1979 f250 351M will turn over, but won't start ...Need some help - Ford Truck Enthusiasts Forums

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1979 f250 351M will turn over, but won't start ...Need some help

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1979 f250 351M will turn over, but won't start ...Need some help

 
  #1  
Old 07-11-2006, 03:44 PM
human_fly_
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1979 f250 351M will turn over, but won't start ...Need some help

I haven't written in quite some time but I am really in a pinch. the short version is: two weeks ago I moved 4762 miles from home and I am far out west without my truck.

My 1979 f250 351M that never really gave me a day's problem, wouldn't start the day with the uhaul, so I left for the mountains and I have to leave my baby behind in my grandmothers driveway. I am headed back east to try to get her going on this thursday, July 13, 2006, but I don't know what the problem is.

1) the starter is cranking the engine over

2) there is no spark coming out of the primary lead from the coil

3) I raced out and bought a computer module, but that wasn't the problem

4) i have heard that there are fusible links in the harness between the firewall and the coil, and another link between the firewall and the computer module. could the proble be fusible, and how can i determine where a fusible link is and what amperage fuse should I replace it with

i got paid last month and next monday i will install, for the drive out west, new cap, rotor, coil, wires, ... does anyone have any idea why i'm not getting any spark? When i turned the ignition back to the off position I got a very faint spark just before the key put the ignition into the off position. the engine picked-up on that and tried to fire, but that wasn't enough.

one of my brothers thinks it could be the solenoid, another brother thought it might be the voltage regulator, and the last bro. thought it was a fusible link. i thought probably the coil, but I have no idea where to start and grandma wants the truck outta her place a.s.a.p.

i will have sporadic access to a computer at the government welfare office in grandma's town so i will check in for replies, but only after thursday.

i would greatly appreciate any and all help to get it going. anyone who has had trouble getting their ford truck to fire, please write...

thanking you in advance,


gratefully, bobby

I'm not sure what the regulations are concerning email addresses in these posts, but I can post my email if you could email me photos of what I am looking for in the wiring.
 
  #2  
Old 07-11-2006, 04:20 PM
Ecuri
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Betting heavily on a bad stator in the distributor. Why? You get spark when switching to "off". This tell me the box and coil have power, but are not getting the inductor pulse to fire. There is a three pin connector at the distributor. One goes to ground (black), the orange and purple go to the coil in the distributor. Put an OHM meter across the colored ones and see if if is is wide open (infinite resistance), also spin the engine for grins and make sure the distributor is turning. Report back. GL
PS: Google up Duraspark II and you will find a wealth of wiring diagrams and advice on how to fix.
 
  #3  
Old 07-11-2006, 05:42 PM
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Thanks Ecuri

I was getting worried that noone would reply to my posting because there have probably been alot of such engine electrical problems talked about in the past.

Ecuri, I know this'll probably sound stupid, but I'm not sure what the three pin connector at the distributor looks like. I will connect an ohmmeter to the orange wire and to the purple wire. What exactly do you mean by infinite resistance? what should the digital multimeter read when it says infinite?

also, how can I change the stator in the distributor? I don't even know what a stator is....i mean, i'm gonna google it, but this problem is looking bigger and bigger and i've never fixed such a thing before.

i looked in the haynes manual but it is still a little unclear to me how to change the distributor. Is it necessary to remove the distributor to replace the stator?
 
  #4  
Old 07-11-2006, 05:52 PM
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Infinite on the meter is going to read like it's wide open, no resistance. The stator can be replaced in the distributor but it's probably easier to pull it. It's also called the distributor pick up. It sits in the distributor and has the wires connected to it. My haynes has pretty good troubleshooting info for it and all of the normal resistance values for testing. It's about a $30 dollar part, and easy to test. The 3 wire connector will be obvious.
 
  #5  
Old 07-11-2006, 09:37 PM
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Couldn't of said it better myself, tractorman, .

Mr Fly, the three pin connector is about 4" tailining out of the distributor, and often hides under the A/C compressor bracket, and yes, the little clips that hold it together break really easy (thats why we have electric tape). I can't find the acceptable resistance for the pick-up coil in my book, hopefully it's in yours. (or tractorman is feeling charitable again). Let's see if it is bad before we get into how the best way for you to fix it is.
Whatever it says on your VOM when turned on and set to read ohms and the leads are not touching is an open circuit reading. I'm guessing here, but over 1000 ohms is prob no good for a pick-up coil.

