My harmonic balancer is due for a rebuild.

Could this be the cause for my idle and voltage dip every 32 seconds when my car is idling? I'm wondering if the slipping damper could be throwing the car off sync?

Thanks.

 

Nope.

GENERALLY the rubberised pulley section of that damper ONLY drives the belt/s.

The V12 drives the alternator belt ONLY, on the 5.3 that is.

The timing wheel is always bolted to the centre hard mounted section of that damper asembly.

I would think the pulley slipping is causing a no charge from the alternator, and the battery simply cannot keep up with these juice hungry cars.

If not a no charge, then an erratic charge rate, which also upsets "Her Magesty" somewhat.

 

Like grant said, it isn't going to throw off the sync, because that belt slipping and the dampener being worn out still doesn't allow any movement in the timing chain. If the alternator belt is slipping that could be the cause though.

All of my XJS alternator issues have been with the voltage regulator and alternator pulley eating belts.

 

I concur! No danger for the timing. But I saw the voltage drop quite a bit (at idle) intermittently, with the delaminated pulley of my VDP's AJ16. I even swapped alternators with the XJ6's AJ16, only to see the same effect. It was worse with lights on (load). It was also accompanied by vibration at the damper and a low pitch rumbling throughout the engine. Not nice!

 

SleekJag,

Did replacing the harmonic balancer solve your problems of:
1. Intermittent voltage drop
2. Intermittent vibration

Was there any (intermittent) effect, that you recall, on the RPMs, that may have been resolved as well?

 

You can check the harmonic balancer by drawing a line from the center to the outer edge over the bushing. Check it after a drive and see if the line still lines up. If the line still lines up you are ok. If it doesnt the outer ring of balancer is loose. If so replace ASAP.

 

I'm sorry to say that the problem went uncorrected and I had to retire the vehicle. There was simply too much for me to fix on that car, esp since I have the two others to care for! But many of her parts will live on.

I can say that the swap alternator that went into the XJ6 is perfectly fine.

 

Does that car have a knock sensor that could be going off from the dampener vibrating around?

 

The AJ16 has 2 knock sensors, but they are not tripped by the vibration. It must be a different type of "noise" or vibration. My VDP's OBD was clear while running with the delam.

 

The cause of this problem was a bad coil. Even though it was new, it was causing the symptoms below to pop up every 32 seconds.

Replaced the coil and everything is back to normal.

Still have to get to that harmonic balancer...

 

I took my 95 XJS out anfmfit looks like my harmonic balancer may be on its way out too. Please follow up on where you get it done.

 

I sent you a PM.