[Mystake]

Still have some gremlins in my Focus.

Bunch of repair work later, I get an engine knock randomly.

On the way to the meet it knocked once at 130km/h, did it again at about 125km/h on the way back.

Haven't had it knock at any other greater or lower speed on the highways but thats the range that I tend to drive in consistently.

I've had it knock at 5200rpm, 4500rpm. I'd been driving a bit aggressive but car had been running for 20-30 minutes ( I don't drive my car hard until I feel that the engine has completely gotten up to operating temperature. Not trusting a little gauge). Can't remember any other occasions.

Oh! Not true. Driving around a few days ago, city driving, it knocked as I was exiting a right turn at a light, shifting into 3rd. I didn't actually feel the knock but I saw the light come on.



Now, here's what I know about the engine, seeing as it's not original and I don't have a history of it.

approx 41 000km. unknown when last oil change was.
new spark plugs, new spark plug wires < this got rid of a misfire I had.
ford dealership had to 'complete' the job from the engine rebuilders as they didn't actually finish the job but gave me the car back claiming they did.
my catalytic converter has broken pieces inside of it, muffler (the cylinder one) has an exhaust leak in it. Welds done locally on some exhaust piping had a pinhole in it but that's been rewelded shut as well.
the MAF sensor was soaked and doused in oil, was subsequently cleaned but I was suggested that it's not meant to get wet, period. Let alone be cleaned, so a replacement MAF sensor was suggested.

car isn't throwing any codes either.

Any ideas? What about datalogging? I know nothing of what it is or consists of, or even what the data it logs is... but is that something I should investigate?

[Mystake]

knocked again today... got a bit close to the 4k rpm range when it did it.


i have no idea what clues I have to tell me what's wrong, so i'm just throwing out facts.

[meford4u]

Any ideas? Maybe not posting on the internet that you were travelling at 130km/hr would be a good start.

First hit on the new site whoohoo.

[hardk0re]

ANY exhaust leak BEFORE your first O2 sensor can have catastrophic effects on your air fuel readings and set you up for some lean conditions causing detonation or (knock). Get your exhaust fixed up ASAP, check the PCV valves, clean the maf with some maf cleaner, and check the plugs to make sure they are not fouled up. Make sure you've got the right plugs, motorcraft platinums. If its any other plug throw it away and pickup some motorcraft ones. also check the wires going into the coil pack, as those fail often causing lost of spark in some occasions.


That said knock really only occurs under load, so are you WOT when the knock occurs or just cruising? Does it sound just like a knock or bang, or is it like marbles in a tin can?

[Mystake]

(05-23-2010, 09:50 AM)hardk0re Wrote: ANY exhaust leak BEFORE your first O2 sensor can have catastrophic effects on your air fuel readings and set you up for some lean conditions causing detonation or (knock). Get your exhaust fixed up ASAP, check the PCV valves, clean the maf with some maf cleaner, and check the plugs to make sure they are not fouled up. Make sure you've got the right plugs, motorcraft platinums. If its any other plug throw it away and pickup some motorcraft ones. also check the wires going into the coil pack, as those fail often causing lost of spark in some occasions.


That said knock really only occurs under load, so are you WOT when the knock occurs or just cruising? Does it sound just like a knock or bang, or is it like marbles in a tin can?

the leak is at the muffler ,not before the O2 sensor.
PCV valve was just recently dealer replaced,
MAF was cleaned by dealership too
i just changed the plugs and wires myself. I went with NGK iridium afaik and bosch wires and I don't plan on changing them unless the plugs are the fault.

the noise the car makes is a bit of a bang, sometimes its silent but the engine stops responding for a bit. as if i had let off the gas pedal.
its happened while cruising and while under load. More frequently under load though.


the marbles in a tin can... no engine tick if that's where you're going.

---

(05-23-2010, 09:21 AM)meford4u Wrote: Any ideas? Maybe not posting on the internet that you were travelling at 130km/hr would be a good start.

First hit on the new site whoohoo.

