1990 f150 won’t start.

I heard of a guy who is super down on his luck (his son was hit by a car, nearly killed and now on life-support. He lost his job spending time with his son and then got evicted) and I offered to help him when I heard that his truck broke down on him.  

1990 F150 4.9 straight 6

it's hard to know exactly what happened but apparently it died on the freeway (he wasn't sure if it was sudden or sputtered) and he threw a bunch of parts at it with no luck.   
 

he thought it was fuel and replaced the in-tank pump but still nothing. 
 

I swapped out the starter solenoid that was bad so now it's cranking but nothing with starting fluid. Hooked up a spare spark plug and not seeing spark.  Put the plug on the coil lead and nothing. 
 

I have 11.3v at the coil plug's power (battery is at 11.6 and on a charger). 
 

I'm not familiar with these ignition systems and I'm hoping someone can tell me what to check and where to check it. Does the spout need to be plugged in or out? Is there a way to test the ECM? I understand there's a relay that powers, the fuel pump and part of the ignition system, and it can go bad, but I don't know if it's true or where that's at.
 

Any help or direction would be greatly appreciated!

See that module screwed to the side of the distributor with an aftermarket label on it?  If you have no spark, start there.

Not sure on the plugs.  Let me look at mine when I get home.

The fuel pump on these is LOUD.  If you turn the key and don't hear it priming there is something wrong.

Good points.   
 

he said there was just a dribble out of the fuel rail so I suspect fuel as well, especially because I don't hear a fuel pump fire on. 
 

but with this apparent no-spark issue I'm just hoping there aren't problems on top of problems.  It's kind of what happens when there is a problem and then someone starts replacing random stuff.  And now I don't know if the ignition stuff he touched was either a. bad or b. installed correctly. 
 

can someone confirm that the fuel pump relay is the green relay in that pile of wires?  I figured I'd start checking to see if it's getting power through it. 
 

lastly, for now, I read there is a relay or a common power for something with fuel and spark which could explain the possible lack of spark and fuel pump powering up.   Can anyone confirm??

There's a fuel pump safety switch in those that can trip. Might need to reset it. Google will tell you the location. 

Aftermarket pumps for the 4.9 seem to fail easy. I changed two in three months on the wife's truck when she had it 

They're the same pump as the 5.0 but the system runs higher pressure on the 4.9 and I think it's hard on non-Ford pumps.

Good luck.

Change the fuel filter too.

The fuse links on this gen F series are known to go bad with age. The one went on my 90 F250 and killed it in the middle of the road. It had been giving intermittent issues before dying outright. I bought rolls of the link material and just did all of them. They're located on the front passenger side

 If it's any help I have the 90 service manual pdf I downloaded from somewhere I can email you 

this is what they looked like on my 250, in case you weren't familiar (I wasn't prior to this)

Great info.  I'll dig into that as well.  
 

the manual can't hurt....  my email is my username at yarhoo

thanks!

Streetwiseguy said:

See that module screwed to the side of the distributor with an aftermarket label on it?  If you have no spark, start there.

This is also where I would start. 

Figured I'd keep you guys posted real time. I'm testing the fuel pump relay right now because I'm not convinced that no spark and no fuel pump somehow aren't related.

So I have constant 12 V power coming to the relay that the ECM is supposed to trigger. I bypassed the relay and the pump still doesn't come on. I checked, and I'm getting power through the inertia switch. But I'm not getting any power from the ECM when I turn the key on. So right now it seems like not only is the ECM not powering the relay but the pump isn't working either. 

jfryjfry said:

Figured I'd keep you guys posted real time. I'm testing the fuel pump relay right now because I'm not convinced that no spark and no fuel pump somehow aren't related.

 

So I have constant 12 V power coming to the relay that the ECM is supposed to trigger. I bypassed the relay and the pump still doesn't come on. I checked, and I'm getting power through the inertia switch. But I'm not getting any power from the ECM when I turn the key on. So right now it seems like not only is the ECM not powering the relay but the pump isn't working either. 

It's been a while and I don't have a schematic in front of me but my recollection is that there should be power on two terminals of the relay and that the ECM pulls the control side of the relay to ground to energize. 

So this thing has two tanks, which apparently each have a fuel pump in the each tank. I've messed around with the fuel pump relay and different pumps but nothing. 
 

update:

after hearing that the eec relay controls things like spark and fuel pumps, I tested it and it seemed bad.   So I swapped in the fuel pump relay and jumpered where the fuel pump relay used to be and voila! We have a fuel pump making noise. 
 

