VS Idle and Vibration issues - please help

[astormsau]

Hey everyone,
Looking for a bit of help. Recently inherited a VS Series 2 Exec with 214,000kms on the clock.
Car has been kept in order but not really maintained.
The issues I had with the car when I got it were rough vibration, the usual vibration and whirring/thumping noise when accelerating under load in overdrive at 80km/hr and the usual crank angle sensor.

My problems; often in drive or neutral when idling at the lights the car is a bit rough and secondly, when cruising up a hill at about 85/90 km/hr in overdrive with the torque convertor locked, the car shudders and gives a bit of a loud groan/vibration when unlocking the torque convertor. Also when cruising with torque convertor locked at about 80-100 with a slight incline, you feel as though the car is shuddering....

I started by replacing the plugs with NGK plugs as recommended for the car and replacing the oil with magnatec and new oil an air filter. I also replaced the leads with Top Gun leads suited for the Commodore, this made the car idle smoother but didn't really resolve the issues above which were concerning me. I had the centre muffer replaced by Performance exhaust as it was rusted through and they checked the system and replaced a few mounts,etc as well as the muffler, its still running the stock exhaust system. I then figured the coil packs were maybe on their way out as one of them had bad rust on the connector when I changed the leads, and they other 2 looked original - the rusted one was aftermarket... This made it smoother but still problems remained.

Next I went to Ringwood automatics in eastern Melbourne, they said the car wasn't locking the torque convertor most of the time when it should due to a blocked value, they installed a new valve (oversized I think) and serviced the transmission and replaced the rear seal, the car now locks the torque convertor when it should but still makes the ugly noise as described above. When queried Ringwood automatics thought the exhaust might not be sitting properly so it went back to Performance who said it was fine and checked it all over. Ringwood autos claims the auto is fine. When I get the groaning and vibrations there is no fluctuations in rpm.

I then had the CAS replaced as that was causing the car not to start sometimes and also had the engine mounts replaced as they were cracked.

I then did the oxy sensor wiring mod at the ECU to resolve the grounding issues and replaced both oxy sensors which I believe were the originals, this stopped the car running rich (black exhaust) - one of the oxy sensors was very black and sooty and replaced the plugs on the passenger side bank which had the crook oxy sensor and was running rich. running better but still not quite there...

I was a bit stumped by the fact the car should be perfect and its still doing the vibration with convertor locked and groaning coming out of lockup. Its alot better but still not perfect and feels bad when locked up in either 4th or 3rd.

Anyone got any suggestions... I tested the resistance of the passenger side top gun leads, cylinder 1 was 15,000 ohms and cylinder 3 and 5 are 25,000 ohms which seems high... im wondering if these leads are duds... or DFI module altho the car never stalls and revvs out fine...

Any ideas?
Drew

[astormsau]

oh and car had a compression test and cooling system test and everything was fine according to my mechanic...

Drew

[Brett_jjj]

Id be looking at the 3 ignition coils.These can cause a vibration feeling through the car when they get old and start to misfire and play up.Get hold of a known working coil (borrow a mates) and swap it over, one at a time, with each of your 3.Drive it each time and see if its any different.If your coils have the cylinder numbers marked on them,they are probably the original coils and they all probably need replacing.The replacement coils dont have the cylinder numbers marked on them.Also if you do find its a coil causing the problem,and have to replace one,try to replace all 3 at the same time,and try to only use genuine holden coils or a good aftermarket brand like MSD etc.

[hako]

I don't like the groaning/vibration when the TQ unlocks - it should be imperceptible. Whilst misfiring can commonly occur as Brett suggests and give the vibration, it will not give the groaning noise. Did the automatic people say anything about a worn torque converter clutch?

[astormsau]

Hi guys. I must have forgotten to mention that the coils were replaced after the plug leads. The new ones are Champion coils from Repco. They made little difference to the performance of the car when replaced. There were 2 originals and 1 aftermarket on the car when replaced but although they tested ok I figured it was best to replace them given their age.

Ringwood autos said the torque convertor was fine. What puzzles me is that if there was slipping wouldn't there be some kind of fluctuation in the revs?

[astormsau]

Turns out it was the torque converter, totally shot. Had a new converter fitted yesterday and the vibration has gone when driving along with torque converter locked up, and also when the torque converter is dis-engaged it is silent. So in this case it was not mis-fire causing the issue but a shagged converter after 215,000km. btw the Automatic itself is still fine although the shop told if it was left for much longer the debris from the converter and heat it was building up would have begun causing issues with the auto.

Drew