Notices
1973 - 1979 F-100 & Larger F-Series Trucks Discuss the Dentsides Ford Truck
Sponsored by:
Sponsored by: Moser

79 ignition problem

Thread Tools
 
Search this Thread
 
Old Sep 30, 2011 | 01:25 PM
  #1  
blkmesamtman's Avatar
blkmesamtman
Thread Starter
|
New User
Joined: Apr 2007
Posts: 24
Likes: 0
From: Snowflake, AZ
79 ignition problem

I have a '79 F-150 with the 400M. It has the electronic ignition. The engine starts right up and the timing is set at 4* advanced. The problem is there is no "mechanical" advance as the engine rpm is increased. I'm assuming the ignition module is the issue.
Has anyone removed the Ford setup for the aftermarket HEI Ford ignition simillar to the GM HEI? Or anyone have an alternative setup to suggest?
 
Reply
Old Sep 30, 2011 | 02:45 PM
  #2  
400 .040over's Avatar
400 .040over
Senior User
Joined: Jul 2011
Posts: 132
Likes: 0
From: levittown,pa
timing should be around 10-12* btdt
 
Reply
Old Sep 30, 2011 | 03:00 PM
  #3  
devino246's Avatar
devino246
Post Fiend
Joined: Mar 2011
Posts: 8,501
Likes: 4
From: Lynchburg, VA
Your distributor is the problem, not the ignition module. Mechanical advance is built into the dizzy.
 
Reply
Old Sep 30, 2011 | 04:01 PM
  #4  
blkmesamtman's Avatar
blkmesamtman
Thread Starter
|
New User
Joined: Apr 2007
Posts: 24
Likes: 0
From: Snowflake, AZ
The timing is set at 4* BTDC per the stick on the hood.

The only thing inside if this distributer is the pickup senser. There is no typical weight advance mechanism in this unit!
 
Reply
Old Sep 30, 2011 | 05:21 PM
  #5  
devino246's Avatar
devino246
Post Fiend
Joined: Mar 2011
Posts: 8,501
Likes: 4
From: Lynchburg, VA
Originally Posted by blkmesamtman
The timing is set at 4* BTDC per the stick on the hood.

The only thing inside if this distributer is the pickup senser. There is no typical weight advance mechanism in this unit!
Go pop the distributor cap off and twist your rotor counter-clockwise. Assuming its not completely jammed up, it'll turn at good bit, thats your mechanical advance. Ive been having problems with mine.
 
Reply
Old Sep 30, 2011 | 08:50 PM
  #6  
NW 150's Avatar
NW 150
Fleet Mechanic
Joined: Jun 2007
Posts: 1,931
Likes: 2
From: Ohio
how far are you revving up the engine? My mechanical advance doesn't start rising until about 1500 or so, it's also the stock curve and nothing with more performance in mind.
 
Reply
Old Sep 30, 2011 | 09:34 PM
  #7  
fmc400's Avatar
fmc400
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Club FTE Gold Member
You can't see the mechanical advance just by removing the distributor cap. All you'll see is the pickup module. You have to remove the breaker plate and base plate to see the mechanical advance. You can't do that until you remove the armature. There's a fair amount of work involved to get deep enough to be able to see the mechanical advance.

Mechanical advance is controlled by centrifugal weights at the very bottom of the distributor. It's not controlled by the ignition module. How are you determining that your mechanical advance is not kicking in?
 
Reply
Old Sep 30, 2011 | 09:38 PM
  #8  
blkmesamtman's Avatar
blkmesamtman
Thread Starter
|
New User
Joined: Apr 2007
Posts: 24
Likes: 0
From: Snowflake, AZ
Let me describe this distributor because some must have something completely different from mine.

