Frequently Asked Questions

This is a list of forum questions that have been asked fairly often, some info I had, and it also includes tips for some maintenance procedures.
Disclaimer: This is not the gospel according to this forum. Merely what we have found and shared with each other. You have to draw your own conclusions, and make your own decisions. It is your bike after all. Everything listed here pertains to the TC88 unless specifically addressed to the EVO or older engines. Keep in mind that as Harley changes the ECM some of these tips may no longer apply, a good example is the 2004 and later series of bikes which are supposed to have a bus mastering system as opposed to separate wire inputs.
If you have anything to add, whether it is in an area already listed here, a totally new area, or a disagreement with something posted here, send me an email
Click on the link below to see the information in that subject area.

TC-88 Head differences courtesy of Tom @ AMS
1999-2004 heads have 8mm valve stems, single groove valve locks, progressive wound "cylindrical" valve springs, postitive stem seals...
2005 heads are different from earlier and later heads ...
2007 heads have 7mm stems, top hat stem seals, "beehive" valve springs, triple groove valve locks, smaller exh valves, different intake manifold mounts, different (read slightly better intake, worse exhaust IMHO) port shapes, There are two different castings ...they can be identified by their casting marks, a "P" with a "+" overlayed (we refer to them as +P castings) or an "M" with flames trailing (we refer to them as Flaming M heads). As far as stock head, the +P heads have "smoother, more consitant ports, and flow slightly better;
2006-08 heads are the same as 09 , except the front 09 head has an extra tapped boss for the different motor mount/frame that the 06-08 heads do not have...although some 06-08 castings have the boss, which can be drilled and tapped for '09 use (found on the '06-'08 Flaming M heads).
Intake manifold bolt hold/ port mating applications:
1999-2005 (note while either MM and Delphi manifolds will mate to heads, they are not interchangable)
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Bank Angle Sensor:
The Bank Angle Sensor is used to shut down the ignition if the bike goes off vertical (you lay it down) by more than 45 degrees. The Bank Angle Sensor (sometimes called the tilt switch) has nothing to do with the turn signal cancellation circuits even though in new bikes it is part of the Turn Signal Module or Turn Signal Security Module.
It's got a hall effect sensor built into it, that's why it's a 3 wire sensor. When the BAS is upright, it puts out something slightly over 0.6 volts dc, and when it tips over, the voltage jumps up over 3.1 volts DC.
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Cam Position Sensor:
The Cam Position Sensor is checked with everything connected and powered up as it needs a reference voltage 5V, and the output on a good sensor should be either >1VDC or 6-10VDC depending where the ridge on the cam gear is positioned with a static engine. While cranking you get a square wave of a little under 4 VDC, but as little as 2 VDC is acceptable.
The Cam Position Sensor was dropped from the TC88 in 2000 or 2001.
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Crank Position Sensor:
The Crank sensor is checked with the ECM disconnected and generates an ACV signal that on a really good sensor is almost 2VAC, but the minimum spec is only <1 VAC. You also want to make sure the resistance to ground is more the 1MOhm.
On a new Crank Position Sensor the resistance between the red and black wire is 1.047k ohms. Just waving a paperclip in front of the new sensor produced an AC voltage of .456.
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EFI Fuel Pump:
The EFI fuel pump is cooled by the gas it sits in, do not run low on fuel for too long a time or the fuel pump may burn up.
Fuel Pump pressure: 43 or 44 psi is where the MM EFI systems run, the Delphi EFI systems run 55 to 62.
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EFI Throttle Position Memory:
The ECM has a memory cell that remembers what the lowest throttle position value is, so the system recognizes that the engine is actually at idle. Off-idle, the ignition timing is handled differently, and won't idle nearly as smoothly if the ECM thinks it is at off idle. If you have to turn the idle down, that's not a big deal, because it will still acknowledge the idle position, but if you have to turn it up, then it assumes it's off-idle, advances the timing, and the idle speed jumps up a few hundred rpm. You know you're fighting it when you cannot get 1000 rpm, fighting back and forth between 800 and 1200. Set it to 1200, then pull the 5A fuse overnight, put it back in and warm it back up fully and reset the hot idle.
