What is a typical reading for knock counts ? Happened to look about 5 miles after starting with moderate driving and reading (OLDPA3) was over a thousand (1253). Is this common ? No retard was present (ESC = 0)

 

No, that is not common or good. If you are logging that many counts something has got to be wrong. You would have that engine destroyed in no time if you were really having that much knock occuring. What scantool or software are you using? I would say that something has got to be wrong with the scantool..... Need more info.......

------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

Is a 1988 Buick Reatta with a built-in scan tool (touchscreen CRT in middle of dash). No audible knock/other noise & runs fine. "C" NA 3800 & 87 PON pump gas. BLM and INT close to 128 at cruise. Thought that OLDPA3 sounded high. When first looked was stable at 1115/45 mph/0 degrees ESC. Jumped to 1253 shortly after stop at light.

Replaced O2 sensor & everything fine - warm crosscounts at idle ranging from 3 to 18. Start from cold first OLDPA3 reading 553. Restart warm & goes to 9999 (repeated). No audible detonation & screwdriver to block sounds normal. ESC always 0 degrees.

Tried the FSM tests. Started engine. No noise audible. Engaged scan display (takes about 30 seconds after start). OLDPA3 reading 1255 but not incrementing. Struck p/s brace with hammer. Jumped to 1525 then 2213 on second strike. No increment after, no ESC retard. Do not think this is normal but manual just says "should increment" and not how much (suspect this is too much but before spending $40 on a new one thought I would check & this type of question gets blank looks other places).

What should typical O(LD)PA3 read ?

Need to be sure I have a stable system befor experimenting with PROM values.

[This message has been edited by padgett (edited November 21, 2001).]

 

Well I am not really sure what it should be reading with that built in scantool (which is pretty friggen nice, if you ask me...). And there may be some sort of a mathmatical formula that needs to be used when reading that or maybe there is somthing wrong with the display. I am just not up on that system enough to say what might be the deal with that seemingly high number of knock counts..... You may want to consult with a tech from a Buick dealer that is familiar with those systems......

But from the sounds of it, the system is operating somewhat correctly if it is logging counts when you hit the engine with a hammer. But it should retard the timing a bit when it ses knock, as far as I know...... But it also shouldn't be recording that much knock in the first place...... Just plain wierd, IMO........???

------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

Tried to check on wife's Bonneville (also a 3800 "C" but evidently it does not record knock counts.

Problem with built in CRT is that you can only see one value at a time. If I check (ESC) while driving, is usually on zero but with heavy load/low rpm (initial accel from 1350 rpm in o/d lockup) can see it pull back 3-4 degrees. This is what I would expect on 87 PON with a/c on. Drops back to zero quickly. Probably should hook up Diacom (plug) so can monitor/record multiple sensors.

Did try replacing knock sensor and does same thing - engine sounds good/is healthy (for 165 hp 3800)/no noise. But counts do jump fast. Guess is just normal.

Just want a good sound baseline of stock engine before I start "fixing" things.