Hello all,

A while back, I wrote about my f-150 and the headaches of getting it to run. The engine died at full speed and I still have not been able to get it to run.

Here's the problem again... I have a carbed 86 300 f-150. The timing is perfect, the distributer has been changed and there's no problem with the distributer gear. It won't fire if I put starting fluid in it. It's getting gas. It's getting spark. Oh, also the TFI ignition module was changed and an msd blaster II coil was put into it before it died. The only error code i'm getting from the pcm reader is 15, which indicates some problem with some sort of water temperature sensor. The truck wont even begin to fire/backfire/anything when I crank it over. Would any of you happen to have any suggestions for anything else to check? -Will

 

Take off the Oil fill cap and see if the Rockers are moving.

Not sure what year they went to a Plastic timing gear but i know my 85' has steel gears. Might not be fatcory though.


The timing gear might of sheared. so the cam might not be moving. It is know to happen.

It's a cheap half way easy fix though.

DT

 

nope, i took the timing cover off and the gears lined up perfectly. i even bought a spare set before I took off the cover. The gears are perfect. Any other suggestions?

 

Ok it's gettin fuel. It's getting Spark. Air? I would think.

What is the Ignition timing set at?

So it's either not enough spark or not enough Air or too much of either. Or at the wrong time.

What do the plugs look like?

What kind of compression.

DT

 

It's hard to imagine that if you have spark and starting fluid that you are not getting some kind of sputter or back fire.

Are you absolutely sure that your timing is correct and not off somehow. I swore I had my distributor in correct once and it was off exactly 180, it happens.

Pull out the #1 plug. Stick finger in #1 plug hole. Have good friend turn engine over by hand until compression is felt in plug hole. Slowly turn engine over by hand until TDC. Look down plug hole. Verify piston is at top TDC. Mark outside of distributor base with a black marker exactly below the #1 plug wire. Take off distributor cap. Distributor Rotor should be pointing exactly at the black dot you made on distributor. In other words pointing exactly at #1 plug wire.

Back to the time... my distributor was out 180 degrees, this is a true story. My friend Ray was in charge of pouring gasoline down the carburetor from a small can, while I turned the engine over in my rebuilt mustang engine. It cranked and cranked nicely, but just would not start, and then finally it backfired. Holy cow it backfired, like an explosion. A huge flame shot out of the carburetor igniting the little can of gas in Rays hand. Now Ray is holding a little can of gasoline in his hand, and that can of gasoline is on fire, so he does what anyone would do in this situation. He throws it. My cuz Paul, an innocent bystander, is astonished and stunned and he just can't move out of the way, as the flying wall of gasoline comes right at him. His eyebrows are burned off, and he is temporarily blinded. The flaming gasoline that doesn't land on Paul, hits the dry wall of the 100 year old garage we borrowed. Paul stumbles out of the garage and leaves me and Ray there to fight the fire. At one point I thought I was going to lose the garage, my Mustang, and my cousins eyesight. It was truly a day of stupidity. Fortunately, prior to that I was intelligent enough to have bought and had a heavy duty fire extinguisher. My cousins eyebrows grew back, the mustang was ok (after rotating the distributor 180) and the old garage was hardly charred at all. That fire extinguisher was the best money I ever spent.

 

Wow, quite a story..I've had some other moments of stupidity with cars, but I don't think I can top that one......yet. Namely, it was one involving a prybar, brakework, my friend underneath the vehicle, and a falling minivan...but that's for another day.
I will say though, in all of this time I have yet to check the compression of all of the cylinders, a tdc check, and the sparkplugs. The truck actually broke down twice. The first time...it began to lag and the oil pressure went down. It seemed as if it was running lean. While I was waiting on the side of the road for a towtruck, the radiator hose blew..long story short, after a new radiator/hose I had to turn the distributer counter clockwise about 10 degrees(forget if retard/advance). I don't know why so much. It ran fine for a while. About two days later, I was heading to my fathers house to use the timing light and tach/dwell meter when it just stopped running suddenly on the freeway. Everything was fine. Oil pressure and temperature were normal. There were no signs of lagging or any strange sounds/smells. I just bought a tdc stop about two days ago. I'll put it to good use. -Will

 

If you haven't replaced your plugs and wires yet, you probably should. If you kept old wires, and upgraded the ignition coil it may have overloaded the old wires. If you can turn the engine over in the very dark of night and the wires are bad you will see sparks jumping everywhere. The guys on this forum swear motorcraft plugs are the best, I use autolite myself. But I always buy high quality plug wires. If not abused a good set will last for ten years, so its a good investment.

