I currently have an engine vibration issue with low idle. It occurred after using a bottle of Techron or at least that is when I noticed it. That tank of shell93 mixed with Techron is already burned up and a new full tank of shell93 is in the tank now however the low rough idle remains. No codes, no lights or any other indication that something may be wrong. My wife says I am just being paranoid but I feel something is slightly off.

Cold Ctart:
Video - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

All is well until the motor warms up. Then at that point I get a low & rough idle.

Warm:
Video - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

You can see the idle drops below the 500 line but when I plug in a diag tool it states idle is around 638-650 at that state.

Money Shot:

Video - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

This video better illustrates the amount of shaking and vibration found in the engine bay. If you look at the throttle cables and fluids you will notice that they are shaking and being shaken around.

Exhaust:

Video - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

Exhaust does not have any smoke or steam, no issues except you can see the muffler shaking and you can hear a rhythmic pulse similar to the way a vintage VW Beetle exhaust sounds.

The question is can I drive with this or do I risk damaging the engine? Is this typical and I am just being paranoid? No lights or DTC/CEL stored so this leads me to believe this may be vacuum related but not certain. Any thoughts or opinions on this would be appreciated.

Thanks.

 

 

Actually, the idle is below 750 in that video. The first line on the tach is 500 RPM, then 750 RPM, then 1000 RPM.

 

FYI, from manual:
......

 

Got fresh plugs and wires? Brand? Could also be early signs of MAF or O2 failure. If it's early signs of MAF or O2 failure, I wouldn't worry too much till you get codes.

Also, I've never sat in a disco that idled perfectly still. They've got quite a bit of factory cam overlap from the factory that makes the idle just slightly shaky. Somewhere around 45 degrees if I remember correctly. Its been a while since I looked up the specs and mathed it out.

The idle speed looks fine according to spec, as number9 has said.

 

thank you. my mistake. carelessly looking without taking note.

Thank you!

plugs were done by the previous owner just before i purchased the vehicle. i can see they are new(ish) but i cannot tell about the wires. the plugs themselves are white with what appears to be blue markings (similar to what a purolator filter looks like) but i wont be able to really tell until i take one out and see what exactly it is and if they're fouled.

the odd thing is that none of this was present for the first 500 or so miles i put on the vehicle it all started after the techron which could very well just be a coincidence. i looked at the maf and there was a great deal of soot on the turbulence/vortex mesh so the sensor itself may be either dirty or on it's way out. it is the original sensor but before i started throwing around $200 here and $200 there to guess at solutions i thought i would inquire with the wise folks on here first.

at this point without any lights or codes indicating error is this vehicle drivable? when it is on the road or highway it is smooth as silk but at stand still or at a light the idle vacillates or if i put the AC on it then kicks up the idle to the point where the vehicle is steady and not shaking. it is not our only vehicle so it can sit for weeks if need be but it is my daughter's favorite so she keeps on insisting on using it. should i give the go or hold off until this is resolved? secondly the fluids and liquids bouncing around like lotto ***** is inherent to all disco vehicles or possibly related to this "issue"?

 

Does your scan tool have live data? If so, look at the fuel trims. +/-10% is the normal, acceptable range, but they can go quite a bit over that before throwing codes.

 

I'd get a can of electrical parts cleaner, NOT throttle body or carb cleaner, and just spray it in the MAF to try and clean stuff. Only do that while the MAF is unplugged and not warm from running. Then give it a couple minutes to dry and try it. You can also throw in another bottle of injector cleaner as the first bottle simply may have cleaned some injectors more than others.

As far as being fine to drive, I'd say yes.I'd probably change the plugs and wires. Copper core plugs can look fine but be internally worn and cause a rough idle. I really like my NGK G-Power plugs in my disco. Just don't get Bosch plugs, for any vehicle for that matter. Other than that you're fine. Get some 8mm plug wires, too. I can't remember which of the three brands is cheapest. Kingsbourne maybe? Anyway, I'd try that. You can re-use the intake manifold plenum gasket and it is worth taking the upper manifold off. Makes the job a lot easier. I usually put a really light coat of RTV on the plenum gasket.

A little confused about liquids and fluids jumping around like lotto *****, I may have jumped over something. Do you mean they're mixing or just getting jostled around because it's shaky?

 

i may just buy a plug and wire kit form BA to be safe and know it was done correctly.

the lotto ball comment was regarding the way the fluid is jostled around and agitated by the rough idle (in the video i showed how the PS and BF are percolating like an old school mr. coffee machine). at this time from a basic eyeball analysis no fluids are mixing but i have not sent out oil for a proper analysis to be certain. under belly was cleaned with a tremendous amount of brake parts cleaner and no fluids have leaked or seeping through to the bottom yet.

It has live data providing the ECU/DME is supported by the Tool. It is mainly for VAG family of vehicles (VW, Audi, Skoda, SEAT etc.)
I will scan again tomorrow after it sat overnight and is a true cold start then monitor all the way through to a warmed up engine.

 

One trick you can use to find out if you have coolant in your oil. Assuming it's just a little and not noticeably milky. Run the engine for a while. I would drive at least ten miles or more. (you may want to try this after a longer trip, to be sure). That way you know it's not likely to be condensation. Heat up a spot on a piece of sheet metal with a torch, pull the dipstick and drip a little oil onto the hot metal. If it has water in it, it will sizzle. Just don't heat the metal red hot. You want it hot enough to cook the water out but not burn the oil. You may have to play around with temp a little to get the best results. You'll know if you have water though. It will boil off instantly.