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Tech Support and FAQs

· Tachometer help · Volt Meter help · Headlight Relay help · Misc FAQs · Instructions · Ask Me ·


Tech Support & FAQs: Tachometers
  • Tach signal calibration - Your tach is calibrated for a standardized tach signal. It is recommended that you test that your signal is compatible with the tach prior to installation.
    Test the tach 'under the hood' (connect the tach leads to power, ground and signal temporarily) prior to installing the tach in the cluster.
    If the tach does not display RPM or the needle bounces, contact me for tuning instructions.

  • Signal strength - Older voltage sensing tachometers were designed to read a square wave signal in the 10 volts range. My new digital (by digital I mean 'electronic') tachs are also looking for a square wave. My new tach movements can handle up to 18V before they shut off for protection, but as configured from the manufacturer they are looking for 10V minimum signal. My old aircore movements were capable of reading from 9V to 18V and these are as well, but these have low as well as high voltage protection and they will go into a self protect mode (shut down) if the signal voltage is too far above or below the expected voltage.
    When doing the conversion I set the operating signal point to 10 volts to account for older ignition systems and MSD boxes. If your tach signal is lower than that you may need to install a signal amplifier. If your signal repeatdedly 'spikes' or jumps to higher voltage, you may need to install an inline signal filter like the SN-20.
    Checking your tach signal strength is easy. Use a volt meter and connect one lead to the tach signal source that you would connect the green tach wire to and the other to ground. With the engine running at approximately 1000 RPM set your volt meter to display AC or DC volts and compare the reading to the table below:

    Ignition type
    AC volts
    DC volts
    Points (stock)
    11
    8
    Pertronix
    9
    7
    MSD box
    3
    1.5
    Notes:
  • Points with ballast resistor.
  • Pertronix Ignitor w/o ballast resistor.
  • Values are approximate, yours may vary slightly.

  • Starting with S/N 5000 my tachometer movements are Digital-Analog. These tach movements receive the signal from the ignition and convert it to a digital input that the tach's logic chip can understand. The digital signal is read by the software burned into the chip and passed to a direct drive stepper motor that moves the pointer.

    There are some modern features that were not possible with the old D'Aresonal, Taut-Band and AirCore movements:

    1. When powered on, the tachometer will perform a self test. This test could range from some needle shake to a partial or full sweep by the pointer.

    2. The tachometer needle does not move or 'float' when the tach is turned. In fact, the pointer will not move below zero and will only move if forced.

    3. The tachometer needle does not require a stop pin at zero. The RTZ function moves the pointer motor to zero when the tach is powered off. Occasionally the RTZ function will not be able to park the pointer. If this happens, turn the ignition on and off, the pointer will park.

    4. Since the new tach has a microprocessor, it has some self protection features. Excessively high or insufficient voltage will put the tach into self protect mode. The tach will not work until the issue is resolved, then it will recover automatically.

    5. The tachometer is also protected against excessive noise on the input side. If your ignition produces an unusually 'noisy' or 'dirty' signal it may make the tach pointer twitch or even bounce. It can also keep the tachometer from working beyond the initial self test. If your signal is noisy you can install a tachometer signal filter to clean it up.

  • My new tachometer doesn't work - S/N 5000+:
  • Some things to check before returning the tach:

    1. When you apply power to the red wire with the black wire grounded, does the needle jump? If yes, go to step 3. If no:
      • Recheck that you are getting 12 volts to the RED wire when the engine is running and the BLACK wire is connected to a good ground (see step 4).
      • If you installed connectors to the tach leads, remove them and try it without the connectors.
      • If you are running an EFI system that uses the tach signal, see step 3.
      • See Checking your tach signal strength above.
      If you have power and ground and no movement then you have a defective tach. Please send it to me for repair or replacement.
    2. Verify that the tach is wired correctly for your ignition system. Your tach should be wired like an aftermarket tachometer:
      • Points or Petronix: Green tach wire connects to the distributor ( - ) side of the coil.
      • MSD RTR (Ready To Run) Distributor: Green tach wire connects to the distributor ( - ) side of the coil.
      • MSD box: Green tach wire plugs into the TACH PORT on the side of the MSD box. DO NOT use the MSD Tach Adapter.
      • Mallory Hi-Fire: Check your wiring instructions, but the yellow lead is usually the tach lead. Connect the green wire from the tach to it.
      • Duraspark or GM HEI: Connect the green wire from the tach to the TACH connection on the coil (Duraspark) or distributor cap (GM HEI).

