VT rough idle, slight miss IDEAS!!??

[aveugotone]

Hey there people, now anyone out there who can give me any ideas to this issue would be awsum i am running out of ideas.......
anyway, i have a 2000 vt v6 and it idles rough, like runs fine then stumbles (like a slight miss type of stumble) for a period of 30 secinds to a minute when it has no load, but if the A/C or lights are on or its in gear....it runs perfect, when load is applied it dosn't miss or stumble or anything when it is driven.... now the plenum is spotless, there are no vac leaks in it, has new coil packs, plugs, injectors, fuel and air filter, had a major service done 2000km ago, MAF sens. is clean runs 95 octane 98 when i can get it.
removed the EGR and plugged both ends yestrerday to see if the EGR valve was leaking and dragging in ex. gas while idling but negatory it seals and operates fine???? any ideas people your help is greatly appreciated!!!!

oh yeah and all the intake is clean including IAC valve and butterfly??? does anyone know at what time after starting and/or conditions that the evap system opens the solinoid for the purge canister and roughly how long it takes after starting to enter closed loop...

[stirringaxe]

The only thing I see not on your list is spark plug leads, they do play up on the VT ?? Might be worth a try.

[aveugotone]

yeah they're brand new, with the plugs and coils???? i dont know?? running outta ideas

[thesupervisor]

mabe the start of a head problem
have you done a compression test?

[aveugotone]

yeah all good 5% of one another..... not good, done the heads and valves at 299000, f*cks me anyone with ideas would be great!!!

[wrx884]

do a self diagnostic and see if u get an EGR fault.

[aveugotone]

already done, checked all EGR the other day all is good.... there is no fault codes in there at all.... f*cks me

[aveugotone]

hey guys, well after rooting around checked the wngine harness for broken wires and high resistance the other day srill no good, but getting a scan tool short;y so see how it all looks, idling the other day in gear for about 2-3 minutes then the engine light came, ran like a kitten but the mil was on then drove 10 metres and it went off, WTF has anyone had this problem happen to them and if so what fuxed it, cleaned MAF again still no improvement, but using a little more fuel than normal i think could just be that its really hot and i am compensating with more pedal and ac, f*cks me, any help peeps would be choice

[gjaym]

Check the cam sensor,mine was missing and would shut down sometimes ,replaced cas but still did it , but ran fine when sensor disconected replaced sensor all good

[aveugotone]

cheers bud will do, let ya know how i go...

[IBLOWN]

I'd be replacing the crank angle sensor first.

damaged Leads will likely miss under load.

Also check the pins in the connector on the DFI module. Make sure theyre clean.

[aveugotone]

does anyone know if the VT V6 2000 model is OBDII compliant or only OBDI ???

[Tsunamix]

It's OBDII. But before you go replaceing everything in sight, it you have leads with hmetal heat shield on them, remove the heat shields.

If that doesn't fix it, hit the wreckers, and grab the Coil Packs and the Timing Module (lives under the coil packs - the coil packs plug into it), and swap them in.

If your in brizzy - I have spare coils.

Yes - it can be the coil packs. Don't forget that the coil packs discharge into 2 cylinders at a time - one on compression stroke, 1 on exhaust. So you can get weird things happening.

I suggest this is the way to go because these are the items that misbehave intermittently, where sensors tend to behave continuously.

[aveugotone]

yeah but all that is good, coils are brand new, leads are new, heat sheilds on or off no difference, replaced CAS today, acceleration is bit better and snap neck kick when u plant it but still slightly surging/idling rough under no load.....

[aveugotone]

some reason when starting up in morning.... right.... it starts, and or take about 2-3 seconds to start, then revs to about 1400 like normal, then stumbles n mumbles and carries on for 5 seconds or so then runs fine.... even if i cycle the key 3-4 times to build fuel pressure still doesnt make any difference, any ideas ppl would be great just about had enuff.... ,most well put a carb and dizzy on less rooting around lol

[aveugotone]

and whenever i rev it without it in gear or the ac or lights on it misses on one cylinder not full on tho, but distinct, but then other times it wont do it when its cold it wont do it only when its hot i am f*cked for ideas.... the only thing i havnt done is the DIS/DFI module so maybe that is the shizz i think.... ebay here i come....

