I am working on  a 2012 Explorer in quite nice condition. 

 The fuel injector is not working. I tested with battery power directly, it works great then down to about 6Vdc. Fuel pressure 50psi. 

When I run the injector test in the diagnostics, I can just hear injector click, but it does not open to squirt fuel. I tested voltage on with injector in place, doesn’t even move the meter. 9Vdc without injector.  
I suspect bad earth in the loom. I do not have a diagram for the early bikes (these have a battery from new). 

 

Ideas?

You have fuel pressure and can hear the injector clicking.  Doesn't that mean the injector is clogged?

I would not expect to learn much by putting a voltmeter across the injector.  The duty cycle is quite short.   You'd need to use an oscilloscope.

 

It is a lot slower in test mode- but you are correct an O-Scope is the way to do it. I will test with one. 

  The injector works just fine if I power it up separately, great pattern and flow. 

For your testing: ECU pin 4 is the high side (+12V) for the injector.   The low side (switched ground) of the injector is ECU pin 18.

There is a small pilot current (89 uA) running through the injector when it is shut.  This allows the ECU to verify the injector is electrically okay.  On the dead ECU I reverse-engineered, I found the IC that deals with this pilot current was fried.  I hope that is not the case with your bike!  

One possible troubleshooting technique would be to power the injector directly from a 12V source instead of via ECU pin 4.

ECU pin 4 wire color is pink.

ECU pin 18 wire color is white with a green stripe.

Thanks for the ECU info. (I will verify this bike is the same). 

 I get ~9Vdc constant on the injector plug (when not attached to injector), but will look to see that earth is working properly through ECU with o-scope today.  ECU connectors look nice and clean, but I put a bit of ACF-50 in there just to keep it that way. 

Battery voltage (this model has a battery mounted below display, unlike later Explorers which have none) shows 11.5 V through diagnostics, but ~12 at the battery. This one runs the fuel pump for a bit when the key is turned on- nice feature. 

 

Owner reported bike was running just fine, then died - like the switch was turned off. (It will run a few seconds with a bit of prime, so appears to be fuel issue)

Edited October 9, 20241 yr by lotus54

I did a bunch of testing today. 

 Finally found: 

11.6Vdc at one side of injector whenever key is on (this early Explorer had battery and key)- and injector connected. 

Injector works great if I earth the other side. BUT it appears the ECU is not suppling a good earth when running the injector diagnostics test.   Hard to get a good reading, even with Oscilloscope. I measured a good earth to the ECU (assuming the black wire is earth, which is seems to be). 

 

So I suspect failed ECU.  Even the importer never could get wiring diagrams from the factory for the early Explorers, so some thing are just testing end to end. 

 

Anyone have a spare working ECU? It appears to be the ‘later’ ECU type. 

5200030212

Edited October 9, 20241 yr by lotus54

Update:

  I decided to do some testing on my 15, to verify what I’m seeing.  And I found out that the injector does not ‘fire’ on mine in test mode either!  Dang.   Certainly surprises me, why have it if it won’t open it? 

Anyway, bike runs great on my ECU- so after starting on mine, I put the 2012 one on my 15 (same unit) and it would start too. So there is something else going on and I wasted time by making assumptions on the diagnostic software tests. 

I thought I would update if someone else does that and makes same mistake as me. 

Something weird going on there.  I have used the injector pump test to drain the fuel tank: https://www.ossa-efi.com/home/chassis/fuel-pump#h.aueu7tpf4lup

Edited October 11, 20241 yr by konrad
changed "injector" to "pump" for future reference

I have used the fuel PUMP test to drain tank, check pressure and flow. 

That works great.

37 minutes ago, lotus54 said:

I have used the fuel PUMP test to drain tank, check pressure and flow.

You are absolutely right, it was the pump test I used to drain the tank.

Just ran the injector test on equipment in my lab.  That test generates five approximately 100-microsecond pulses, 1 second apart.  So yeah, that is not going to squirt any fuel!

I think maybe they did it that way so it would not flood the engine?   It's more of a test for the design engineer than the repair technician.

Thanks for making me take a look at it.

Get anywhere with this one? Konrad and I have been going back and forth on my cooked ECU and it seems like this is another failure unless there is something else going on. Maybe an issue with the way the early Explorers are wired or how the harness is run? 

I suspect harness. But Adrian said he never could get a diagram for those. 

 

 New ECUs are around, but I would want to either replace to take harness all apart to verify ok.