Question about 1988 Ford Escort EXP

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Escort idles to fast

Idles about 5000 rpm or more driveing in gear shut down ignition and back on will idle down. step on accelerator speeds up again will not go back to idle.

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If you've tried to reset the idle pins on the throttle plate and that did nothing and also checked the throttle postion sensor (TPS) and engines codes, then it could be that the air bypass valve (APV - electronic engine control idle control valve) is simply stuck open.

The APV is a little black (3") solenoid valve bolted on the front of throttle body, 90° from the TPS that, when energized, allows addtional air to bypass the throttle plate (as if you were holding the pedel down some). It's the fancy modern equivalent for the much more complex 100% mechanical assemblies that were in old time carbs that set high idle air flow when you also had set the choke.

The APV is used (energized - opened) to set the high idle when the car is cold and closes (de-energized) when the engine reaches temperature. It can get all fouled up with recylced exhaust and/or crankcase recirculation fumes from the emmission control system. If you take it off and manually actuate the piston, it should move in and out freely and, all by itself, it should return (via a spring) to the normally fully closed position. If not, try cleaning it with some brake cleaner or get a new one.

My problem that made me discover and fully understand my APV was a bit different but it was all about the idle being wrong and irregular, be it low or high, but not where it should be, for no good diagnosible reason, and once I cleaned and reinstalled my APV, the problem was 100% solved.

Posted on Aug 17, 2008

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Engine idles up to 2500 and after 5 or 7 seconds, goes back down to 1200 rpm 2002 escort SOHC

Clean out the throttle body carefully and replace the auxilliary air idle valve. There is a resetting process for this valve so dont just fit and hope!
Check on Google or forums but i think ...when fitted you turn on ignition but dont start car , then put the accelerator pedal slowly to fully open, hold it for a min then release. start and drive car until warm and the recheck.
If the idle is high then settles it is not an air leak. It is something stuck that then releases which is only throttle flap or idle valve. It is always a goid idea to replace fuel, oil, air filters on normal service intervals.

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2007 VW 1.6 FSI 1KZ will shut off when at operating temperature. It will always restart and might or might not shut off again. Usually it happens after starting and pressing the accelerator. Other times it...

Have the 'Throttle' or 'Accelerator' re learn performed. Some will re learn as follows : Turn ignition to RUN with engine OFF. Push throttle pedal to the floor and hold it there for 30 seconds.

Turn ignition off and then release throttle. Start engine and allow it to idle until warm ( 80C.) Do not rev the engine or put it in gear dueing warm up. It must be allowed to warm up at idle only. When you hear the radiator fan come on, turn engine off. Wait 10 seconds and restart engine. Test drive.

This procedure MAY have caused the throttle to relearn. If the same problem is present, go to dealer or VW shop and have them 'relearn' the throttle with a scanner.

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The car is all on normal condition until I filled the gasoline to the fuel tank (over the standard value) ,I left the gas station suddenly the speed goes down then the engine stopped , I try to ignition...

You overfilled the tank and screwed up the fuel vent canister. Usually the car will not run, dies while idling, or surges if you try to drive, also if you try to fill up again you might find it difficult to fill your tank fast because the canister is not venting the tank

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Have the fault code read as it may be a throttle position sensor or idle speed sensor that is at fault.

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"Could this be a throttle positioning sensor problem?" - probably not. The Throttle Position Sensor (TPS) tells the computer how hard you are stepping on the gas. It does not really control idle speed.

Your problem is more likely the Idle Air Control (IAC) valve. This is a small electric valve that the computer can open and close in small steps to set the idle RPM at the desired point (a little higher when cold, then down to normal speed when warm). The IAC valve is notorious for getting all crudded up inside. Then it sticks open too much (really fast idle speed) or sticks shut (really low speed).

You can try taking it off the engine, cleaning it with carb cleaner spray, and putting it back on. That is easy and cheap.

