Follow up from "91 civic won't start"

Strangest damned thing.. I get in the car, switch to the ON position, wait
for the fuel pump to finish.. Crank, and it starts w/ no problems.. Idle
was a bit rough at first (I don't blame it, it hadn't been used for almost
2 months) .. I took it around the block and it was back to normal..

Only thing is the CEL is on, and the codes are 6 and 16.. I'll be looking
these up shortly.. Hopefully it's nothing too expensive/complicated to
fix.. I plan on selling the geezer, and considering I just got laid off, I
could use all the money I can get!

Thanks!

 

Ok.. 6 is ECT Sensor.. 16 is Fuel Injector System... I'd be willing to be
bet the 16 is because it's gunked up or something from sitting for so
long... That code has come up before and gone away after a computer
reset.

The ECT Sensor code has been there for a while (even after reset).. I've
been meaning to test it.. I need to figure out a way to degrease the area
safely so I can get to the parts.. It's a mess in there.

 

Get some "brake degreaser". This stuff is very flamable, so let it
evaporate
completly before starting the engine. Before buying a new thremistor,
be sure
to check to see if you have the correct voltage at the ECT end. I
found some
damaged wires going to my MAP that had to be damaged during the wiring
harness construciton. Back track the wires through each connector if
there are
problems. The resitance of my ECT was around 2700 Ohms at 70F. I will
get try and look up the exact reading this evening and post if for
you. You can compare it to the Air Temp sensor as they are very close
in the 1990 and 1991 civics that I tested. This is a very important
sensor! The ECM appears to use coolant temp as the primary variable
for seting FI on pulse width. It looks like everything else follows
something like this. Water temp, RPM, air temp, MAP, TA, O2, PA, the
alternator loading (with heater fan and AC having their own inputs),
then brake status. A friend is reservse engineering the machine code
from a sick ECM. RPM is actually first but it isn't really a senosr
variable because if the distributor/ECM can't figure RPM, the FI won't
open at all. With all the other sensors, the ECM drops to a fall back
assumption, that while the engine will run, it won't run very well.
Terry

 

It is also common for a failed fuel pump main relay to set a diagnostic
trouble code (DTC) 16. The ECT is about 200-Ohm warm.

Rick