Tachometer

[TymeKeeper]

Ok, here is the problem: My Tach reads zero, when the key is off, normal, I turn the key to start it, the tach jumps to 3000 rpm, I start it, it jumps to 3500 rpm, and goes up and down from there. No more then 4000 though... what is the deal? I know it is an automatic transmission, and I don't really need it, but it is there and it is anoying.. Dead Link Removed any idea's??

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Jim
'92 Eddie Bauer Explorer
Dual 2.25 exhaust, no Mufflers
Drilled AirBox
Cobra 148GTL W/K40 Mag
235/60's
My Baby!!

 

[george]

YOU WOULD NOT BELIEVE THIS, I HAVE THE SAME PROBLEM WITH MY TACH. ITS BEEN ABOUT 1 YEAR WITHOUT AN EXPLAINATION. IF YOU HEAR OF A CURE TO OUR WACKY TACH PLEASE CONTACT ME. JUST TO TELL YOU, MY 92 EXPLORER HAS 89,000 MILES WITHOUT ANY PROBLEMS EXCEPT THE WACKY TACH.

GEORGE AT GRSJMS@AOL.COM

 

[TymeKeeper]

A friend of mine told me that it might have something to do with the distributer but I don't know, it is kinda expensive, and if that is all, well when I do replace it, that will fix my problem. Hopefully someone else will have some idea's.


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Jim
'92 Eddie Bauer Explorer
Dual 2.25 exhaust, no Mufflers
Drilled AirBox
Cobra 148GTL W/K40 Mag
235/60's
My Baby!!

 

[BarryM]

My tach is somewhat screwed as well. If I take its word for it, at highway speeds I'm cruising along at 1000 rpm and shifting around 9000 rpm. Right.

 

[BigDave]

Just so that your guys know, the Explorer does not have a distributor. It is an electronic ignition engine. Look under the hood and see where the spark plug wires start.

Just so you know.

Dave

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Big Dave
'94 XLT 4x4
modified air box
K&N airfilter
"Take her easy, and if she's easy take her twice.." (The trail I mean..)

 

[TymeKeeper]

That is what I meant, just couldn't think of what it was called.. Dead Link Removed

 

[Ken Hayes]

I was hoping to find a solution to my Tach problem.

Same problem just happened today after I pulled out into traffic in front of the Grocery Store. Key on - 3000 RPM rev maximum under 4000. If any one has found the answer, Please let me know. I will do the same. I will pull the Haynes manual out this week.


Thanks

 

[Big E]

I don't have this probelm but I might have an answer...If I understand you right..when you start the vehicle up the engine revs up to 3000 or 3500 rpm....if this is the case...it might be the air bypass valve (I think that is what it is called) it is located on the upper intake just after the tps on the right hand side... Hope this helps.

Eric

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I would rather push a Ford than drive a Chevy!

 

[TymeKeeper]

Nope, it is before I start the motor. When the key is on "on", then I start it, and it goes up from there..

 

[Big E]

Oh...well...I will ask my Electronics instructor tomorrow night and see what he says.

Eric

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I would rather push a Ford than drive a Chevy!

 

[gijoecam]

I had a similar problem in my 91 ranger (same dash then)... solution was a new tach... you don't need to replace the instrument cluster, or even take the old cluster out of the dash like it says in the shop manual. I watched the tech do it in about 10 minutes when I was working at the dealer... First, remove the trim ring from around the IC. Next, remove the screws that hold the clear cover on the IC. (I wish I could tell you how many there were, but that was like 6 years ago!) Then, using a small screwdriver, pry the edge of the tach out of the IC real gentle like... it should pop right out. Finally, pop the new one in, reassemble it, and viola! There you have it... good as new! What usually happens is that some of the windings on the back of the guage can break, gorund, or short, and that creates a semi-permanent field around the needle magnet... If you tried really hard and looked really close, you might be able to fix the old one, but I believe it's only about a $50 part, so it's probably not worth the headache. I'd find one at a junk yard and use it. Hope it helps.
-Joe-

 

[TymeKeeper]

I was thinking that, I just might have to try it out. I was thinking about the white faced gages too, might do that at the same time.. Thanx Dead Link Removed

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Jim
'92 Eddie Bauer Explorer
Dual 2.25 exhaust, no Mufflers
Drilled AirBox
Bosch Platinum plugs
Low Temp Pro Thermostat
Cobra 148GTL W/K40 Mag
235/60's

 

[Ken Hayes]

How to fix your Tach

I fixed my tach today without replacing it!!!! The reason the tach fails is due to its design. The coils that control the needle movement are mounted to brass studs that are fastened to a circuit boad with nuts. The pads under the nuts build up oxidation or corrode over time. When this happens, there is intermittent contact. If only one of the nuts loses connection, you will have an imbalance. Actually you lose half of the magnetic field, that's why the needle goes to 3K on the 6K tach.

Remove the trim bezel. Remove the screws holding the clear cover. Remove the cover. Pry the tach out.

You then can snug down the nuts on the back side for a temporary fix.

If your electonically inclined, disassemble the whole tachometer, clean the pads, reassemble, and solder the pad/nut/stud. That's what I did.

Replacing the guage is much easier though.

THANKS

 

[TymeKeeper]

Great, I might just have to tear into it!!!!! Thanx

 

[gpaps]

My tach does the same thing. Has anyone replaced the tach? If so, how much does it cost and how long does it take to fix?

 

[BarryM]

removing tachometer

Doesn't take long at all. Remove ashtray and assembly, remove radio, pull off dashboard trim, remove screws holding on clear plastic cover, then gently pry up and remove tach.

It gets a little tricky if you're trying to remove the entire cluster assembly, as you have to reach around the back and remove the speedometer cable - which may require disconnecting the speedometer cable at the transmission to provide yourself enough slack to reach in behind the cluster. You also have to remove the two screws holding on the gearshift indicator.

BarryM

 

[TymeKeeper]

But if that isn't the problem, then there is no point in doing it.. I'm not convinced that the tach is the whole problem... I personally thing that there is a wire under the dash that chaffing, or grounding out.. I have removed the tach, and cleaned it up, with minimum results. It started it when I mashed the gas petal really hard... Started right then.

 

[BarryM]

89 Mustang

I just replaced my tach today with one from an 89 Mustang. Seems to work ok, but I don't know how accurate it is anymore. Better than the old one anyway. I didn't replace the whole thing with the faceplate, just the motor itself. Mounting holes don't quite line up but I secured it good and you can't tell from the front.

B

 

[TymeKeeper]

I would think if the mustang tach reads close to what the original one did, then it should be pretty close anyway. I don't think the original ones are all that close as it is.

 

[sirhk100]

My tach is doing the same thing as described at the beginning of this post. I pulled it out this weekend and cleaned the contact points on the 4 nuts that hold the board to the tach. I also cleaned the posts that are inserted into the IC. This didn't fix the problem for me. Have any of you figured out a fix for it? Those of you that replaced the tach, did it fix the problem? Did you guys use tachs out of an EX or did you find them in a different donor vehicle? I'm going to try and pull the tach out of my friends Ranger and try it 1st to see if it works before I pay for a new one. Any updates on peoples attempts to fix this would be great!!!!