The 300 is a tough engine and if you haven't heard any bad engine noises, then the engine is probably fine. Does the gauge indicate oil pressure when you crank it over?

Turning the distributor counter clockwise will advance the timing. Advancing the timing will make the engine turn over slower, (provided it's firing) If you turn the distributor too far 30 degrees max, in either direcetion you will actually move the complete firing order up/or back one so that the number four or five cylinder is firing when the #1 cylinder is supposed to be firing. Most of the sixes I have seen have a small index mark on distributor and block. If the timing is really screwed up I start by setting the distributor back to the base mark and it will run. Not a great method, but works when you are far off the mark and don't have the tools you need.

Was the distributor hold down bolt very tight. If you could turn the distributor by hand it could have moved going down the road.

 

The plugs, wires, cap, and rotor are all brand new. The engine doesn't do anything at all when I play with the timing on the distributer. I did find something interesting today though... I found out that there are several missing vacuum lines going from the carb to this funky panel on top of the engine near the firewall. I think it goes to several vacuum switches. Also, I found several wires that were disconnected. One, I think, is a vacuum sensor. It's a little round thing connected very near to the pcv valve. Could this be a computer or wiring problem? I have no idea how much of the ignition is controlled by the computer, but i do know that there was some sort of slow voltage leak in the vehicle. It would drain my battery within several days if I didn't run it. -Will

 

I think you should do a compression check. Compression checkers are relatively cheap and can give lots of information about an engine.

Do you have good spark? A spark tester is only about $10 at autoparts stores. Plugs inline with the spark plug to see if the spark will jump the gap.

If you think that the vacuum leaks are sufficient to stop the engine running, plug them all at the manifold/carb. If it starts then hook things back up one at a time.

If you have spark, look to see if you have fuel. You may have fuel at the carb, but if it is dumping the fuel at a high rate then the plugs will be wet when you remove them. Flooding will stop it from running.

Is the distributor turning? Seems a silly question.

Another thought, although it will show up in a compression test is did the cam break? Pull the valve covers and see if all of the valves are operating.

 

hello again,


I know that the distributer is turning and it's developing spark. I have a spark checker and a compression gauge. In the past, i've always just held the sparkplug to the block to check for spark. I've only checked compression on cylinder 1 though, and it's getting good compression. I can't remember off the top of my head, but it's better than 150. I guess i should check all of the cylinders. I'm usually pretty confident about vehicles, but I can't seem to diagnose the problem with this one. -Will

 

Oh, reminds me..

When I bought the new distributer/plugs/wires/cap/rotor, I forgot to take note of the sparkplug wire order. When I plugged in the order from the haynes manual, the car wouldn't run. Now, I remembered that the old distributer cap had cylinder 1 marked. I used this as a guide and the truck ran. The haynes manual was off by 90 degrees. I know this seems stupid, but what's the correct order for this vehicle. Note:it ran fine for six months after I changed the distributer.

 

Is there gas in the tank? Not diesel? If you filled it with the wrong fuel it will quit.

 

I am sitting here pondering your problem.

Are you pulling off the spout connector or unpluging the single wire connector before checking the timing?

Pull the vacuum advance line off of the distributor and see if it helps. I don't know exactly how this hooks up on your motor, but it worked on a 1982 I was working on.

It is possible that the outside of the harmonic balancer has rotated and is not lining up the timing correctly even though the marks line up. Are there two sets of timing marks on the engine? There is on mine.

You can check the timing without the engine running. Hook up the timing light like normal and check the timing with the engine cranking.

Catalytic converters can plug up. I have heard of it but never seen it.

Compression sounds good on 1. Definately pull the other plugs and check all of the cylinders.

 

Dunno....Sounds like a classic case of ignition module
harness problems...Sure sounds ignition related to me,
being it was running and then suddenly quit. The 74 F-100
I have had quite a few bouts with that, when owned by
the previous owner. I'd check all the harness connecters,
and make sure they are clean and tight. All grounds good,
etc...
There is one other thing I've seen...Once on the 74, we
were on the interstate, and it did that...Was running great
one minute, and then just quit and rolled to a stop...
The problem that time was the bushings in the carb for the
butterfly, or whatever it was, suddenly sprang a big leak
and it was too much to run...Actually, I was able to finally
get it restarted and nursed it on the RV site we were going
to. But...We had to install a rebuilt carb before we could
leave to go back home.
But still...We've had the ignition cutout do the same thing,
and when that happens, it will not run, snort, or whimper...
Nuttin....And to top that off, we *did* sometimes see a
weak spark...But it wasn't enough to run. Fixed the harness
connector...Bingo...Cranked right up..
MK