crazy high egts until..

[hose101772]

until i retorqued the knock sensor.egts dropped from 1600f all the time to 12-1300 cruising.still shot up under boost.afc always would hit 2000hz even on the most hacked up by-pass-a-matic maf youve ever seen.i read somewhere that the 1g ecu didnt recognize anything past 1600 and the ecu will pull timing anything over 1600.this seems to be the case in mine as half throttle would keep the egts down,spool it up and temps peg out.well actualy its dead at the moment.headgasket went and i burned the head's and block's bridges between 3 and 4(way milled head,had 200lbs on all 4 on 9/1's).going back with 2.4 this time and im just going to make the maf flow problem worse.so within the next month i need to find a better way for air metering.any suggestions?thanks.

 

[Phoenyx]

Originally posted by hose101772
i read somewhere that the 1g ecu didnt recognize anything past 1600 and the ecu will pull timing anything over 1600.

Not true. The pocketlogger doesn't display past 1606Hz, but the ECU is totally capable of reading beyond that (and the MAF will give a higher signal too). And no, the ECU will not pull timing based on the airflow going beyond 1606Hz. You are running lean somewhere and getting knock would be my guess.

-M

 

[hose101772]

well guess that was wrong.what about 2000hz then cause it was hitting that by 5500-6000.on the chart display of afc the hz signal would peak then jump all around.as far as lean-no.slobbery rich if anything .9 always on o2 with boost.was adding fuel w/550's @40lbs on afc.not much mind you but 5% on the plus side.really im just wondering at what point does the ecu start pulling timing.it has to some where pre fuel cut.just at what point?

 

[Phoenyx]

Originally posted by hose101772
well guess that was wrong.what about 2000hz then cause it was hitting that by 5500-6000.on the chart display of afc the hz signal would peak then jump all around.as far as lean-no.slobbery rich if anything .9 always on o2 with boost.was adding fuel w/550's @40lbs on afc.not much mind you but 5% on the plus side.really im just wondering at what point does the ecu start pulling timing.it has to some where pre fuel cut.just at what point?

The ECU will only pull timing when it senses knock significant knock. How much and what it determines as 'significant' is anyone's guess.

-M

 

[FastRthenU]

Hose101. You are right and wrong about the timing being pulled due to higher hz counts. Remeber the the ecu is a spread sheet of tables basically. The hight the hz count, the less timing the computer will allow for safty reasons. So its not really pulling timming but no allowing alot of it either. So when you have a S-afc, and big injectors. If you use the afc to take out a lot of fuel. Like -20-30%. The computer allows more timming due to it thinkin its not geting alot of air. Its the opposite if you ahve the settings +30+40%

 

[hose101772]

i know the less sig the ecu gets the less timing it will pull-posted while back about that.what im getting at is my hz signal goes crazy after it hits 2000hz.let out of throttle and its fine again.i read somewhere while doing a search on this subject that the ecu wouldnt recognize anything over 1600-well that maybe wrong but mine still goes nuts at 2000.is mine bad or is this just the way they are.i've tried 3 different mafs in different states of hackedness all have the same problem after 2000hz they jump all around.the more hacked the higher in the rpms it would hit 2000hz-<-the reason for hacking-but i cant seem to hack one far enough to keep the signal inorder.makes sense that a turbo ecu would pull timing if overrunning maf condition is detected.safe guard for loss of boost control.is this an afc problem lack of scale to match the maf or is it a maf/ecu limitation.another funny thing-mines never hit fuel cut,from 20f to 100f temps-running @20lbs.got any opinions on maf translator,need to find something quick-motors here and im 2 weeks out before i get it all together.

 

[4pistons]

mine still goes nuts at 2000.is mine bad or is this just the way they are.i've tried 3 different mafs in different states of hackedness all have the same problem after 2000hz they jump all around

You're chasing your tail for no reason. The ECU will read above 2000hz but when the engineers designed it they never figured any technician could ever read that high while on static diagnostic equipment so none of the circuitry we tap into through the diagnostic port will show it. None of the loggers actually read deep into the ECU. They only pick up what the ECU is programmed to release to the diagnostic port.

I got this basic explanation from Todd Day a few years ago....back when you could get a hold of him!

Rick - '91 GSX