No injector pulse.

[Zorks77]

Hi all, I have been trying to get this ranger fixed for months now. Here is the problems and what I have done and checked on it.

Oh this is a 1989 ranger, 2.3l 4 speed. It's DIS system with no cam sensor.

I have checked and replaced the fuel pump, cleaned the fuel lines, replaced the fuel filter, replaced the injectors and o rings, cleaned the fuel rail. I have spark on all 8 wires and plugs. I have replaced the timing belt, it was bad. The crank sensor was replaced since I was right there with the belt. I have checked cleaned and verified all the ground wires. I am getting 40+ psi at the fuel rail. I am finding no bad or broken wires. I can start this truck with ether or gas strait down the throttle body. I have chked and replaced if needed the relays, the inertia switch is working. I have tried to start it with out the MAP plugged in, still no change.

Before I had ever touched this truck, a so called mechanic tried his hand at it, no change since then. He said he tried a new PCM and it still didn't not change the status. When this truck broke down, it had just a couple days prior had a new fuel pump and filter put in. Then it just died out of the blue. There is no codes in memory.

I am at a total loss on this thing. I have read everything I could find around this subject and tried to add ground to the trigger with, it will start then flood and nothing more. Oh I did also verify the tps and iac as well as the egr.

Like I said I am at a loss and not sure what direction to go from hear. And so far prodemand and alldata have been little help outside of the wiring diagrams.

 

[fastpakr]

I am at a total loss on this thing. I have read everything I could find around this subject and tried to add ground to the trigger with, it will start then flood and nothing more. Oh I did also verify the tps and iac as well as the egr.

Does 'tried to add ground to the trigger' mean you grounded the injectors and they immediately flooded the engine? If so, sounds like you've confirmed power to the injectors. Have you done an end to end continuity test of the ground side back to the ECM?

 

[RonD]

Welcome to TRS

Crank sensor starts the ball rolling by sending its Pulse to the ICM(ignition control module) located on front side of intake manifold
ICM then starts the spark timing and SENDS that pulse to the PCM so it can start/time the fuel injectors.

PCM has no direct connection to Crank Sensor, and doesn't even know you are trying to start the engine until it gets that Timing Pulse(PIP) from the ICM

So I would check that wire

Wiring diagram here: https://therangerstation.com/tech_library/EDiagrams/files/Diagram_Ignitionsystem_1989_2_3.JPG

PCM is labeled ECA and Pin 56 is the PIP wire, Dark Blue
Pin 16 is the Ground so also needed for pulse to be "seen"

 

[fastpakr]

Good to know. I never realized the wiring sequence was sensor->ICM->PCM. The PIP wire would make perfect sense in that case.

 

[RonD]

Yes, 1994 and older EEC-IV computers got injector timing from distributor module or ICM(spark module) for distributorless.
Some 1994 and earlier distributorless did have Cam sensor, so would set a code if PIP signal was not there but Cam sensor pulse was
But with no Cam sensor pulse PCM has no idea PIP is missing so can't set a code


Good advice, check that injectors have 12volts with key on, they share a common wire, the red wire, so if it lost 12v connection then no injectors

ICM and coils get 12v from key on, ignition switch

Injectors and PCM get 12v from EEC(PCM) Relay, Brown base relay in engine bay, and in 1989 the EEC Relay may use 30amp fuse OR Fusible link to power these, and it could be blown
So check that injectors have 12volts with key on

 

[tomw]

I was thinking TFI... but don't know the vintage systems. Same dealio.
tom

 

[Zorks77]

Does 'tried to add ground to the trigger' mean you grounded the injectors and they immediately flooded the engine? If so, sounds like you've confirmed power to the injectors. Have you done an end to end continuity test of the ground side back to the ECM?

Yes, I have power to both wires.

Thanks for the info. I am going to check out this wire 56 and see what happens. I will let you guys know if this corrected it.

Thanks guys!

 

[Zorks77]

Welcome to TRS

Crank sensor starts the ball rolling by sending its Pulse to the ICM(ignition control module) located on front side of intake manifold
ICM then starts the spark timing and SENDS that pulse to the PCM so it can start/time the fuel injectors.

