Explorer EFI won't start

[snipes243]

I’m currently working on a rebuilt 302 engine that has been converted to Explorer EFI. At this point, the engine cranks but will not start. Initially, we experienced some popping from the headers.

We began troubleshooting by checking the cam position sensor (cam synchronizer), suspecting it may have been installed 180 degrees out. To verify, we brought cylinder #1 to top dead center (TDC) on the compression stroke. From there, we reinstalled the cam synchronizer using the proper installation tool, aligning it approximately parallel with the engine centerline. This adjustment appeared to help, as it eliminated the backfiring through the exhaust.

Next, we verified that the engine is getting spark by removing a spark plug and observing it during cranking. Spark is present. We also confirmed that there is fuel pressure at the injector rail.

Using Forscan, I performed a KOEO (Key On Engine Off) test and retrieved the following fault codes:

• P0708 – Transmission Range Sensor Circuit High Input
• P0605 – PCM Memory Failure
• P0230 – Fuel Pump Primary Circuit Malfunction
• P1702 – Transmission Sensor Out of Range

The two codes that concern me most are P0605 and P0230. I have been unable to clear these codes, even after removing power from the PCM for more than five minutes.

Regarding P0230, the fuel pump runs continuously as soon as the key is turned on. I attempted unplugging the fuel pump and clearing the code, but the code remains.


At this point, I’m beginning to suspect a faulty PCM, but I’m open to other possible causes or suggestions. Thank you for the help.

 

[Viperwolf1]

Make sure you have good grounds at the pcm.

 

[Bruners4]

Was this Explorer EFI system pulled from a known running vehicle?
Uncontrolled fuel pump running is a sure indication that here is something in the PCM. But I would double check wiring and relay to verify that the control signal from the PCM is telling the relay to stay on.

 

[Boss Hugg]

Fuel pump should only run for a second or two before the engine starts to turn over. Sounds like a bad pcm or bad wiring??

 

[snipes243]

Messed with it a little more the Fuel pump is grounded out even with the PCM unhooked it runs. I'm thinking something in the Ron Francis Bread board isn't wired correctly. So thats next on the list to dive into.

 

[Boss Hugg]

Sounds like a relay stuck. Cheap relays do that easy. My dad fought a short in his 06 super duty for a long time. Turned out it was a bad relay to the fuel pump. He couldn't hear well enough to know the FP was still running when he shut the truck off.

 

[rjrobin2002]

Messed with it a little more the Fuel pump is grounded out even with the PCM unhooked it runs. I'm thinking something in the Ron Francis Bread board isn't wired correctly. So thats next on the list to dive into.

Switch the fuel pump relay with another relay, their are several with the same part number and see if the fuel pump starts acting right

 

[EFI Guy]

The two codes that concern me most are P0605 and P0230. I have been unable to clear these codes, even after removing power from the PCM for more than five minutes.

Regarding P0230, the fuel pump runs continuously as soon as the key is turned on. I attempted unplugging the fuel pump and clearing the code, but the code remains.


At this point, I’m beginning to suspect a faulty PCM, but I’m open to other possible causes or suggestions. Thank you for the help.

Sorry, late to the game here. I haven't had much time to browse the forums lately.

My understanding is that the RF breakout board grounds the relay at all times, which means the pump is running anytime the key is on. This will cause the p0230. Short of tearing that breakout box thing apart and wiring the relay correctly, there is nothing you can do about it.

P0605 can be a power failure on the KAM circuit, or a checksum failure. If your PCM has power on pin 55 at all times, then it is not a KAM failure. However, disconnecting the battery will show a KAM fault code if you read the code on the same ignition cycle that you reconnect the battery. If you cycle the ignition a couple of times and that code is still present, then it's probably a checksum failure.
If it is a checksum failure, it means that the computer's internal memory does not pass the checksum test. You'll need to reflash it properly and see if the code goes away. The PCM itself could be bad, but that's pretty rare.