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EFI Wandering Idle (MM systems, might work on Delphi):
Reset the ECM
1. Cycle the Ignition switch on and off 10 times, waiting for the fuel pump to do it's thing and the ignition lights too each time.
2. Take off the right side cover, pull off the top of a small black fuse holder there and remove the 5 and 10 amp fuses.
3. Wait 15 - 20 mins. Put the fuses back in and try it.
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Emissions Testing:
Dump a couple of ounces of gas line anti-freeze into the tank, basically alcohol that burns clean and dilutes the stock emissions. Also change the oil and have fresh plugs in it before you put it through testing.
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Engine Temperature Sensor:
You can use a DVOM to do a few tests. Unplug the ET and check the resistance across its 2 terminals. With the engine at a temp of 60 to 90 degs it should have 1.4K to 6.9k ohms resistance. you can unscrew the ET, cool it to 50F and test its resistance, it should be between 4776 and 7164 ohms.
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HD Customer Service Number
HD customer service hotline at (414-343-4056).
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HD Radio Source:
The radio in the Electra Glides is made by:
Radio Sound
1713 Cobalt Drive
Louisville, KY 40299-2499
Toll Free: 800-367-4506
(502) 267-6768 voice
(502) 267-6794 fax,
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Intake Air Temperature Sensor:
The IATS is on the rear of the intake manifold, inboard behind the throttle position switch. note: most often there is a small amount of corrosion on the connector and simply unplugging and reconnecting will fix the problem. Test its resistance with a DVOM. At 86F it should have 1933 to 2900 ohms resistance. Remove it and cool it to 50F, it should have 4776 to 7164 ohms.
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Manifold Absolute Pressure Sensor:
Troubleshooting: There are 3 wires terminating from your MAP sensor. One of them is your reference voltage from your ECM. Another is a ground wire and the other one is a signal return wire.
Check to insure there is voltage on the reference line (pin C R/W) If you have a reference voltage to the MAP sensor you need to pin into the other two wires:
A.) with the map sensor connected.
B.) do not use a ground on the bike.
With the MAP sensor connected to the harness, pin into the ground (pin A Bk/W wire)and signal return wires (Pin B V/W wire). Set your DVOM to "DC Volts" (if it's not a auto ranging meter set it as close to "over 5 volts" as it allows). Apply vacuum to the vacuum port of the MAP sensor. Your meter voltage should rise and fall with the vacuum being applied and reduced.
If the voltage doesn't rise/fall: That does NOT mean it's a bad MAP sensor at this point.
The first thing you want to do is check your ground wire for continuity/breaks. Use your DVOM set to "Ohms" (Ohmmeter) and check the ground wire from the MAP sensor terminal to the ECM terminal. You will need to disconnect both ends. (at this point, if the ground wire is good the MAP is _most_likely_ bad). If you have continuity in your ground wire check the signal return wire for continuity. If you have continuity in both and you have a reference voltage (and your MAP voltage has no change with vacuum applied/released) you have a bad MAP sensor.
If you have a good reference voltage and you *do* get a rising/falling voltage with the MAP sensor *connected* to the ECM harness, check your ECM grounds (-) and power (+) connections. If they are good, and the MAP sensor is good, you have a bad ECM.
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New Security Module Installation (TSSM):
When you install a new security module (TSSM) the ECM must learn to recognize it.
1. Install TSSM.
2. Remove the lighting fuse.
3. Set run/off switch to run, verify security lamp is not blinking - i.e. it is disarmed.
4. Turn the ignition switch on.
5. Press the starter button one time, bike will start and stall and will cause bad password DTC. Wait 10 seconds. The Security lamp will come on and the ECM will enter password learning mode. If ignition switch is cycled it will exit the learning mode.
6. After about 10 minutes the ECM completes the auto learn and the Security lamp turns off.
7. Quickly turn ignition switch OFF - ON. This has to be done real quick so the ECM does not shut down.
8. Repeat the steps from "wait 10 seconds" to "quickly turn ignition switch" two more times.
9. Turn ignition off and install lighting fuse. Give the bike about 15 seconds before you turn it back on.
Password learning complete.
Now you need to perform all the steps in the owners manual from vehicle delivery onwards.