I switched tanks and didn't hear anything so maybe that pump is bad, but replacing the eec relay seems to have got me somewhere - I now potentially have fuel pumping. 

it looks like we have very weak spark out of the coil but nothing out of the plug wires.   Put a spare plug in the coil lead and super weak spark.  Pulled a wire off of a plug and put it on the spare plug and nothing.  
 

would a bad/faulty module cause a super weak spark?   Or a bad coil??

In reply to jfryjfry :

I could see it going either way.  I'd probably lean towards the module first, though.  You can always test with pretty much any TFI type coil

In reply to jfryjfry :

I think it sent but mailing from. Phone is hit or miss.

let me know if you don't see it

Weak spark implies that you have spark control, and an almost dead coil.

Sounds good.  I'll get a few parts but start with the coil. 
 

my forensic mind is trying to figure it out though.  So far I've replaced a bad brand new starter solenoid  and found a bad eec relay. 
 

I think the eec relay took a dump and left him stranded   Then, while he was trying to fix it, unnecessarily replaced the starter solenoid, fuel pump, cap, rotor, plug wires   
 

the new solenoid ended up breaking immediately and when I put the old one (also a fairly recent one) back on it was fine   

Since we know there aren't many coincidences, I have a hard time believing that the ignition has died at the same time the eec relay died.  Possible that he messed something up when swapping the ignition stuff around??  
 

and thanks for the links.  I haven't seen them but will keep looking!

Streetwiseguy said:

Weak spark implies that you have spark control, and an almost dead coil.

Depending on the exact failure mode... eh.

The TFI module on those had a class action lawsuit on them for leaving drivers stranded on the side of the road and are a known weak link.  The TFI coil, on the other hand, I've never seen one go bad that hasn't had the wiring messed with to change it away from stock.

Main reasons I suggested starting with the module.

I know it's a common refrain, but is there a failing ground somewhere causing a bunch of power to get pulled through components that don't like that?  I agree there is likely a connection between all the issues happening at once.  

In reply to GhiaMonster :

Good thought.  It's not rusty at all (socal) but I wouldn't be surprised if this was the case.  
 

I'll do this when I check the fusible links.  
 

I'll be getting the parts to try out later today and report back

jfryjfry said:

In reply to GhiaMonster :

Good thought.  It's not rusty at all (socal) but I wouldn't be surprised if this was the case.  
 

Rust is possible near the coast. Could also be a loose ground from prior owner.

In reply to L5wolvesf :

Very good points.  
I'll be checking in a few. 
 

just returned from Autozone with $100 worth of coils modules and relays. (1 each!)

I'll report back soon

In reply to jfryjfry :

From the first post I've been meaning to tell you you're a good man for taking on this task/challenge! 

Haha thanks!  I just want it fixed for the guy.  
 

I know the problem is simple but I can't find it. 
 

so I know that the quality of Autozone stuff is questionable....   but I put the new coil on and no start

new module and no start

my buddy is gone so I don't know if it is sparking any differently than before (weak off of the coil only). 
 

ughhhhh

the good news is the new relay works so that's done

Mr_Asa said:

Streetwiseguy said:

Weak spark implies that you have spark control, and an almost dead coil.

Depending on the exact failure mode... eh.

The TFI module on those had a class action lawsuit on them for leaving drivers stranded on the side of the road and are a known weak link.  The TFI coil, on the other hand, I've never seen one go bad that hasn't had the wiring messed with to change it away from stock.

Main reasons I suggested starting with the module.

I've sold a great many TFI modules myself.  I may have never tested one carefully enough to notice if it wasn't completely dead, but it was in my first reply as well.

I am getting full voltage through the fusible links.  
 

I ran jumper cables from the negative post to the block and to the body. No change. 
 

i'm not convinced that my buddy really saw weak spark off of the coil and now we aren't seeing any spark. 

while the fuel pump is working and I have pressure at the rail, ether makes no difference   And I am not sure if the injectors are even firing 

I feel like im at a point where I need some specific things to start checking for voltage or continuity. 
 

I'll start digging through stuff online but if anyone is familiar with these computers and ignition I'd love some specific things to check. 
 

(eg power at places for the computer, for the spout, etc)