So I guess my engine has been doing this awhile, I just finished putting my car back together after it has been sitting for over six years while I go through various disasters in my life. I have replaced a multitude of parts, I don't know if any of them caused this problem or added to it as I just got my exhaust finished and can now hear my detonation (open headers/y-pipe before, I heard something but I wasn't sure what it was.)

I set my timing more than once to factory spec, I've tried advancing and retarding it by as much as 10 degrees either way, I can't get my engine to NOT knock when I plug the electronic advance back in with anything less than 6 degrees ATDC timing. There is no knock if I set the timing to 6 BTC and leave the EST connector unplugged, I get immediate and very bad knock as soon as I plug it in under these conditions: part throttle when the load is steady (after I reach and hold a particular RPM), and when letting off the throttle. I cannot hear it under acceleration, light or heavy, or at idle.

The knock is so bad I thought it was my valves needing severe adjustment, I did those today (twice) and decided to retime the car the second time and discovered that was the problem. I can't believe I've driven the car as much as I have with it like this.

What I've tried so far:
Double checked plug wire hookups/secure
More/less fuel (all I did was remove vacuum from the pressure regulator so it would give full pressure the whole time, that seemed to help slightly)
Did the valves (twice)
Checked all external electrical connectors, including knock sensor
Swore loudly

Not checked but I want to:
May have wires reversed on the pickup coil, I keep thinking about this, I remember arguing with myself about which way was correct when I put it back in after testing it
Try running without the aftermarket chip (no tune, just temp changes and remove air/egr, a few other things)
AFR. Running 24lb injectors at 44psi, by my calculations that should flow roughly the same as the factory 22lb injectors at 50psi. I wish I could turn my regulator down more, 44 psi is as low as I can get it.

New parts recently (only listing what may affect it)
Walbro fuel pump
TPS (adjusted correctly, along with IAC)
New intake gaskets
Full tune up, MSD ignition parts, Bosch Platinum Plugs
TPIparts.net basic reflash chip
O2 sensor
Removed smog & EGR (wondering about the EGR, I've heard other people say they've had problems with that even when it's been removed from the ECU)
160 thermostat (but it runs alot hotter, I'm missing my front air dam. Probably also has something to do with the timing).

 

well it might be a rod going. what engine is it? If its a 3.4v6 mine did the same then and then it finally blew. It was a rod. But honestly it could be a numerous of things. Which so far you done what i know. A bent valve or piston slapping. hope this helps.

 

Engine is the one in my avatar. How could it be anything but detonation when it only occurs when the timing is advanced? If a rod or valve or anything mechanical was wrong wouldn't it more than likely make a bunch of noise regardless of timing and more in relation to engine RPM & load, which it doesn't.

I forgot to mention in my first post but it occurred to me a few minutes ago that it detonates both under load while parked if I rev it & hold RPMs or let off, never does it while fueling to accelerate or rev.

 

If you set the base timing, keep the light connected after enabling the EST. How much advance is the EST allowing?

With the EST active you can tap the KS and see if the system retards spark. The sensor may have a problem, or the retard in the programming may not be effective.

 

Question; why are you disconnecting the EST to set the initial timing?
The "Set Timing Connector" is the one to disconnect.

Edit: EST is that for carbed engines. My TPI has a ESC not an EST.

 

I may be using the terms interchangeably, I am using the correct plug to set the timing. I will try this other stuff when I get home tonight.

 

To add another piece to my puzzle, I just fired it up and it appears to only ping when in closed loop.

I checked the wires to the pickup, they are on correctly, it runs like absolute poop when I switched them.

I am installing a new knock sensor right now and triple checking the plug wires again.

 

Well that didn't help me out any and the plug wires are perfect.

Timing with EST plugged in when initial timing is set to 6 degrees is about 12 degrees at idle, I would estimate about 25 or so max when I give it throttle.

WOT does not induce pinging (when I'm in park) nor does it ping when revving down from WOT.

Anything part throttle pings when the revs begin to hold steady for the amount of gas I'm giving it and as it revs down.

 

Close the thread, "pinging" is no longer being affected by my engine timing, must be a bigger problem.

 

For what it's worth, I had a Dodge truck that did the same thing and it turned out being an intake gasket leaking between the lifter valley and one of the intake ports.

 

uh....you said the car set for over 6 yrs. Did you by any chance pump out that 6 yrs old gas? I think it would be safe to say that 6 yr old gas is pretty much as good as water and bad gas could cause it to "ping"