Hi everyone,

I bought a 1990 F150 2wd with a 4.9L straight 6.

This truck was bought new in 1990, the owner died in 1995, and it sat next to their house for 20 years. Ran great when last parked. 70k orig miles.

I pulled it home, and my first goal was to get spark out of the motor. I have power going TO the coil, but no spark out of it.

I just replaced the coil, but still no spark.

Any ideas?

Thank you!

Joe

 

Perhaps cap, rotor, and wires?

 

I'm getting no spark coming from the coil . . . which is before the cap/rotor.

 

I would suspect the ignition module mounted on the bottom of the distributor, it's very common for that to go dead. And just to clarify, if the ignition module goes dead you will get no fire from the coil.

 

I just replaced the ignition module and still no spark.

I am wondering if it is the ECM. Since it sat for 21 years, can these things corrode and go bad?

Is it possible to test the ECM?

Thanks everyone.

Joe

 

I bought an 87 f150 , 4.9... sat since 1993, i got it , had no spark.

one of the issues was, there was no power going to eec relay, therefore no power to ecm or fuel pumps. i ran a hot wire to the eec relay and put in a inline fuse, because the original wire was fried. that solved the problem.

I pulled the ecm plug, i think its pin 1 , red wire, turned the key on, put a test light probe in the pin hole, grounded the clamp and no light. ran the new wire to ecm, the light came on . hooked everything up, and it started.

 

Just unplug the ECM and see if spark returns.
If spark returns then either the ECM is bad or you have bad grounds (pins 40 & 60) or no power the ECM (pins 1, 37 & 57).

If spark does not return with the ECM unplugged and you have power at the two small wires at the coil with the key on check the wiring between the coil and the ICM. If wiring is OK and the CEL does not go out while the engine is cranking change out the distributor if the distributor is turning while the engine cranks.



/

 

Sounds like you had bad wiring at the starter solenoid or bad wiring under the sockets of the two relays.

 

Quick update:

If the SPOUT connector is unplugged, it has spark.

When I plug it back in it has no spark.

Fuel pump relay and EEC relay only have 5 volts on the winding side. If I unplug the ECM, it goes up to 10 volts . . .

Any ideas? Thank you all so much for any help you can provide,

Joe

 

So it is the ECM keeping you from having spark but sounds like it may not be the ECM itself.

Not sure what you mean by winding side of the relays.
Both relays have a wire to ground from the coil of the relay and a power wire to the coil.



/

 

CHECK OUT THIS SITE:
http://easyautodiagnostics.com/ford/main-index

one of the better posts

 

Thanks, guys,

The diagnostic site is awesome, but I am still stumped by my no-spark problem.

Here is an update:

Cranks but no spark.

replaced the ignition coil
replaced the ignition control module
replaced the ECM computer (new from Rock Auto)

Still no spark

BUT when I remove the SPOUT connector, it sparks great.

Is there something that I need to check BEFORE the ECM? I'm so confused by this . . .

Any help would be greatly appreciated.

Joe

 

. . . also I am still getting 5 volts to the fuel pumps . . . not sure why that is . . .

 

Sounds like the wire (circuit 324) from the SPOUT aka timing test lead shorting bar (jumper) to the ECM is shorted to ground.

That is normal after one second with the key in the ON position.
If it does not go to battery power for the one second then the fuel pump relay or the power relay is not working (closing) and they may have bad wiring under their sockets or no power on their yellow wires.

 

DId you figure it out? If not, check out the thread i posted sounds llike our trucks literally had the exact same problem and they are the exact same truck except mine is 4x4