If cleaning does not fix it, you need to buy a replacement valve and put it on. Pretty easy to do but costs more $$$.

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Feb 17, 2012 | 1992 Nissan Pickup

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I have a 1992 E350 motorhome with a 7.5 in it. I just had to replace the fuel pump. After replacing the pump it idles rough and runs rich. I did pick up an engine light and after getting the codes...

There is a few options but first I am hoping with your fuel pump replacement that you replaced the fuel filter if not do it first.
next have you checked you throttle body idle speed control device... See below on diagnostics
The curb and fast idle speeds are controlled by the Engine Control Assembly (ECA) and the Idle Speed Control Bypass Air Valve (ISC-BPA) . The ISC-BPA valve is not adjustable. A large increase or decrease in closed plate airflow from the calibrated level will not allow this device to control the speed.
The idle speed setting procedure has been revised considerably to reflect the expanded application of the Self-Test idle speed options and because the throttle body incorporates an orifice in the throttle plate to control idle airflow as part of the sludge tolerant design.

Throttle bodies with sludge tolerant design are clearly identified with a Yellow/Black decal. This decal warns that the throttle plate stop screw must not be adjusted counterclockwise (backed off), as this will not reduce the engine speed but may cause the throttle plate to stick in the bore. Backing out the screw may be required if the throttle body has been previously serviced (a plug in the throttle plate orifice may be present) or the plate stop screw tampered with (TPS Self-Test output out of range). The decal also warns that the throttle body must NOT be cleaned inside the bore, as this cleaning will impair the sensitive coating. The sludge accumulation will not affect the idle air flow. The cleaning procedure for the ISC-BPA still applies.

A change in idle airflow can occur not only at the throttle body but other areas as well. You should enter the idle speed procedure only after other possible causes in the following areas are eliminated.
  • Contamination within the idle speed control device
  • Lack of fuel system control (excessively rich or lean)
  • Throttle sticking or binding
  • Engine not reaching operating temperature
  • Incorrect ignition timing
  • Incorrect or clogged PCV system
  • Vacuum leaks (intake manifold, vacuum hoses, vacuum reservoirs, power brake booster etc.

  • Transmission is in PARK (A/T), or NEUTRAL (M/T)
  • Parking brake is applied (automatic brake disconnected where applicable)
  • Wheels blocked
  • Engine at operating temperature
  • Proper fuel pressure and no exhaust smoke
  • Correct and clean PCV system
  • Heater, A/C, and other accessories OFF
  • Ignition timing is set to specification
  • EEC-IV diagnostics have been performed and vehicle malfunction indicated service output codes have been resolved.
With the engine OFF, connect a tachometer, according to manufacturer's instructions. Disconnect the negative (-) terminal of the battery for 5 minutes, then reconnect it.
START the engine and let stabilize for two minutes. Goose the accelerator and let the engine return to idle. Lightly depress and release the accelerator, then let the engine idle.
If the engine is not idling properly, turn the engine OFF, and proceed with this procedure.
Disconnect Idle Speed Control Air Bypass Solenoid.
START and RUN the engine at 2500 rpm for 30 seconds.
Place the transmission in PARK (A/T), or NEUTRAL (M/T).
Using a tachometer, verify the idle speed is at 650 +/-150 rpm.

NOTE: A plug in the throttle body orifice will decrease idle rpm. Where as an orifice without a plug will increase idle rpm. Orifice plugs and installation tools are available in service kit # FOPZ-9F652-A.