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There is a lot of brand loyalty to be found, and that is a good thing, but it can make things confusing. HD uses an air cooled engine and whatever brand of oil you buy should be recommended for use in an air cooled engine. Air cooled engines get and stay hotter than engines that are water cooled in addition to the oil. Basically any oil that is formulated for an air cooled engine, in the right viscosity (20-50, 75-90, etc) for where you are using it, will work just fine as long as it is changed regularly. That said, synthetic oils do run cooler and have a higher (on average) temperature point where the oil starts braking down.
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Oil Filter:
HD oil filters and automotive oils filters are not the same animal. When they design a filter several things come into play. The pressure the oil is under, the size of the filtration media, the amount of oil per second which flows through the filter media under a specified pressure, and the pressure which will open a pressure relief valve if the filter element media gets clogged thus flowing oil around the filter but not filtering it. HD motors do not have the same oil pressure as an automotive engine does. The TC88 flows oil to the filter first and then to the engine, if the filter clogs up you want that pressure relief valve to operate as opposed to starving the engine of oil while pressure builds up. The following comes from a lot of research with guys who live and breathe this kind of stuff - food for thought.
The HD Oil Filter is made by Champion, but they would not give out specs due to contractual requirements. As advertised it has a 10 micron synthetic filter element.
WIX filters are better in terms of filtration. 5 micron synthetic element and have the same relief valve settings. (part number 51215 for black, 51225 for chrome) also carried by NAPA.
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Throttle Position Sensor:
Should be set for .42 volts by adjusting throttle stop with throttle backed off.
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Trouble Light on After Starting:
If it is staying on for approx 8 sec **after** the engine starts it means something was out of tolerance at one time, tripped a fault sensor, and there is a stored trouble code.
Only the dealers scanalizer can pull the code, translate it, and reset the memory so it is gone .... or after 50 starts it will go away by itself.
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TSM/TSSM Troubleshooting:
Invoking TSM/TSSM diagnostics
1: Set Run/Stop switch to off
2: Turn ign key ON-OFF-ON-OFF-ON
3: Press the left turn switch two times and release. *The signals flash 2 times for a Domestic TSSM
4: Press the right turn switch 1 time and release. *The signals flash 1 time.
5: Press the right turn switch 1 time and release. *The signals flash 2 times.
6: Press the right turn switch 1 time and release. *The signals flash 3 times.
7: Press the left turn switch 1 time and release.
   There is a 1.5 sec pause between flashes to distinguish between 1st and 2nd digit of codes.
   There is a 4 second pause between codes, then it will loop and repeat codes.
   If the light comes on for 4 seconds after invoking test then goes out for good, there are no codes stored.....test over....turn ignition off and wait at least 10 seconds before turning ignition on again.
8: To clear codes (after repairs) press and hold left turn switch for 4-5 seconds at end of test. * The signals flash 2 times to confirm your request.
11= Battery voltage high
21= left turn output fault
22= Right turn output fault
25= Ignition enable output high
31= alarm output low
32= alarm output high
34= starter output high
35= accelerometer fault
41= Ignition switch open/low
Possible causes for Trouble Codes:
11= battery voltage >16.0v/battery charger used/voltage regulator fubar'd. (pin 1 / Bn/Gy)
21= bulbs/shorts/bad connections if no voltage on pins 5 or 6 with 4ways on TSSM FUBAR'd
25= should be no voltage present on pin 10 with key off. (Lt Grn/Gy wire on TSSM)
31&32= Middle pin on siren goes low voltage to set off the alarm, high voltage to stop the alarm. If the siren responds with 3 chirps instead of 2 the siren battery is fubar'd.
34= Starter relay and coil are grounded via TSSM when disarmed and ignition on.
35= TSM/TSSM Fubar'd... bank angle and tamper will not function when this code is set.
41= Signals will not flash due to shorts, bad connections/wiring/bulbs/TSSM fubar'd
*If the turn signals flash six four way flashes shortly after key on, it indicates an error code has been logged sometime in the last 3 ignition cycles. On vehicles with TSSM, the security lamp will also light for eight seconds after the bulb check if historic codes are present.
*The security lamp will stay on if current code(s) are set. If a historic code is present, the security lamp will light for 50 ignition cycles or until the code is cleared manually.
