I'm fishing for suggestions here guys.

93 Pontiac Firehawk LT1 Le2 Heads, Le1HL cam, A4
Stock fuel pump, 30# SVO injectors.

We've been working on the tune on and off for quite a while now.
For the most part it seems pretty solid, but I can't for the life of
me solve this knock retard issue. I beleive this is what's causing my
car to be sluggish off the line.

Looking at the logs, i can see that when I open the throttle to 100%
the ECM is retarding my timing by 4*, then slowly puts it back to 0*
within a few hundred RPM. Then it does it again when I shift.

The O2 sensors seem fat and happy hovering around 900mV.
MAP is up around 97 kPa at WOT, 32 at idle.
Injector pulse width stays around 16.00 mS tp 16.40mS at WOT.
The knock count only increases by 1 or 2 each time.

At idle and at WOT, the car seems to stick around 30-34* adv.

I can send you the log from TunerproRT or dump it to a speadsheet/graph
for you if you want to look at it.

 

What kind of gas do you run?

Do the 1993 PCMs use a knock module like the 1994-1996 PCMs do? If so, I'd be tempted to try an LT4 knock module. Your setup may be producing valvetrain noise which is being picked up as knock falsely.

 

I'd say that's pretty normal knock retard, especially if I goes away after a couple seconds.

You could always unplug the sensor and see if it makes a difference. I was getting about 3 or 4 degrees at the track so I uplugged it and it didn't run any faster.

 

same with me it boggs stumbles i dunno just does not rev normal but when it does that it may in some cases jump to max 15* retard, others like 9, and the spark advance goes right to zero. But goo smooth with the idle it wont do it just quicker steps on the pedal. Soo i dunno also


headers, magnalfow muffler no cat straight pipe instead no egr

 

Try unplugging the sensor and see if it helps.

 

okay I unplugged the sensor and it does not give me knock counts, but the spark retard in datamaster still goes to 15*. So how does that make sense?? What else will make it retard timing when the sensor is unplugged.

 

also the map will jump to 96 kpa from 32.1 , and the afgs jumps to 101.96 from 10

 

actually I found out if i unplug both the map and iat it runs good and there is no more spark retard!!! So now eithier sensor must be shot, the map is new so it must be the iat that is garbage.

 

Butt sex?

 

Nope, just a thread pirate. arggg .

 

could be burst knock. You can disable that in the tune fairly easily and it shouldn't harm anything.

 

That is the telling.... Disconnecting the knock sensor does not disable spark retard. Instead the lost signal (resistance I think) causes the ecu to pull the maximum of 15° to protect the engine. You can trick the computer to think there's no knock but you can't remove the signal altogether.