Tachometer not working

[BPaulsen]

Following the advise given by fellow TDR members when reading up on the topic of tachometers and installation using the search function, I ordered for my '92 an



ISSPRO R5503 tach (that's the "enhanced visibility" unit) and the ISSPRO R8912-92 "sensor kit" (installation kit), made specifically for the later 1st. generation Rams that have the 4-wire connector below the dashboard, as well as the R7602 gauge holder kit.



Although the diagrams supplied by ISSPRO could be better, less confusing in regard to where on the back of the gauge the wires need to be attached, installation is not rocket science, since there are only 4 wires to attach: green for the gauge light, black for ground, red for power, and white for the actual tach signal.



Long story short, tach is nicely installed in "perfect" location, light works, but tach doesn't.



I removed the 24V resistor, soldered all connectors, double checked every connection, called ISSPRO's tech support, but can't get the tach to work.



My questions are:



1) HOW, as in FROM WHERE, or IN WHAT WAY, does the tachometer get the "signal" with the stock connector in place, since there are no magnets on the harmonic balancer?



2) HOW can I check the signal, if possible?



3) Does anybody have any idea what the problem might be, as in where to look for it, and how to proceed?



Thanks!

 

[dpuckett]

Looking at your volt gauge, it looks like you need to turn it on, first. Seriously, check the gap for your crank sensor- should be . 050" +/-. 001" It is about 10:30-11:00 as you look at your harmonic balancer.



Second, do a search on tach function. Lots of stuff recently (last year) on this very topic. You could need more stuff. Or just order the tach sensor kit for the 89-91 trucks.



Daniel

 

[BPaulsen]

now works!

Thanks, Daniel!

In fact, I did the search again, and read and read and read and now the tach works.



What was the problem?



Well, the factory ISSPRO harness with the BUILT-IN FILTER (small circuit board protected by red shrink tube) was the problem. I read about another member having been unable to get a signal, so I unplugged the gray wire deep down at the factory plug, and held a plain wire up to the tach and voila! . . . without the filter it works!



Now I'll open the ISSPRO wiring harness, remove the filter, then solder everything back together without it, the right way.



Boy . . . I sure learn a lot on this board!

 

[MBergman]

That's the same tach I'm planning on installing, even though the pointer is white instead of red like ALL my other gauges.

Quick question(s) for you. How are the wires attached to the back of the tach? Are they just simple blade connectors? It sounds like I may be able to just wire it myself to the connector, since the filter and the resistor are both not needed. I've got a pigtail that plugs into the factory pigtail I'm using to light the other gauges.

Marc

 

[BPaulsen]

The wiring diagram provided by ISSPRO is a bit confusing, but assuming your truck acts the same way like mine (doesn't like the filter), you can indeed wire it yourself (if you really want to save the $20).

What you need is 4 of those very small female connectors which you attach, with wires, to the factory thingi under the dash.



You then need 2 regular-sized female connectors and 3 small blade or ring connectors to be attached to the gauge's back.



Wait . . . that's 5!



Yes, you'll have to bride the gauge's ground to the bulb's ground, assuming you want your light working.



Instrument light automatically works with dimmer. Still WAY TOO BRIGHT (and orange), so I'll have to paint the two tach bulbs with green glass paint for some consistence with the stock gauges.



If you have any problems let me know and I take a photo of the tach's back when I have it out (takes but 30 seconds to slide it out).



Hindsight: since the EV unit was CHEAPER ($120) than the regular one, I opted for it. But since I personally like it to look as close to the stock gauges, I would buy the regular one, if I had to do it again.

 

[unclemarc]

tach

I have the same tach and had the same problem,after a half dozen phone calls to isspro I finally got it straightened out. Hooked the tach up per instructions worked but no light,switched ground on back of tach,tach didn't work but had light. After last final phone call they told me to put a small "jumper"wire between posts on back of the tach{if I remember correctly}works fine now. marc

 

[dpuckett]

Ok, let me see if I got this right. With the EV series tachs, it wont work withe the wiring harness, but it seems the regular series tachs WILL? I am confused. If someone wants to send me the filter and other doo-hickie, along with some instructions, I'd pay shipping. I got a quote from ISSPRO for $44. xx for the wiring kit I can live without it for that.



Dieselman359 (where has he been, anyway?) said hw was having problems getting his to work, til he got the plug in from ISSPRO, and then it worked. Weird.



DP

 

[BPaulsen]

The final verdict

Don, the tech master from Isspro called me, and we had a chat that cleared the whole thing up.



So let me summarize, for everybody else out there:



First of all, you can get the ISSPRO wiring harness R8912-92 for exactly $21. 83 from Piers (latest price 01/07). It's nicely done, with gray housing, that blends pretty nicely into our dashboards.



The wiring harness has 5 wires, of which we only use 4: red for power, black for ground, green for light power, and then EITHER the white one or the yellow one for the tach signal.



If you have the 2-1/16 standard series tach, you need to connect the white wire with the soldered in "filter" for your tach signal.

If you have the 2-1/16 EV series or the big tach, you need to connect the yellow wire without the filter for your tach signal.



So if you have a truck from 91. 5 on that has the factory tach connector below the dashboard, AND you want to hook up a standard tach, you really need the kit. Twenty-one bucks well spent, and I personally would buy it anyway. Yes, you can make probably make one for 5 bucks, but what's your time worth?

 

[Sri Ram]

So if you have a truck from 91. 5 on that has the factory tach connector below the dashboard…

As a point of clarification, my 91. 5 doesn't have the under-dash hook-up. Oh, and it's sounding like a lot less of a headache to buy the vibration damper sensor kit at this point.

 

[MBergman]

Thanks for the info. I'm going to be using the EV series, so it looks like I get to save the $20!!! That's a weeks worth of fuel to run 2 more wires up to top of the dash. I'm cheap and can spare an extra 5 or 10 minutes. The factory plug for the tach is the exact same connector as the cruise control switch connector behind the horn pad. I had an extra set of connectors from a salvage yard Dakota I'm using now.

Guess I'll be calling Isspro to see if they will build me a tach with the orange pointer.

Marc

 

[MMeier]

As a point of clarification, my 91. 5 doesn't have the under-dash hook-up. Oh, and it's sounding like a lot less of a headache to buy the vibration damper sensor kit at this point.

How does this kit work? I'm trying to use a tach that was getting its signal from a pick up mounted in the bellhousing before. Swapped to a NV4500 and do not want to take the chance of cracking my new bellhousing, what are my options? Tach is from S. S. White Technologies, they sold the tach division to Mr. Speedometer, but they are on "summer break" for another week. I want my tach working!!:{

 

[Sri Ram]

How does this kit work?

The kit is comprised of two magnets and a sensor. the sensor mounts on an oil pan bolt under the vibration damper. The magnets are glued to the damper 180 degrees apart. They produce two signals for every revolution of the crankshaft. As far as I know, the kit is designed to work with the ISSPRO gauge. Don't know if it will work with yours…You might find out more from ISSPRO technical help. Just call them.