Good morning-

I should probably state that I'm a noob when it comes to cars/trucks/automotive, but have people available who can translate most stuff for me so it's all good. Bought my lightly used '93 f150 last december, not a single problem up until now. 3 days ago I go outside to start the truck, and the starter engages but the engine won't catch. It was suggested from other sites that I remove the distributor cap and reseat it and examine the plugs and so on. That was tested and appeared to be ok; also checked the cable from the coil to the distributor, but haven't been able to rule that out... All I know is that there's spark coming from the coil. I've tried tripping the fuel switch by the brake pedal, and that made no difference. Also the check engine light is not on, which rules out some things... Also when im cranking the starter the engine sometimes sounds like its going to engage but then doesn't.

Basically, at this point, I have no idea whether its an electical problem or a fuel problem, there's evidence to suggest its both or neither.

There are a few ideas that have been suggested that i don't know how to pursue- checking the fuel pressure (No idea where the cap is for it) and possible using ether to see if that'd help start the engine (Don't know the best place to spray it).

ANY help that you could offer would be GREATLY appreciated! the people at the ford store have been most unhelpful. "Well, it might be a problem". "Oh, I suppose it could be a fuel problem." "Oh, yea... that could be it too, I suppose."

One other note to add: the day I went out to start it, there was alot of moisture and rain. This is the first rain we've had and all the snow has melted. I thought it could be a moisture problem, since the only time the vehicle has not started properly is when it got moist/rainy/humid out that day. It's still moist/rainy/humid out, and the truck won't start. I did try spraying WD40 on the distributor cap and cables, but it made no difference.

 

do you hear the fuel pump come on briefly when you first turn the switch to on? You might have spark coming out of the coil, but do you have it coming from the distributor to the plugs/

 

An update- Just finished the latest round of diagnostics on the truck. I checked the fuel line and there is fuel running through it- there is noticeable pressure. Also tried removing the air intake tube and sprayed some ether in there, no effect. Also there is spark going to the spark plugs (Pulled 2 out and tested them for spark). They have spark- but there is no fuel in the spark plug cylinder, it's bone dry. From my understanding, this narrows down the problem to fuel injectors or something between that and the fuel gauge. Is a correct deduction, and what else could be going wrong with it to keep it from getting gas to the plugs? Thanks again in advance!

 

Your deduction about it not getting fuel would sound correct, but when you sprayed ether in it it should have ran for a second or two or atleast got a pop out of it.

 

If a car or truck or any engine at that matter doesnt turn over its one of these things, no spark, no fuel, or no air or compression. now you said the truck was fine and it just stopped working. what did you do the last time you used the truck? did it make any strange sounds? Did it drive different? loss of power? did this ever happen before? any warning signs or anything some more detail might help me diagnose the truck since im not physically there to see it and test it. First make sure your air filter is clean and not pluged. Then check your vacuum diagram on your hood and make sure all your vacuum lines are connected and not leaking. Then if all that is good check all your spark plugs for proper gap and list the color of the tip and if there is any damage on the porcelin part. then you can get an ohm meter and test the injector for resistance and see if it is within specs. (i will list specs tomorrow). if you just turn the key on and hear a buzzing your fuel pump is working and if all these things pass you will need to do a compression test and check the fuel filter. of course dont get me on these order i just typed it up fast before bed. you can do it in any order from easiest to hardest.

 

if there IS spark and turns over freely and doesnt sound any different doing so then the ether SHOULD make it run for a few seconds its getting spark and fuel you must have just not sprayed enough, now that i think about it did you open the butterfly valves on the throttle body when you sprayed the ether in there? it has to be at WOT to get the ether past the throttle body and into the intake plenum then in to the engine when it cranks over and sucks it in..

 

Last time I used the truck it ran completely normal. Nothing was different about my last trip that any of the trips I've made with it before. The only strange sound, though probably unrelated, was the belt making a squeaking sound. I applied some belt dressing and the problem went away. The truck started several times after that with no problem. It did drive different in that when I came off the interstate one or both of the left wheels were making a clicking noise when I wasn't breaking or accelerating and coasting at a slow speed (20 MPH or lower), however this problem has occured since I got the truck and goes away after the truck sits for an hour or two (That's a problem for a different post). There has never been any loss of power in the truck. I've never had any problems starting the truck before. No warning signs or buzzers or anything like that have popped up since this occurred or ever before for that matter. I have two gas tanks and have tried using both when I try to start it; yes, when I turn the key I can hear the fuel pumps working the same as they did before this started. Thanks alot for the rest of the tests, I'll get started on them this afternoon.

