Bronco II= no run now

[Stic-o]

Ok so I came home today went to back into a space, poped the clutch and she stalled. Now she will not start again, just cranks. I 've narrowed it down to a eletrical problem. I have no spark at the coil, I tried replacing the coil and still nothing. So now I'm doining this:scratch:

Now here is where I through a monkey wrench into this. On the solinod next to battery the are some fusabe link attached to it. Some one has added a regular fuse at some point (I saw a receipt in the truck about this but it was from about 10 years ago!), and I have no idea what it goes to What I do know is when I turn the key it blows. I also know there were a few boxes of fuses sitting in the truck, like this thing was eating them. This fuse goes to a yellow wire into the loom and then I don't know where, this could have nothing to do with it or something...Not sure.

Thought please!!!!

 

[Tbars4]

my f250 is looking better , sorry, i would help if i could....

 

[Stic-o]

Ok so it's running again.....I wish i were more excited

So I replased the coil any way, then I replaced "the fuse" with a 25amp. (was 20amp) Then she started right up HUH? So I did one more quick check...I pulled "the fuse" and then she would not start again. put "the fuse" back and she starts. Note: the fuse does not blow anymore...for now So now I don't trust the thing, some where there is a arcing problem it sounds like. Not sure really what to do now... the only other thing I can think of is the coil was really lose in it's box. maybe it was arcing somehow?

 

[Tbars4]

i'm glad to here at least that it's running...i had something like that on an old toyota...if you can, find what that fusable link is for thru haynes or chitons..the only book i have for that year is my f250 book...on fusable links i have found junkyards to be very knowledgable on them since they are a highly sellable part and only go to an exclusive item...good luck and stock up on them fuses for your race to work

 

[410Fortune]

yellow wire is a power feed, most likely the power feed for your interior fuse panel, I will have to check my 88 books

where does the yellow wire attach to? the battery?

When you get fed up with the 88 and its wiring harness you can always upgrade to a 93 style wiring harness with the good power distribution box, oh and those come with the 4.0L OHV

I had ALOT of problems with my OEM 2.9L wiring harness, I fugyred mostly it was because it was so old and I began to poke around under the hood alot, wires were breaking in a few places

If you can show us the yellow wire or tell me where it goes I can tell you what it is

 

[Stic-o]

Dead again!

Ok so I made it 3/4's of the way to work, and it died. Once again the fused blew.

Ok so this is what I got so far. There are three fusable links that connect to the starter solinoid from the wireing loom. (there is another one too but it does not go to the loom, it goes back tords the firwall on it own). This yellow wire one looks like the fuseable link meted at some point and somone put in a regular fuse in. Now, this fuse somehow conrols the power to the coil to get spark, and is only live when the key is in the on postion. That is when the fuse blows. So there is short somewhere. To add to it, the truck idleing really weird, up and down 500-1000rpm again I think this is the short related, add it was messing with the spark some how.

Jamie if you could tell me where the wire goes that would be great!

 

[410Fortune]

okay I have my 1987 Bronco II/Ranger wiring book in front of me

the yellow wire actually should be brown on the other side of the fusible link that attaches to the solenoid, BUT it appears in your case the previous owner removed the brown portion.

There are two yellow leads from this source in the book.
the factory fusbile link is listed as 18 ga it does not give me an amperage for the fuse

Your 25 amp may not be enough but you should check with Ford to find out what amperage the fusible link blows at brown at solenoid/yellow after the link.

the yellow wire goes to your IDLE SPEED MODULE as circuit 37 = "
battery to load"

the other lead would go to the "choke relay" which I am not sure your 88 has.


I am NOT sure what the idle speed module is, it may in fact be part of the PCM or it could be referring to the TFI module on the distributor. I am digging into that right now

According to my wiring schematics the ISM is located near the diagnostics test port in the engine bay (near your heater blower)

 

[Stic-o]

Yes there are two yellow wires I can't remember which one is the one is changed over though.

I remember only seeing two relays, by the diagnostics test port. They are mounted off the fender well, and have a lot of wires going in them.

Also the system blew out a 30amp no problem to. I keep trying bigger fuses

What really bugs me is that I got it working for awile again last night. Does the neutral saftey switch in trans have any effect on this? It seems like both time it has died I was shifting.

 

[410Fortune]

no NSS does not effect this I dnt believe.

The wire does not go to a relay, it goes to an idle speed module, which may very well be the TFI module on the back of your distributor.

You may have to cut the wire loom apart to find where the wire goes and the short in the circuit.

If it leads to the TFI module I would replace that sucker
especially since you just had to replace the coil for a no spark condition.

We need to find out exactly what a Idle Speed Module is, I simply dont remember since its been so long since I had a 2.9L.