PCM has no direct connection to Crank Sensor, and doesn't even know you are trying to start the engine until it gets that Timing Pulse(PIP) from the ICM

So I would check that wire

Wiring diagram here: https://therangerstation.com/tech_library/EDiagrams/files/Diagram_Ignitionsystem_1989_2_3.JPG

PCM is labeled ECA and Pin 56 is the PIP wire, Dark Blue
Pin 16 is the Ground so also needed for pulse to be "seen"

Ok. I have checked pin 56 at PCM to dis and I am getting 1.2 -/+ ohms on that wire. That is at the connectors, not back probed. Would this be more suspect to being on pin 16 for the problem, or should I be almost no resistance on 56 ?

 

[Zorks77]

I have tested pin 16 from PCM to ecc relay and only finding 1.5 ohm of resistance. Not sure at this stage where to go from here.

 

[Zorks77]

Ok. So I have made progress. It's now actually trying to start and getting gas. But that's it. Does anyone know real specs to pressure bleed off on the fuel rail after the fuel pump shuts off after priming the lines. It gets to 45 psi then settles about 38 psi and bleeds off to 7 / 8 psi within 15 seconds. This sounds like a leak to me. I have zero puddles under the truck, and no signs of fuel on the intake.

 

[kishy]

I don't know the exact specs but that's way too fast. It should hold somewhere around 40PSI for quite a while...I would expect to see it hold that for an hour or more in a perfect system with everything in good shape.

Possible leakdown opportunities if there are no leaks you can find outside the truck:
check valve inside the pump
the rubber fuel line inside the tank between the pump and the fuel pump hanger/sending unit
pressure regulator on the fuel rail allowing all pressure to return to tank
pressure regulator on the fuel rail sending the fuel into the vacuum line
one or more injectors not properly closing leaking fuel into cylinders

Since you've had your hands on the pump (89 is a single pump setup with the pump in the tank, right?) then it shouldn't be the fuel line inside the tank, or you'd have noticed it was damaged.

The pressure regulators can go bad but last a really long time usually. It's worth looking at.

 

[Zorks77]

So now I have repaired any open ground wires I had. Pin 20 and 16 we're both open at pin 6 on the icm, it showed zero ground. So I made a temp connection and grounded the icm to the chassis. I am still not getting the injectors to fire unless I ground them out and then I it tries to fire and start but can't since it's flooding. I have cleaned all harness grounds and eca/ PCM grounds as well. I am at a total loss now. If anyone has an idea where to go from here. I could throw a icm at it, but I am not sure that's the cure.

 

[Zorks77]

Ok, the regulator is new. Not to say it couldn't be defective. I will recheck my lines again. Could be an option ring for all I know.

 

[RonD]

The computer gets the injector timing from the TFI Module, the PIP signal
If it doesn't get/see a PIP signal computer doesn't even know "you want to start the engine"
i.e. there is no connection between computer and starter motor

PIP = Profile Ignition Pick-up
Its the pulse from the Hall Effect sensor inside the distributor

Since you know you have Spark then there is a PIP signal at the TFI module, and it should be seen on computers pin 56, a pulsing voltage when engine cranks(distributor turns)
No PIP at pin 56 = no injectors

Pin 36 is the SPOUT(SPark OUT), it is a signal FROM the computer back to the TFI module, it is used to advance or retard spark timing based on Driver input, like throttle position
Engine will run without this wire, it would just be less responsive, you actually disconnect this wire to set base spark timing

EEV-IV pins here: http://www.auto-diagnostics.info/ford_eec_iv

 

[kishy]

With it being a twin plug DIS setup, I'm wondering if there might be some value in following this troubleshooting guide for the ICM: https://easyautodiagnostics.com/ford/2.3L/icm-and-crank-sensor-tests-1

I had to go through this to narrow things down when I had issues doing my swap (which turned out to be cam timing, but the info is helpful regardless).

Specifically, there are tests (8 and 9, on pages 5 and 6) which reveal if the crank sensor is outputting the two distinct signals it provides.

As the crank sensor is providing two signals, it may be possible to still have spark but not have fuel if there is a crank sensor issue.