for about 2 - 3 minutes then it runs fine. Well almost fine.. still has a slight roughness to it. WTF is that?

Spark plugs - Done
Leads 8mm - Done
O2 Sensors - Done

I have no clue!... What do you think? Car has done 97,000kms. ..Johno

[Darcon666]

Injectors need a clean???

[crazzy-johno]

I have read that on a few forums. Should do it to rule it out, but. always runs premium shell V. should I try some injector cleaner? or seeing as though the car is nearly 100,000ks should i just replace them?

[VYMAD]

I have read that on a few forums. Should do it to rule it out, but. always runs premium shell V. should I try some injector cleaner? or seeing as though the car is nearly 100,000ks should i just replace them?

I don't think it's your injectors. Would be looking at other things first. I run injector cleaner through my V6 periodically to keep them clean. Imo 100,000 k shouldn't warrant new injectors yet. Sorry, can't help with other ideas, I've got intermittent starting probs myself at the moment.....DOH!

[Darcon666]

...still has a slight roughness to it. WTF is that?

... is the reason why I said injectors.

My toy has almost 130,000 and gave the injectors a proper clean @ the 110,000k service... made a huge difference, smoother idle, better economy, better acceleration and well worth the money.

[crazzy-johno]

OK! nice! I'll put some injector cleaner through it anyway still this problem is really started to bug me aye.. loosing all respect for the car over it

[crazzy-johno]

typing this with greasy hands.. just pulled apart the throttle body for somethin to do .. and really.. should find the inside coated with (thick oil)

[crazzy-johno]

engine check light finally came on when it started it shit.. so hopefully track down a scan tool. Cause the people at holden do not give me a warm and fuzzy feeling

[Kingston_99]

also check your leads are all pushed in. mine did this a few days ago and i found #2 lead was arcking on the side. pushed it in abit and fixed the problem

[RiCeY]

Sounds like leaky injector/s. When you park fuel leaks into the cylinder and fouls the plug/s but eventually cleans itself up when driving.

Code will probably be for misfire.

[crazzy-johno]

Hi ricey. With the injector/s is there a way to test/clean them at home?

[RiCeY]

Not really, to be cleaned and tested properly you need the proper equipment.

This is a test/clean rig..

[crazzy-johno]

Just thinking how it wouldnt do that on the initial start?

[RiCeY]

Dunno may leak till u lose enough fuel pressure to stop it then the fuel evaporates overnight or runs down the cylinder walls into the oil pan and the combustion chamber dries out.

[crazzy-johno]

That is pretty impressive gear there mate!

[crazzy-johno]

Thank for that thought Ricey. so should i be looking more at injector or maybe seals?

[RiCeY]

Not mine just googled the image haha

But you can see the tubes for flow testing etc and the bath is for ultrasonic cleaning of the injectors.

[RiCeY]

Thank for that thought Ricey. so should i be looking more at injector or maybe seals?

Injector itself, may not be the issue here, just one possibility...

[crazzy-johno]

ahhh gota love google! Nah i get ya thanks heaps for a the possibility though! Cause after doin o2, plugs, or leads. i had no idea where to begin

[soop]

Replace the fuel filter. I had the same issue, chassed it for ages did everything you've mentioned and more. $15 fuel filter and it goes fine.

[crazzy-johno]

I'll give the fuel filter a go.. cause im poor at the moment ive replaced the fuel filter about 20,000 ago but i cant remember one thing... when you pull the clips off the actual filter. will the fuel run out of the lines? or just what ever is left in the filter?

[RiCeY]

lines and filter

[crazzy-johno]

well ill give the fuel filter ago this arvo for shiz giggles. Wheres a good place in Brissy to get injectors done?????

[crazzy-johno]

Replace the fuel filter. I had the same issue.

did you have exactly the same problem??? rough running on a hot start then it would smooth out?

[crazzy-johno]

Some thing else of noticed! Something it is doing constantly! While cruising at 80kmh the revs sit on about 1100. When you start to accelerate... it reva from 1100 to 1400 and when is gets between 1400 and 1450... I don't know how to describe it.. it bombs out, like its lost all back pressure. I'm pretty sure (HOPING) that solving 1 problem will solve the other. Exhaust has been checked and crossed off the possibilities list.