VS V6, With a miss

[Brett_jjj]

Hi, I own a V6 VS Commodore, It runs perfectly except for when it has not been started for a day or longer, It misses on 1 or 2 cylinders when it is first started and clears itself after 30 seconds or so of idling. But it only does it when it has sat for over a day or two, I can drive it in the morning, go out in the afternoon and start it, and it does'nt do it. Just does it when sitting for a day or more, it starts fine if its been sitting for less than 24 hours. I Have changed plugs, leads, coils, fuel filter, air filter and fuel pump. No difference ,although it does run a lot better. But this stupid miss is still there after sitting. Anyone got any ideas ?

[pjdm1980]

Maybe check the codes on your car first?
Checking error codes VR/VS (Revised)

[Brett_jjj]

Yea I have checked the codes and only got code 12, normal.

[ORIXVywags]

I have the same issue, Leave it for whole day, Jump in Starts rumble rumble rumble and purrs like a kitten,
I have changed injectors, plugs, leads, coils , fuel pressure reg, air filter, fuel filter, o2 sensors (both), temp sensors, everything

I have been lead to believe that the next thing that DFI is buggered, saying that my 3-6 coil is not getting the power outage to charge the coil

Im not paying out the a$$ anymore, Im going to swap with mates DFI see it still does it

I will have a crack this weekend, Keep you in the loop

[aceventura]

There was a post some time back regarding injector o-rings causing a vacuum leak while the engine was cold and making the engine run rough. As the engine heated up the o-rings sealed back up. I reckon I had this problem once. You may be experiencing something very different, but it is just a thought?

[ORIXVywags]

I thought that, but the new injectors had new O-rings, and they seal I had them checked after installed,

I have physically watched the engine when I turn it over, no hissing, and had a compression test

I mean all the money spent on it makes it drive fantastic, just on cold start is the issue

[aceventura]

I had a rough idling on starting issue after I had my injectors reconditioned. I can't put my finger on it but the issue stopped about the same time I took the leads off the injectors and rotated them backwards and forwards. I can't even remember why I was doing it. May have been coincidental, but about a month later I someone post this thing about the injectors, making me wonder if this was what fixed it???

Could just be that Shire air, it also coincided with moving away from the area

[Brett_jjj]

I'm gonna check my injectors, they havent been touched.
The motor has done 150,000km, was a reconditioned motor from redlands in Brisbane.
The only trouble I have had was a lefthand side inlet manifold gasket blow between water passage and inlet manifold runner, and was pumping water through the cylinder and out the exhaust pipe, at the time I installed the new gaskets, i fitted new O-Rings to the bottom of the injectors and all was fine. In the last 6 months this problem started and has been slowly getting worse. The reconditioned motor i'm sure would not have come with new injectors or manifolds, so the car has done 385,000km, so the injectors are probably due for replacement, i'm not giving up, i'm gonna keep sussing it out, I'm gonna go and get new injectors and see what happens then. Will post on JC what problems, if any, I find.
I fix my own cars and always have done, never really have any problems, but this one has got me stumped, because it runs so good, except at startup after sitting.
Thankyou for taking the time to answer my question.
Johno.

[Brett_jjj]

Just thinking back to when I did my inlet manifold gasket, The gregories manual said to put petroleum jelly on the new injector O-Rings, Page 43, Step 8. Then if you go to page 125, Step 1 of the installation, They say to lubricate the new O-Rings with clean engine oil. What is the go with this??, and which one is right, because I used the petroleum jelly, and have just noticed about the oil, while looking through the manual.

[hako]

Petroleum jelly (vaseline) and clean engine oil are both dino oils......interchangeable.....safe to use either.

[Brett_jjj]

Thats good to know then, spun out when reading the manual, thought I might have made a mistake.

[aceventura]

Just a note, any vacuum leak around the manifold will cause problems, as it will trick the MAF - it need not be the injector o-rings, could be any seal. Not sure how you go about diagnosing the problem though.