1990 f150 won’t start.

I'd pull the cap and make sure the rotor is actually in there. Because I've left them on the fender before.

Can you get an analyzer on it have the truck tell you what it's unhappy about?

An off-the-wall question comes to mind... could this be a security thing, like maybe it doesn't like the ignition key ID? On a related note, does this model have the resister "pellet" in the ignition key? With the ECU running basically everything, including spark and fuel, it makes me wonder.

Pulled cap and rotor is there!  It's all new stuff 

no spark from the coil to a plug. 
 

I've looked and asked and there is no security system nor any kill switch.  The key is basic, no resistor.  It's a barebones stick shift manual windows 90 f150. 
 

it is obd1 so maybe it could show a code but the cel goes out when I start cranking

These won't start with a weak battery even on the 200amp start setting on the jumper. I'd try a new battery. 

It's got a recent battery and cranks solid.  We did add a jump pack to it since we were seeing 8v at the coil when cranking but no change. 
 

I suppose it could still be the battery but nothing about it says bad battery.  But I'll swap in a known good battery for fun and report back

In reply to jfryjfry :

It has a CEL, though? I don't know the dance, but I know I've seen it on YouTube to get the codes flashed out. Amazon has Ford OBD1 tools in the thirty-something dollar range if that seems worthwhile.

EDIT: I don't know if this is an especially good video, but wanted to provide an example.

It has a light but it lights up when the key is turned on and goes out when you start cranking, like they do when everything is ok.  
 

so I don't think there are any codes

TFI module has been suggested several times.  The module screwed to the side of the distributor.

I wish i could help, but this is before my time in terms of hardware.  That and all of the directions are the ones I would guess, too.

But I have an OBDI beeper I made my first week of work- for free.  Or use a paperclip and just read the light flashes.  Just don't spend $30 on something you can do for free.

In reply to Streetwiseguy :

I replaced it with no change already. 
 

granted, it's with an Autozone unit so I can't say it works.  I'm going to try and test it somehow today. 
 

I also replaced the coil with an Autozone unit and same thoughts  

i am taking everyone's suggestions to heart, I promise.  
 

So you checked the fuses and whatnot- did you check the voltage at the coil?  Maybe there's a break somewhere to there?

Checked fuses and all seem good. 
 

I found a trouble shooting guide and it indicates that the pip sensor in the distributor is good but that the module is bad. This is the new AZ one. 
 

I went and got another, same thing. 
 

I doubt I have three bad modules, two being brand new.  But they are failing the test. 
 

I can only think that the computer must be bad. 
 

also of note is that the fuel pump continuously runs and supposedly it should prime for a few seconds and shut off. 
also the check engine light stays on while cranking which I was told could be another sign of  a bad computer. 
 

the computer is an AZ rebuilt one that is about 1.5 years old.  
 

Have you confirmed the computer is getting power? 

I also just put an LED test light on one of the injectors, and both wires just light it up solid. It's not flashing. I assume this is a legitimate test to see if the injectors are being pulsed and if so, it means they're not which is another sign that maybe it's the computer

In reply to rslifkin :

Sorry, missed your comment!

I have not.  I assume it is but perhaps it isn't!  I will check 

I hope the truck is running by now, but if not...

If the fuel pump is running and the injector LED test is just list up, is it flooding? I guess I mean that as a sanity check on the LED test, given that it doesn't sound like it's been hosing the engine down with fuel... I think injectors also fall into that list of stuff that's often fed constant 12V and actuated by switched ground if that changes the analysis of the LED test light. I suppose that's down to how the light was arranged.

Also, while I think at this point you've established that you have a new, working EEC relay installed, I found this diagnostic series that seems to provide quite a bit of detail on testing everything around it and they have some other writeups which may be applicable to this truck.

Sounds like the computer is not seeing engine rotation. That could be a number of things, in functional order: distributor pickup (coil), TFI module, wiring, computer.

Does it even have CKP or CMP?

