hello guys, i have been reading the forums here for a while now, and unfortunately, have a bit of a problem with my old truck, and im hopeing that someone here has a bit more insite into it.

it is a 89 F150 4.9L, M5od, 4x4. it died on me the other day ( no spark). i replaced the PIP, and the TFI module, and still no spark. if i pull the spout, i get spark, but pcm will not fire the injectors. the wires from the TFI to the PCM ohm out good, i have good voltage on PCM pins 37, and 57. grounds are solid on pins 40, 60, and case. all fuses and fuse links are good. eec and fuel pump relays are operating normal. 55 psi fuel pressure at the rail KOEO. no codes in the pcm. if i leave the spout out i can get the engine to run on propane throught the intake, but there is no activity on the noid light at the injector.
my instincts tell me that it is probably gonna be a bad tfi module, even tho it is new, but i would like to hear if there is something that i am missing or should check.

thanks in advance.

 

Why did you replace those parts? Did they test bad? Do you have a Haynes manual? It contains an EXCELLENT ignition diagnostic procedure which, if you follow exactly what it says, will positively ID any ignition faults.

No matter what, I always recommend trashing the original relays & upgrading to the later Bosch/ISO style, as described in this caption & the NEXT few:

 

Sounds like you have a bad EEC Computer to me.

 

yep. i managed to get ahold of the pc-ed for my truck and ran through the pinpoint tests. all of them lead to a bad pcm. now just need to track one down.

 

Most parts stores can either order you a reman or send yours out for $90-150. Junkyards should have plenty, but you'll have to actually dig thru the trucks to find the right one - they probably won't be able to tell you over the phone. Ford used to offer them for $250, but I haven't checked in several years.