First Conversion Help Needed!

**mtbraun** · 10-31-2017

Update - I corrected my wiring error and installed the oil pressure switch with its wiring. The tan wire from the oil pressure switch is currently unhooked as this is for the dash display.

Anyway, when I turn the key on the fuel pump will not cycle. I can cycle the pump from the test port on the fuel pump relay. I went through the troubleshooting diagram for code 54 Fuel Pump Circuit and when I try to test the circuit between 465 (green/white wire from ECM) and ground, after turning on the key the circuit does not show power within two seconds. The troubleshooting guide suggests a open circuit 465, short to ground, or faulty ECM. I have traced the wire from the ECM to the fuel pump and all looks fine.

Now here is where it gets weird. Every time we turn off the key, the fuel pump will cycle for approximately 2 seconds. The fuel pump will not cycle when the key is turned on, only immediately after it is turned off.

In addition to this, when I turn on the key, I still get 7 flashes on my SEL. Does this suggest a faulty ECM?

We tried jumping pins A/B on the ALDL and then the SEL flashes 2 times. Also, for whatever reason as long as the ALDL pins are jumpered the IAC valve extends into the throttle body. The only reason I noted this is I heard a faint sound from the engine when we jumped the pins. I'm not sure if that means anything or not.

Really need some help here.

**Six_Shooter** · 10-31-2017

Yeah, there's something up with the ECM or the way it's powered.

When you turn the key on, there should be a single flash, and then stay on until the engine is running.

**mtbraun** · 10-31-2017

I'm going to grab a different ECM. Question - when grabbing another 1227747, do I need to switch the small chip from the old ECM if the new ECM is not from the same size engine? I have a burned PROM chip already.

**jim_in_dorris** · 10-31-2017

I would try a stock chip first, you may just have a bad chipburn. If you do switch the ecm, for test purposes, leave the old chip in until you verify the cel blinks properly

**mtbraun** · 11-01-2017

so my local u-pull has a tub full of ECMs but no 1227747. Are there any quick options available to use a different ECM with my burned chip? I think the answer is no but wanted to double check before I bought another 1227747. I don't have my stock chip as that was sent to dave when he burned my new one.

**mtbraun** · 11-02-2017

I was able to find another ECM, tried that with the same result. I suspected a power issue with the ECM and traced all my wiring to the power relay. I am running two relays, one Bosch style 5 pin for injectors and ECM power, and I retained the factory fuel pump relay. So when probing terminals on the power relay, I discovered that pin 87a had power when key off, but NOT key on or crank. Pin 87 did not have power at key off, but had power at key on and crank. Guess which terminal my ECM was wired to? 87a! So after I spliced the ECM power wire into terminal 87 the fuel pump cycled as it should and the truck started right up.

So now the question is, is that a fault in my power relay or is pin 87a only hot with key off?

**Six_Shooter** · 11-02-2017

Typical Bosch style relays will stick the connection of terminal 30 between 87a and 87. 87a being connected to 30 when the relay coil is not energized, and connecting 30 to 87 when it is energized.

So it sounds like your that is functioning the way it's supposed to.