The answer to one of our burning questions

[adsm08]

No, not gonorrhea. The tach question.

I have noticed that it pops up every so often, people asking if they can take a 1st gen tach cluster and throw it in place of their non-tach cluster. Some say it works, some say it doesn't. I've been looking over my own non-tach truck and my 88 parts truck that does have a tach, and I found the difference.

The 87 has one wire coming out of the coil's trigger port. The 88 has 2, one for the trigger, one for the tach test signal. Once I am done going over the harnesses I will post back with what needs to be done to make it work.

 

[superds]

I actually had more questions about herpes than gonorrhea...

I've put tachs on several non-tach vehicles and I thought it was simple as plugging in the tach sensor wire into the port on the coil? I didn't think there was a recurring question about it. I've never done this on a Ranger, but other Ford vehicles of similar vintage: 84 Bronco, 83 F150, 94 F150.

 

[adsm08]

I see it pop up every few months. Someone asks about it and no one can agree.

 

[superds]

I must just not be in the right subforums to see the questions.

I think what you've discovered already is pretty sound evidence that it would work.

 

[Twister]

Ive been wondering this, everytime someone asks it, everybody says it wont work. If it does then i am definitely getting a set.

 

[adsm08]

I must just not be in the right subforums to see the questions.

I think what you've discovered already is pretty sound evidence that it would work.

Oh, it will work, you just have to run the tach test wire. Haven't figured out exactly where that goes yet.

 

[AgPete139]

Do it, write and article, submit it to the Tech Library. Prove everyone wrong.

Personally, I have no experience with Gen I or II, only the tach I installed on my Gen III.


Good luck! Show us those pics, man!

 

[Ranger Dave (B25)]

AD, when you figure that one out, answer this:

Why does the tach on my B2500 suddenly jump up to 4500 rpm, and stay there until I hit a bump or tap on the cluster lens?

 

[jhammel85]

AD, when you figure that one out, answer this:

Why does the tach on my B2500 suddenly jump up to 4500 rpm, and stay there until I hit a bump or tap on the cluster lens?

Who knows! My truck does this from time to time too. But it's the speedo that does it to me..After that it reads incorrectly for a day or two.

 

[Twister]

Any progress one this, i am interested in putting in a factory tach?

 

['99 EB Explorer]

lol...i've added a tach before.

But it was a '96 Chev Caprice with an MSD ignition booster and it had a plug for a tach.

Easiest install I've ever done! lol

 

[adsm08]

AD, when you figure that one out, answer this:

Why does the tach on my B2500 suddenly jump up to 4500 rpm, and stay there until I hit a bump or tap on the cluster lens?

You probably have a bad wire that is grounding out, or a bad solder in the cluster.

Who knows! My truck does this from time to time too. But it's the speedo that does it to me..After that it reads incorrectly for a day or two.

I have no idea why your speedo would do that. You prolly need a new head tho.

Any progress one this, i am interested in putting in a factory tach?

I just haven't traced the tach test wire back yet. I'm pretty sure the tach and non-tach dash harnesses are the same. All the 86 to 88 dash harnesses are supposed to be the same.

 

[Twister]

I just haven't traced the tach test wire back yet. I'm pretty sure the tach and non-tach dash harnesses are the same. All the 86 to 88 dash harnesses are supposed to be the same.

What about for an 85?

 

[Ranger Dave (B25)]

You probably have a bad wire that is grounding out, or a bad solder in the cluster.

Something easy to fix, obvious to the naked eye? I know jack-cheese about chasing electrical gremlins, except that I don't care for it.

 

[adsm08]

Ok, so I'll update this at the request of 85_Ranger4x4.

My ultimate finding was that the plugs were wrong. The left hand head is part of the cluster body and cannot be removed for individual replacement. Also, the plug cavities in the body were different between the two. The pinouts were all sorts of wrong and the plug bodies were barely even the same shape, it wasn't even possible to jam the plug into the hole.

Given that I already wanted to take my dash out to clean and the 1st gen dash is not at all hard to remove I installed the dash harness from my donor truck as well as the instrument cluster after swapping my speedo head (I don't like the 88MY font on the odometer and that odometer actually pretty closely represents the real mileage on the engine I installed), and it works perfectly.

Unfortunately it looks like the swap is not plug and play, it would seem from what I found that you need the cluster and the harness. I didn't dig into possibly re-wiring the harness at all though. I also am not sure that it isn't a model year change since my donor truck was an 88 and the one I was putting parts on was an 87.