Outer Limits 4x4 Board

Posted: **Tue Oct 13, 2009 4:03 pm**

Hi I originally posted in Toyota Tech but wondering if anyone had any different ideas for me?
http://www.outerlimits4x4.com/ftopic188975.php

Hi,

Car is an 87 Hilux d/c. 4y-c

Recently in the last month or so my car has developed a pinging noise when accelerating.
At idle and when backing off the accelerator at any speed the noise is non-existent.
It is the same noise that the car makes when in a gear too high for a hill, if that makes sense lol.
Since developing the noise I have changed petrol stations and changed to premium for multiple tank fulls.
I have also changed the oil and oil filter.
I checked the timing and my manual says that the timing should be 4degrees at idle. It was at roughly 14degrees. I have moved the timing back to 4degrees but the noise if anything seems more prominent. :(
(Could it have been moved to a higher degree for a reason ?)
There is also vacuum pressure in the little emissions hoses, I don't really understand the hoses and their purpose so that wasn't a thorough test.

Does anyone have any suggestions as to the cause of this noise?

I have tightened the air box and checked the engine mounts.
To make things more confusing to me with a passenger in the front the noise is quieter.

What am I missing guys? HALP ME!!

thanks.

Posted: **Tue Oct 13, 2009 5:04 pm**

IF it is indeed pinging( pre ignititing) from your engine and adjusting the timing has altered it sounds like you need to do a road tune for the timing. Find 1 hill where it does it and do multiple runs adjusting the dizzy as you go to find the spot where it stops.

Maybe sort out your vaccum first. Its prob for vacuum advance of timing. a road tune will get you sorted in the meantime and help eliminate probs

Posted: **Tue Oct 13, 2009 6:06 pm**

Does it have a harmonic Balancer rather than just a pulley?

Some of them did, they can slip giving you an incorrect timing reading.

Get it on TDC firin on #1 & check this first.

If all is OK then it may be really carboned up, 4YC's are renouned for this. Do an upper cylinder clean.

It may also be running lean, this can cause the same issue.

Does it run on when switched off?

The 4YC carbies are crap & tend to give a lot of lean run/idling/flooding issues.

Posted: **Tue Oct 13, 2009 8:51 pm**

I recon you have a vaccum leak and its causing it to run lean.

Outer Limits 4x4 Board

noise when driving.

noise when driving.

4y