** TROUBLE-SHOOTING GUIDE **

[HondaFan81]

TROUBLESHOOTING GUIDE: CHECK THE BASICS FIRST!!


Check BATTERY for SECURITY.

Check BATTERY GROUND CABLE & NEG TERMINAL for Quality, Cleanliness & Security @ Battery.

Check BATTERY GROUND CABLE for Quality, Cleanliness & Security @ Engine Mount/Transmission.

Check BATTERY GROUND CABLE for Quality, Cleanliness & Security @ Fender.

Check U/H FUSE BOX GROUND CABLE for Quality, Cleanliness & Security @ RH Side of Engine Compartment.

Check BATTERY POSITIVE CABLE & POS TERMINAL for Quality, Cleanliness & Security @ Battery.

Check BATTERY POSITIVE CABLE for Quality, Cleanliness & Security @ Starter Motor Solenoid.

Check Starter Solenoid Wire for Quality, Cleanliness & Security @ STARTER MOTOR.


Check These FUSES in U/H FUSE BOX:

Fuse #15 - 80 Amp - Batt+ 12V.
Fuse #24 - 7.5 Amp - ECU/Radio/Clock Back Up
Fuse #28 - 10 Amp - EFI Main Relay Switching
Fuse #19 - 50 Amp - Ignition Source

Check These FUSES in UNDER DASH FUSE BOX:

Fuse#2 - 15 Amp - EFI Main Relay/TCU/EMCU/Fan Timer/Charge Light
Fuse #9 - 7.5 Amp - Starting Circuit

BATTERY VOLTAGE TEST.

Ignition OFF
Remove NEG Battery Cable, then Remove POS Battery Cable.
Select VOLTS
Connect RED MM Lead to BATTERY POSITIVE
Connect BLACK MM Lead to BATTERY NEGATIVE.
VOLTAGE => 12.7 Volts - OK
VOLTAGE < 12.7 - Check Battery Electrolyte Levels & Top Up If Necessary.

LOAD TEST BATTERY.

Connect Load Tester to Battery
Remove Cell Caps (If Applicable)
Apply Load to Battery for Max 15 Seconds.
Observe Load Tester - Voltage Should Hold Steady around 9.0 Volts and Battery Cells clear of Bubbles.
If Voltage Drops and Steadies between 6 - 9 Volts and clear of bubbles then Battery will need charging.
If Volts drop slowly towards 0 - 3 Volts and if any Cell's Bubble, then the Battery Has a Dead Cell. Batteries with dead cells Will Not Hold Charge. Replace Battery.

BATTERY CRANK VOLTAGE.

Ignition OFF
Disconnect Small Black/White Wire from Starter Solenoid .
Connect RED MM Lead to Main Starter Motor Wire.
Connect BLACK MM Lead to BATTERY GROUND.
Turn Ignition to START and observe Multimeter.
Voltage Drop should be approx 3.0 Volts.
NO Voltage Drop - Check Wiring Connections, Check Ignition Switch, Check Starter Motor, Check Starting Circuitry.
Voltage Drop > 3.0 Volts. Check Wiring Connections, Check Battery, Check Ignition Switch, Check Starter Motor, Check Starter Circuitry.

ALTERNATOR OUTPUT CHECK.

Extremely Important: DO NOT DISCONNECT BATTERY CABLES WHILE ENGINE IS RUNNING.

Check ALL ALTERNATOR Connections @ ALTERNATOR and BATTERY for Quality, Cleanliness & Security.
Check ALTERNATOR Drive Belt Quality & Tension.
Connect RED MM Lead to Battery POS.
Connect BLACK MM Lead to Battery GROUND.
Make Sure Battery is Fully Charged.
Start engine.
Operate engine at 1500-2000 RPM

Check Alternator Output Voltage.

