"Cam's Ol' Blue"- 1986 F-150 Base Ex-State of Oregon

[ArdWrknTrk]

So, let's look at those pages...
I see a resistor in line before the dg/y goes into the ECA, but I don't see a tach output.








Was the EEC 4.9 never available with a tach?

[thefraze_1020]

Well if that is the case, that would be one (unfortunate) answer to why my tach doesn't work.

[ArdWrknTrk]

I honestly don't know Cam.

We should get Dave (Fuzzface) or David on the case because it surely seems unlikely that a tach wasnt an option on your truck.

I'm only looking at the diagram shown in the EVTM, but they deal with specific circuits, not the whole thing.

[ArdWrknTrk]

I'm a dumbass.
It's right there on the first page pointing straight up, wire 11 (see pg 95)



640 r/y hot in run. Lower left



60 bk/lg (ground)

[ArdWrknTrk]

Sorry
It's hard to do this on a phone.  

[FuzzFace2]

ArdWrknTrk wrote

I honestly don't know Cam.

We should get Dave (Fuzzface) or David on the case because it surely seems unlikely that a tach wasnt an option on your truck.

I'm only looking at the diagram shown in the EVTM, but they deal with specific circuits, not the whole thing.

Good you found it as I don't know how much help I would have been.
My truck is an 81 with a 300 six and all I had to do was swap in the tach gauge cluster and it worked.
So if anything had to be done at the ICM area to get the tach to work I did not need to do.

Yea looking at the wiring on a phone can be hair pulling
Dave ----

[Sac79]

I swapped in a tach cluster and did not have to do anything either. And I had EEC. Not sure if it will work now with the HEI, I'm hoping so.

Here's a pic for reference. All the nuts are tight.

[ArdWrknTrk]

I think it should be easy enough to 'prove' ground, key on power and that the all important tach pulse wire is good all the way to the coil.

There are only a few connectors that might be corroded. (easy to check, and clean)
At least we can follow the whole circuit now.

If all that works it must be the tach.

[Gary Lewis]

There's only one more connector, C169, and it is said to be a brown 2-pin near the fuel pump relay, meaning on the driver's side of the firewall between the brake booster and fender.

[ArdWrknTrk]

It's shown on pg 95 (above) which seems to be the correct page for a 4.9 w/EEC

Which EVTM are you using Gary?
Is it on this site?
Maybe I missed it

[Gary Lewis]

Sorry, I missed that you'd posted that page already.  And that one is from the '86 EVTM.  The one I'm using is from the '85 EVTM, both of which are on the site.  

Both are correct for all trucks in the circuit we are referencing, meaning the tach.  The only difference is that for 1985 and earlier the wire was black with light green dots.  In '86 the dots turned into stripes.

However, lots of other things are shown on those pages, and in particular the fuel tank switching arrangement did change between trucks with different engines and # of tanks.

[ArdWrknTrk]

When i go to electrical I only see the '81 & '86 EVTM.  
If I had known the correct year was there somewhere I should have used it.

[Gary Lewis]

Say WHAT?  You can't even see the '84 or '85 that lie between the '81 and '86?  

[ArdWrknTrk]

I get this:

[ArdWrknTrk]

No wonder it's more frustrating for some of us than others.

[Gary Lewis]

You are seeing a years-old menu.  Note that yours starts with Ammeter, and misses out the 3G Conversion and Alternator pages.

Could you clear the cache?  There's something seriously wrong and I think your browser is remembering the site the way it was two years ago.

[ArdWrknTrk]

Ok, I wiped cache, I still see the same menu.
Maybe it's a Chrome thing?

[FuzzFace2]

Gary Lewis wrote

You are seeing a years-old menu.  Note that yours starts with Ammeter, and misses out the 3G Conversion and Alternator pages.

Could you clear the cache?  There's something seriously wrong and I think your browser is remembering the site the way it was two years ago.

If Jim is on a phone how would you do that?
Don't think I have ever heard of it done on a phone but guess there has to be a way?
Dave ----

[ArdWrknTrk]

I can, and did!

Chrome version 80.0.3987.162

[Gary Lewis]

I'm using Chrome on my Windows devices, but Safari on my iPhone.  However, I just tried Chrome on my phone and it shows the whole menu.

Maybe try another browser?