    3. Low tach signal: When sharing the tach signal (with a system such as EFI) the tach signal may be too weak to trigger the tachometer. There have been cases where the newer MSD-6AL boxes with the gray tach signal output wire have not generated enough signal to trigger the tach. In this case you will need to contact MSD for a signal splitter or booster. Another option is to send the MSD box back to MSD for them to check/repair the output signal.

    4. Low input power: The tach will perform it's self test when the switched voltage (RED wire) is receiving 9 volts (DC) or more. However... The tach needs 10 volts (DC) to drive the needle. It is possible to get a successful self test and not get an RPM reading. For this reason, do NOT connect the tachometer RED wire directly to the + side of the coil. Ford ignitions have a ballast resistor (the infamous 'pink wire') between the ignition switch and the coil. Without a load (i.e. key on, engine off) the coil + post will show 12+ VDC. When running this voltage drops to it's ballasted voltage between 6 an 8 VDC. This is insufficient to power the tach. Make sure the power supply to the tach has full battery voltage when the engine is running.

  • My new tachometer doesn't work - Prior to S/N 5000:
  • Some things to check before returning the tach:
    1. Is the tachometer needle on the wrong side of the stop pin?
      Symptom: You can rotate the pointer backward (CCW) from 0 to 60 but not from 0 to 10 (CW).
    2. This can happen during shipping or if the tach loses signal or voltage while the needle is beyond it's 'tipping point'. The 'tipping' point is around 3500 RPM on a 6000 tach and 4500-5000 on an 8000 RPM dial.
      Caution: DO NOT try to lift the pointer over the stop pin! To correct this you have two choices:
      • Take the tach out and manually rotate the pointer counter-clockwise back to zero or
      • Reconnect the tachometer leads, start the engine and rev it past the tipping point. Once past the tipping point the needle will become active again. Reduce the RPMs to idle and shut down the engine. The needle will rest on the stop correctly.

    3. Does the tach move freely? If you gently rotate the pointer clockwise to 2500 and release it does it return to zero smoothly? If not, please read the "My tachometer needle sticks" section below. If it does, go to step 3.
    4. When you tap power to the red wire rapidly with the black wire grounded, does the needle jump? If yes, go to step 4. If no:
      • Recheck that you are getting 12 volts to the red wire and the ground is good.
      • If you installed connectors to the tach leads, remove them and try it without the connectors.
      • If you are running an EFI system that uses the tach signal, see step 5.
      • See Checking your tach signal strength above.
      If you have power and ground and no movement then you have a defective tach. Please send it to me for repair or replacement.
    5. Verify that the tach is wired correctly for your ignition system. Your tach should be wired like an aftermarket tachometer:
      • Points or Petronix: Green tach wire connects to the distributor ( - ) side of the coil.
      • MSD RTR (Ready To Run) Distributor: Green tach wire connects to the distributor ( - ) side of the coil.
      • MSD box: Green tach wire plugs into the TACH PORT on the side of the MSD box. DO NOT use the MSD 8920 Tach Adapter.
      • Mallory Hi-Fire: Check your wiring instructions, but the yellow lead is usually the tach lead. Connect the green wire from the tach to it.
      • Duraspark or GM HEI: Connect the green wire from the tach to the TACH connection on the coil (Duraspark) or distributor cap (GM HEI).

