Wow, there's at the same time plenty information and plenty questioning points in your posts, gents.

Jim, the two pics are different snippets in time because I wanted to share the change in BDTC value with you guys. Actually that change from 12 to 10.6° occurs every 2 seconds or so.
I know I have limited knowledge, but the different colors for the two different "BDTC"s in the graph may be employed to discriminate between the two banks?


I didn't even notice the "lack of activity" under the knock sensors, and I wouldn't even thought about it.
Could that mean that both are bad?
According to this then (disregarding the "GM" directing), if the knock sensors were bad shouldn't I have had a CEL?
By the same token, having no knock sensors' activity and no CEL could mean that actually there's no unwanted detonation/knock detected?
If I try to make sense of what I experience with the engine and what I read from you guys, maybe indeed the knock sensors are bad anymore.
Jack, to answer your question, on cold starts actually the engine feels pretty smooth with no misfires, but it still has a detectable noise, "diesel" like.
- The belt jumping is out of the question, as I just checked it a few days back. It had a little slack, but I adjusted the tensioner. That didn't change the accelerating vibration.
The only other thing I can think of is that I may have mounted back the bank 1 (passenger side) camshaft wrong after cleaning the heads, although I don't understand how would I have done that.

I'll do more investigating with the VAGCom on my next day off.
Anyway, I appreciate your comments, ideas and sharing guys. Thanks a bunch.

 

If the Knock sensors are not picking anything up then that's good even if they were bad they are not adding to your problem. They wait for any vibration if a vibration puts pressure on the internal disk it will send voltage to the ecm. So no voltage is good voltage. However the ECM also can detect misfires by the crank speed sensor. Your engine slows every time a misfire occurs and the ECM and crank speed sensor can target the cylinder that way.
FYI if you removed them they need to be torque to a specific value too much or little will change the value of the internal disk.

understanding the knock sensors;
http://en.wikipedia.org/wiki/Piezoelectric_sensor
If this problem has been there since the rebuild, I would check the cam. If it has just started I wouldn't check it.
You know you rebuilt it correctly, checking only takes the idea that it's in there wrong out of your mind so you can think of other things that are wrong. Crazy But true!

Spend more time messing with the vag-com in the advanced measuring blocks section, It's slower and tends to drop me more, but it helped me learn all of the measuring blocks. You can see the variable timing per each cylinder in there. look at that. See if it is targeting one cylinder. I think you are looking at the overall timing it will say bank 1 and bank 2 in mine but you need to check per cylinder to hopefully hone in on the problem.

Try clearing your fault codes and set readiness. see if it goes away. None of the codes you have would create a problem for the timing. ODD.


Hey maybe you can do what the guy before you did!
Locate the good cylinders and put auto lite spark plugs in them so they're all bad

BTW"I don't have a cell phone, I don't have an IPod, I don't have many things that some people could swear would not be able to live without." AHHH Remember the good Ol' days! although the internet was no doubt the greatest learning tool ever invented.

 

I didnt mean to imply the Knock Sensors where bad, just that they arent picking up on a problem.

The 'Idle Stabilization' is at -1.3 when the timing is pulled. This isnt the amount of pulled timing, I think, its the amount the Air Idle Motor is correcting to compensate for the pulled timing.

I'm still of the mind to actually pull the plugs and look. Did you change plug wires already?

Without knowing what I'm looking at in those screen shots (no labels), its hard. But, here's what I know, mechanically, will cause light misfires under load:

Bad plug
bad wire
lean cylinder (injector)
rich cylinder (injector/intake valve)
cylinder leak-down (valve/ring)
oil fouling (seals/head gasket)
water fouling (head gasket)
collapsed lifter
vacuum leak
PCV system leak
EGR leak


All of these obviously would be mild and prolly hard to find, and of course, you've already replaced most of it.



Also, If your misfiring, why is there no CEL? Are we sure its even engine vibration your feeling? Vibration at acceleration could be a CV joint as well... ?

 

Mine won't illuminate a CEL until it misfires like 30-40 times. However it tries to correct the problem immediatley. Maybe it's just a few mild ones. Not enough to trigger a CEL but enough to raise hell.

I was thinking that checking the cylinders individually on start-up it might show a cylinder misfiring just a few times. With mine if one cylinder misfires it encourages everyone else to join in and have some multiple misfire fun with it. Dirty little orange headed bastards!

 

I'll try to respond dilligently.

1) I didn't use the torque wrench when reinstalling the knock sensors.
2) Set readiness - since the 1995 C4 is pre OBDII, VagCom doesn't let me set readiness, as it gives me a "OBDII non-compliant" message.
3) Things I have changed: spark plugs, wires, vacuum lines - including freshening up the hoses for the PCV Y-shaped valve, the injectors seals, vacuum reservoir, EGR valve gasket, cleaned the breather hoses, the manifold, the throttle body butterfly flap, ; replaced head gaskets, intake manifold gaskets, exhaust manifold gaskets, throttle body gasket, valley pan gasket, valve cover gaskets - the driver side I believe started to leak, (either improper mounting by yours truly... or the rubber they put in it is just crap);
4) I would assume that if the "Idle stabilization" shows signs of correction, then my Idle/Air Control Valve is working.
5) Jim, believe me, the vibration is engine related! It always happens at certain RPMS and especially when accelerating a little more abrupt. It does however seem to phase out when using the "kickdown", as the engine smoothens out. Maybe Jack can relate to what I'm saying and explain better.

6) CV Joints were both replaced, along with new wheel hubs AND bearings!

Thanks guys!

 

Jim, the only way to experience the vibration is to kick the engine back 2 degrees it's sort of a rough on acceleration a little doggy.I felt it as I went up Hill or took off from a light. It levels out when coasting along. If he had a distributer he could turn it right out, That's what it feels like. I'm wondering if it's to do with the Ignition control module or something slow in between.

We need more diagnostics!

What's taking so long? LOL!

 

Then I would have to say its sensor or ECM related as the program changes during WOT (or close to it) and ignores certain sensors, goes to preset timing MAPs, goes full rich on fuel, ignores O2 sensors, etc (goes into Open Loop Mode). If it was plug/wire/coil/injector related it would only get worse at WOT. So those can be discounted for now. As can Cam and Crank sensors, fuel filter, and anything else that would cause problems more at WOT.

Whats your TB Sensor doing?

 

Jim, do you mean the Throttle Position Sensor?

Jack, sorry I'm so slow. I leave in the morning and get back when is already dark. The last ounce of energy is spent to just get in the house

 

Jim, WOT is when it happens. When you let off (no torque needed) it smooths out. Timing is not advancing as the rpm level increases and the retarded timing is causing the vibration... Maybe?

I think, Chefro is that correct?

Chefro since you can't take it on the road via lap top. You may be able to replicate it by putting it in gear and giving it gas with the brake on. That might be enough to see what's happening. Anyhow You have your work cut out for you this weekend. I was just kidding about the Diag.

 

Ya.. Throttle Position Sensor..

Jack: If he's giving enough to 'kickdown' and 'it smooths out', then that would imply it's only under light load. (I'm assuming he means 'kickdown' to mean downshift under acceleration).