Vacumn problem? (VS Ecotec)

[Dan VS 231]

Ok so my car is running again after many hours in the shed and a bunch of new parts.

Now there seems to be a problem with a vacumn unit that mounts to the back of the manifold. The unit has two vacumn pipes that run under the manifold, one runs to the pollution canister up front and the other runs to the throttle body. The car is running rough after it idles down and seems to be pulsing on idle too. This unit is also pulsing and ticking something like an injector does normally (which are just reco'd so it shouldnt be them).

What is that unit and would it cause the car to run rough and what is it worth to replace? The revs intially were spiking badly when changing gears in the shed too but that seems to have calmed down now.

Cheers.

[EREXON]

Id say the MAF (mass air flow) sensor. just before the air filter.
Dunno if this is a problem with holdens but alot of high performance vehicles seem to have MAF problems and this causing rough idle and the needle just keeps trying to settle down but just keeps jumping up and down running very rough.

Try pull the codes and see if anything is wrong and go from there?

[hako]

That pollution canister you mention will be the purge solenoid - it 'may' be locked open allowing air to be sucked into the throttle body upsetting the idle. This should give a code 97. Gregorys has a test procedure which I can forward.

[Surfwagon]

If you still have the original factory elbow where that vac line from the purge solenoid goes to the TB it may be cracked as they invaribly do with age.
The tube between the purge valve and TB is plastic (good) with rubber at each end and it's these rubber parts that perish.

[Dan VS 231]

We did check all those pipes and changed the unit to tb line as we felt it was a bit short. A mate with a diagnostic unit came over last night and plugged into the port under the steering wheel dash but couldnt get a reading. He think it might only read certain model cars.

Also after more investigation we are thinking it might be the throttle position sensor as the revs still spike when changing from neutral to drive. Hopefully we can get the car in at his workshop today an run it up for a diagnostic. Because without computer help we are just looking and pointing and possible problem areas right now.

Thanks all for the ideas. Will soon find out more. Cheers.

[Surfwagon]

The TPS is self positioning so even if you had changed your TB the TPS resets its idle and full throttle value once you restart the engine.
To make sure it is reset, turn on your ign without starting the car and push the pedal all the way to the floor and if someone is with you check that this is full throttle on the TB then release the pedal back to idle position and the TPS is reset.

[Dan VS 231]

I guess we could check that one out tonight. Other than that it rules it out and its back to the drawing board.

[hako]

You don't need a diagnostic tool to download fault codes - just a paperclip. Instructions are at:
Checking error codes VR/VS (Revised)

[Dan VS 231]

After much searching I finally found some wire to act as the paperclip and found the codes: 12, 64, 65, 76 and 97. The 12 came up first but I stuck around and got the others.

Code 64 - LH Oxygen Sensor Lean (O2)

Code 65 - LH Oxygen Sensor Rich (O2)

Code 76 - Air/Fuel ratio variation between left and right banks

Code 97 - Canister Purge Solenoid and/or Circuit.

Now the 64, 65 and 76 would explain themselves as if the LH O2 sensor is running way off like it is then there air/fuel mix would be different between banks.

The 97 is my original problem and now its confirmed. Any ideas on the cost of the unit from Holden and would I need to replace the canister or just the unit at the back of the manifold?

I have wanted to get new O2 sensors just because for a long time and it has been a bit rich lately. A new purge unit will also sort out the other code. Cheers for the advice all.

[hako]

Try pulling it off and wash in a solvent - maybe petrol or injector cleaner and also double-check all vacuum lines and elbows as Surfwagon suggests. No use buying a new one when the old one can be cleaned. The Gregory manual outlines an electrical test on the actual solenoid.

[keygen]

my o2 sensors have given me grief b4 , rough idle etc .

i found info on this site that suggested cutting the pink wires to this/these sensor/s . if they are 4 wire sensors .

if u cut these wires , sensor side , worst case , i believe , is that u'll chew a bit more fuel till u've reached operating temperature . which i've found to be very little & i do know my sensors require replacing anyway .

car still runs very well .

[Surfwagon]

my o2 sensors have given me grief b4 , rough idle etc .

i found info on this site that suggested cutting the pink wires to this/these sensor/s . if they are 4 wire sensors .

if u cut these wires , sensor side , worst case , i believe , is that u'll chew a bit more fuel till u've reached operating temperature . which i've found to be very little & i do know my sensors require replacing anyway .

car still runs very well .

You have to be careful to cut the pink heater power wire from the ecu which means checking the on the loom side of the sensor connector because for some reason unknown to mankind Holden doesn't run them in the same order on the sensor side of the connector.
If you were to cut the sensor side pink it would be one of the earth wires.
This has been discussed at length before.
I cut the proper pinks and it definately helped my fuel consumption by at least 2L/100klm.
Early VS's only had a 2 wire O2 sensor (no heater) and the only reason Holden changed to 4 wire (with heater) was for emmissions, to have the fuel maps go into closed loop operation earlier instead of waiting for the exhaust to heat up the O2 sensors as they have to be above 320degC to work properly.
Your exhaust once engine is warmed up is in excess of 400+degC.

SW

[Dan VS 231]

Speaking of O2 sensors we have done the ring around for some and apparently there are 2 kinds genuine and aftermarket and in this case the genuine is cheaper by $10 at only $110 each. Does that price look right to you all and if it does I will make the move and hopefully fix some of the issues going on.

[Surfwagon]

Do a ring around of places to get genuine parts because you should be able to get them for under $100each, I only paid $55 ea trade and I can't belive they are charging an extra $50+ for retail.

[Dan VS 231]

Yeah I will now because $110 look a bit high to me. That was from our local Auto1 where my dad gets trade due to how long he's been going there. Maybe their book was a bit off. Ill check out the local Holden dealer tommorow and see what they can do for me.

[Surfwagon]

Yeah I will now because $110 look a bit high to me. That was from our local Auto1 where my dad gets trade due to how long he's been going there. Maybe their book was a bit off. Ill check out the local Holden dealer tommorow and see what they can do for me.

Found these Genuine Holden O2 sensors on eBay;
HOLDEN OXYGEN SENSOR 4 WIRE VS VT VU VX VY VZ - eBay, Air Intake, Fuel Delivery, Car Parts, Accessories, Cars, Bikes, Boats. (end time 05-Mar-09 13:36:42 AEDST)

SW

[Dan VS 231]

Got the new O2 sensors in last night and took it for a drive. Runs like a champ now and no more roughness or pulsing on idle. The right side sensor was clean almost unmarked but the left side (which was giving the codes) was char black and just plain blocked etc. Ended up paying just over $70 each with gst from Metro Motors Holden. Much better than the other quote and seems to have fixed the problems, now for some cruising for good times and to settle everything in and give the computer time to readjust itself again.

[Surfwagon]

Good to see you didn't pay a fortune for the O2's and that they have worked to fix your problem.

[kopper69]

Wouldnt hurt to clear those codes too, so that if any more come up in the near future you dont go chasing old codes. To clear the codes you can disconnect the battery or remove the 20A engine fuse. A couple of seconds should be plenty, but it wouldnt hurt to do something else for a minute. Recheck the codes and they should be all clear. After your next drive check the codes again and make sure there are no new codes coming up.