If voltage is > 15.1 Volts, Voltage Regulator is overcharging and may be faulty or Battery may have Low Voltage and Volt Reg is Overcompensating. If Battery Voltage Is Low refer back to BATTERY TESTING. If Battery Voltage is OK. Replace the Alternator.
If voltage is less than 13.9 Volts, Voltage regulator is not charging.
Apply Load (Lights, Acc, Radio Etc) until voltage is between 12.0 and 13.5 volts. Check amperage - should be => 30 Amps. If amperage is less than 30 Amps, Replace alternator.

TESTING ALTERNATOR WIRING.

With engine at N.O.T, stop engine, unplug alternator harness, turn key to ON position WITHOUT engine running.

1. Check for BATTERY VOLTAGE between the BLACK/YELLOW wire and GROUND.

If no voltage is present check dash fuse No. 2 or inspect for an open in the BLACK/YELLOW wire.
Charge Warning Light should not be on. If "Charge Warning Light" is ON, check for SHORT to GROUND in WHITE/BLUE wire, check for Shorted Integrated Control Unit (ICU) or Shorted ABS Control Unit (if the vehicle is equipped with these items.)

2. Connect jumper wire between the WHITE/BLUE wire and GROUND.

If "Charge Light" comes on, circuit is GOOD.
If "Charge Light" does not come on, then check for a BLOWN BULB, OPEN circuit in the WHITE/BLUE wire, open circuit in the BLACK/YELLOW wire between the warning light and the dash fuse box or between dash fuse box and ignition switch.

3. Check for battery voltage between WHITE/GREEN wire and GROUND.

If VOLTAGE is present, circuit is GOOD.
If VOLTAGE is NOT present, check for OPEN in WHITE/GREEN wire, faulty ECU or faulty Electric Load Detector (ELD).

4. Turn ignition switch OFF and Reconnect Alternator Harness and check Green Plug For Security in Alternator.

Check ECU Ground @ Thermo Housing for Quality, Cleanliness & Security.

Check Ground @ Valve Cover & PS/ALT Bracket for Quality, Cleanliness & Security.

Check All Other Grounds in Engine Bay and Dash Fuse Box for Quality, Cleanliness & Security.

Check for Stray Current due to Poor Grounds.

Refer to this Thread: Cooling System Electrolysis

Now Check The Mechanical Side of It.

Check ENGINE VACUUM

Connect a Vacuum Gauge to a Direct Vacuum Source
Start Engine and Run @ Idle to N.O.T.

Observe Vacuum Gauge Needle.

- Good Vacuum Reading Will be Steady Between 18 - 25 In Hg
- Readings Between 14 - 18 In Hg Indicates Incorrect Ignition Timing.
- Readings Between 8 - 14 In Hg and Needle Fluctuating Indicates Sticking/Bad Valve Adjustment.
- Readings Below 8 In Hg Indicates Low/No Compression, Incorrect Valve Timing, Vacuum Leaks.

Check Fuel Pressure

Refer to this Thread: Fuel Pressure Diagnosis

Check Compression Pressures

Refer to this Thread: Checking Compression

Check Base Ignition Timing

Refer to this Thread: Checking Ignition Timing

Check Base Idle Speed

Engine @ N.O.T

No Engine Load (Lights, A/C, All Accessories Off).

1. With Ignition OFF, Remove Wiring Connector from IAC Valve.
2. Start Engine and allow to idle (No Load)
Base Idle should be 550 +/- 50 RPM. (If ECU Light comes On - Ignore It)
3. If Base Idle is not to Specs - Adjust Base Idle Screw in @ top of Throttle Body.
(If Engine Stalls. Turn the Base Idle Screw in the Throttle Body 1-2 turns then repeat Step 2 and reset to specs)
4. Switch Ignition Off & Reconnect IAC Valve Wire.
5. Remove the 7.5amp "BACK UP" Fuse for 10-15 Seconds to Clear ECU.
6. Start The Engine and Allow to return to Curb Idle.
7. Curb Idle Should be @ 700 RPM +/- 50 (MT in Neutral - AT in Gear D4)

Bleed Cooling System.

