Knock? The cause...

[XiKeiyaZI]

Let me get this out of the way.

I currently have no logging tools. =/ At this very second.. I'm moving and can't purchase one.
Car is basically stock. No tuning tools.

Now, onto the issue.

When I start up my car.. it runs fine. It starts with 1100+ idle.. and then lowers to 750ish as it should. Well.. when I back out of my driveway and head down the road...by the time I pass 2-3 blocks my CEL comes on. Knock. The car then pulls timing.. becoming sluggish and reducing power.

I have noticed that my exhaust manifold glows a little after driving. It's nothing like super bright or anything.. just a dull glow.

This is Knock, correct? What would cause this? What could I do to resolve it? It just started doing this the past few days. Then again.. this happened around the same time I developed and oil leak on the return line from the turbo. =X Still need to fix that.

Anyway, any ideas?

 

[rEclipserGST]

Your timing seems to be off. I had a backyard mechanic change my waterpump a few years back and he didn't set the timing correct. My manifold & turbo would glow red, come to find out my timing was off 40 degrees. Is your temp gauge fluctuating at all? I bet it is after hard runs.

Check timing and report back. You def at the least need a logger man.

 

[ramsack]

could be running super rich, causing knock. this plus retarded timing would make the manifold glow pretty quickly.

 

[XiKeiyaZI]

Timing is dead on. I checked last week, infact. ;P

a symptom of my car is that I can set the ignition timing via the CAS.. and it seems like it loses it a day later..

I can ground the timing, Time the ignition with a timing light (done by crank, but by the CAM marks seems to be better), stop the engine, unground, and then restart the car and it runs GREAT. Like.. Amazing. No CEL, no nothing.

1 Day later it's back to doing the same thing. =/ I spent about 25 minutes last week getting the ignition timing peeerrfect. The next day.. it ran crappy again. Could it my CAS? Would it do this if it were 180* out?

 

[ramsack]

if it was 180 out your car would barely run, if at all. try a different cas, but i don't think that would be the issue. i really couldn't say what your issue with losing timing would be. if it's a green top cas it either works or it doesn't. the ecu could be causing the issue, as well.

 

[XiKeiyaZI]

It's Greentop. Could barely tell due to it's age.

The ECU is fine. I pulled it and checked it out. It was reman'd back in 2005.

 

[ramsack]

what makes you say it is ok? and who rebuilt it?

i really don't understand how you're losing timing. like how far off does it get? if timing slips, it's going to slip in one direction really, so you're gonna run out of adjustment room. the only other thing it could be is your cam timing is changing itself constantly.

 

[XiKeiyaZI]

I can't really calculate an approx slip in it... but from the changes I've felt in the car, I'd say about 5*.

Ellaborate on this CAM timing thing? o.o

And I say it's okay by visual inspection. No Leaking/bulging caps. No markings on board.. front or back. Looks immaculate. I checked this all out when I yanked it to check for eprom.

 

[ramsack]

i really can't elaborate on the cam timing.

my friend and i were putting a timing belt on his engine while on a stand and we got the timing perfect. turn it a few revs and it would be off. redid the timing belt probably 3 times. then we took off the crank sprocket and saw inside someone had ground away the slot for the key, and it was slipping every time we turned the engine over.

 

[XiKeiyaZI]

Ahh. Yeah, I checked for that when I took it apart. ;P

I timed the car during lunch.. it was back about 3*. I got it perfect again.. hopped in and BAM.. CEL... though it took a little longer to come up.

=/

 

[ramsack]

i really don't think knock should give you a CEL. if the knock sensor is bad it will, but having knock won't. i have bad knock every time i accelerate and no CEL from it ever.

 

[jmartinez1228]

i really don't think knock should give you a CEL. if the knock sensor is bad it will, but having knock won't. i have bad knock every time i accelerate and no CEL from it ever.

I have had the same thing happen i had a really bad knock sensor and got insane amounts of knock but never a CEl. How are you determining that you are getting knock in your CEL?
My car gets phantom CEL's while driving but it never stores in the ecu for some reason. It comes up while driving and then goes away but the car drives the exact same...weird aint it?WTF

 

[XiKeiyaZI]

I have had the same thing happen i had a really bad knock sensor and got insane amounts of knock but never a CEl. How are you determining that you are getting knock in your CEL?
My car gets phantom CEL's while driving but it never stores in the ecu for some reason. It comes up while driving and then goes away but the car drives the exact same...weird aint it?WTF

Erm...o_o

Assuming that a CEL = Check Engine Light...

It comes on.. I run the code via a Test light at the data port.. get an error 31

Error 31 = Knock, correct?

 

[big_d]

I'm not sure what's stopping you from picking up a new knock sensor. I wouldn't doubt it's the original 20 year old gooey sensor. Replace it so you know its good when you begin upgrading... and yes Error 31 is the knock sensor.

 

[jmartinez1228]

ECU Code Checking

According to vfaq yes, did you check the actual knock sensor for any goo,slime coming out? The knock sensor itself may be bad which is why you are getting a CEL and maybe not because your getting knock?

 

[DSM1G90]

Could be knock sensor, but it could also be the ECU if a driver inside the ECU that runs the knock sensor has gone out on you where you said the ECU, visually, looks fine..and drivers are something that has to be bench tested out with test equipment.

I went through the same thing earlier this year until I sent the ECU in for warranty repair - had a ground trace that was blown. Got the ECU back and it runs so smooth that I can't even tell it's in idle at times.


Try another knock sensor to see what is what with the code thing.



Good luck-DSM

 

[XiKeiyaZI]

I replaced the old Knock Sensor when I got it. @__@ I'd certainly hope it hasn't ruined this one....

-Sigh- and damn I don't wanna buy another ECU. T__T

Thanks guys. I'll check when I get home!

 

[ramsack]

Did you torque the new knock sensor with a torque wrench or just tighten it down with a guesstimate? If it's too tight it can make some phantom knock and overrespond.

 

[XiKeiyaZI]

... I don't... remember.

-.-; Yeah.. gonna check when I get home. My luck? It's hanging losely from the block.

 

[XiKeiyaZI]

.....Resolved.

Turns out... The ground wire was somehow frayed...-.-;; Reconnected that and BAM.. NO CEL.

 

[rednesss]

I'm having some issues myself, what ground wire was frayed?? The knock sensor wire or another one??

 

[XiKeiyaZI]

The wire from the harness to the knock sensor plug.