Oh no 130km/h... and I'm the slow guy on the highway.

[Spinal]

Out of curiosity have you done an oil change?

[sonic_mikey]

(05-23-2010, 06:13 PM)Mystake Wrote: the noise the car makes is a bit of a bang, sometimes its silent but the engine stops responding for a bit. as if i had let off the gas pedal.
its happened while cruising and while under load. More frequently under load though.


the marbles in a tin can... no engine tick if that's where you're going.

---

sounds like bogging not engine knock?

[Mystake]

(05-24-2010, 04:30 AM)Spinal Wrote: Out of curiosity have you done an oil change?

Got me there. Doing one tomorrow.

Ford dealership didn't recommend me for one though when they had it, though they did check the oil and oil levels. I know this because they checked my dip stick and noticed it wasn't actually the right one for my engine so they remarked it appropriately.


as for the engine knock, I say its knock because the sensor is coming on and the rpms jump when it happens. Not in the way a bog would, imo.
edit: i've seen the rpm's jump about 5-700 worth when the knock sensor's come on.

[hardk0re]

is the (!) light comming on ????

[Mystake]

(05-24-2010, 11:33 AM)hardk0re Wrote: is the (!) light comming on ????

Yes.

[hardk0re]

The (!) light typically is an electrical short or ground fault for the ECU.

[sonic_mikey]

(05-24-2010, 11:51 AM)hardk0re Wrote: The (!) light typically is an electrical short or ground fault for the ECU.

my owners manual says that lights for a cooling system/transaxle issue

[Mystake]

(05-24-2010, 01:58 PM)sonic_mikey Wrote: Every focus i've seen with intermitent (!) has been electrical issues.

(05-24-2010, 11:51 AM)hardk0re Wrote: The (!) light typically is an electrical short or ground fault for the ECU.

my owners manual says that lights for a cooling system/transaxle issue

mikey, at first the (!) was electrical. That problem has supposingly been fixed. There was a damaged plug on my engine wire harness that the dealer replaced. That was the start of everything.

I'll take it back into the dealership tomorrow. I hate electrical issues and I'm not dealing with them :p
especially if I'm hunting down an electrical short...

[hardk0re]

Mikey, sorry I had edited your post instead of replying..DUHH!

anyway most of the (!) i've seen have been electrical..

[Mystake]

ca n i actually be tol how the oil change woulda been relevant?

[sonic_mikey]

(05-25-2010, 04:46 AM)Mystake Wrote: ca n i actually be tol how the oil change woulda been relevant?

a bunch of different reasons, if the oil is old and nasty it can degrade the fuel so much on it way through the PCV system that is lowers the octane rating causing detonation/knock. Not to mention improper lubrication can lead to increased engine drag and over loading

[Mystake]

update...

car still knocks but infrequently. did it today twice within 2 minutes, with enough severity I guess to cause the entire car to lose power and then have it all come back within a second.

kinda scary when you're not expecting it. knock, then everything goes dead... then comes back.

also it doesn't maintain speed going up hills on the highway. i can start going uphill at 130 and get to the top doing 120, but on flat or slight incline it'll maintain 130.

As for the oil, it was half full and clean when I went to get it changed.

The (!) light according to the dealership said its the Powertrain Warning Light, its supposed to come on before the CEL does.

[Spinal]

(06-06-2010, 02:36 PM)Mystake Wrote: The (!) light according to the dealership said its the Powertrain Warning Light, its supposed to come on before the CEL does.

so its a warning light for the warning light?

[Mystake]

(06-06-2010, 10:44 PM)Spinal Wrote:

(06-06-2010, 02:36 PM)Mystake Wrote: The (!) light according to the dealership said its the Powertrain Warning Light, its supposed to come on before the CEL does.

so its a warning light for the warning light?

Lol that's what I said...

[Mystake]

Have had the MAF sensor replaced. Helped the car gain some much needed power back but she's still knocking harder than ever.

It's sitting in the dealership garage right now being worked on.