*If the siren Chirps 3 times instead of 2 this means time for a new siren battery.
*There can be codes set in the TSSM without any visual indications ie: Security lamp/ Signals
*There needs to be 12.0vdc available from the main battery
*IF you render the key fob useless and did not program a personal override code in the TSSM, you are not only buying a new fob, you are buying a new TSSM as well. Once it learns a key fob, it learns no
TSM/TSSM Pinouts
1= Battery (Bn/Gy)
2= Ignition (Gy)
3= VSS/Serial Data link
4= Security indicator (Bn/V)
5= Left turn Feed (V)
6= Right turn Feed (Bn)
7= Right turn switch input (W/Bn)
8= Left turn switch input (W/V)
9= Start relay Control (Tn/Gn)
10= Ignition enable signal (LGn/Gy)
11= Alarm signal (Lgn/Bn)
12= Ground (Bk)

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Ultra Headset DIN Plug Pinout:
Looking at the 7-pin connector with the index groove in the connector at the twelve o'clock position, the bottom pin is #2. So clockwise from the index groove the pins are #6, #1, #4, #2, #5, #3, #7.
6 is the shield/ground (one o'clock position)
1 is the microphone input (three o'clock position)
4 is the microphone ground (five o'clock position)
2 is the speaker ground (six o'clock position)
5 is the left speaker positive (seven o'clock position)
3 is the right speaker positive (nine o'clock position)
7 is the handheld PTT (eleven o'clock position)
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Ultra Headset DIN to Walkman Adapter:
These people sell a plug that converts the connector on your bike to a walkman type headset plug so you don't need to worry about the above information. - 5 pin DIN to 1/8" converter (part number 95088)
Allows you to listen to your bike's audio system through any pair of WalkMan-style, personal stereo headsets.
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Spots on with high or low beam:
This is one way to do it, there are others. Behind the fairing is a single pin connector tucked up by the radio area. In the schematics it is connector 109A/B/C.
1. Disconnect this connector
2. Measure each end of the connector with the ignition switch on and the spot switch on (multimeter or 12v trouble light will work)
3. The end that HAS 12v on it needs to be taped up so it does not short to anything - it will no longer be used. This 12v is coming from the low beam voltage and feeds the spot switch, that's why when you go to high beam you lose the spots because the high beam switch removed the low beam voltage.
4. Find 12v (typically orange/white wires have 12v on them when the ignition sw it turned on) and feed the other connector that did not have voltage when you did step 2.
5. Done.
note: this works for the bikes down under too. In Australia the spots are only allowed on with the high beam, so instead of connector 109A being mated to 109B for downunder bikes it is connected to 109C which feeds the spot switch the high beam voltage.
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Charging System checks:
1. First and foremost load test the battery. Most places like AutoZone will do it for free. Even if it measures over 12.5 vdc it can still be bad under a load. Battery is typically rated at 19 amp hours and 270 Cold Cranking Amps (CCA).
Start the engine and measure DC Volts across the battery terminals, the regulator should be putting out 14.3 - 14.7 vdc at 3600 rpm and 75 degrees F.
2. To check the regulator unplug it from the stator. Take a test light and clip it to the negative terminal of the battery and then touch first one pin and then the other on the plug that goes to the regulator. If you get even the slightest amount of light from the test light the regulator is toast.
To do this with a meter: black lead to battery ground, red lead to each pin on the plug, start with the voltage scale higher than 12vdc and move voltage scale down in steps for each pin. Any voltage is a bad regulator.
3. On the other part of the disconnected regulator plug. Set the multimeter for Ohms x1 scale and measure for resistance across the pins of the stator. You should read something around 0.1 to 0.2 ohms for the TC88 32 amp system.
4. Then check for continuity between each pin on the plug and frame/engine ground. The meter needle should not move (infinite resistance)(digitals will show infinite resistance) if the meter needle does move (indicating continuity)(digitals will show some resistance), recheck very carefully. If the meter still shows continuity to ground the stator is shorted (bad).
5. Set the meter to read A/C volts higher than 30 volts (the scale setting for voltage should always be higher than the highest voltage you expect or you may fry the meter). Start the bike, and measure from one pin to the other on the plug (DO NOT cross the multimeter probes! - touch them to each other). You should read roughly 16-20 vac per 1,000 rpm.