    6. When sharing the tach signal (with a system such as EFI) the tach signal may be too weak to trigger the tachometer. There have been also been cases where the newer MSD-6AL boxes with the gray tach signal output wire have not generated enough signal to trigger the tach.
      In this case you will need to contact MSD for a signal splitter or booster. Another option is to send the MSD box back to MSD for them to check/repair the output signal.
    These are general troubleshooting directions. The best thing to do is check with the manufacturer of your ignition system. For wiring purposes you are connecting an AutoMeter type electronic tachometer.
    • My tachometer needle sticks - out of cluster
    • Chances are the pointer assembly was jammed down onto the pivot shaft. Honestly, the best thing to do in this case is send it to me with a note explaining what happened. I will repair it and send it back to you at no charge. If sending it back is not an option please contact me.
    • My tachometer needle sticks - in the cluster
    • Check that the inside of the lens is smooth. Aftermarket lenses are notorious for having burrs in the center that make contact with the pointer hub causing it to 'stick'. If burrs are present remove them.
    • What about the original tach wiring?
    • If you have an XR7 or other model that came with a factory tach, you will need to install a jumper in the factory plug to complete the ignition circuit. You can use the original wiring as the 12VDC switched power source for your tach as well. Simply connect the red wire from the tach into the jumper.
    • Can I use the original wiring from the coil for my tach signal (green) wire?
    • No. The original wire from the ignition switch to the coil has a built-in resistor (the infamous 'pink wire') that will reduce the signal from the coil. The signal allowed back through this resistor will not be strong enough to drive the tach.
    • My tachometer is bouncing around at all speeds - what's wrong?
    • Depending on your ignition system you may need a line filter for your tach signal. This inline filter costs around $25.00 and is available here or from Classic Instruments. There is a wiring diagram for the SN20 in the Miscellaneous Wiring Diagrams section.
    • Prior to S/N 5000: My tachometer needle is on the wrong side of the stop pin!
    • This can happen if the tach loses signal or voltage while the needle is beyond it's 'tipping point'. This point is around 3500 RPM on a 6000 tach and 4500-5000 on an 8000 RPM dial. Caution: DO NOT try to lift the pointer over the stop pin! To correct this you have two choices:
      1. Take the tach out and manually rotate the pointer counter-clockwise back to zero
      2. or
      3. Reconnect the tachometer leads, start the engine and rev it past the tipping point. Once past the tipping point the needle will become active again. Reduce the RPMs to idle and shut down the engine. The needle will rest on the stop correctly.
    • What changes do I need to make to use one of your converted tachs?
    • The only changes are to the wiring. The converted tach will bolt right in using the original mounting holes and hardware.
    • What size wire should I use on my new tachometer?
    • The tachometer is wired with 20 gauge so 20 or larger (18, 16, 14, etc).
    • Where do I get the switched 12 volts needed for the converted tach?
    • If you had an OEM tachometer you can tap off the original tach wires (the two you connected or jumpered).
      If you have a '67 or '68 you can tap off the IGN side of the Instrument Voltage Regulator on the back of the cluster.
      If your cluster has the printed circuit on the back you can trace the IGN side of the IVR back to the connector or use any switched source like the radio or heater feed.
    • What do you mean by "with your core"?
    • If you are sending me your gauge as a core you do not have to pay the (refundable) core charge, but I will not ship your order until your core arrives. If you do not want to wait that long you can pay a core charge when you order, I will ship your gauge and then send you a check for the core charge when your core arrives here.
    • What do you mean by white pointer or orange pointer?
    • Some gauges had an orange pointer, or needle. Some folks want their white pointer changed to orange. It's easier for me to keep track of what someone wants when the pointer color is included in the order.
    • My factory tachometer stopped working. Can you fix it?
    • If by 'fix' you mean 'convert', sure. I do not repair or calibrate the OEM movements or circuitry.
    • My factory tachometer doesn't work. Can you convert it?
    • Certainly. I do not use the original movements or circuitry. I replace them with MODERN components.
    • Do you convert plastic or metal case tachometers?
    • I can convert either style.
    • Can I use a shift light?
    • Sure. Your tachometer is the same electronically as most aftermarket (Autometer, Sun, VDO) tachometers. Just buy a shift light add-on kit from Jegs or Summit and wire it per the manufacturer's instructions.
    • I've read/heard/been told that I should NEVER convert my tach to the minus side of the coil. Is that true?
    • Yes, it is true that you should not have your old technology original movement converted.
      No, it is not true that you shouldn't convert your tach. I can replace your 40+ year old movement and circuitry with a modern lifetime warranty tach movement for a fraction of the price of getting it repaired. And it comes with a LIFETIME warranty.