 

Does the selected fuel pump run for one second and then stop when you turn on the key or does it run all the time the key is on?

 

Take it to a reputable shop and have them diagnose it.

 

if you have done all the test i stated before here is also something that may be the problem take your digital meter and turn it to a continuity mode then locate your fuse box and touch each lead to the metal part of each fuse it should beep. if you dont hear the beep change out all the bad fuses. if that is all good without trying to start the engine turn your meter to dc voltage and check directly on the battery. you should have no less then 10.8 volts i know other people will tell you 9.2+ is ok but 10.8 is recommended. if it is less charge the battery. send me your email and i will send you step by step instructions to check anything you want on your truck free of charge. its too big to list here. i will copy and paste my factory manual for the sections you need and email it to you. hope you already figured it out. i'm in phoenix,az if you are in the area i can probably stop by and help.

 

Drain Testing
Check for current drains on the battery in excess of 50 milliamps with all the electrical accessories off and the vehicle at rest. Current drains can be tested with the following procedure:
WARNING:
DO NOT ATTEMPT THIS TEST ON A LEAD-ACID BATTERY THAT HAS RECENTLY BEEN RECHARGED.
CAUTION:
Do not crank the engine or operate accessories that draw more than 10A. You could blow the fuse in the meter.
NOTE:
Many computers draw 10 mA or more, continuously.
NOTE:
Use an in-line ammeter between the battery positive or negative post and its respective cable.
1. Insert the test leads in the input terminals.
2. Turn switch to mA/A dc.
3. Disconnect battery terminal and touch probes.
4. Isolate circuit causing current drain by pulling out one fuse after another while reading the display.
5. Current reading will drop when the fuse on the bad circuit is pulled.
6. Reinstall fuse and test components (including connectors) of that circuit to find defective component(s).
*Normal Engine Vacuum at Idle ³ -51 to -74 kPa (15-22 in-Hg)

FUEL PRESSURE SPECIFICATIONS
Engine Condition 4.9L 5.0L 5.8L 7.3L Engine Running 45-60 psi 30-45 psi 30-45 psi 41-55 psi 30-45 psi
310-415 kPa 210-310 kPa 210-310 kPa 283-379 kPa 210-310 kPa
Key ON Engine OFF 50-60 psi 35-45 psi 35-45 psi 35-45 psi 345-415 kPa 240-310 kPa 240-310 kPa 240-310 kPa.. sorry this didnt line up right email would be best.

 

Thanks for the offer of instructions- I'm working on tips and hunches from 10 or so people that think the ignition module is something that often goes... 3 ford garages have confirmed that it is indeed the most likely possibility at the moment. Though I'm not entirely convinced of their opinions, a local garage has offered to test the old switch and to let me test a new one in the truck free of charge. If you have instructions relating to the location and removal of the ignition module they would be most helpful. Thanks in advance!

 

It is very unlikely it is the ignition control module but it is possible. The remote located Ignition Control Module very seldom goes out like they did when they were mounted on the distributor.
You also say you have spark that makes this unlikely also.
I did not want to say this yet but it sounds more like a bad PCM Computer.


But can you answer the question I asked above?
Does the selected fuel pump run for one second and then stop when you turn on the key or does it run all the time the key is on?


To answer your questions above here are the locations of the two items.


The location of the Ignition Control Module (ICM):




The Location of where to check the fuel pressure:



/

 

When I turn the key on but do not start it, I hear the fuel pump run for one second and then stop. This is true for both of the pumps, front and rear.

 

OK the PCM sounds like it may be OK and so does the PIP and the ICM.
Take the cap off the distributor and crank the engine, does the rotor turn?
If it does turn does it point to #1 on the cap when the pointer on the crank lines up with TDC on every other revolution?
If so you may want to do a compression check of the engine.