OK, some background info: 22RE that Dave's Off Road did a harness for. Inline fuel pump, and pretty much stock everything else. I was driving it home from work Sunday and as I pulled it into the garage it just died. I checked it over and found no power to the EFI at all due to a blown fuse.

Next, I have traced it down to a dead short to ground on one of the (+)'s that feed the EFI. I pulled it all apart and seen what might have been a couple possibilities as to why it shorted, but nothing concrete. I unplugged all the sensors and the ECU thinking maybe a component failed internally, but still a dead short to ground. I called Dave's and he confirmed that if it wasn't obvious, I had to take the harness apart and find the wire that is the problem.

Today, I pulled the entire harness out, unloomed EVERYTHING, and found nothing. I taped it all back up, pulled it back through the motor and hooked everything up, and now it doesn't blow fuses, BUT it won't run. Turns over, but nothing else. The CEL only shows a 21, which is the o2 sensor, but it has always showed that.

What to look for next??

I was driving it home from work Sunday

sorry no answer for ya, but wish I could drive a FToy home from work everyday! :smokin:

Won't fire? No fuel or no spark.

Pull a plug and look for spark.
Crack the cold start injector and check for fuel spray. Are you hearing the fuel pump whine?

Does it have and o2 sensor???
Your post does not say if it is there or just throwing a code.

If you burn through your o2 wiring and it grounds out, the truck will blow the efi fuse and will not start.

Just a thought....

Does it have and o2 sensor???
Your post does not say if it is there or just throwing a code.

If you burn through your o2 wiring and it grounds out, the truck will blow the efi fuse and will not start.

Just a thought....

Main circuit opening relay? Seen that. Looked plugged in, bent pin, same symptom.

Does it have and o2 sensor???
Your post does not say if it is there or just throwing a code.

If you burn through your o2 wiring and it grounds out, the truck will blow the efi fuse and will not start.

Just a thought....

Yes it has an O2 sensor. I checked that wiring, and everything is good, unless the O2 shorted out internally??

Won't fire? No fuel or no spark.

Pull a plug and look for spark.
Crack the cold start injector and check for fuel spray. Are you hearing the fuel pump whine?

Didn't check for spark because that is mainly ran off of another harness, but I'll check it...
I didn't hear the pump at first, but now the short is gone it runs fine.

Main circuit opening relay? Seen that. Looked plugged in, bent pin, same symptom.

It didn't move to make the original problem, but I did inspect it during the "hunt for the short" process...


I worked a long shift today, but tomorrow after work I plan on "pinning out" the ECU connectors according to the FSM and see what comes of it. Thanks everyone. Any other advice short of propane (believe me i've thought about it) is greatly appreciated!

sorry no answer for ya, but wish I could drive a FToy home from work everyday! :smokin:

Believe me it's not a completely fun ride. My rear driveshaft is my first attempt at one, and I didn't get it completely true. It vibrates pretty bad above 50mph, so I go backstreets everywhere. My trip to work in my car is less than 20 minutes. In the FToy it's closer to 40 minutes...

When you say dead short on one of the "positives that feed the EFI" what exactly do you mean? Is the short before or after the ECU ? If it's before, in other words you remove all the wires from the ECU then back probe toward power and it shows to be shorted then it's not an engine component like a sensor, it's wiring or maybe main relay. If you can reach both ends of that wire then disconnect it and measure resistance of the wire then resistence to ground. Does the wire in question go to more than one place?

When I went to the wires fed by my switch panel that supplies battery voltage to the harness, and used my meter, one of them showed zero resistance to ground. I unplugged the ecu, and all of the sensors it still showed ground. After pulling the harness and checking it over, then relooming it it now does not blow the fuse, but still does not run. I have yet to try anything posted here, but will tonight.

Any other advice short of propane (believe me i've thought about it) is greatly appreciated!

Pump gas is just so darned convenient! :laughing: I won't push you the propane route to solve this problem.

Keep us posted.

Well I feel like a dummy...

Today is the first day off since I tore it all apart last week, so I went out there this morning to re-evaluate my problem. I first checked for spark, and I had none. BIG CLUE! So, I looked, and there is a plug on the ignitor that I have to supply (+) to seperately from the rest of the harness. Among the other things I did, I also wrapped that wire in with a couple others to "clean things up" a bit. When I plugged it back in the "plug", I put it on the wrong terminal. I took 2 seconds to switch it, and now it runs great!

Thanks again for the replies. Sometimes it is more simple than it seems...