I purchased my first LR about 3 weeks ago. A 96 Discovery with 88,000 miles on it. The first thing I tackled was the CDL. Got it to work with the help of this and another forum (thank you). The linkage was decent on mine, the problem turned out to be the solenoid in the t-case.

Last week:
I cleaned the axle vents, the rear was pretty clogged, the front looked brand new.
Installed a rear pinion seal
Changed the oil in both axles and the t-case.

This week:
I changed the spark plugs (autolite 64 gapped to .040). The wires look fairly new (STI brand) so I didn't change them.
Checked the air filter, it looks fairly new.
Changed the oil in the swivel ***** (the pass side leaks I see)
Fixed the rear window ECU, it had the bad solder.
Fixed the RR window guide on the regulator with nylon washers.



Now:
Since it's been warm here I have been driving with both front windows open. I hear a noise....a ping on acceleration when the engine is warm. The engine does not seem to miss or sputter. The tachometer does not fluctuate, no check engine light (if it works). Gasoline has been sunoco mid grade but I'm going to use premium for now on after reading a thread where spike broke it down on cost.

So after searching around a bit for threads where "ping" was used I have some ideas:
MAF
Y-pipe bolts
Exhaust manifold/manifold gasket cracked

Tomorrow I'm going to check the y-pipe bolts, the plug wires and look around the air box area for anything obvious.

I know diagnosing a sound over the internet/written words is tough but...What are your thoughts?

 

run a few tanks of premium then get back to us

 

and add a bottle of techron to the gas

 

or BG44K. If Techron, use 2 bottles. One won't do the whole tank.

Premium fuel only... period.

 

Good stuff

And think about it, if the preowner let it carbon up, that will encourage pre-ignition even with decent fuel.

congrats


luck,greg

 

There is a big difference "ping" , "tick", and "knock"

"ping" is pre detonation, the sound of a ping very distinctive.

tick sounds usually come from a cracked manifold or d-pipe, or a noisy lifter in the head.

knock is a bottom end noise that is usually piston slap or bad rod bearings.

an exhaust crack/tick will be consistant in its sound. going along with the engine as it excellerates.

a ping will sound like marbles are bouncing around in the cylinder.

maybe youtube the sounds to see if you recognize the sound your truck is making.

my bet is that you have a crack in the mani or d-pipe or noisy lifter

 

If you need exhaust manifolds, check out Will Tillery, roverguy.com. Go to his website, it is barebones but it has his phone number, give him a call for immediate pricing and delivery.

I got a used exhaust manifold from him at an excellent price including shipping. I also got my cross tube and rotoflex from him.

 

The problem is that I have a half a tank now, I'm going to fill it tomorrow with premium...

What is techron and where do you get it? I assume it's a addtive?
What is BG44K and where do you get it?

Will the additives in premium clean it out...or atleast help it?

It's not a "tick" I know what those sound like, I had a Jeep that ticked.. It is also not a knock like a bearing. Nor is it a rattle like marbles in a coffee can. The best word I can use to describe it is a "ping".

I'll keep him in mind.


One other piece of diagnostic evidence:
With the vehicle in park, it does not make the sound while reving the engine manually at the throttle body.



Thanks all!

 

pinging is usually a sign of pre-detonation caused by using the wrong gas or excessive carbon build up on the pistons. It's not pining in your driveway because it's not under a load...go climb a steep hill at full throttle and i bet it will ping like crazy.

 

Today I checked the plug wires and airbox/MAF connections. Nothing obvious that I could see. I would think if it were related to those items it would miss instead of ping so I probably wasted my time.

I did not check the y-pipe, which bolts come loose? The ones on the manifolds or the coupling by the trans?

As I mentioned I had a half tank of mid grade gasoline. I added 7 gal of sunoco premium. Wishfull thinking but it didn't make a difference.

I don't know, maybe "ping" is not the right descripton. I definately does it under load and accelerating. Kinda sounds like valve chatter...like when you are driving a manual trans veh and your in too high of a gear. But it doesn't continuously make the noise like in the above scenerio, it only lasts a quick second like "one ping" instead of "rattle rattle rattle".