NORTH AMERICAN TURBOCOUPE ORGANIZATION

Frequently Asked Questions

All articles contained herein are for reference only. 
NATO and it's members take no responsibility for the outcome of any modifications or repairs.
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Below is a listing for most of the topics above (not in the order as shown), except those items which open in a new page.         

How do I adjust the timing?

Shut off warm motor and hook up timing light.  Locate the SPOUT (SPark OUT) connector, which is a little plug in the harness from the TFI module on the distributor.  It is about 8" from the distributor.  Remove the SPOUT plug and start the car.  Check timing.  Stock setting is 10 degrees BTDC.  Adjust by loosening the distributor hold down bolt (17mm, PITA to get at), and rotate distributor to set timing.  Going to 12 or 13 degrees from the stock 10 degree setting gives better low end, off boost power, but can lead to detonation under boost.  Every car seems to like a different setting, so you will have to experiment with it.  When done, REMEMBER to reconnect the SPOUT connector before you drive the car.  At Idle, with the SPOUT connected, timing will be in the 20+ degree range.  If you should have to remove the distributor, then it is very important that before you pull the distributor out to work on it, mark the direction the rotor is pointing on some external reference point.  (TIP):  If you set the engine to TDC (Top Dead Center) for the number 1 cylinder so the rotor is pointed at the number 1 wire terminal on the distributor cap.  Then remove the cap.  Note that the rotor should be pointed toward the outside, front bolt for the upper/lower intake.  That's your reference point.

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TPS/Idle Adjustment by Keith Nubel

1-  First bring the engine up to normal operating temperature

2-  Turn the engine off and unplug the Idle Air Control. This is located on the backside of the Throttle
     Body near the firewall. This device is a round cylinder approximately 5 inches long with a (2) bolt flange
     and 3 wire male / female plug connector.

3-  Using the small adjustable wrench adjust the base idle to 700 – 800 RPM

4-  Locate the Throttle Position Sensor (TPS) on the Throttle Body. This is also located on the backside of
     the Throttle Body near the firewall. This is a black plastic device with (2) screws that allows adjustment
     and (3) wire male / female connector. Connect the voltmeter to the TPS and ground. The wire should be
     the one with a green strip.

5-  Using the small Phillips screwdriver adjust the TPS output voltage to approximately 1.0 volts. Most turbo
     tuners find that setting your voltage to around .90 - .95 volts works best. I set mine around .94 volts.

6-  Turn off the engine

7-  With the engine off and the voltmeter still connected move the throttle linkage slowly from idle position to
     wide open and back to idle, look for a steady increase and then decrease in voltage without any voids or
     dead spots. Any voids or dead spots would indicate a faulty TPS.

8-  Plug in the Idle Air Control

9-  Start the engine. The engine’s idle speed should settle in around 1000 RPM

10- Take the Turbo Coupe for a test drive

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Acronyms & Abbreviations

ACT - Air Charge Temperature

ATDC - After Top Dead Center

BTDC - Before Top Dead Center

ECT - Engine Coolant Temperature

EEC - Electronic Engine Control

EGO - Exhaust Gas Oxygen sensor

EGR - Exhaust Gas Recirculation

IAC - Idle Air Control

ISC - Idle Speed Control

KOEO - Key On Engine Off; a self-test mode of the ECA

KOER - Key On Engine Running; a self-test mode of the ECA

KS - Knock Sensor

PCV - Positive Crankcase Ventilation

PIP - Profile Ignition Pickup

SPOUT - SPark OUTput; signal from ECA

TF I - Thick Film Ignition (module)

TPS - Throttle Position Sensor

VAF - Vane Air Flow

VAM - Vane Air Meter

VAT - Vane Air Temperature

WOT - Wide Open Throttle

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Brake Bleeding by Martin Bokesch

On the brake bleeding, the antilock system requires a bit different approach than conventional brakes. If your going to bleed the system, its the right time to flush them, which means keep bleeding until the fluid runs clear as well as no bubbles. As the T/C uses an electric brake pump and a pressure storage accumulator the system is different in the requirements for bleeding. The front brakes can be bled the old fashioned way. One person pumping and the other opening and closing the bleed screws. There is no need to start with the rear brakes first as they are isolated through the system antilock valve, but its a good habit to do it by the book.

