V8 AU Fairlane not running when hot Heeeeelp Pleeeeease!!

[GTLexus]

OK, I have looked on the search function, and on the forums and to no avail.

This is the issue

I have a 99 AU V8 Fairlane on dual fuel with 199000kms.

It was running rough at idle on both petrol and LPG and then when accelerating it would not want to accelerate and run even rougher. The idle is that bad that the whole car shakes.

I replaced the coil packs, spark plugs, and ignition leads.

Cleaned K&N airfilter
Checked wiring connections on engine
Cleaned throttle body
Cleaned contacts to airflow meter
Changed oil and filter while I was there
Changed fuel filter

After all this the car still idled roughly and I took it for a drive and the acceleration was like it was still misfiring. I ran it on both petrol and LPG and it had the same symptons. When I got back in the driveway the car temp was at normal. I shut the car off and when I went to start it, it did not want to fire. I rechecked the leads and connections and they were all OK, out of desperation I gave the airflow meter a tap and the car started. It idled roughly and was backfiring.

It seems the hotter the car gets the worse it becomes.

Does anyone have any idea what to do next?? I have had the car towed to 2 mechanics and both of them could not find anything wrong with it

[stavros68]

Common problem with AU V8, harmonic balancer it will cause it to miss, the more you drive it the rubber seal gets hot causing it to vibrate .

[peterban]

I had trouble after converting the V8 LTD to gas with it running rough on gas and petrol.
It wouldn't run properly on either fuel and it was like it was running on 4 cylinders
It turned out to be the mixer.
The gas guy took it off, pulled it apart and sprayed the inside with a carby cleaner.
Every now and again it plays up and I just carefully take it apart and clean it myself.

The system I have has an Impco mixer installed in the middle of the intake pipe.

It seems it gums up every now and again and as it also affects the air getting to the engine it affects both the gas and petrol side of things.

[jeffb]

I would check the harmonic balancer, if the crank angle ring is not right it wont run, and if the weight has shifted it will vibrate running.

[GTLexus]

thanks guys, will try the harmonic balancer, seems to make sense

[5.0 ED]

although im not discounting it, but the ring on the harmonic balancer isn't connected to the rubber side it is part of the centre solid part, have seen many faulty and not one that has caused running issue's apart from bad shaking, particularilly bad at about 1300-1400rpm.

I'd be more inclined to check the actual sensor itself.

[mik]

could it be getting gas and petrol causeing flooding? crank angle sensor?

[peterban]

I thought that was what mine was doing as it ran the same on gas and petrol.
It was the fact that the alloy part connected to the diaphram that lets the gas in doesn't move freely and blocks some of the air entering the engine and so starves it of air.
Does your car have a mixer in the intake or just the ring like what is on the e-gas cars?

[GTLexus]

it has a mixer on the intake pipe.

this was checked by an lpg mechanic as well.

The car is definitely idling roughly and extremely rough on acceleration.

I will find how to chack the sensor first as it will be easier and if OK go the balancer route. Went to start it today and it has a flat battery so have put it on charge and with the weather we are having in Sydney I won't be able to test it until it clears up (the P6 LTD takes up both garages

[fordlover]

Originally Posted by jeffb

I would check the harmonic balancer, if the crank angle ring is not right it wont run, and if the weight has shifted it will vibrate running.

common on the 6cyd engines too