Ford Repair Questions? Ask a Mechanic for Answers ASAP
Ok, is the inertia(fuel cutoff) switch tripping or staying in the on position?
Is there factory or aftermarket anti theft system on your Ranger?
Ok, and no power to the fuel pump Or the injectors - both lack signals, correct?
Ok, have you checked the fuel pump relay and the pcm main relay in the engine compartment relay box?
Ok, the fuel pump and injectors are on different circuits and there are only 2 common denominators - the pcm main relay and the pcm. If the relay is good, then it is a faulty pcm. I see nothing else in the wiring diagram that ties into both
The pcm relay sends a signal to the fuel pump relay, which is why it could cause both issues as it being bad means no signal to the fuel pump relay or to the pcm, thus creating no power to the fuel pump and no injector pulse as no signal from the pcm to the injectors to pulse.
You can check for signal to the maf sensor, vss sensor, or other sensors while cranking. If signal is to them, then wiring is fine from the relay to the pcm and we know it is the pcm
If you swapped them that much, one should have been good, so we can eliminate the relay. Check for signal(power) at maf sensor, iac valve and other sensors. If you have signal, then wiring from pcm relay to pcm is good, and this leaves just the pcm
Should be the red wire at the iac valve and the maf sensor.
Should be at least 10v while cranking
ok, sounds good
Ok, no wiring break between the pcm relay and the pcm. So this only leaves the pcm as the culprit
Ok, sounds good. I will be here everyday
Hello, let me see if I can be of assistance? Does the check engine light come on when the key is turned to on and go out when cranking? Do you have communication with the pcm using a scan tool? Any codes stored key on engine off testing?With the fuel pump relay removed do you have 2 sources of power at the fuel pump relay,one constant and one for a few seconds when the key is cycled to on? If you jump across the fuel pump relay does the fuel pump kick on and send pressure to the fuel rail?
Ill be right back, picking up some dinner round the corner
Ok so it wont communicate with either scan tool or it will with a second scan tool? No codes then? You have a good blue spark but no injector pulse? Will it run a few seconds if you spray carb cleaner into the intake?
Ok its possible the bulb is burnt out for the check engine light, under normal operation if the eec power relay is working properly it will turn on the check engine light when the key is on. Since you can communicate with the pcm with a scan tool it should be working. When you crank the engine the check engine light turns off if you have an rpm signal which you should since you have spark. You should also have injector pulse with spark long as the pcm is getting an rpm signal. If you scan tool can look at live sensor data and look at rpm that would be helpful.when cranking it should read a few hundred rpm. The eec power relay sends power to the fuel pump relay to energize the fuel pump a few seconds. Then powers it continually once the engine is running. Here is a schematic of the system to help know where to jump across relays for testing output of the eec power and fuel pump relay.
SInce you have no ignition pulse its possible you have an open circuit in the wiring that sends the rpm signal from the ignition control module to the pcm
One fuel pump relay wire is hot all the time, the other gets power from the eec power relay as shown in the diagram, to energize the pump you want to jump across the switch side of the fuel pump relay to pressurize the fuel rail
One for a short time, other all the time direct from a fuse to the switch side of the relay. The coil side of the relay is energized for a few seconds to complete the fuel pump circuit by closing the fuel pump relay switch side.
One wire sends pulse to injectors 1,2,3 Tan. White wire does injectors 4,5,6 so check for pulse on all injectors.
Ok, Pin 30 for the fuel pump relay should have power all the time from the number 22 fuse 20 amp in the power distrubtion box under the hood. Pin 85 at the fuel pump relay should only have battery voltage from the eec power relay whe the key is turned to on for a few seconds to prime the fuel pump. If it is hot all the time the eec power relay ground circuit from the pcm is shorted to ground and leaving it energized all the time. It could be causing a voltage drop if this wire is grounded all the time pin 86 on the coil side of the relay light blue/orange wire. Since the pcm is new id suspect a wiring issue between the relay and pcm if its not working as described.At least check both sides of the fuel rail for pulse since two wires pulse the two different sides of the coil.
As I mentioned the rpm signal goes from the crank sensor to the ignition module, which fires the coil. Then sends the rpm signal to the pcm to fire the injectors. Either the rpms signal isnt being send from the ignition module, or wiring is bad from the ignition module to the pcm
Pin 22 at the pcm is the ground control for the fuel pump relay. light blue/orange. its all shown in the pdf files i attached
It should set codes for a profile igntion pickup signal or loss of rpm with a scan tool
Could be related possibly. Need to verify rpm signal is going from ignition module to pcm, check pin 22 for short to ground for fuel pump relay circut.