  1. DO NOT clean the throttle body, check the plate orifice plug.
    • If there is no plug, turn the screw clockwise to the desired rpm.
    • If there is a plug from previous service, remove the plug, then adjust the screw in either direction as required. Screw must be in contact with the lever pad after adjustment.
  1. Turn the engine OFF.
  2. Disconnect air cleaner hose.
  3. Temporarily block the orifice in the throttle plate with tape. If the orifice already has a plug from previous service proceed to Step (e).
  4. RESTART the engine. Check the idle speed, using a tachometer. NOTE: On vehicles with Mass Air Flow Sensors, reconnect the air intake duct hose prior to rechecking the rpm. If the engine stalls, crack open the throttle plate stop screw, but DO NOT over adjust.
  5. If rpm continues to be fast, perform KOEO Self-Test.
    • If TPS output code is within range, remove tape from throttle body and check for other possible causes.
    • If TPS output is out of range, adjust screw for proper TPS code. Lever must be in contact with the screw.
    • If rpm is still fast, terminate the procedure and check for other possible causes.
  1. If rpm drops to 650 rpm or lower, or the engine stalls, turn the engine OFF, disconnect the air cleaner hose, and remove the tape from throttle plate.
  2. Install an orifice plug with proper color code according to the throttle plate orifice size.
  3. Reconnect the air cleaner hose. START the engine, and check the idle rpm using a tachometer. Turn the throttle plate stop screw clockwise until an idle speed of 650 +/- 25 rpm is achieved. NOTE: DO NOT turn the plate stop screw counterclockwise. This may cause the throttle plate to stick at idle.
Run the KOEO Self-Test for proper TPS code output.
Reconnect the Idle Speed Control Air Bypass Solenoid. Verify the throttle is not sticking in the bore, and the linkage is not preventing throttle from closing.
START the engine and idle for two minutes. Goose the accelerator and let the engine return to idle. Lightly depress and release the accelerator, then let engine idle.


Remove air inlet tube(s) from throttle body.
dak408_16.gif STEP 2
Select the proper color plug by using the Go/No-Go gauge pegs, included in the service kit (FOPZ-9F652-A).
Starting with the largest diameter gauge peg, attempt to insert through the throttle plate orifice.
If the gauge peg goes through the orifice, use the corresponding color plug.
If the gauge peg does not go through, proceed with the next smaller gauge peg for Go/No-Go Test.
NOTE: It is important that the largest Go/No-Go combination is used to determine the proper plug size.
If the smallest gauge peg does not go through the orifice, use the reamer bit and handle included with the service kit to enlarge the plate orifice. Wipe bearing grease on both sides of the plate orifice and on the reamer bit to hold the brass chips. After reaming, wipe plate clean and then return to Step 3 to determine the proper plug size.
Using the installation tool from the service kit, push the plug into the orifice until bottoming out at the throttle plate.
Open and snap closed the throttle several times to verify proper plug retention.
Reconnect the air inlet tube(s).
Reset idle rpm per engine requirement using the throttle plate stop screw.

Hope this helps

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1 Answer

Noise at shut down

The noise is caused by the engine running on after the ignition is shut off. It makes noise because the pistons are rattling in the cylinders from incorrect timing. This has nothing to do with the mechanical or electronic timing of the engine. The engine runs on either because of hot glowing carbon deposits in the cylinder head or because the engine was shut down when it was running too fast. Sometimes the carbon can be literally blown out by running the engine at high rpm for a short time. Put it in second gear and run it for a couple of miles on the highway. If this does not work the heads will have to be removed and the carbon cleaned out manually. The shut down when running too fast problem can be caused by the idle being set too high or by shutting the engine off before it has reached idle speed. If you can adjust the idle speed try reducing it. If not always hesitate before shutting the engine down to let it reach idle speed. Good Luck!

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1 Answer

Trying to set my rpm on a 84 cutlass supreme brougham,3.8l v 6 231 cu in vin am i suppose to set this i using a inductive tach reader it idles at 750 range(not sure if thats where its suppose to be...

the fast idle is set when the choke is close to set the cam on the HIGH STEP. turn the car off hot, now pull the accelerator back and close the choke with your hand, now let the accelearator back to idle, now the idle is on the high step, carnk the car and set the idle speed, the base the fast idle screw is against the step on the pass side of carb.

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1 Answer

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Yes your choke is sticking

Jul 09, 2009 | 1996 Isuzu Trooper

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