 

[410Fortune]

okay in my 1989 wiring book (sorry I dont have 88) the 37 yellow wire goes to the PCM, it is a power feed (dua) for the computer.

On your truck this may be the power feed for the PCM relay (EEC power relay) the black relay on your fender wall......the brown and green are for the fuel and AC, the black one is for the PCM

Check your black relay hombre, it may be toast.
Might be just that simple

 

[Stic-o]

Something leads me to belive it's something over near the coil. After I changed the coil it did't pop the fuse anymore, yet I don't think the coil was bad (have not tested yet) It's completly random or something getting bumped around, which makes sence if it's a short somewhere. I may not get a chance to play with it tonight, we'll see.

How can I test the relay? Also Should there be three relays there? A/C, EEC, Fuel pump? There were only two there, but the looked like there was a mounting for a third. Maybe some one removed it all? I saw no wiring for a third though.


Looks like the relay is only $10-15 bucks
http://www.napaonline.com/masterpages/NOLMaster.aspx?PageId=470&LineCode=ECH&PartNumber=AR242&Description=Electronic+Engine+Control+(EEC)+Relay

 

[410Fortune]

3rd relay would be for AC, I assume you have AC living in CA

If the previous owner BYPASSED the EEC relay and wired it directly to power you may have an issue

But we are getting ahead of ourselves here, first lets find out where the yellow wire goes, or basically what the idle speed module is, I suspect its the PCM or TFI module.

Ignition problems on this truck almost always lead you to a bad TFI module

Search a bit on the TFI if you are not familiar with them.........no spark = first thing I check is the TFI after the coil is verified good

 

[Stic-o]

3rd relay would be for AC, I assume you have AC living in CA

If the previous owner BYPASSED the EEC relay and wired it directly to power you may have an issue

But we are getting ahead of ourselves here, first lets find out where the yellow wire goes, or basically what the idle speed module is, I suspect its the PCM or TFI module.

Ignition problems on this truck almost always lead you to a bad TFI module

Search a bit on the TFI if you are not familiar with them.........no spark = first thing I check is the TFI after the coil is verified good

Coil is good, I just replased it, but there is no spark there, but it relates to that stupid fuse. The EEC relay makes some sence actually.

and Yes, it has A/C, and works Great!!! R12 is still good in it, I ran it all the way to my dad's the other day and it got dam cold in there

 

[Albino 94LTD]

Are you sure it's spark and not fuel? I have an intermitten fuel pressure issue I haven't started to deal with on my '88

 

[410Fortune]

intermittant fuel pressure issue and 1988 = first check for gas inthe vacuum line that feeds the pressure regulator

Then listen to the boost pump in the tank.

If th eboost pump is weak or dead the truck can still run, but suffer from low pressure at times because the high pressure pump is not being fed with enough gas.

 

[Stic-o]

Are you sure it's spark and not fuel? I have an intermitten fuel pressure issue I haven't started to deal with on my '88

Yes, that was the first thing I checked, there is no spark at the coil.

 

[Albino 94LTD]

intermittent fuel pressure issue and 1988 = first check for gas inthe vacuum line that feeds the pressure regulator

Then listen to the boost pump in the tank.

If the boost pump is weak or dead the truck can still run, but suffer from low pressure at times because the high pressure pump is not being fed with enough gas.

[hijack]

When she dies, she dies. Last time it took 35 minutes before it started back up agian. No pressure at teh schrader in the rail.

What kind of sound does the tank pump make, it's not a whine like the X is it?

[end hijack]

 

[Stic-o]

Ok she's running again...sort of

I replaced the EEC relay, you were right Jamie, that is exsactly where that wire went. I now here the relay click when I turn the key on Not that I evered payed atention to it before Fuse does not blow, but there is still a problem. She still idling crazy. 500-1000rpm up and down. You can here a clicking from in the disributor that kinda goes with the idling if that makes sence

I'm thinking the TFI is screwed up. I remember the guy I bought it from said it Idle weird so you set the idle a little high at and it ran fine. When we changed everything (plugs, wires, cap, rotor) we didn't touch the idle. It seem to run great, and idle fine. I need to some homework on this TFI thing, Jamie what are my options if I replace it?

 

[Stic-o]

Ok so we never did figure out what this idle speed mod is. I have a feeling it's part of the TFI. Yeah!

accoring to my Haynes book, The EEC Relay goes to the coil,o2 sensorand the computer. So we know the Coil is getting juice again. I noticed the coil is attached the distibutor of corse, and I woderful friend TFI. Now my question is could I get a backfeed or something from the TFI, and it go all the way back to that fuse at the starter solinoid? Am I crazy here? I'm no Electric guru here...

 

[Turdle]

Is this a mechanical distributor-with a vacuum advance advance plate?