EFI questions

[Bruce Plecan]

-----Original Message-----
From: dzorde <dzorde at geocities.com>
To: diy_efi at esl.eng.ohio-state.edu <diy_efi at esl.eng.ohio-state.edu>
Date: Sunday, January 24, 1999 10:15 PM
Subject: EFI questions

When in doubt read the spark plugs.  AV can look lean, but the signs of
detonation are always present, from what I've seen.  Now, I'll fully admit,
it's been years since doing much AV gas reading.  Try a load of good
racing gas if you have trouble reading the AV stuff.  And I've got zero
time reading australian AV Gas.
  Pipe coloring is dead in my book.
Bruce



>Hi everyone,
>
>Been a while since I've had any questions so here goes.  Finally got around
>to fitting an O2 sensor to my car (can say that on avgas it still works
>after 20+ hrs of operation).  This car has a Wolf 3D running the engine
>using MAP, TPS and associated temp sensors.
>
>Anyway my car has always been running with bright white tail pipes, hence I
>figured it was lean.  With the O2 I have found something I can't explain.
>The O2 is always around 0.82V going to 0.9V+ when accelerating (seems very
>rich), however car runs beautifully. If you lean of the fuel maps to reduce
>the O2 readings the car just won't run, seems like complete fuel starvation
>as soon as you touch the accelerator (even tried hardwiring the heated O2
>shell to the -ve battery terminal to ensure the voltage wasn't floating or
>anything stupid).  Why can the car only run when rich (had it on a real gas
>analyser and it said very rich as well) ?  Is it the high compression
12.8:1
>(or so) ?
>
>Another question, because the system is speed density, when you back of the
>accelerator the engine unloads and picks fuel delivery for its new suited
>map point (lower load range) causing the O2 to read almost 0V (very lean).
>Is this normal for a speed density system ?  It seems correct to me as the
>injection is based on looking up a base value in the map, but it doesn't
>seem very healthy for the engine to lean of everytime you back of.  I have
>been thinking this could be why I have white tailpipes as the car is
>spending most of its time on and off the gas when racing.
>
>Lots of questions, but this one has me puzzled.
>
>rgds
>
>Dan     dzorde at soanar.com.au
>