1987 - 1996 F150 & Larger F-Series Trucks1987 - 1996 Ford F-150, F-250, F-350 and larger pickups - including the 1997 heavy-duty F250/F350+ trucks
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Last year I started building a new trail truck. 95 Extented Cab short box 2wd 300 E4od. I changed all the drive train and swapped the motor for an 89 460 out of an F-superduty.
I have the computer, ignition module and distributor from the donor 89. I also bought a factory 460 engine harness, computer and module from a 96 F-250 at the junk yard.
I have the truck assembled and it will not start. The truck cranks, has 36-40 psi during the initial key turn, and has spark. I had tested the injectors with a noid light and they are not getting a signal.
I am kinda lost besides tracing all the wiring. Is there a good source out there for factory manuals for this era truck? Or a good source online?
Haynes usually has pretty good wiring diagrams. If you can get a hold of a Ford EVTM (Electronic and Vacuum Troubleshooting Manual) that would be your best bet. If you can find out which pins on the PCM(s) control the injectors, you can backprobe the circuits at the PCM for injector signal to determine whether you have a wiring problem or a module problem.
The fuel injector pulses are sent by the PCM. The main input to create that signal is the PIP, aka stator in the distributor. I have seen a few cases where the PIP sent out enough signal to trigger the coil but not enough to trigger the PCM to fire off the injectors.
There is also a feature built into the PCM to not fire the injectors during cranking if the throttle position is wide open. The TPS is the feedback sensor. If the TPS output voltage is pegged near VREF the injectors will not fire.
Have you tried checking for codes? Many times there can be an issue without having a Check Engine Light on.
This site, Ford Fuel Injection , has tons of info as well as some EVTM info you can view/download.
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Randy A | Central Illinois
Just another thought, is the pcm getting an rpm signal? You may have a bad cam or crank sensor.
I believe the PIP is responsible for that signal in his setup. Hell, I'd throw a distributor at it just because the PIP sensor was at fault in my 460 swap. The truck started and ran, but it had NO power at all. Swapped the distributor with a used unit and had power galore.
I did overlook asking if you have supply voltage to the injectors? If the supply was missing there would be no way to trigger the noid or the injectors even if the PCM was pulsing the injectors to ground.
The 1989 Ignition is in the Ryan link above and here is the 1996 Ignition system below.
I would like to know what systems you are using, you said you have the whole 1989 and 1996 wiring and computers but I did not see what you installed on the 1995 truck.
What distributor did you use?
What color is the ICM you used?
What Computer (PCM) did you use?
What wiring harness did you use?
Is any of the wiring from the 1995 truck?
What size engine was in the 1995 truck before you started?
Have you check continuity from the ICM PIP pin to the PIP pin at the PCM plug?
If so what PCM pin number did you use?
The 96 & 89 PCM PIP pin is #56.
Thanks everyone, I am going to try to do more checking on it today. I have a haynes manual, but was looking for something more in depth.
The 89 motor rand before I pulled it from the truck. ( I drove it. ) Right now I am using the factory 95 wiring harness connected to the 96 460 engine harness with the 89 Distributor. I have the 89 PCM & ICM, along with the 96 PCM & ICM. I have tried different combinations of both. The 89 ICM is Gray and the 96 is Black. What is the difference between them? Does the PCM ever control the ignition? I think the computers should be basically the same, I think, except for the 96 being an E4OD and the 89 being a ZF.
I have a test light and a Multimeter to test the circuits with. Do I need anything else?
96 engine harness is from a SEFI not a mass Air truck.
The 96 harness attached to the 95 harness at the square plug by the underhood fuse box. the 89 Distributor pluged directly into the 96 harness. (same plug) According to different online parts stores, all 460 EFI distributors should be the same.
I have tried using the 96 PCM & ICM together and then the 89 PCM & ICM together. The 96 parts came from a truck at the junk yard.
I have tried using both of the 460 computers at different times. From what I have found, they look like they are pinned the same. Except the 96 computer also has the ability to run a E4OD which I am not using.
From about 1993 1/2 Ford Trucks and newer Computers need the Black ICM. Most diagrams show 1994 and newer.
It all depends if you have a start wire running from the starter solenoid to the Gray ICM or not.
All 1994 and newer trucks and maybe 1993 1/2 do not have the start wire.
The IDM (Ignition Diagnostic Monitor) is the way the computer checks on the Ignition system. The 1993 and older trucks got the IDM from the Ignition Coil through a resister and the 1994 trucks and newer get the IDM from the Black ICM.
Your problem is either you do not have a complete path from the PIP or the TPS to the Computer. If the TPS pin at the computer is around 4.5 VDC to 5 VDC the injectors will not fire. As you know the injectors will not fire either if the PIP signal is missing also.
It sounds like you may have already ohmed out the PIP wire from the ICM or PIP sensor to the computer. You will also have to check the voltage at the TPS pin on the computer also.
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