Yes, its hard to say whats gong on for sure without checking for a short to ground on the fuel pump relay,with it being energized though it should have fuel pressure at the rail. The loss of injector pulse is most likely a bad ignition module or wiring inbetween it and the pcm to convey the rpm signal to fire the injectors, its firing the coils.
One thing to check besides the circuit is to see if the EGR flow sensor(DPFE Sensor) is shorted, this can cause odd things to happen. It is a metal block if original or black plastic with two hoses coming off the exhaust manifold, a tube with two hoses. Uplug this sensor and see if normal operation happens,just a shot in the dark. But worth checking as is unplugging the altenator.
Does it have an egr valve?Some models didnt have one, was just a thought.
You dont have fuel pressure at the rail? Im sorry, the relay wont energize unless you get a ground signal from the pcm so with the key on both will be hot.Pin 22 grounds the coil side of the relay and should shut the relay and send power to the inertia switch and then to the coil.
Pin one at the ignition module should be the rpm pulse signal to the pcm Gray/orange wire. Like I said if you look at the schematic it shows all this stuff, at the last pages it shows the connectors and pin numbers. It goes from pin 1 ICM to pin 56 at the pcm
Yes, left front radiator support. Ive given you the schematics and connectors to test the circuit.
Open circuit if unplugged on both sides, should have less than an ohm resistance. If not run a wire from the icm to the pcm and retest
If you hold both test leads together that shoud be a normal continuity reading.Sould be less than one ohm depending on the range you have the ohm meter selected to.
If you are on mega ohm seting for instance it will show zero. You want ohms depending on the meter it will have a range selection to scale the meter.
Ok with 1.0 ohms the wiring is good, id go with an ignition module and retest for injector pulse
That I couldnt tell you off hand. Good luck and let me know if you need more help.
No problem, just get back to me tomorrow and let me know if you got it going with the ignition module. If I was helpful remember to leave a positive rating for assisting you
Long as its getting an rpm signal to the pcm on the pip signal wire it should have spark and injector pulse. You are sure the pcm is online, you replaced the eec power relay and fuel pump relays with known good relays?
If you have spark and no injector pulse it has to be gettin rpm signal to the ignition module to command the coils to fire.
Yes, but if you are swapping a bad one with a good one it can cause a different circuit fault if swapping from eec to fuel pump
And you dont feel the fuel pump relay click? No fuel pressure? No injector pulse?
and the ground signal wire from the pcm to the fuel pump relay ohmed ok? If you hook up a test light to the positive battery terminal and cycle the key on does it light the test light for a few seconds to indicate a ground signal?
Then that circuit is a short to power somehow, that wire is only a ground circuit for the fuel pump relay, it is hot with the fuel pump relay removed?
Something is backfeeding that circuit, is anything else jumpered into thhat wire as it runs off to the datalink connector? The self test connector for the scan tool.
Well im running out of ideas on this one, either there is a vehicle sensor that is backfeeding the pcm shorted out, or the wire for that circuit is shorted to power which is why the wire is dim.
EEC Power is energized with key on, it feed power to the injectors and many vehicle sensors, as shown in the circuit i gave you, you can unplug each of the sensors on the circuit and see if the powr goes away indicating a shorted circuit backfeeding the pcm
yes run a new wire for that circuit and retest
Right, that dim light pin 22 wire should not have any voltage on it, it is the ground circuit from the pcm to ground the fuel pump relay, you know when you jump the relay the fuel pump operates. Rerun that wire for the ground circuit from the fuel pump relay to the pcm and diagnostic connector
It doesnt have battery voltage? Less than battery voltage.You are confusing me
Thats the power supply from the eec power relay, run a new wire from the eec power relay to the fuel pump relay, you must splice this into the rest of the circuit,make sure the other sensors on the same circuit have battery voltage.If you cut the wire, it will tak away power from the other sensors, splice into it from a point of good voltage
I cant keep up with the incorrect information you are giving me.WHat color is the wire that is lighing up dimly when you turn the key off, does pin 22 from the pcm show a ground signal like ii asked earlier when you cycle the key to on for a few seconds.
Why are you testing the red wire for ground? Thats a power supply.
Im opening this question up to another expert, ive tried what I can but I feel like we are going in circles here