BTW, our exceptionally polite manners and attitude is earning you special patience and attention..... Oh, your Canadian! Nevermind.....
 
  #6  
Old 07-11-2006, 10:10 PM
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With the wires disconnected from the dizzy, purple to orange should read 400-800 ohms. Orange to ground and purple to ground should read over 70,000 ohms. Black to ground should be 0 ohms while operating the vacuum advance. Good luck and let us know how you do. This information can be found on a certain website that has certain manuals available for viewing by the way.
 
  #7  
Old 07-12-2006, 02:13 AM
Mil1ion
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1) the starter is cranking the engine over

This is a good thing,
Is there 12 volts at the I terminal of the starter solenoid when you crank the engine?


2) there is no spark coming out of the primary lead from the coil

Primary voltage should be 12 Volts during cranking of engine.

If there is no voltage with key in RUN position....check the Ignition Switch for being faulty

Secondary Voltage should be about 15,000 volts coming of the center hole of the coil headed for the distributor cap



3) I raced out and bought a computer module, but that wasn't the problem
You should have taken the one already in the truck and had them test it while you were there

4) i have heard that there are fusible links in the harness between the firewall and the coil, and another link between the firewall and the computer module. could the proble be fusible, and how can i determine where a fusible link is and what amperage fuse should I replace it with

do my 12 volt test at the primary terminal with the KEY ON of the coil first. Its the small connection with a + sign next to it

i got paid last month and next monday i will install, for the drive out west, new cap, rotor, coil, wires,

You may not need them,..... Read My Sig :

... does anyone have any idea why i'm not getting any spark?
Broken wire, bad connection of lug to distributor.
Many times the problem has been a broken wire where the distributor plugs into the haress. The wiring get brittle, then maybe a short to the engine happens



When i turned the ignition back to the off position I got a very faint spark just before the key put the ignition into the off position. the engine picked-up on that and tried to fire, but that wasn't enough.


Possible ignition switch problem. Do my other coil/wiring harness test first to confirm

one of my brothers thinks it could be the solenoid,

He's wrong ..if the coil does't get 12 volts from the starter solenoid at start up,. the coil gets 8.8 volts from the ignition switch anyway

another brother thought it might be the voltage regulator,
He's wrong too.. the charging system and igntion system are 2 different things

and the last bro. thought it was a fusible link.

He's wrong as well....maybe get some new brothers with right answers ?
If you can crank the engine with the key, the fusible links are fine.. do the headlights come on when you pull the headlight switch out ?
Wipers work ?
Heater ?


i thought probably the coil, but I have no idea where to start and grandma wants the truck outta her place a.s.a.p.

Tell Granny the best Ford minds will get this truck running soon


 

Last edited by Mil1ion; 07-12-2006 at 02:19 AM.
  #8  
Old 07-12-2006, 02:35 AM
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As Mil1ion/Dennis said "Possible ignition switch problem." I have a Ranger and the ignition switch went bad it would trunover but wouldn't start so i took it apart and Jerry-riged it to made it to a parts house. if it was me i would od the coil/wiring harness test first to confirm it.

Good luck!!!!

Nick
 
  #9  
Old 07-12-2006, 02:39 AM
Mil1ion
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I forgot.

Try this.

Attach a 14 gauge wire from the battery + Post to the + terminal of the coil.

Try to start the engine.

If it starts and runs,(shut it off right away) the problem is the key switch or the harness for it.

Key Off......then Remove the jumper wire to shut the engine off.
 
  #10  
Old 07-18-2006, 12:48 PM
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hi folks! owe you all a million, but still working on it

Well, guys, I got to granny's place and I checked the coil and it was o.k. after all. next I tried the stator, or magnetic pick-up, not sure which is the correct terminology, but when I connected the ohmmeter it read 1. then i turned-off the ohmmeter and turned it back on and the leads from the meter were not touching each other, or anything else and the meter showed 1 and then i did the test again between the purple wire and the orange wire and it was 1. the wipers still work, the lights work, the engine turns over, the rotor is turning, but no spark, so I'm sure you guys are right it is the stator. i have a full distributor here so i will replace the old one and put in the reman. i've read the manual several times and i have the #1 piston in tdc right now, so i'm headed back out to grandma's house to get down to business. can any one tell me what the timing should be set at, i mean offset to? it's a 351M bored .030 over (*in case that matters at all*). My haynes doesn't have the timing spec's listed therein. I will be back here in town tomorrow, so i will check to find the new posts.