    Tech Support & FAQs: Volt Meters
    • I broke the tab off the bottom of the face. What do I do now?
    • This is pretty common. I'd say that 90% of the ammeters I get in for conversion are missing the bottom tab. The tab cannot be repaired or replaced, so I recommend you use a small amount of RTV silicone to hold the outer faceplate in place. Using silicone will allow you to separate them if you ever need to.
    • My Volt Meter doesn't work.
    • Check that it is wired correctly. A quick test is to reverse the wiring. You won't hurt the gauge by doing this and reversed wires is the most common reason for a new gauge to not work. Also, make sure that you have a good ground and that your power source is live when the key is on.
    • Do I have to use a switched power source?
    • If you don't the gauge will slowly drain your battery.
    • Can I re-use one of the original ammeter wires as my power source?
    • No. Both ammeter wires are 'hot' all the time. You want the voltmeter to turn on and off with the ignition switch.
    • What size wire should I use to connect my volt meter?
    • 20 gauge or larger (18, 16, 14, etc).
    • Where do I get the switched 12 volts needed for the volt meter?
    • If you have a '67 or '68 you can tap off the IGN side of the Instrument Voltage Regulator on the back of the cluster.
      If your cluster has the printed circuit on the back you can trace the IGN side of the IVR back to the connector or use any switched source like the radio or heater feed.
    • I wired my gauge backwards. Did I damage it?
    • Nope. Wire it right & it will work.
    • Why does the needle disappear when the key is off?
    • You have an older gauge with no stop, or your stop pin is missing. Send it back to me & I will add a stop pin.
    • What do you mean by "hold for my core"?
    • If you are sending me your gauge as a core you do not have to pay the (refundable) core charge, but I will not ship your order until your core arrives. If you do not want to wait that long you can pay a core charge when you order, I will ship your gauge and then send you a check for the core charge when your core arrives here.
    • What do you mean by white pointer or orange pointer?
    • Some gauges had an orange pointer, or needle. Some folks want their white pointer changed to orange. It's easier for me to keep track of what someone wants when the pointer color is included in the order.
    • What orange paint do you use for the pointer?
    • I use Hi-Po Parts "HP-FLRED".

    Tech Support & FAQs: Headlight Relay Kits
    • None of my headlights work
      1. Do the headlights work without the relay boxes (using factory connections)?
        If YES: Goto step 2.
        If NO: You have an unrelated issue. Check your fuses, headlight switch, battery, all connections, etc.
      2. When you turn the lights on and off does the controller box click?
        If YES: Check your power feed from the battery to the controller box.
        If NO:
        1. Check that you have the correct kit for your car: the controller plug with a silver dot on it plugs into the main harness of the vehicle. The controller plug(s) with no silver dot connect to the headlight harness. Early years (67-68) also have an A on one of the mounting ears of the controller.
          Another way to tell which controller you have is to look at the plugs. The 67-68 type A controllers have 1 male pin on the input (main harness) side and the 69-73 type B controllers have 2 male pins on the input connector. If you do have the wrong year contoller(s) contact me to get them exchanged.
        2. Check that you are plugged into the correct harness. The parking light plugs are also 3 wire plugs, but wired differently. (click here for printable step by step diagnostics of this problem.) Remove the box(es), reconnect the factory connectors and check that all lights work. Next, unplug the headlight harnesses and verify that the headlights do NOT work, then plug the box(es) into those connectors.
    • Only one side works
      1. Do the headlights work without the relay boxes (using factory connections)?
        If YES: Goto step 2.
        If NO: You have an unrelated issue. Check your fuses, headlight switch, battery, all connections, etc.
      2. When you turn the lights on and off does the controller box click?
        If YES: Check your power feed from the battery to the unresponsive controller box.
        If NO:
        1. Check that you have the correct controller box for your car: the controller plug with a silver dot on it plugs into the main harness of the vehicle. The controller plug(s) with no silver dot connect to the headlight harness. Early years (67-68) also have an A on one of the mounting ears of the controller. If you do have the wrong year contoller contact me to get it exchanged.
        2. Switch the contollers side to side.
          • If the problem moves with the controller you have a defective controller.Contact me to get it exchanged.
          • If the problem does not move with the controller check that you are plugged into the correct harness. The parking light plugs are also 3 wire plugs, but wired differently. (click here for printable step by step diagnostics of this problem.) Remove the box(es), reconnect the factory connectors and check that all lights work. Next, unplug the headlight harnesses and verify that the headlights do NOT work, then plug the box(es) into those connectors.
    • Do your kits work with 2 headlight systems?
    • Yes they do.
    • What's the main difference between the Mini and the Full kit?
    • The Mini uses one relay per circuit - low & high and one circuit breaker for all the lights. Much the same as if you added relays 'the old fashioned way'. The Full kit has seperate relays for each circuit and additional circuit protection for each side.
    • What Halogen bulbs should I use?
    • Direct replacement halogen bulbs are available from most car parts stores. For 4 headlight systems as #5001 (low beam - outer) and #5006 (high beam - inner) bulbs. For two headlight systems get #6014 and make sure it says HALOGEN on the box. These bulbs will go right in with no modifications.
    • Does your kit help if I keep my regular (non-halogen) bulbs?
    • Definitely. Many people do not switch their bulbs after installing a relay kit because of the improvement.
    • What kind of plugs does your HRKP have for the motors?
    • The motor leads have no plugs.

    Tech Support & FAQs: Others
    • My HR001 horn relay keeps blowing fuses!
    • There was a typo in the early instruction sheets that said to use a 10A fuse. This should be a 15A fuse.