Back Brakes:

The back brakes have to be bled with the accumulator charged up. Jack up the car and block it. Turn the ignition on and let the brake boost pump build up pressure and cut out. Start with the right rear, have someone push and hold the brake pedal down, do not pump, leave the key on as the pump has to be able to kick in to rebuild pressure during the whole procedure on the back. With the pedal down, open the bleed screw for about 10 seconds, then close it. CAUTION there is a lot of pressure at the screws, so open slowly. Also, don't run the brake pump motor for more than 20 minutes at a time, as the motor may overheat and kick out. There is a thermal overload switch in the motor to protect it so if it does stop, you'll have to wait for a while until everything cools down. Do this until the fluid runs clear, no bubbles. Move to the drivers side and do the same. Alternate between the 2 sides until the fluid is clear and no bubbles. It helps if you can slip a tube over the end of the bleeder screw and insert it into a bottle with some water in it. If air is coming out of the system, the tube end submerged in the collection bottle will show up as bubbles. When the bubbles stop, the air is out. I mentioned using water because brake fluid is not mineral oil, so why waste it. Brake fluid is actually made up more of an antifreeze solution.

Front Brakes:

The front brakes bleed with or without accumulator chare pressure. Just use the same hose and collection bottle set up, start on the passenger side. Have you "helper" pump the pedal up and down about 5 times. Get into the habit of counting this down so you get a sequence developed. At the 5 pump, pump down and hold the pedal down. Do not let go until told. With the pedal held down, open the bleed screw slowly and allow the fluid to drain. Unlike the back brakes, the fluid will come out in a steady stream then weaken and drop ff to no fluid at all. When this happens, tighten the screw and pump it again, hold bleed, tighten and keep repeating the process until the fluid is clean and no air. Move to the drivers side repeat. Again, as with the rear, do both sides at least twice to ensure there is no more air in the system. When all done, with the key on, brake pressure built up in the accumulator, pump the brakes about 15 times to settle the fluid and pistons into place. Turn the key off. Pump the brakes again, counting the pumps. at between 15 to 20 pumps, you should notice the pedal pressure increase. This means that the accumulator reserve has been used up and all is well in the brake world. It’s safe to take for a cautious test drive to settle everything back in. Any less than 15 pumps, and you still may have air in the system. One word of advice, check the fluid reservoir often, real often, nothing worse than bleeding it out of fluid and having to start over again.

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Dim Headlight Fix

Age and sun will eventually cause the headlight lenses to become yellowed or cloudy and sometimes even fogged with moisture inside.  The headlights are still available from Ford, part numbers are: (E7SZ-13007-A) and (E7SZ-13007-B) and the list price is around $45.oo ea. 

To replace the lights, pull the halogen headlight bulb (DO NOT TOUCH the bulb with your fingers or it will burn out in a short period of time) out of the back of the lamp (don't loosen the screw on retainer lock) and remove the in-board parking lamp (between headlight and grille). If headlight alignment is OK, there is no need to TOUCH THE ADJUSTOR SCREWS AT ALL, just release the mounting bolts behind the header panel, undo the lamp and pull the whole headlamp and adjuster unit out in one piece. If you have examined the assembly, and noticed that the adjuster screws need replacement, here are the part numbers for those pieces:

(2 for each headlamp)#E7SZ-13032-C ($5.44 ea.)
(1 for each headlamp)#E7SZ-13032-D ($5.41 ea.)

There is no need to buy the whole headlamp assembly since it will end up being far more  expensive than purchasing the needed parts separately. To continue, you will see 3 twist locks on the back of the adjuster panel. Turn them to open (they are hard to turn, brittle, and may need replacement!) and the old plastic headlamp will separate from the adjuster plate. Re-install the new headlamp on the adjuster plate, twist the locks closed and bolt the unit in place. Re-install inner marker light and check the headlamp alignment and you can see at night again! It's a very easy repair and will make a 100% difference.

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CenterForce Clutch Info. 1988TC specific: 

Info provided by Center Force (CF) http://centerforce.com/ tech. dept.   

