In my datalog sessions I am seeing knock retard around 15-20degrees at all times but no knock counts. how is this happening? my Spark advance will show around 25-30 degrees and then 15-20 of it will be retarded for who knows what reason. Anyone have any input?

 

Is your base timing in the chip set to a high number? When looking at spark advance in the logs I've seen, the spark relative to TDC is from the table, and the spark relative to reference has the base timing subtracted out.

 

I've only got my distributor timing set to 10 degrees, and that is what I have it set to in the chip constant.

In the logs (tunerpro) I am watching both the timing relative to TDC, and the timing relative to distributor. and then I have knock retard. and and idle its pretty constant at 20 degrees, sometimes sways between 15 and 20. and after a short (slow) acceleration run, after I let off the gas pedal, the knock retard drops to 0 for a few seconds.

 

Could you post a log of it, to clarify what you mean?

 

Not sure how I can do that with tunerpro? Can I export a log file that I can copy/paste?

 

Ok sorry I don't know how to post a log file.

But anyways, I will be simple. The laptop shows that the ecm does not detect any knock counts whatsoever, BUT! it is always showing knock retard upwards of 15-20 degrees.

 

might I add I have a code 43 I cant get rid of.

 

Sort out the code 43 and go from there.

Without fixing that first, your wasting your time.

Follow the factory procedures and you should find your issue.

later
Jeremy

 

Thats the problem, I can't figure out the code 43. Which I'm sure its also why I have this weird knock retardation problem.

 

Well I did some reading on the code, And one site suggested that if it is between 4-20 degrees retarding (Which I am). Even with the knock sensor disconnected, It could be the circuit inside the ecm itself, I am going to borrow one from work tomorrow and see if that itself fixes the issue. I don't see a wire going bad just from repinning ecm's.

I'll post back up tomorrow with my outcome.

 

Ok this is weird. Pin B7 on my old maf ecm is supposed to be the wire for the esc or knock sensor. Howeve the wire that actually plugs into the knock sensor looks white. How does this wire go from white to black?

 

The code 43 will have the ECM retard the timing. Fail safe feature

On the MAF 3rd gens the knock sensor goes to a filter module located on the firewall. Small black plastic about 3 x 3 x 1/2" in size, label has a 3-letter code on it.

That box decides whether there is knock present or not, and lets the ECM know.

RBob.

 

My guess bad ESC.... Had the same symptoms when my ESC wasent correct put in my 749 ecm.

Search for the chart for code 43.......

 

You're using a 727 now, right? I think the knock sensor is supposed to be rewired directly to the ECU. Did you do that? I'm guessing you put the "old" ESC signal into the new knock sensor input. That circuit won't detect knock correctly. Also, not sure, but I think the 727 requires a different knock sensor than the '89's '165.

 

Yes yes, that makes sense, I never ran across the part in my conversion that I had to bypass the external 'filter module'. I will defintely take a look for that.
RednGold86Z, I did purchase the correct knock sensor however so that is taken care of. I swear man, if you ever come back out to cali, I will buy you a drink.

 

Well that was definitely the issue, Still can't believe I never even ran across this part in my ecm conversion swap. No more check engine light for me. No more spark retard. It now functions properly. Now onto spark tuning. Check my other thread. I owe you big time, RednGold86Z.

 

if I ever get back, I'll try to hold you to that deal. Heck If I ever get back, I'm buying everyone in sight a few beers. About to sign a 2 year contract (and this time, not for pennies). pooor cars aren't gonna have a fleck of paint on them.