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Discussion Starter · #1 ·
search turned up nothing

it's a 1990 with a 351w, and absolutely no spark

so, where is my ignition control module, and other various components that i should be testing?

reference pics would be useful, as i'm a virgin to ford motors, as well as multimeters

not stoked about having to do it in 20* below either, but i have till sunday to get her up and running before the bylaw guys have it towed



please help
 

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Discussion Starter · #3 ·
i just wanna find out which of those is screwing me, a new coil is like 70 bucks, so if that's not the problem, i dont want to have to spend the money on it, know what i mean?
 

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yo,
Ignition Control Module (ICM) Location pic @ distributor
Source: by Jem270 & Steve83 (Steve, That dirty old truck) at SuperMotors.net



Test; "...Test ignition module output with a test light put the test light between the two wires at the coil harness if it flashes TFI module and PIP are functioning. test power supply to the TFI module by using the chart; PIP test distributor mounted TFI only, Test for AC voltage from pin 6 of the TFI module with harness connected to negative BATTERY terminal by cranking engine. AC voltage should be 3-8.5 volts; PIP test remote mount TFI only, disconnect the distributor harness and test for 12v+ at pin 8 with the key in the run position now disconnect the S terminal at the starter solenoid/relay to disable the starter and turn key to start position test for voltage again. Hook the S terminal back up to the starter solenoid/relay test for AC voltage from pin 1 of the distributor to the negative BATTERY terminal by cranking engine. AC voltage should be between 3-8.5, measure from module pin 6 to distributor pin 1 resistance should be less than 5 ohms and finally measure from pin 6 of the remote TFI module to ground you should get more than 10,000 ohms..."
Source: by theramsey3 (Chris) at FSB
No Spark Troubleshooting, General; "

...Secondary ignition voltage can shock you. Do NOT hold or touch a spark plug wire while cranking the engine. disconnect one of the plug wires from a spark plug and place the end of the wire near a metal surface on the engine. You can insert a small Phillips screwdriver into the end of the wire (the plug boot), or a small bolt or nail to provide a conductive path. Then crank the engine and look for a spark to jump from the screwdriver, bolt or nail in the end of the plug wire to the engine. If you do not see a spark, there is an ignition problem..."
Source: by aa1car.com

COIL Test; "...test the primary circuit for resistance it should be .3-1 ohms & test the secondary circuit from the coil negative to the plug wire output, resistance should be 8,000 to 11,500 ohms; to test the coil primary circuit you should have already tested for 12v+ from coil to ground with key in run position now you need to test from TFI pin 2 to coil negative with harnesses disconnected resistance should be less than 5 ohms; test from coil negative with only the coil harness disconnected to ground should be more than 10,000 ohms..."
Source: by theramsey3 (Chris) at FSB
 

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Discussion Starter · #5 ·
it seems i have to take my distributor off to get at my TFI module?

it looks jammed pretty tight in between the distributor, and some other thing, doesnt look like i can dismount it without moving that out of the way
 

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Wolfchant have you started any of the tests Miesk5 mentioned up there like the ones with my name at the end? you might not even need to pull the TFI you may find a bad coil or a bad EEC relay? or a bad connection. Do you have a haynes manual? If you do all the information up there and more is in section 5 of the haynes.
 

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Discussion Starter · #7 ·
well i'm trying to get at the TFI, it's 25* below, so i'd like to bring it in the house and test it there, that way i'd also have much better access to all the pins to make sure i'm testing properly as well
 

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What I am trying to say there could actually benefit your cause there, Test the coil first on the truck it will take less time (about 25 seconds start to finish) to test the coil than it will to take the distributor out of the engine. Test the power make sure you get 12v+ to the coil then test the resistance of the primary and secondary curcuits, as soon as you test the coil test the power supply to the TFI module

 

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Discussion Starter · #9 ·
so how do i tell which is primary and secondary circuits on the coil?
 

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so how do i tell which is primary and secondary circuits on the coil?
Seriously? Miesk5 already posted that information that was originally posted by me. Did you click on any of the links he posted? There is good information there. click read learn you will find out almost everything you need to know about the ignition system.

COIL Test; "...test the primary circuit for resistance it should be .3-1 ohms & test the secondary circuit from the coil negative to the plug wire output, resistance should be 8,000 to 11,500 ohms; to test the coil primary circuit you should have already tested for 12v+ from coil to ground with key in run position now you need to test from TFI pin 2 to coil negative with harnesses disconnected resistance should be less than 5 ohms; test from coil negative with only the coil harness disconnected to ground should be more than 10,000 ohms..."
Source: by theramsey3 (Chris) at FSB
 

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Try this it is almost the same information but a little different set up.

Ok so your bronco wont start. It cranks over but has no spark. There are a few possibilities for why lets take a look at them.




A) You have a bad ignition coil, no power or signal at the coil. How do I test for this?