With Engine Cold, Remove Radiator Cap.
Fit a Funnel into the Filler Neck.
Loosen the Bleeder Nipple at the Thermostat Housing
Premix Adequate Amount of 50:50 Coolant & Water(At least 4 Quarts) in Container.
Pour Coolant Mix into funnel and watch Bleeder Nipple for Coolant.
Continue to Fill Funnel until Clean Coolant Flowing out with no Air Spurts.
Allow Level in Funnel to drop to just above filler neck
Tighten Bleeder Nipple.
Remove Funnel.
Wash away excess Coolant from Engine and Radiator.
Start Engine & Run until Aux Fan Cuts In (AC Off)
Observe Temp gauge and Top Up Radiator with Coolant as necessary.
Refit Radiator Cap
Take Car for Drive.
Recheck Coolant Level when Engine has Cooled right down & Top up if necessary.

Fit New Spark Plugs & Wires

Mark Distributor Cap and Remove Spark Plug Wires
Remove Spark Plugs and Discard.
Inspect NEW Spark Plugs for Faults/Cracks
Check Spark Plug Seating Surface has Sealing Washer fitted.
Check Spark Plug Gap
Apply light Coating of "Never Seize" to Threads Only.
Install NEW Spark Plugs carefully - Do Not Drop into Tube.
Tighten By Hand, Then Tighten with Ratchet Until Firm (Do Not Over Tighten)
If Refitting Plug Wires - Check Plug Wire Stems & Inside Plug Wire Boots for Cleanliness/Dryness
Refit Spark plug Wires to Relevant Cylinders (Marked Previously)
If Replacing Plug Wires - Fit Spark Plug Wires to Relevant Cylinders & Distributor Posts (Marked Previously)

** You'll probably find that 99% of engine related problems can be diagnosed and/or fixed by checking these items. **

Cheers
-The GURU-

[HondaFan81]

TPS DIAGNOSIS:

This seems like something that some people are confused about, so I thought i'd clear some things up...



Modified from a previous reply....
TPS only gets a reference of 5volts. That means the Yellow/White wire should
be 5 volts, the Green/White wire should be ground, and the Red/Black wire
is gonna be dependant on where your throttle plate is, between about .5 ->
and 5 volts. If you're sensor is bad, you will be seeing a bad voltage on the
sensor wire, also make sure you have a good ground at the connector.

Best bet is to get a labscope, and do the following....
Get a normal labscope with 2 test leads. Put one test lead to a good ground,
battery negative would work. Put the other test lead to the Red/Black wire
of your TPS.
Then, once you get that hooked up, turn the ignition to on (all the way, but
not running (KOEO).
Adjust your scope to show 1-2 seconds(100ms/div), and 5 volts(1v/div).
Then, in about the timeframe of 1-2 seconds, open your throttle plate and
close it by hand, smoothly. you should see an ant hill basically... here's an
example all though it's a crappy one, just something i pulled off google....



If you get something like this next one, then your tps is bad....


and if you don't get the anthill, then you either have bad wiring, or your scope is set up wrong.

In *most* cases, TPS has very little impact @ idle, and it will run *OK*
without it. When it has impact is when you are getting air into the intake
(vacuum leak), and the TPS reads closed throttle.

After all, TPS does not determine fuel pulse width, thats mostly dependant on
MAP. TPS will just add or decrease the number of pulses made, and it only
makes a difference under change for the most part, i.e. acceleration/decel,
not idle.

This sensor get's it's ground along with the o2 sensor, the IAC, and other
sensors etc, so if you have a grounding problem, then you may have
problems with other components as well. These all ground through the
thermostat housing.

Testing Recap-
5v at the yel/wht wire, ground @ grn/wht, and variable based on thottle
position at red/black, KOEO, or KOER.

You can use that wiring diagram to see that there are many connectors as
well, where you can backpin, and check for good signals there. So remember, if you think you're not getting voltage to your TPS, DON'T
GIVE IT BATTERY VOLTAGE!

Posted by: 92accordexpower