have 94 gmc 3500 6.5 turbo 200000+ miles runs good but won't start even when warm
with out cranking and cranking and cranking has new pmd-lift pump-crank sensor-clear
fuel return hose-(no bubbles)new filter,good fuel. dtc codes 19 36 18 25 62 ?(done with
paper clip lite count)ses lite stays on, tried to erase by disconnecting batteries -didn't work
read somewhere engine should start/run with optical sensor unplugged-(it won't) but will run with new crank sensor unplugged what is function of crank sensor? could this be part of my problem ? also noticed if you pinch return line from inj pump to stall engine it will
start right back up as long as you don't turn key off otherwise its crank,crank,crank
tested fuel solenoid-ok - lift pump hot wired -tried different pmd,s any other ideas?
any trick to reset ses lite?

 

I have a 95 Chevy and to reset ses light, while using your paper clip to check codes with the key on hold down on the break pedal and the throttle pedal at the same time. Hold for 30 seconds and then turn key off and release pedals, should reset and flash 12 only if the same as mine.

 

cleared old codes now get code 19 crank position error has new sensor still have to
crank/crank/crank to get started any ideas?

 

Will truck still start with crank position sensor unplugged.

 

yes truck will start and run with crank sensor unplugged,but crank/crank/crank

 

turns out my hard starting was a bad wire connection in the crank sensor plug in
front of IP as engine should run with optical sensor unplugged and mine wouldn't
I was able to get started with crank sensor unplugged using optical sensor but it
had to be cranked/cranked/cranked with boosters(hard starting) a buddy e-mailed
me a wire diagram I tested all speed sensor circuits to ecm under dash for open circuits
by unplugging crank sensor and ecm plug using multi meter set to beep when circuit
is good plugged everything back together and it started great. touched speed conn plug and it stalled wouldn't start, wiggled plug and it started wiggled again it stalled .
there are 3 wires in connector (5volt- ground -signal) my problem was signal connection in
plug from harness learned a lot surfing the web for info,hope this might be of interest to someone. I now have extra pmd/liftpump/crank sensor which I probably didn't need
if someone needs a diagram I can e-mail one for 95 gmc 3500 6.5 f or s vin prefix

 

AC Delco CPS ONLY!
Aftermarket CPS are often bad out of the box.