[Claudy]

Yer the module itself could be buggered, mates car had same problem changed leads, coils and plugs but didn't change anything, put on a spare coil pack and module I had and was fine

[Claudy]

Also maybe try injector cleaner?

[aveugotone]

injectors are new bud, brand new VDO ones....

[aveugotone]

well, finally got xome codes out of it today.... bout time...ended up with 32,44,48,76 now im not sure what sensors are linked on the same circuit as one another but, i have got 32 for MAF sensorsignal missing, 44 for lean exhaust, 48 for camshaft sensor signal missing and 76 for short term fuel trim problem... now if hypothetically, the cam sens. was nackered, it would put the fuel injection out slightly, as it times the MPI. if the airflow sensor was knackered the engine wouldn't see what air was entering the engine therefore could be running lean or rich, and cause rough idle and set code 44, any one else think similar??? but if one of the two sensors was knackered or i had a open or shorted circuit what other sensors run in with these two???? thinking maybe i should just get the multimeter and find out... could take a while, checked for broken wires the other day and didn't find any.... ideas, suggestions, any thing would be awsum...

[Brett_jjj]

When I first got my VS ecotec,after a few weeks it just started to idle really rough at the lights etc and just ran crappy in general,it even stalled a couple of times whilst trying to idle.I checked the error codes,got error code 48 showing up,so I checked the cam angle sensor and its wiring etc,all good.I then removed the cam angle sensor from the timing cover to check out the sensor pickup magnet, which is located in the cam sprocket and triggers the cam sensor as it passes it,and to my suprise, the magnet was completely gone.I removed the timing cover and luckily I found the broken magnet stuck to the side of the engine,luckily its a fairly strong magnet..What had happened was theres a plastic cage type thing that holds the magnet in the camshaft sprocket,this had come unclipped and had moved forward, and the magnet then hit the sensor which smashed the magnet out of the sprocket hole completely,it left a good score mark on the sensor where it hit too,so you could clearly see what had happened.I replaced the pickup magnet, $80 from holden!!, and refitted it all back together,its been 5 years since that happened and shes still going good.Ive since found out that with these V6 motors,this is not as uncommon an you might think,quite a few people over in the USA have had this happen with these engines,and apparently they glue the magnets plastic cage to the camshaft sprocket to stop it from moving forward and hitting the sensor.I just wish Id read this info before Id replaced mine,I would have glued it as well.Anyway,if you dont find the cause of error code 48,this pickup magnet might be worth checking out.Its a pretty rare thing to have happen,but it still can happen...and it will cause the car to run and idle like crap..

[aveugotone]

hey thanks mate pulled cam angle sensor out the other day, the sprocket just had hole in it no cage no nothing..... might have some shit rolling around in the bottom of the timing cover i think.... tomoro job i beleive... i thought the pick up worked by magentism when the sprocket went around then when the hole passed nothing, but in fact the other way round.... cheers bud let ya know how i go....

[Brett_jjj]

There is a heap of holes around the camshaft sprocket,one of these holes is offset out further than the other holes,this is the hole that the magnet is supposed to be in.
EDIT:Heres a picture of the pickup magnet and where its supposed to be located in the camshaft sprocket.

[psycho_smurf]

If you have cleaned your MAF with carby cleaner then its probably rooted it. Clean the contacts for the various sensors, disconnect the negative terminal for 10 mins, run the car again and check to see if the error codes still exist.

[aveugotone]

cheers bud was looking for a picture of magnet..... got one now....


na bud i use windex and a toothbrush... gets all the dirt off it and is all good.... even after reset the same 4 codes are still there... well they clear but come back....