GQ - Vibrations when turning and at take off and slow acceleration

[Pauls4x4]

Hi all,

Starting to get stuck into some of the issues with my recent purchase...1991-2 GQ 3.0 Carb.

Few things I've noticed.

1) if the wheels happen to be turned (this is, going around a corner) when taking off, I notice a grumbling feeling coming back through the steering wheel. It appears to be more prominent the more the wheels are turned. Could this be the universal joints? or could it be something more involved?

2) also when taking off, I get a vibration and noise coming from the transmission (I think) until I get up a little in speed and then it disappears. Only seems to be at take off, if I try accelerating from fast walking pace in second gear, I don't get the same noise or vibration.

3) lastly, the engine is old I know so not expecting miracles but it does seem to be tired when accelerating and really struggles getting to and going past 3500 rpm. That is regardless of whether I'm on LPG or Petrol. I have replaced sparks and leads, distributor and tried adjusting % to TDC but doesn't really make that much if any difference. New spark plugs helped a bit.

Unfortunately, due to finances, I have to do as much as possible as a DIY but these have me stumped as I'm not a mechanic and don't know what might ne causing the above. If any one has any suggestions or could point me in the right direction, it would be greatly appreciated.

Other than the above, she seems to go ok and has been back and forth between Sydney and Melbourne a few times without any drama.

Thanks in advance!

Cheers

[threedogs]

front end noises could be wheel bearings or CVs or even steering box
Also get a compression test to see how tired things really are

[Family4x4]

The vibration when taking off could be a clutch problem.

[Pauls4x4]

Thanks for the info guys I just hope its nothing to expensive!
cheers

[nipagu7]

just some possible causes ; 1 & 2 ; if this is your 1st 4x4 and if you have mud tyres this could the vibrations you can feel which would be sensed as tyre noise the faster you drive .
3 ; I am not familiar but would look at valve adjustment , maybe worn timing chain , have you changed the oil , if so , what oil did you use and be careful not to overfill the oil . fuel /air filters may need replacing ?

[kevin07]

check engine mounts

[Pauls4x4]

Thanks for all of the replies. I haven't had a chance to investigate further yet but I will check the suggestions listed.
Cheers all!

[Robo]

0 deg sounds very wrong.

lpg likes more advance than petrol.
check your manual for timing specs and give it 2 to 5 deg more to compensate for lpg.
not to much advance as you may induce ping whilst running on petrol.
and 2ndly you lose a bit of top end power advancing the timing,
but you really have to forgo the topend as lpg will never be any good an std timing settings.
also plug gap needs to be approx. .2mm smaller for lpg.
see how that sets you up.
x2 on doing a compression test.
cheers.
oh what size tyres are you running larger than std will make it slow to accel.

[mudnut]

Hello, Paul, and welcome to the forum. When run on LPG for long periods, some components in the carby can dry out. In the past, some members have suggested doing a carby kit, and then switch it to start on petrol all the time. The RB30 runs a timing advance diaphragm and a clutch break diaphragm. These can split,(especially if the engine has backfired), causing vacuum leaks and/ or the advance to stop working. This engine uses a timing belt which must be changed out every 100000 ks. Also check that the second stage of the carby is working properly. Some times they can bind at different positions and not allow the engine to rev freely.