Binder

I've never had a knock sensor on my 7747. Just installed EBL and want to add the knock sensor. What sensor/ system would I need? I know little about these sensors other than some have external controllers and some have controllers in the ECM. Looks like the EBL input is pin B7?
What parts do I need to get?

RFmaster

Binder

7747 uses external ESC amplifier - converter module and depending on application different part numbers were specified by GM

For non roller 350
ESC module 16128261
Knock sensor 10456288

305 is different - use search on TGO

//RF

Binder

Thank you! Now what about wireing them up? Right now I only know where one wire goes into the ECM but not where it comes from. How does the sensor connect to the controller?
Maybe I should ask this in the electronics forum?
Thanks.

RFmaster

Binder

Probably more appropriate in TBI forum. Here is what you need:

//RF

Binder

Got some parts today. New sensor from GM and went to the yard to get plugs and a ESC also. I'm guessing the ESC is either expensive to buy or goes out often. Every rig I looked at had the ESC removed but one, it's a PN 16075521. I'm going to give it a try and see how/ if it works.
Thanks again.

Cflick

Rediculously easy to test.
Install the thing, start the engine.
Watch the spark advance on the display. ( you did say EBL ? )
Take a socket extension long enough to reach.
Put one end on a head bolt. ( I'd pick one as far away from the sensor as you can reach )
Rap the other end of the extension with a 1 or 2 oz tap hammer a few times quick, or with the handle of a 3/8 ratchet.
Note that this sounds just like real ignition knock !
You should see the timing retard, and possibly the engine will slow down if you do this
at low idle. Might even stall. If you see timing retard, it's working.

RBob

iTrader: (1)

With ESC modules it is the best bet, to try different ones. They are all tuned to different acoustics. And, every engine has different sounds. Although I've found the earlier ones seem to report less false knock. . .

RBob.

Binder

On another (probably) unrelated note, my timing at idle seems to jump around a bit. Jumps between about 18 and 22 deg at a fairly steady idle. Idle moves a bit too but not enough to go between cells. Commanded idle SA is 20.04. I think the timing is moving the idle and not visa versa. I noticed this before with my timing light on my old ECM but it was hard to be sure but now I can see the timing on the data log, it's definately moving. All components are recently new. Small cap HEI style dist. No knock at idle. No commanded retard that I can tell.
Is it possible that this is normal? What could possibly be the cause? I think this may be a hardware issue but I'm open to anything.
Hmmmmm?

RBob

iTrader: (1)

There is idle stabilization SA. Can zero out the SA tables (2) and see if that helps the idle. Stock engines can use more stabilization SA then modified ones. Just cutting the amount of SA in half may help smooth the idle.

RBob.

Binder

SA- Idle state SA ? I don't have it active, I'll try it.
Thanks.

RBob

iTrader: (1)

The Idle state SA is to have a set timing for idle. This prevents the SA from moving around due to MAP & RPM fluctuations. Can be helpful. There is also idle stabilization SA. This removes timing when the idle is too high, and adds timing when the idle is too low.

Look for the 'Spark Advance, Idle Speed Control' tables in the cal doc. There are four tables, 2 for SA and 2 for MAP compensation. You can zero out the 2 SA tables to eliminate idle stabilization SA.

SA - Idle Low Compensation
SA - Idle High Compensation

RBob.

Binder

Good progress. I zeroed out the two tables, SA - Idle Low Compensation SA - Idle High Compensation and tured off the table, Idle state SA (it was active already). SA is now nice and smoothe in the data log.

Idle unfortunately didn't get much better. Now the only thing that moves around at idle is MAP, it only moves like 3 points. Adjusted the table MAP- normal/ transient filter to have more filter in the normal, I turned it all the way down to 5. It looks to me like this filter is basically only for idle? It did mellow out the MAP a bit but still not there. I also tried Nalpha mode. It seems that Nalpha always wants to cause a slow surge. Goes lean then comes back. I didn't have data to put into the MAP table for Nalpha so I just tried to put in values at idle. It's going to take some experimenting to figure Nalpha out so I turned it back off.
Making progress and idle isn't too bad so I'm going to leave it for now and move on to Main VE and then main SA tuning. Now if I could only get my LM-1 to work right......

Binder

Finally got a chance to do some driving/ tuning today. Tuning fuel open loop with locked BLM-INT's 128. This put my fuel to the "open loop vs AFR and RPM" table which is farely rich throughout. Went on to try some timing adjustment and found than even at max advance of 41.81 deg prety much everywhere but idle I still got little to no knock, just enough to know that the sensor is working. Is it possible that the fuel is too rich to allow knock? Should I retune fuel to stoich and try timing again then set fuel?

Binder

I know the goal isn't to get it to knock but it seems the timing adjustments just aren't having much if any effect on performance, like it doesn't make a difference.....