6. If the battery was good under load test, if the stator is NOT shorted to ground, and the stator is putting out A/C voltage, then the regulator is bad (most likely even if it passed step 2).
Generally the following is true:
    22 amp system produces about 19-26 vac per 1,000 rpm, stator resistance is about 0.2 to 0.4 ohms.
    32 amp system produces about 16-20 vac per 1,000 rpm, stator resistance is about 0.1 to 0.2 ohms.
    45 amp system produces about 19-26 vac per 1,000 rpm, stator resistance is about 0.1 to 0.2 ohms.
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No Fuel Flow (carb):
The petcock on most bikes is vacuum operated, using vacuum from the intake manifold. This means that inside the petcock there is a vacuum diaphragm that, when there is no vacuum stops the flow of fuel. Either the diaphragm can wear out, get a hole in it from something in the fuel flowing past that the screen did not filter out, or the vacuum hose from the intake manifold to the petcock can leak.
If you isolate the problem to a lack of fuel (assuming you have plenty of fuel in there):
1. Open the gas tank fuel fill cap and try again. If it starts and runs then most likely the air vent hose for the tank is clogged up and as a result the tank will not flow fuel.
2. Turn the petcock to 'reserve' and try again, if it starts and runs the petcock screen inside the tank is clogged above the reserve position and needs to be cleaned. - otherwise ...
3. Disconnect the vacuum line from the intake manifold and petcock, plug one end and suck on the other, it should hold a vacuum.
4. Disconnect the fuel line from the petcock, install the vacuum line on the petcock, with the fuel flow switch in main suck on the vacuum line a little, fuel should flow out of the petcock. If it does you have a fuel line to carb/carb problem.
5. No fuel flowing is either a clogged petcock screen or hopefully a broken diaphragm.
6. Turn the petcock to off, loosen the large jam nut on the base of the petcock and turn the petcock so you can see the back side of it.
7. Hold the back of the petcock to the body and remove the four screws. The body is spring loaded.
8. Slowly let up on the pressure and allow the back side of the petcock body to move away from the petcock. Look in there. Observe which side of the diaphragm the spring is on.
9. Very gently turn the petcock valve to main and fuel should flow - if it does not the screen is clogged. If it does ...
10. Put the spring on the other side of the diaphragm and reassemble. Turn the petcock back to where it is supposed to be and tighten. Connect all lines. Start the bike.
note: This makes the petcock "free flowing", when you stop the bike shut the petcock off. If you do not Murphy may rise up and get you. Occasionally the engine stops with a cylinder in the intake stroke and it provides just enough vacuum through the intake valve (which is open at this time) to start a siphon action. The gas from the carb is sucked into the cylinder and since the petcock is freeflowing it does not stop. The cylinder fills with fuel and washes out the rings allowing gas to fill the oil pan. Real messy when you hit the starter button and gas/oil starts spitting out on the ground.
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Bleeding Brakes:
Go buy a trigger pull oil can (the kind that when you pull a trigger (lever) it squirts oil) and label it "DOT5" so you don't use it for anything else and contaminate future brake fluid. Then a small diameter piece of hose is clamped over the nozzle where the fluid squirts out.
1. Remove the top of the master cylinder.
2. Obtain an old syringe or something (turkey baster) to suck out the excess fluid in the master cylinder.
3. Put DOT5 in the new "oil can" and gently squeeze the lever until the hose on the end of the nozzle is full of DOT5.
4. Loosen the brake bleed screw slightly and slide the end of the "oil can" hose over the brake bleed screw.
5. Squeeze the lever. This will squirt brake fluid into the brake bleed screw and force fluid **up** the brake lines to the master cylinder. Air in the lines will float up the lines also.
6. Observe the master cylinder and as necessary remove some brake fluid as it fills to overflowing.
    note: Sometimes it helps to tap the brake line with a wrench to "jog" the bubbles loose. When doing dual disks I always start on the brake cylinder on the left (farthest from the master cylinder), not sure if this is necessary or not but it makes sense to me.