To test the coil get out the DMM= Digital Mutli Meter. Test the primary circuit for resistance. It should be .3-1 ohms. Test the secondary circuit from the coil negative to the plug wire output. Resistance should be 8,000 to 11,500 ohms. If coil is out of this range replace it.



Test for power at the coil with the key in the run position. Test ignition module output with a test light put the test light between the two wires at the coil harness if it flashes TFI module and PIP are functioning.

Coil primary circuit wiring(see the below picture for TFI module pin out)

to test the coil primary circuit wiring you should have already tested for 12v+ from coil+ to ground with key in run position now you need to test from TFI pin 2 to coil negative with harnesses disconnected resistance should be less than 5 ohms

next test from coil negative with only the coil harness disconnected to ground should be more than 10,000 ohms.




B) You have a bad TFI= Thick Film Ignition module. Can I test that?

If you have a distributor mounted TFI you can test it yourself; However I highly recommend you have it tested at the parts store of your choice several times to get it hot during testing. Most TFI problems are intermittent and only occur when the module is hot, Not all but most, so you need to create the environment in which it is failing to test it.

test power supply to the TFI module by using the chart below.

If you have a remote mounted TFI module you have to take it in to test it.








C) My TFI module is good what else can cause this? Your PIP in the distributor might be bad. well how do I test for that?

PIP = Profile Ignition Pick up

PIP test distributor mounted TFI only

Test for AC voltage from pin 6 of the TFI module with harness connected to negative BATTERY terminal by cranking engine. AC voltage should be 3-8.5 volts

PIP test remote mount TFI only

disconnect the distributor harness and test for 12v+ at pin 8 with the key in the run position now disconnect the S terminal at the starter solenoid/relay to disable the starter and turn key to start position test for voltage again. Hook the S terminal back up to the starter solenoid/relay test for AC voltage from pin 1 of the distributor to the negative BATTERY terminal by cranking engine. AC voltage should be between 3-8.5

measure from module pin 6 to distributor pin 1 resistance should be less than 5 ohms and finally measure from pin 6 of the remote TFI module to ground you should get more than 10,000 ohms.

remote mount module distributor harness


Feel free to PM me to critique me or to add anything.

For the original post see post#19 here> http://fullsizebronco.com/forum/showthread.php?t=180544
For a few more Ideas and discussions on this subject look here> http://fullsizebronco.com/forum/search.php?searchid=3800791
 

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Get inside where it's warmer so you can work effectively, a Haynes Repair Manaul is a must or go here: www.broncolinks.com for a little research time to get familar AND you need to know how to "pull codes" from the vehicle computer as well for an acurate diagnosis or your just guessing....

To pull codes easily you'll need either an OBD-I or II Ford Code Reader/book which costs $29.99 to "plug in" to the test connectors...OR use a paper clip to "pluse" for codes...PITA....:rofl:

To remove the TFI = thick film integrated module you need to loosen the saftey "lock bolt" at base of the distributor so you can TURN the distributor for better access and removal but make a referecne mark so you can turn the distributor back exactly where it was otherwise you'll have to re-set the timimg so it will start and run properly.
There's a special tool "ignition module socket, mfg by Powerbuilt # 648420 so you can remove the screws on the module to replace it BUT to test it you just need to turn the ignition key to the "RUN" position, engine off.

I don't remember what I paid for the "socket" maybe $15.00 range....?

Good Luck ~ :thumbup
 

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Discussion Starter · #13 ·
ok, im reading with a kind of archaic multimeter, but it's telling me i have 6.66 yes, you read correctly, 6.66 kilo ohms on the coil secondary, which im gonna assume translates to something along the lines of "my coil is fubar"?
 

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Yes it is time for a new coil. Don't buy an MSD coil they are crap and made in CHINA.
 

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Discussion Starter · #15 ·
i'm still gonna test other stuff though, i also have to finish fighting the passenger side engine bay to change out the last 3 spark plugs closer to the firewall, and my god it's tighter than a virgin in there, any tips on that?

as well as fishing a spark plug out from under the exhaust manifold?

and here's the archaic multimeter that i have to thank just as much as you guys for potentially saving my day

 

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Discussion Starter · #16 ·
coil has been replaced, tested for spark didnt test ICM, but i picked up a spare unit anyway, so i dont have to buy one when it goes, anyways, i have spark now, but it got dark so i still have to finish the spark plugs, thanks for the help guys
 

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I'm glad you figured it out. I hope thats all thats wrong with it.
 

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Discussion Starter · #19 ·
that's tomorrow's forecast, today was 25* below........celsius, hopefully tomorrow she'll be running, when i finally have the rest of the spark plugs in, and then i can park her in the back yard so the bylaw guys will F*%K off, then it's time to pay one last fine before i can register and drive the hell out of her


I'm glad you figured it out. I hope thats all thats wrong with it.
i hope so too, but if it's not that, it's the ICM, and i picked one of those up today too, so it'll just be a matter of replacement if it's that
 
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