jonathan_ed3

iTrader: (4)

1998 LS1 PCM. Car won't start. No power to the fuel pump. PCM has 12v ign at pin blue 19, 12v hot at blue pin 20, and ground at pin blue 21. With the key 'on' shouldn't there be 12v signal coming off of pin blue 37 to power the fuel pump?

I don't have an oil level sensor on this engine. I think I remember that the fuel pump circuit and the level sensor are related.

Will not having this sensor prevent voltage from hitting the fuel pump circuit?

Open to other ideas. I want to start this thing!!!!

DuoDS

The fuel pump signal that comes off your PCM needs to go to a relay. The fuel pump pulls way too much power for the PCM to be hooked directly

Tongboy

if the engine isn't running you'll normally only see voltage at that pin for a few seconds after you cycle the key. it doesn't continually feed until the engine is running.

duods is right though - you need a relay on that

Old Geezer

iTrader: (3)

PCM needs to see a tach signal B4 the fp is turned on. [After initial prime.]

jonathan_ed3

iTrader: (4)

I have it relayed/fused but my relay wasn't getting any switched power so I was checking voltage at the PCM.

Can anybody tell me about the low oil level sensor? I don't have one. Will that prevent the PCM from sending voltage to the pump?

How do I bypass that if so?

bczee

iTrader: (12)

You do not need the Oil Level input. that would goto the BCM for gauge readings.

You will only get a voltage for a second or two from the PCM to prime the pump/system once you turn the key on. If the PCM doesn't get a signal that the engine is running, It will then cut the voltage to the FP relay.

Are you getting voltage on Key IGN for a second or two, and if the engine is running, are you getting a constant voltage reading ? If not. check your wiring.

bjamick

iTrader: (31)

Ya you need someone to turn the key on while you check the wiring coming out of the PCM (green wire). Should be 12V for 2 sec, then shut off. If you are not getting 12V then, check your wiring like previously said.