Ford Repair Questions? Ask a Mechanic for Answers ASAP
One last thing to check is to make sure you have battery voltage at the PCM on Pins #37 and #57 at the PCM with key on.
With everything you have checked and verified its still pointing to a bad PCM.
Glad to be of help. OHM check each and every fuel injector. From your description, you have a shorted injector. A shorted injector will cause your PCM to shut down injector pulse to protect itself. Also check your PIP & TFI module connections. See video: http://www.youtube.com/watch?v=_g8PdrT0MCU
Injector specs: Injector Resistance Specifications
That's what it sounds like to me. Let me know what you find out. Don't forget to check your connections at distributor. See these forum links:
Did you ohm the injectors themself? Did you watch the video?
What were the readings?
Checking at injector connector does not rule out a shorted injector. You need to ohm the injector, not the connector. All readings must be within 2 ohms of one another and be within specs. Let me know your readings.
Here's a link to test your TFI circuit: http://easyautodiagnostics.com/ford_ignition_module/distributor_mounted_module_1.php
Follow the instructions at this link:
There may be a wiring problem or bad connection so you need to check continuity and check coil pick-up. This is what gives the injector pulse signal to computer.
Ok, I'm going to ask again, what are the ohm readings of your injectors? Did you ohm the injectors themself with connector removed as in video?
Typically the injectors will be 12-14 ohms.
The specs for your vehicle are:
Before we do that check your TPS sensor.
If TPS voltage exceeds 3.7 volts with the throttle closed, This will shut off the injectors, since the computer uses this strategy to clear a flooded engine. Use a DVM, a pair of safety pins, and probe the black/white and green wires to measure the TPS voltage.
If this checks out it may be a problem with PIP sensor or connections.
The PIP is a Hall Effect magnetic sensor that triggers the TFI and injectors. There is a shutter wheel alternately covers and uncovers a fixed magnet as it rotates. The change in the magnetic field triggers the sensor. A failing PIP sensor will often set code 14 in the computer. They are often heat sensitive, increasing the failure rate as the temperature increases.
Spark with the SPOUT out, but not with the SPOUT in suggests a PIP problem. The PIP signal level needs to be above 6.5 volts to trigger the computer, but only needs to be 5.75 volts to trigger the TFI module. Hence with a weak PIP signal, you could get spark but no injector pulse. You will need an oscilloscope or graphing DVM to measure the output voltage since it is not a straight DC voltage.
See http://www.wellsmfgcorp.com/pdf/counterp_v8_i2_2004.pdf and http://www.wellsmfgcorp.com/pdf/counterp_v8_i3_2004.pdf for verification of this little detail from Wells, a manufacturer of TFI modules and ignition system products.
Here's a TFI wiring diagram:
Make sure you have the correct TFI module.
Here are the comparisons:
Ok, let me know. Here's an excellent forum link with a lot of information:
There is probably a relay somewhere in the system that has failed. Get your manuals out and start tracing wires until you locate them in the drawings. I feel like its a relay going to the computer, mainly the ECC main relay (EFI relay). Check the EEC and fuel pump relays mounted inside the pass side kick panel for activation. Locate the fuel pump relay (for 86-90 Mustangs, its location is under the driver seat). Check the 12V trigger wire to the EEC relay from the ignition switch. Also check the fusible links at the starter solenoid on the d/s inner fender. When you find the one component thatis not sending the power through as it should, there is your problem.Start tracing the systems and check for voltage at all of the proper places leading to the ignition and fuel controls. recheck for injectors pulse....if test light doesn't blink = test the injector pulse signal wire for continuity between the injector connector to the ECM connector. The resistance reading should be less/equal to 5 ohms? OK = ECM is kaput, needs to be replaced? NOK = trace and repair wiring harness.
See this Forum link
Relay wiring diagram
ECC relay location
Test the injector pulse signal wire for continuity between the injector connector to the ECM connector. The resistance reading should be less/equal to 5 ohms? OK = ECM is kaput and needs to be replaced? Not OK = trace and repair wiring harness. The TFI module sends the signal to the computer. If you are getting the signal from TFI module, the problem is either in the wiring harness or computer. If you are not getting the signal from TFI module, the problem is either PIP sensor or TFI module.
When the engine is being to be turned by the starter (~200 RPM or less), the PCM has no idea where the crank is in its rotation and must wait to get a signal from the distributor before it can synchronize the fuel delivery to the crank position. During that very short time, it fires all injectors together.When you turn the distributor manually, you are simulating this pre-sync "CrankMode" condition and they will all fire together. If all fire together when the engine is actually running, then it is in limp mode.
Chase the codes, check your harness grounds. Verify your computer code matches the engine. The PCM is not getting an important input that it needs. More likesomething isn't plugged in or the wiring harness has become damaged.
There are only four possibilities. The PIP sensor is bad, The TFI module is bad, The computer is bad or there is an open or short in wiring harness. I'm going to take an educated guess and say your TFI module is defective since you swear all connections are good and you have tried a known good distributor and replaced the computer three times. Keep in mind a bad coil can damage a TFI module.
Did you verify you have power to ICM at #3 and verify you have on-off pulse at ICM #2 and pulse at IDM pin 4 at computer & have ground at ICM #1? See diagram:
I learned one thing, you can't assume anything, it needs to be physically checked and check PIP & computer grounds. Check ignition switch to make sure there is power to coil+ in run & crank position. Power goes through starter relay in crank position.