    • Why are my Pedapter 001 voltages wrong?
    • The switchable Pedapter voltages are advertised as 12 and 9. In reality, the 12V line is B+ which is full battery voltage. Car folks say 12V instead of B+ so that's what I use in the description.The '9V' line is actually the OEM (stock) ballasted B+ line normally referred to as 'the pink wire'. Since it has a ballast resistor, the voltage will vary depending on load. With no load you will see higher voltage, but not full B+.

    General FAQs:
    • What is this " CA residents Prop 65 Warning" all about?
    • Anyone shipping anything into the state of California that has any trace of any of the 900+ chemicals on California's Prop 65 list - be it as part of the finished product or used in the manufacture of the product - may be fined up to $2500 a day unless the recipient of the product has been warned per Prop 65.
      Since a lot of the parts used in my products were manufactured in the dark ages of the 1960s and 70s and no one (but CA lawyers) knows what the definition of low enough exposure is, it is easier to display a warning to buyers with each product than it is to research each and every component.
      It's either that or stop selling to Californians and I don't think a lot of good sensible people should suffer because they have been overrun by liberals, lawyers, hippies, tree-huggers or misinformed well meaning voters. You can click on the warning to go to their website.
    • Do you offer your gauges in white face?
    • No. All gauges are made to look like they would have if FoMoCo had made them.
    • Can you give me your artwork so I can have white gauges made?
    • No.
    • Can I buy the parts from you and convert my own gauges?
    • No, I don't sell kits or parts for gauge conversions.
    • What are your shipping charges?
    • I ship one item USPS in the lower 48 for $10.00. Addition items cost more, as do Hawaii, Alaska and outside the USA. Please click on the blue 'Ordering' or 'Shipping' menu button for details.
    • Do you ship internationally?
    • Yes, I ship to most countries worldwide. Additional shipping fees apply, please click on the blue 'Ordering, Paying & Shipping Info' menu button for details.
    • How do I send my core to you?
    • Instructions for packing and shipping your core to me can be found by clicking on the blue 'Ordering, Paying & Shipping' menu buttons.
    • Do you sell LEDs and/or printed circuits for my gauge cluster??
    • No.
    • Do you buy cores?
    • Yes. I buy usable tachometers, clocks, clock deletes and some ammeters for cores. They don't have to work, but they do need to be in good shape. Note that I do not pay the same amount as I charge for a core. I charge more than they're worth so people will return them. Please refer to the 'Cores' section at the bottom of each product page for details about core condition.
    • Do you take cores as partial payment or in trade?
    • Yes I do. I don't necessarily need everything I sell, some are easier to find than others, but feel free to contact me and we will work something out.
    • Why are some core fees a lot higher than others?
    • Some cores are harder to find than others. If I notice that people are not returning cores for a certain product I raise the core fee to entice them to send in their old meter so I can convert it for someone else.
    • Do you convert dials to white face?
    • No. I used to sell white face tachometers for 71-73 Mustangs (the M7123TW), but only because the paint used on the dials from those years ages badly. If you want white face I can convert your tach after you apply the white face overlays.
    • Do you do speedometers?
    • I reface trip odeometers and paint speedometer pointers but am not set up for anything more than functional testing of the speedometer itself.
    • Can you recommend someone that does speedometers?
    • Not from personal experience. I suggest doing a google search.
    • I've read/heard/been told that I should NEVER convert my tach to the minus side of the coil. Is that true?
    • Yes, it is true that you should not have your old technology 40+ year old original movement converted.
      No, it is not true that you shouldn't convert your tach. I can replace your 40+ year old movement and circuitry with a modern lifetime warranty tach movement for a fraction of the price of getting it repaired. And it comes with a LIFETIME warranty.
    • What size wire should I use with my new tachometer / Voltmeter?
    • You should use quality 20 gauge or larger (18, 16, 14, etc).
    • Do I need to install a fuse for my new tachometer / Voltmeter?
    • Normally the line you are using for power is fused. If you want to add one, install a 1A fuse for tachometers and 0.5A for a voltmeter.
    • I have heard that you let people test your new products. How do I get in on that?
    • If you are interested in field testing something, click here.
    • I am interested in a product but it's "in developement". Can I order one now?
    • You can't order one, but if you email me I will put you on a list and contact you as soon as the product is available.
    • Do you fix or convert clocks?
    • Yes, I do mechanical clock repair on OEM movements and can convert many clocks to quartz if you like.


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