Pickup coil testing? intermittance possible?
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More Turbo
Joined: Oct 2011
Posts: 636
Likes: 5
From: down a red dirt road
Pickup coil testing? intermittance possible?
hey guys im curious if my pickup coil is bad although the truck still runs?
i dont know if theres such a thing as a p/u coil going bad or on its way out or weaken over time? Ive only heard of them just completly going bad like the wires break within it or something.
the other thing is can you take a multimeter and ohm em out?
i have a new one available to compare ohmage to the old one if anybody thinks it would be worth the time.
id rather change out the whole distributor than just the pickup coil because i think maybe the advance is jacked up also, just trying to justify it.
i dont know if theres such a thing as a p/u coil going bad or on its way out or weaken over time? Ive only heard of them just completly going bad like the wires break within it or something.
the other thing is can you take a multimeter and ohm em out?
i have a new one available to compare ohmage to the old one if anybody thinks it would be worth the time.
id rather change out the whole distributor than just the pickup coil because i think maybe the advance is jacked up also, just trying to justify it.
Rusty Roller
Joined: Oct 2011
Posts: 1,423
Likes: 5
From: Santa Cruz Mountains
Here's a link to a similar post. Hope it helps!
https://www.ford-trucks.com/forums/8...ckup-coil.html
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https://www.ford-trucks.com/forums/8...ckup-coil.html
.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
First question is: what's the problem? Is there one?
It's tough to effectively test a pickup module. They can be on the edge of failure, but not exhibit any issues until they get hot. The trouble is once the truck shuts off and you try and test it, often times it has cooled down enough to measure fine. However, you can use an ohmmeter to check for gross failure. Check the resistance between the ORANGE and PURPLE wires coming from the distributor. It should be between 400 and 700 ohms. There should be no continuity between either wire and the BLACK wire.
It's tough to effectively test a pickup module. They can be on the edge of failure, but not exhibit any issues until they get hot. The trouble is once the truck shuts off and you try and test it, often times it has cooled down enough to measure fine. However, you can use an ohmmeter to check for gross failure. Check the resistance between the ORANGE and PURPLE wires coming from the distributor. It should be between 400 and 700 ohms. There should be no continuity between either wire and the BLACK wire.
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More Turbo
Joined: Oct 2011
Posts: 636
Likes: 5
From: down a red dirt road
right fmc the black just grounds inside anyway.
idk truck just dont run right anymore but i think the heads are shot although a vacuum guage has a solid reading.
im gonna be swappin engines but im gonna be in an awesome mood if it runs the same! Lol.
the truck has been popping out the pipes, almost like fuel is getting ignited halfway back and makes a rattling continuous pop down the highway, and under a load like pulling another vehicle makes a heavy boom boom boom like a huge impact gun or something.
it got worse and worse and would backfire shifting to third and while at highway speed randomly. now ive swapped carbs and not backfiring but cant get the carb tuned right since it dont run right.
this weekend on the highway it would act like it lost fuel pressure and it drops off then would start buckin like crazy, let out throttle be fine for a quarter mile and start again and was a pain to keep it going 50 mph.
it seems to only do it when the engine is hot.
it has flat spots from hell in low rpm when taking off and grabbing a new gear but will scream at higher rpm after you kick the accelerator pump i guess.
i was thinkin about putting the other carb back on to see if does any better but idk.
idk truck just dont run right anymore but i think the heads are shot although a vacuum guage has a solid reading.
im gonna be swappin engines but im gonna be in an awesome mood if it runs the same! Lol.
the truck has been popping out the pipes, almost like fuel is getting ignited halfway back and makes a rattling continuous pop down the highway, and under a load like pulling another vehicle makes a heavy boom boom boom like a huge impact gun or something.
it got worse and worse and would backfire shifting to third and while at highway speed randomly. now ive swapped carbs and not backfiring but cant get the carb tuned right since it dont run right.
this weekend on the highway it would act like it lost fuel pressure and it drops off then would start buckin like crazy, let out throttle be fine for a quarter mile and start again and was a pain to keep it going 50 mph.
it seems to only do it when the engine is hot.
it has flat spots from hell in low rpm when taking off and grabbing a new gear but will scream at higher rpm after you kick the accelerator pump i guess.
i was thinkin about putting the other carb back on to see if does any better but idk.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 790
From: Simi Valley, CA
Applications: ALL 1974/79 FoMoCo V8 vehicles except 1979 LTD/Grand Marquis 351W w/EEC.
MSRP: $86.56 // FTE Ford Dealer Parts Dept sponsor tousleyfordparts.com price: $52.37.
-------------------------------------------------------------------------------------
The DuraSpark ignition module is mounted on the left fender inner apron.
Engine heat, especially radiating from a V8's red hot left exhaust manifold, is the mortal enemy of these modules.
When replacing, use some washers to space the little charmer further away from the apron, cuz the more airflow, the better.
The 3 step scenario of a failing DuraSpark ignition module:
1) Module overheats, engine dies. Module cools down, engine restarts almost at once.
2) Module overheats, engine dies. Module cools down, engine restarts in an hour...or so.
3) Sooner or later, usually sooner, the module overheats, BURNS OUT. Now the engine will not restart.
Taking the module to an autoparts store to be tested: Since it's cool, it will test OK unless the little charmer has burnt out.
Little charmer: The modules used in the 1970's were such terds, that Ford techs referred to DuraSpark as NeverSpark!
Lead Driver
Joined: Mar 2004
Posts: 8,924
Likes: 153
Have you put a fuel psi gauge on it yet to see where your at ? Have you checked the fuel line front to back and everywhere it might be touching something ? Have you done a psi test on all the cylinders ? Have you had a timing light on it ? Does this engine still have a 2 barrel with the factory carb spacer ? Sometimes the pot metal carb spacer plate can burn out underneath and cause problems like that.
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 790
From: Simi Valley, CA
Have you put a fuel psi gauge on it yet to see where your at ? Have you checked the fuel line front to back and everywhere it might be touching something ? Have you done a psi test on all the cylinders ? Have you had a timing light on it ? Does this engine still have a 2 barrel with the factory carb spacer?
Sometimes the pot metal
carb spacer plate can burn out underneath and cause problems like that.
Sometimes the pot metal
carb spacer plate can burn out underneath and cause problems like that.Not only did the little charmers tend to carbon up, but heat caused them to MELT internally.
The FoMoCo service part replacement (parts sold at the parts counter) EGR/carb spacer plates were cast iron.
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