Parts are for 1988 Thunderbird Turbocoupe 

Stage II  part# CFT360035 

Approximate prices: 

Stage II clutch   $145

Disc                     $95

Bearing               $32 

CF tech. dept. states the Stage II has the same pedal feel as Stage I except
the Stage II has better gripping power in upper rpm range around 4500
Common mistakes can be avoided by replacing the following: 
Replace Bearing Retainer Collar  (aka the Quill)  approx $40-50
Replace Dowel Pins with new ones regardless of condition
Resurface Flywheel or replace if damaged or worn excessively.

Important Info About: (from CF tech. dept)

Aluminum Input Shaft Retainer Bearing Collar  Click Here  This item is one of the likely cause erratic clutch operation, high pedal effort, improper release/engagement and most common; clutch chatter.

Self aligning type throw-out bearing installation tip  Click Here

Clutch break-in  Click Here

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O2 Sensor Info (General): 

Normally, an oxygen sensor is designed to last about 50,000 miles.  Its life can be shortened
by contamination, blocked outside air, short circuits, and/or poor electrical connections. 
The oxygen sensor can become contaminated by, but not limited to the following:
 
    1. Leaded fuel - leaded fuel is the most common cause of O2 sensor contamination.
        Lead particles can coat the ceramic element and the sensor cannot produce enough voltage output
        for proper operation.

    2. Silicone - Sources are antifreeze, RTV silicone sealers, waterproofing sprays, and gasoline additives.
        Silicone tends to form a glassy coating.

    3. Carbon - Carbon contamination results from an excessively rich fuel mixture. Carbon in the fuel can
        coat the sensor, too.

With this in mind, you may want to visually inspect the O2 sensor itself. When doing so, check to make sure that the outside of the sensor and its electrical connection's) are free of oil, dirt, undercoating, and other deposits.  If outside air cannot circulate through the O2 sensor, it simply will not be able to function.  Also keep in mind that the O2 sensor only generates anywhere from 0-1 volt,  and averages around .5 volts. A poor or deteriorating electrical connection is not only frustrating but could also prevent this small voltage from reaching the computer (or an Air Fuel gauge). Always be sure to check the electrical connections as well.  Testing the O2 sensor output is another way to ensure proper operation. A digital voltmeter can be used to test the output of an O2 sensor.

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O2 Sensors and Air/Fuel Gauges (In-depth): 

The A/F Ratio Meter is a voltmeter with a range of 0 to 1 Volt. The meter displays the output voltage of the vehicles oxygen sensor through 20 LED's. The first LED will come on at a voltage of .050V, the second at .100V, the third at .150V, etc. 

   LEAN RANGE:    Four red  LED's  (.050 to .249V)   

    STOICHIOMETRIC  RANGE:   Ten yellow LED's (.250 to .749V)

   RICH RANGE:   Six green LED's (.750 to 1.000V) 

