Ping Doc, et al:
got an 89 S10 Blazer, Vin Z, TBI, 4.3, 700R4:
new TPS, IAC, cleaned and rebuilt TBI, new FPR <to include spring>, CTS, MAF
<or is it MAP?> sensor, O2 sensor. Basically everything but the knock
I'm running rich as evidenced by the soot-coated exhaust pipe and the smell
of gas at the pipe.
Computer throws no codes, I have logged data from WinALDL but am not sure
how to interpret it.
Am installing an Air/fuel gauge, but haven't had time to do more than
physically mount it due to the weather and having my garage full of crap
<just moved into a house>.
No info on fuel pressure. I would assume a dying fuel pump would put out
less fuel and therefore make the engine run lean.
Air filter is a K&N, and is cleaned regularly.
Checked base spark timing as per the manual- disconnect the ESC wire, set
timing to 4deg BTDC, reconnect. When I check the timing during operation, it
retards to abotu 10deg BTDC. So apparently there is something being told to
the ECU to make it retard. I can hear no spark knock or other mechanical
noises other than a tapping exhaust pipe or something of the sort at idle,
which goes away with application of throttle. Again, haven't had time to
I'm getting 14MPG, and I bet if I track this down I can get 3 more. She's
running REALLY retarded <!?> and really rich...
Doc- you said something about the HB being off a tad- how would one check
for that? I know normally you can pull a plug, put a dowel in the motor, and
turn it over by hand till you're at TDC and compare the HB's position re:
the timing marks. However, this basically being a smallblock- the spark
plugs enter the head at an angle, so that would be a ballpark operation at