The cap is ~5'' OD and is grey.
The body is ~5" OD by 2 1/2" tall and is blue plastic.
This all is on the Alum base which goes into the block.
Inside the distributor is the trigger device and the vacuum advance hook up and of cource the rotor. NOTHING ELSE!
Trying to turn the rotor counter clock wise or clock wise produces no movement
 
Reply
FTE Stories

Ford Trucks for Ford Truck Enthusiasts

story-0

Top 10 Fords at 2026 Carlisle Ford Nationals

 Joe Kucinski
story-1

3 Best / 3 Worst Parts of Modern Ford Ownership

 Brett Foote
story-2

10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

 Pouria Savadkouei
story-3

Every 2026 Ford Engine Explained

 Brett Foote
story-4

10 Ugly Ford Trucks That We Still Kinda Love

 Joe Kucinski
story-5

10 Things Every Truck Owner NEEDS (2026 Edition)

 Michael S. Palmer
story-6

Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

 Verdad Gallardo
story-7

Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

 Joe Kucinski
story-8

2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

 Brett Foote
story-9

Top 10 Ford Truck Tragedies

 Joe Kucinski
Old Sep 30, 2011 | 09:56 PM
  #9  
devino246's Avatar
devino246
Post Fiend
Joined: Mar 2011
Posts: 8,501
Likes: 4
From: Lynchburg, VA
Originally Posted by blkmesamtman
Let me describe this distributor because some must have something completely different from mine.

The cap is ~5'' OD and is grey.
The body is ~5" OD by 2 1/2" tall and is blue plastic.
This all is on the Alum base which goes into the block.
Inside the distributor is the trigger device and the vacuum advance hook up and of cource the rotor. NOTHING ELSE!
Trying to turn the rotor counter clock wise or clock wise produces no movement
Maybe your mechanical advance is locked up then. Idk if the weights are under a plate or something, but they are in there. Its physically impossible for the ICM to retard or advance the ignition timing. The ICM controls dwell time.

EDIT: Yeah, what fmc said.
 
Reply
Old Sep 30, 2011 | 10:10 PM
  #10  
montana_highboy's Avatar
montana_highboy
Post Fiend
Joined: Apr 2008
Posts: 8,261
Likes: 15
From: Big Sky Country
Originally Posted by blkmesamtman
Let me describe this distributor because some must have something completely different from mine.

The cap is ~5'' OD and is grey.
The body is ~5" OD by 2 1/2" tall and is blue plastic.
This all is on the Alum base which goes into the block.
Inside the distributor is the trigger device and the vacuum advance hook up and of cource the rotor. NOTHING ELSE!
Trying to turn the rotor counter clock wise or clock wise produces no movement

Sounds like an aftermarket dizzy, but the same physics still apply, there's a mechanical/centrifugal advance mechanism inside that will advance the timing as your rpm's increase.
 
Reply
Old Oct 1, 2011 | 01:44 PM
  #11  
blkmesamtman's Avatar
blkmesamtman
Thread Starter
|
New User
Joined: Apr 2007
Posts: 24
Likes: 0
From: Snowflake, AZ
I removed and disassembled the distributor. It is a Motorcraft (Ford) unit. The mech advance is under the trigger mounting plate and it is not in good condition.
So a Ford HEI distributor has been ordered which will help clean up the engine compartment and simplify things. The wireing for this original ignition was in need of repair.

Thanks for the help everyone!!!!!!!!!!!!
 
Reply
Old Oct 1, 2011 | 02:33 PM
  #12  
gfw1985's Avatar
gfw1985
Cranky Old Guy
Joined: Mar 2008
Posts: 3,562
Likes: 6
From: Raphine, Virginia
Don't throw it away. You might wind up needing it back.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Art
1973 - 1979 F-100 & Larger F-Series Trucks
18
Dec 9, 2007 09:36 PM
marty60
1973 - 1979 F-100 & Larger F-Series Trucks
14
Jun 24, 2007 05:08 AM
heathkiks
1973 - 1979 F-100 & Larger F-Series Trucks
3
Apr 2, 2006 08:08 PM
Judson4.9L
Ford Inline Six, 200, 250, 4.9L / 300
6
Dec 6, 2005 07:28 PM




All times are GMT -5. The time now is 05:50 PM.

story-0
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-1
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-2
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-3
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-4
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-5
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-6
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-7
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-8
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-9
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE