1986 carbed 351 wiring questions

[boonebronco]

It is fixed . Turned out to be the new ICM was just as bad as the one I removed.

THANK YOU Very Much Bronco Joe and Shift 1313 for your help. Now I dont have to **** my Bronco....

On To The next project...lol

I am trying to track down a no start issue, and at the same time repair, rewire a cluster under the hood of my Bronco.

I have run into a couple very specific wiring problems.

Most of the wiring diagrams for a 86 Bronco want you to have fuel injection. Not me.

All the wiring diagrams I have found shows three hookups on the starter starter relay. B+, S, and the wire to the starter. I have a fourth hookup...I which I believe is for the ignition, or its just the wrong starter relay in there.

On wiring diagrams for a 83 and previous I show what looks to be my relay. Does anyone know if the 86 carbed 351 would be the same as the 83, or was it changed. If it was changed, how does the coil get the power for the secondary circuit (know that its start time, need more power) to kick in????

Sorry, I am prolly way over confusing this, but after 8 hours of wiring today, I'm gonna pull my hair out.

Thanks, Dave

 

[BroncoJoe19]

Dave,

Before I finished writing my welcome message to you and encouraging you to ask questions, you already asked a question! You must be psychic or something.

Unfortunatley I may not be able to help you too much because my bronc is and EFI '90 however I am certain there are others on this forum who have an '86.

Good luck and welcome.

joe

You may want to look into these

http://cgi.ebay.com/ebaymotors/1986-Ford-B...p3756.m20.l1116

You may watch ebay for a bronco EVTM Electrical and Vacuum troubleshooting manual for your year.

Here is an example of the detail that you can expect vs a chilton or haynes manual

http://broncozone.com/forums/index.php?sho...amp;#entry73714

 

[boonebronco]

I've got the FSM's, chiltons, haynes, helms, and the ford stealership on speed dial at this point, but none of them even agree with what I should have...

 

[BroncoJoe19]

I've got the FSM's, chiltons, haynes, helms, and the ford stealership on speed dial at this point, but none of them even agree with what I should have...

I have a Haynes manual and on page 5-5 figure 5.2 there is a diagram of a four wire set up.

I t seems to be out of order, perhpas you missed it, and hoepfully it will help.

If you don't get an answer here, you may try posting pictures, and if that does not help, then look in your local yellow pages for a shop that rebuilds starters and generators. IE.. experts in the field.

Good luck

joe

 

[boonebronco]

Thank you for the quick response.....you just helped to prove I'm either looking way to hard at this or have lost my mind, or there is more than 1 Haynes manual for this thing. That would be good to. My haynes fig. 5.2 is on page 5-4 and its of a three post set up. Post A - Sig. wire, Post B - B+ wire, Post C they call Ign Enable, but its what runs to the starter. Mine has a forth post marked I, but its a small post, not the one that runs to the starter. If you go to napa to buy a new starter relay, they actually sell both the three and four post for a 86. I just cant find where the fourth wire would be on mine. On the wiring diagrams it shows three from 85 on, and four from 84 previous. Hope that helps.

 

[shift1313]

i believe for some reason in 85 and 86 on the 351 ford used the duraspark ignition and not the tfi like all other years. This may be where your wiring diagram discrepancy is coming from.

for the starter relay. You have two large lugs with heavy gauge wire running from your battery and to your starter. There will probably be two more small lugs(about a #8 *****). One will be your 12v signal, the other will be ground. The 12v signal comes directly from your ignition switch in the dash. The ground is used on some vehicles and not on others. It wont hurt to ground it, but some vehicles ground the body of the solenoid to the fender.

if you apply 12v across the two smaller lugs it will close the contact between the larger lugs. Almost all of the relays i have purchased will come with a plastic cover for the mounting ****** to isolate it if you are using a 12v ground wire, they will also have a small cover over the un-used small lug.

Is this the only wiring issue or is there something else that I missed?

A no start issue could be more than a few things. Not getting 12v to the starter solenoid. Gear indicator switch is bad(only will crank in P or N) bad starter solenoid. Bad ground...

hope this helps

 

[boonebronco]

You may have just answered it. I was not certain why I had two smaller lugs, when I should have only been seeing one. If there was originally a cap on the one and never used, I have made it past my starter relay issue.

My no start issue may have nothing to do with the relay, but since I wound up head deep, I am unwrapping the entire harness up front, Checking each wires resistance, getting rid of some entertaining splices, etc...I had just made it to the starter relay....to my stupid mind, I said four posts, I am missing a wire for one of the posts.....and here we are....

My no start (what started all this wiring nightmare to begin with) is I have power to the coil in run mode, I think I have power to the coil in start mode, but have no power out of the coil when I try to start her. New Coil, actually the second new coil, thinking I replaced a bad with another bad.

Had my ICM mod checked and was told it was fine. Started trying to track it down in the wire harness and ended up buying 8 colors of primary wire, you get the point from there.

 

[shift1313]

well you can check the coil resistance to see if its good. also if you do have the duraspark ignition you have 3 wires coming from your ignition switch. there is a by pass wire that powers the coil during "start" and during "on" there is a ballast resistor that the 12v runs through before it see's the coil. Does your Tach work? or do you have a tach? If you do and it is jumping or moving while your cranking then you are getting V out of the - side of the coil. from there it goes to your ignition module(which is powered by the ignition switch as well but it bypasses that ballast resistor also.""side note: if you have power at your ignition module(red wire) but not at your coil its probably an issue with that ballast resistor""

Your entire ignition ground is located on the black wire going to your distributor. If this is bad you could have proper ignition coil power but no go at the rotor.

 

[boonebronco]

Have Tach, it does bounce a little while cranking.

The resistance of my ground wire to distributor is fine.

I have power at the red wire in run, and white wire in start mode.

Am I crazy to think its the mod??

 

[shift1313]

do you have good power and ground at the ignition module?

 

[boonebronco]

Power to the red at run and white and red at start.

Ground is good.

Is it true that I should have a pulsating light on a 12 volt tester on the neg side of coil during start mode???

 

[shift1313]

pulsating light is new to me

 

[BroncoJoe19]

pulsating light is new to me

IN this thread bidibronco talked about checking the distributor with a probe light.

Starts with post #9

http://broncozone.com/forums/index.php?s=&...ost&p=72467

 

[BroncoJoe19]

IN this thread bidibronco talked about checking the distributor with a probe light.Starts with post #9

http://broncozone.com/forums/index.php?s=&...ost&p=72467

Also from within that thread...

Haynes says if you attach a light from the coil TACH to a good ground, and it stays on brightly but doesn't flash... "the problem is in the primary circuit (open for TACH to module) or ignition control module (stuck open transistor). Check primary circuit harness continuity from TACH to ignition module first.

 

[boonebronco]

Yes, but is that for the duraspark as well??? In the Haynes manual it says that test is for the TFI - IV.

I'm lost....

 

[BroncoJoe19]

Yes, but is that for the duraspark as well??? In the Haynes manual it says that test is for the TFI - IV.I'm lost....

Don't hold me to it, but I think it would blink/flash even with a points and condensor distributor. I suspect that it would be a valid test with the duraspark as well.

Is yours NOT flashing?

 

[boonebronco]

nope.....guess this has been narrowed right down

Since a re-manned dizzy is only 20 more than the pick up coil, Im guessing the re-manned for me.

Is there a real advantage of a MSD or accel for the extra money??? If so, what would it be??

Thanks so much for the help

 

[BroncoJoe19]

nope.....guess this has been narrowed right down
Since a re-manned dizzy is only 20 more than the pick up coil, Im guessing the re-manned for me.

Is there a real advantage of a MSD or accel for the extra money??? If so, what would it be??

Thanks so much for the help

Ooops!

In reviewing the Haynes manual for additional info regarding the various systems:

The blinking light test would NOT indicate distributor for the Duraspark III system.

AND...

Haynes says if you attach a light from the coil TACH to a good ground, and it stays on brightly but doesn't flash... "the problem is in the primary circuit (open for TACH to module) or ignition control module (stuck open transistor). Check primary circuit harness continuity from TACH to ignition module first.

 

[boonebronco]

I edited the top post but just in case...

It was the ICM, the new one was just as bad as the old one...

Bronco Joe and Shift...Thanks so Much for your help!!!

If we ever meet, the first beer is on me.