OK, SO ENGINE IS DEAD, CRANKS BUT IS DEAD
AND now doing pump tests wrong. (as most do)
the relay has 4 pins.
to test the relay you must crank the dead engine.
and all fuses good first.
do not try to test the relay for the short prime pulse or go slowly mad. (2 man job and slow meter you will fail)
prime pulse 1second long, some even disable prime too cold outside, so I never trust the prime.
crank the engine.
2 man crank the dead engine (my guess what's up)
the contractor in the relay 2 pins ,one pin is 12vdc full time key on and 2nd one goes to 12vdc when relay energizes. (and pump gets 12vdc to it cranking.
the RELAY coil does that. in the relay.
the RELAy coil has 2 pins, 1 on this truck 4.3 is grounded hard, other coil is PCM
and is 12vdc from PCM, to coil 0v coil is dead.
that is how it works and how to test it correctly
learn the PCM cuts fuel 4 or more ways,
the facts are (have schematic up now)real.
ECM fuse B not blown or FP relay be dead.
PCM C2 pin 9 runs the relay coil
fuel pump not dead or its ground rusty.G402
Ok other coil pin on relay is grounded G102.
so he PCM sends 12vdc to the relay C2-B7
if not the relay will be dead.
fuse B is hot all the time so super easy to check
12vdc both ends of fuse is good for sure cranking
all fuses to PCM must be good.
battery voltage cranking is near 11v below 10v bad things happen.
if you scan the PCM it may tell you why it fails
why not scan any modern car first?
best on any dead engine, (but cranks fast)
all fuses good
scan it cranking
the check spark first not fuel fuel first
cant burn gasoline, with no spark.
the PCM(ecu) cuts fuel injectors if spark is detected by PCM bad.
the PCM cuts spark and fuel if crash SRS sensors tripped.
the PCM cuts fuel for other reasons even tps bad.
The pump is last. to test./ on any dead EFI engine
and do so cranking.
use a voltmeter to find it.
the pump is bad if 11vdc makes it to pump actual
cranking, and rail is 0psi.
if the FPR fails 2 ways stock closed PSI is 2 times normal and floods, engine if FPR is stuck open
PSI is 1/2 normal or less and engine dead or starves for fuel, weak engine and or idles a bit and stalls
see why I asked whats up? no told./
the real deal
my generic schemo. but is true.
×