also, i would like to publicly acknowledge that Mil1ion was right about wasting money, i wish there was a money emoticon the send your way. thanks guys, for your help and i will kepp you posted tomorrow as to what happened after changing the distributor. and, in fact i am anxious to start it, but i will ask if there are any tips about what i should look for or be cautious about before starting it up I will read before cranking it over. i'll get here to town to read any posts before i start it, cause i don't wanna mess it up this far along.

again, thank you
 
  #11  
Old 07-18-2006, 12:54 PM
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You never mentioned if you tried a jumper wire from the + post of the battery to the + terminal of the coil to try and start it

Did you ?
 
  #12  
Old 07-18-2006, 01:17 PM
Ecuri
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You'll need a distibutor wrench, there about 5$, if you don't have one.
Clean around the base of the distributor really well so you don't drop a bunch of dirt in the internals.
Mark where the vacuum advance points, you'll have to use your imagination, and maybe some masking tape.
Mark inside the base cap where the rotor points, marking both the edges is better than marking the center.
When you pull the distributor out, the rotor will rotate, note where it stops, you'll want the new one pointing here when you stab it in and it will rotate back to the right spot as it goes in. Getting it to drop back onto the oil pump drive rod is the only real problem you might face (other than it is stuck and won't come out at all, but let's not be negative .)

If it does not want to drop, pull all the plugs to unload the engine from compression so it turns easy, put your big breaker bar and socket on the front crank bolt and wiggle back and forth while a friend applies light pressure down on the distributor. Get it back on TDC, make all you marks line back up. Snug it down, a check the timing.

Of course, my book says, "see the under hood sticker" for the number,
Thinking 12B.

Also, use a little never-sieze when putting the distributor back in, the Al of the distributor makes a battery of sorts with the Fe of the block and likes to get stuck together over time. GL, I think you got it now.
 
  #13  
Old 07-18-2006, 02:23 PM
Mil1ion
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Your specs are on this page
http://mil1ion.clubfte.com/78Calibra...e-upSpecs.html
look at the spec page for calibration code 7-72-R11

I think yours is 14* BTDC.
 
  #14  
Old 07-20-2006, 10:48 AM
human_fly_
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still working on it...

Yeah, Mil1ion Dollar Man, I tired the wire from the + on the battery to the + on the coil and nothing at all.

I wasn't able to make it into town yesterday to check this forum, and I was itching to get the distributor out and the reman in. I'm glad I waited to see what y'all had to say because I've never heard of a distributor wrench or thought of marking the inside of cap and noting where the diz actually comes out of the block.

I'm on my way home with a print-out of all your suggestions and I will get back to you when I have tried thisthings.

I won't be back at the computer before I start, but I'm not sure what to do if the dis. doesn't want to mate with the oil pump drive rod. If I'm really in a jam I'll let it sit and drop back for more advice.

Thanks again for your help.

hey, do you guys ever actually get together, or do you live in the same city or something. It'd be kinda cool to actually see all you brainers put something together, like a rockin FTE monster yruck or something, cause you all really know what you're talkin about.

til tomorow
 
  #15  
Old 07-20-2006, 11:44 AM
Mil1ion
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A distributor wrench is a 1/2" wrench in a partial U-shape with the boxed end for the dizzy bolt.It stands about 10" so it clears the cap to allow for turning.


EDIT: I found a picture.
http://www.etoolcart.com/browseprodu...ench-V201.html

Just wiggling the rotor back and forth will allow it to drop on the oil pump rod.

Just stay "patient" !


GTG's.

I try to get to Ontario every year in the summer or fall.
But this year I won't be as finances are too tight.

If you scroll down thew main forum page to thew ontario chapter at the very bottom of the page (just above the TEST forum).

those guys are always talking about getting together.

The Arthur Ont. show (Ford truck Nationals is on the August 19th/20th ) and a few guys will be there.
 

Last edited by Mil1ion; 07-20-2006 at 11:49 AM.

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