It seems that I am getting detonation around idle on my car. It is around 1000rpm, below that and above that there is none, but on that particular RPM there is, what sounds like, detting. Sounds like there are stones rattling around the plenum.

 

As many people know that I have just finished a rebuild, although the basic timing is correct the actual timing will be out. The idle is also very low and unstable.

Can bad timing cause the detting at idle? I presume it can.

 

The battery is also very very low and hardly manages to start the car. The battery is also not holding the charge, probably for 2 reasons; it is an old battery and it is has been off charge for 7-8 months and has gone completely. Could a poor battery cause detonation by creating a poor spark?

 

We had the car up to 3000rpm and it was running smooth. It as only last night that it was detting, hence I think the batter is not helping.

 

Any thoughts please.

 

Stuart

Sometimes folk get the plug for det sensor and the VVT mixed up, maybe worth a look to double check!

You sure its not the lifters? You'll seriously struggle to get detonation at those revs, if at all possible :confused: Oil level ok? Is the CAS in the centre of its adjustment range?

EGR removal?? ;) :eek:

 

i seriously doubt its the battery.

 

as andy says, you sure its det?

 

at that low revs it would have to be timing severly out. poss very poor fueling (low pressure??). was this with engine hot/cold?

Nah he left the EGR on :slap: silly boy!!! :D

THe alterator was not connected up at first because the loom was not in the ideal location so we started it without it. It didnt make any clicking sounds then.

 

We connected up the alternator and now its making the sound.

 

We did take one of the cam covers off though too as I had a little oil leak which is now sorted and we took the cover as it looked like the oil was coming from there, but it wasnt.

 

Could it be the cam covers rattling? I find it very strange that it makes the sound at 1000rpm but at 3000rpm is perfectly smooth and purrs.

 

Any one know what type of plug lead to use to connect to coil 1 to test the timing?

I got a light gun but it cant detect the pulse from the PTU wire.

 

Mark, I dont think its the VVT but I will check it.

LOL!! perhaps youve blown the alternator then. have you tried disconnecting the alt belt ?

 

you should never run an engine with the alternator disconnected cos it can blow the diode/recifier pack.

 

you can prob butcher any old plug lead as long as it fits over the plug, then push the other end into the coil pack

i cant see it being det either tbh.

Stuart,

 

Is the sound a kind of rattle? does sound like cam rattle, the variable valve timing cam pulleys can cause this, especially noticable after they have been removed for cam end seals etc, the noise will be evident in a specific rev range as the cams "shake"

 

When tightening the centre retaining nut for each pulley there can be a tendancy to spring/ displace the internal mechanism if the tighten force is applied in jerks rather than a smooth motion ( with a torque wrench ) if this occurs the nut must be undone and the pulley re-settled and the nut done up again in a smooth manner.

 

Of course if the cam end springs are worn / loose then the same noise can be produced, assuming this is the fault I would suggest replacing the springs and re-tightening as suggested, be aware different spring ratings can be purchased to change the speed / rate of the cam auto adjustment, if they are standard cams etc. do refit standard springs.

 

Hope that helps.

 

Jeff TT

Ive got the same prob, :mad: plus need new turbos

Erm, sounds more like it could be just the alternator bearings on their way out. As Jeff says this can also be caused by the VVT cams but since it was fine when you first started it, I'd check whats changed since then first. Alternators don't like being left lying around, the lubrication in the bearings seems to come out over time. Take the belt out and try spinning the alternator pulley - does it spin smoothly and quietly?

Erm, sounds more like it could be just the alternator bearings on their way out. As Jeff says this can also be caused by the VVT cams but since it was fine when you first started it, I'd check whats changed since then first. Alternators don't like being left lying around, the lubrication in the bearings seems to come out over time. Take the belt out and try spinning the alternator pulley - does it spin smoothly and quietly?

 

 

the movement of the alternator is very smooth and quite firm.

 

The mechanic neighbour of ours said that the metalic clicking sound is the injectors the the rattle he is not sure of.

 

However, the cam covers where taken off and put back on while I was at work, and I found one of the side bolts for the cover not screwed in. I will try to put that back on tonight and see if it was the cam cover which has been rattling.

 

When I say that before the alternator was not on when there was no sound, the alternator was in place and had the belt on or the water pump wouldnt work. The power leads for the alternator where not plugged in at first.

 

I am going to attempt to set the timing correctly tonight.

 

Where in the book does it tell you about setting up the timing correctly?

 

I want to get it idleing correctly first. Its bouncing round 500rpm but stalls if you dont interveen. Also the engine is idleing at 500rpm or you can use the accelerator to about 1500 rpm. There is no inbetween.

 

Stuart