Fuel pump won't operate
Long story short, I think the ECM is bad but would
like a second opinion before I spend the money on
a new one.
I swapped the fuel filter after having contaminated
fuel, after the swap I couldn't get the van running. I
didn't purge the air out but the Chilton's manual
doesn't say to. I did the same in the past with the
same result, swapped the whole fuel pump and got
it running. So, I did the same thing now but no
results.
For what I've checked: the fuel and injector fuses
as well as the fuel relay under the hood check
good; relay has been swapped and pin checked
multiple times. I get 12 volts to both fuses and
both sets of relay terminals; 85/86 with key off/on,
30/87 with key on. I cannot get voltage to the fuel
pump connector without shorting the 30/87
together; when shorted I get 12v. Initially I could
get fuel flow by turning the engine but not any
longer. I've never got fuel flow with KOEO.
Continuity from the relay to the pump is good with
both power and ground. I hooked up a fuel
pressure guage and only got 5psi, at this point I
assumed it was the fuel pump.
I took out the ECM, nothing looked or seemed
damaged but I can't find schematics to test power
out to the pump.
Is there a way that I can isolate the issue to the
ECM or something else before I spend more
money on unsure fixes?
If you lower the tank just enough to get to the connector you'll be able to test voltage directly at the pump
Luckily Kia thought of this, there's a panel inside the van to access to connectors and pump. That's where I checked for voltage and continuity
Doesn't the fuel pump wiring t off after flowing through relay and fuse to run to data link connector on one side and the pump itself on the other? What's the voltage there?
It does, it tees to the ECM and then again to the diagnosis connector (I don't know where this is). I'm having trouble finding which connector and on go to the ECU and from it though so I haven't checked voltage there.
Now that I have something to look at....I would test the following locations, because it isn't very often for the ecm to be the cause (not saying it doesn't happen though)
One way to find out where it t's....trace the wiring back from the fuel pump
Sorry for the delay. First off I couldn't find the slice or JB07 pin 2 yet but I've been digging. I think I found the connector JB04 pin 17, it gets no voltage but gets continuity to the pump. It only gets voltage when I short the relay terminals together. I'm not sure about this going to the 'diagnosis connector' cause this wire goes to the fuel pump connector I connected to the battery and got the pump to operate. Hopefully that makes sense, I'm just confused on something in there. Considering I can get volts to the pump by shorting the relay terminals, would it be likely there's something wrong with the 85/86 side of the fuel relay?
Is that with key on or off? Is there a matching relay on a nonessential system (heat/ac for example) that you can swap out for a brief test?
That's with key off. I've swapped the fuel and main relays with known good ones.
I went through and shorted power and ground manually on each relay and they were good. Finally got to the ECM pin 76, shorted it to ground and got the pump to work with key on. So I'm thinking either the ECM or the ground coming out of it. I'll try to find the schematics.
Wasn't able to find helpful schematics, I ended up splicing a ground wire to pin 76. Only thing it doesn't do is turn off the pump after a minute of the key being on.
Just make sure it shuts off when you turn the key off