The STOICHiometric (STOICH) air/fuel ratio is the chemically correct ratio, theoretically all of the oxygen and all of the fuel are consumed. The mixture is neither rich nor lean. However, due to the fact that combustion is never perfect in the real world, there will always be a small amount of oxygen left in the exhaust. This small amount that is left is what the oxygen sensor measures. The smaller the amount of oxygen that is left in the exhaust, the richer the A/F ratio is, and the higher the oxygen sensor voltage is. The on-board computer or Power train Control Module (PCM) monitors the voltage from the oxygen sensor. If the PCM sees an oxygen sensor voltage greater than .450V, it immediately starts to reduce the amount of fuel that is metered into the engine by reducing the on time to the fuel injectors. When this happens, the A/F ratio starts to go in the lean direction, and the oxygen sensor voltage starts to go down. When the voltage drops below .450V, the PCM immediately starts to increase the fuel metered to the engine by increasing the on time to the fuel injectors to produce a richer A/F ratio. This occurs until the oxygen sensor voltage goes above .450V. This repeating cycle happens very fast (many times per second). The PCM is said to be in closed loop. It is constantly monitoring the oxygen sensor voltage and adjusting the on time of the fuel injectors to maintain a STOICHiometric A/F ratio. This A/F ratio produces the lowest harmful exhaust emissions, and allows the catalytic converter to operate at peak efficiency, therefore reducing the exhaust emissions further. Since the oxygen sensor output is non-liner and very sensitive at the STOICHiometric A/F ratio it will cause the A/F meter LED's to bounce back and forth rapidly. A very small change in A/F ratio causes a large change in oxygen sensor voltage as can be seen on the graph. This causes the A/F ratio meter LED's to rapidly cycle back and forth, and is normal operation when the PCM is in closed loop and trying to maintain a STOICHiometric A/F ratio. The oxygen sensor is very accurate at indicating a STOICHiometric A/F ratio. It is also very accurate at indicating an A/F ratio that is richer or leaner than STOICHiometric. However it can not indicate what exactly the A/F ratio is in the rich and lean areas due to the fact that the oxygen sensor output changes with the oxygen sensor temperature and wear. As the sensor temperature increases, the voltage output will decrease for a given A/F ratio in the rich area, and increase in the lean area as shown on the graph. During wide open throttle (throttle opening greater than 80% as indicated by the throttle position sensor) the A/F ratio will be forced rich by the PCM for maximum power. During this time the oxygen sensor outputs a voltage that corresponds to a rich A/F ratio. But the PCM ignores the oxygen sensor signal because it is not accurate for indicating exactly what the A/F ratio is in this range. The PCM is now in open loop, and relies on factory programmed maps to calculate what the on time of the fuel injectors should be to provide a rich A/F ratio for maximum power. The A/F ratio meter should indicate rich during this time. During hard deceleration the PCM will command an extremely lean mixture for lowest exhaust emissions. This may cause the A/F ratio meter not to indicate anything. The A/F ratio is so lean that it is outside the range that the meter will indicate.

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Ball Joint Inspection: 

Most (if not all) Fox cars have wear indicators built in to the ball joints. The spring puts the ball joints under load, so the "grab the tire and shake" doesn’t really work here. Look at the bottom of the joint - the flat part. There is a circular part in the center, maybe 3/8" to 1/2" diameter. If this is sticking up (pointing down) from the flat surrounding area less than 1 mm, the joints are worn. If it is flush with the flat area, the joint is BADLY worn.

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Checking Codes without a scanner:

First off, pick up the diagnostic connector so it is facing towards you with the two open pins on the top and the four pins on the bottom (you are looking at the side opposite the wires).  Next connect a jumper wire to the R.H. top pin and to the single wire lead.  Next connect a test light to the 2nd pin from the left in the bottom row and connect the alligator clip of the test light to the positive post of the battery.  Now turn the key on and the test light will flash out the codes.

BTW, when using the CEL light to pull codes, make sure the bulb is not burned out, or removed by a previous owner. The CEL should light up when the key is turned to the run position with the motor off? If it doesn't, the bulb is probably burned out or missing.

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8.8 Differential Capacity 

Ford spec book calls for 4 pints + 4 oz of friction modifier

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EGR Cleaning: by Dave Compton http://www.DaveCompton.com/

Fords are notorious for EGR problems. 

The EGR is a simple system that allows exhaust to be drawn in to the intake tract.  If you don't have flow, it won't  work.  It's purpose is to reduce Nitrides of Oxygen, (NOx). Clean the EGR valve.  The passage in the actual valve gets mighty gummed up with carbon.  Look carefully at how  the flow works so you make sure it's clean enough to flow.  On a few cars, the passage in the upper intake was clogged so badly, that I had to ram it clean with a screwdriver!  The connections were flaky on the EGRV solenoid, the "relay" that switches the vacuum when it gets an electrical signal from the EEC-IV.  This caused a No EGR condition code 34. 

On another car, the connections on the EGRV solenoid, were gummed up.  Once the connection was cleaned, code 34 went away, and you could tell EGR was flowing during the beginning of the Self Test. 

Quick check: 

Run EEC-IV diag, KOER.  First the RPMs will come up.  Watch the diaphragm of the EGR valve.  It will open, moving back about a half inch, and the engine will sound, different.  If this happens, EGR is fine, no code.  IF you get a code, the flow is blocked, most likely with carbon deposits in the EGR valve itself.  Clean it.  Note, the code 34 may not disappear on those cars that were modified through an emissions recall.