Untried by me but some say you can use an old IV bag and tubing. Fill the bag with DOT5, connect the tubing to the bleeder. Fluid tends to reach its own level so if you hang the IV bag higher than the master cylinder it will flow up the lines and into the master cylinder (of course you can always apply pressure to the IV bag and force the fluid up the lines). Remember to siphon off the fluid entering the master cylinder as it starts to overflow.
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Changing Fork Oil (non-cartridge type):
There are a couple of ways to do this, but regardless the valve core for the front air adjustment must be removed first - bleed off the air before removing the core or figure on chasing the core around the garage.
1. After the core is removed, remove the fork drain plug and catch the fluid that comes out in a can or whatever.
2a.  Option One:
    1. Insert a tube into the fork oil drain hole with the other end of the tube in a measured amount of fork oil.
    2. Apply suction to the air fill adjustment valve and suck the fork oil up into the fork.
    3. Remove the tube in the drain hole and quickly replace the drain plug. It helps if vacuum can be maintained on the air valve by an assistant or by clamping off the tube that connects the vacuum device to the air fill valve.
2b.  Option Two:
    1. Get another trigger pull oil can (see bleeding brakes) and label it fork oil. Fill it with the appropriate amount of fork oil (you may have to fill it more than once depending on how much it holds).
    2. Put a hose on the end of the 'oil can' nozzle and insert the tube into the fork oil drain hole.
    3. Squirt the fork oil into the fork by repeatedly squeezing the trigger.
    4. Pull the tube and insert the drain plug.
3. Install the air fill valve core and add air.
note: Some of us have found that it helps if you locate a bolt that fits the drain plug threads and center drill it to act as a tube, then the hose from the oil can can be clamped to this bolt.
Untried by me but some say you can use an old IV bag and tubing. Fill the bag with the right amount of fluid, connect the tubing to the drain hole and walk away. Fluid tends to reach its own level so if you hang the IV bag higher than the fork it will flow up into the fork (of course you can always apply pressure to the IV bag and force the fluid into the fork).
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Trouble Codes:
The following trouble codes are valid up to 2002 bikes (I only have shop manuals for 99 and 02 so I can't speak to any newer bikes). Keep in mind that though a trouble code calls out a specific component, the actual problem may be in the component circuit. A good example is that code 24 will call out a bad coil, but a bad spark plug, or no compression will throw this fault too.
11Throttle Position Sensor (EFI only)
12Barometric Pressure Sensor (EFI only)
14Engine Temp Sensor (EFI only)
15Intake Air Sensor (EFI only)
16Battery voltage low
21,22Turn Signal bad (21=left, 22=right)
23,32Injectors (23=front, 32=rear) (EFI only)
24,25Coil (24=front, 25=rear)
31,32Alarm output bad (31=low, 32=high)
33Fuel Pump Relay (EFI only)
34Idle Speed Control (EFI only)
41Crank Position Sensor, Check Engine light bad
42Cam Position Sensor (removed from tc88's in 00 or 01)
43Security Status Power, Vehicle Speed Sensor
44Bank Angle Sensor
52,53,54,55ECM fail (EFI only)
56Crank/Cam timing
61no TSM/TSSM data
63ECM/TSSM serial data
99bad password
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EVO Misc:
1991 EVO engines use 5/16 automotive fuel line hose for the oil system lines.
Thermal breakers for the 30 amp main and 15 amp subsytems can be purchased from the automotive BUSS fuse racks.
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Tail Lights:
The front of the bike uses a light that holds a dual filament bulb (the part that lights up is a filament) so it has running lights (on all the time) and directional signals (flash when needed). The rear lights are single filament lights and are used only for directional signals. There are several options to make the bike more noticeable to folks behind you.
1.   Buy two of the front light housings and mount them on the rear. All you have to do is run one extra wire to each. This extra wire connects the running light (on all the time) in the rear light to the running light in the new light housings. To find out which wire in the new housing is the running light, jump 12v to each wire and the wire that is the dimmest is the running light.
2.   Buy and plug in any of the "black boxes" that use the stock single filament to light and blink when necessary. (Don't ask me how I feel about black boxes - <grin>)
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Stage One:
Stage One mods to the bike really wake it up. HD has to restrict the breathing on the bike to get it past the emissions requirements. Basically what you are doing is to open up the air intake and the exhaust allowing the motor to breathe the way it was meant to.