Nockenwelle said:

Does it even have CKP or CMP?

LOL. No.
Closest is the hall effect sensor in the distributor.

I had used the write up that Jesse linked and it looks like the pip sensor (the Hall effect sensor) is working.  
 

I believe it is the computer. 
 

anorher guy wanted to work on it and it was blocking my driveway for a few days (I figured I'd have it up in a day) so I let him take it.  He is concluding that it's the computer as well and I believe is going to replace it. 
 

I'll keep y'all posted

jfryjfry said:

I also just put an LED test light on one of the injectors, and both wires just light it up solid. It's not flashing. I assume this is a legitimate test to see if the injectors are being pulsed and if so, it means they're not which is another sign that maybe it's the computer

One thing I found while troubleshooting my engine a while back was that if you plugged in the distributor while it was out of the engine (i had a spare) and spun it you could hear the injectors clicking open and closed.

I'm not sure of the electronic circuit that tells the fuel pump to build pressure, but I have had a bad fuel pressure regulator kill the engine and keep the pump trying to prime. 

Just a few small things that you might want to check before dropping money on a computer, but I agree with the troubleshooting up till now.

This video might help. https://www.youtube.com/watch?v=llYFDC5-sa0&t=628s

Those computers are known for developing leaking capacitors on the circuit board. When they leak, they can damage the board. I had new ones soldered into the board on my Lightning before it developed a problem.

Based on all of the troubleshooting, it sounds like the EEC might be dead. It could also be a bad pin, bent or pushed back in the connector to the computer

The truck runs!

a new (Autozone I believe) computer was indeed the solution.  
 

it kind of sucks to put all that work into it, diagnose it (albeit with only mild confidence) but not have the satisfaction of hearing it fire up. 
 

im still not sure how it had both a bad eec relay AND a bad computer, nor am I sure why we didn't see spark when I pulled the spout plug (I read several places that it won't let the motor run but will show spark if the computer is bad). 
 

but now he gets his truck back.  And there's some bad weather right now so it will be good to get him off of the motorcycle. 

 

A huge thanks to the generous soul who contributed money to him through this thread.  It makes me very happy that I found this community. 

Well sounds like it's not running again. 
 

this is what he said:

I don’t know what’s wrong with the truck, the battery is full but I’m getting no power, not even when I cross the wires at the solenoid. I’ve not done anything else except put a multimeter to the bm battery and the ground and alternator and solenoid. You know me and mechanics have little place together when it comes to diagnostics. It was running great though, I stopped at tge super market and got back in it and it won’t start. The fuses are good. The dome light is off. The horn and lights don’t have power either

Me:

That should be a pretty easy check….   The battery has 12.6.  That’s good.  When you have the black of the meter on the battery ground and you touch the large solenoid post that has all the wires on it, it should also read 12.6 because that large cable goes straight from the battery positive to the solenoid. 

The other large post on the solenoid should only have power when you’re trying to start it. 

That’s very strange that it has power.  And stranger that the one with the wires only has 8.something volts and the other has full voltage.  

Check the cables from the battery to make sure they are in good shape and tight.  Check from the battery to the solenoid (positive) and the battery to where it bolts to the frame/body/engine (negative)
 

Jumping the two terminals of the starter solenoid is what would force the starter to turn over.  

That tells me something is wrong with the starter.   It’s new so it should be under warranty.  I’d pull it out and replace it. (Disconnect the battery first)
 

Is someone turning the key to start it in the picture that shows voltage when you have the meter on the negative and the solenoid post with only one wire/cable?

him:

The key was turned to the on position when the voltage was low, and turned to the off position when it was higher. What do you think would happen if I tried to clutch start it while rolling? I’m on a slight decline that might get me up to enough speed to pop it in second gear before I run out of runway. But then I’ll be in the sun if it doesn’t work. Right now I’m under a tree, which is nice since the Loma Linda sun is pretty rough

these are the pics he sent: