Throttle position trouble

Check the resistance on the throttle position switch using a Haynes Manual and a volt ohm meter to get the correct readings.

• Controlling the idle speed taking the throttle body itself is what the purpose of the MTIA (Main Throttle Idle Actuator) is.
• The throttle is particularly devised for low opening angle (05, 195).
• The features of the airflow differ for low and high opening angles.
• This circuit has a gradient of the mass air flow function of TPS which is lower for small angles that allow it to be more accurate while handling the idle speed control.
• A classical Bowden cable actuates mechanically the idle speed throttle.
• A voltage signal that changes in proportion to the throttle plate angle is catered by the throttle position sensor (TPS).
• It will be seen that the signal voltage will change from about nearly 5.0 V at idles to about 0.2V to 0.4 V at wide-open throttle.
• The TPS is one of the most indispensable inputs needed by the ECM for fuel control and other functions such as idle, wide open throttle, deceleration enleanment, and acceleration enrichment.
• DTC sets when the TPS voltage is at 04vThe TPS could be your problem but also I have had the EGR valve stick open on them engines which was causing a few different codes. But in the case of the TPS you should buy an AC/DELCO TPS i have noticed after replacing the original with an aftermarket or cheaper one that they usually different as in they need to be adjusted to get the correct position (reading) to the ECM, but they are not adjustable. you should have the EGR valve checked on this engine if it has never been replaced before
• but also its wise to open the throttle and clean that area out real good, be sure to get the throttle plate good. It can build up a line of carbon which will throw the tps out of sync.
  I think this might be your problem to begin with.

Need to get it checked from the service center, it needs a tuning.

Dear Sir/Madam,



An engine surge is usually caused by a fuel system management or drivetrain failure. The fuel management system utilizes sensors that monitor emission output and engine performance are communicating with the main ECM (engine control module) controlling fuel mixture, timing and emission management systems. While the engine is surging the ECM is "hunting" by adjusting the fuel mixture and timing. These adjustment are made by the ECM in a isolating manner as the ECM tries to satisfy its coordinates. These coordinates are not satisfied because of a system malfunction, we have listed some of the most popular problems and repairs below.

Troubleshooting Procedure


A. Test for DTS's (Diagnostic Trouble Codes): For this you need a trouble code scanner, this is a small hand held electronic device that plugs in to your cars OB2 (OBD11) diagnostic connector. Locate your vehicle's computer connector (ALDL), most are on the lower driver's side. In some vehicles you might need to look around a little, on the passenger's side, and around the center console under a plastic cover. For more information, check your owner's manual. This device gathers information that was stored in your cars ECM. This information or trouble code can inform you about the system or sensor that is malfunctioning. Look up the code in our diagnostic trouble code chart. After repairs have been made use the code scanner to clear trouble codes and recheck system.

B. Testing Fuel Pressure: Test for proper fuel pressure with a fuel pressure gauge. Connect the gauge to the test port on the fuel rail. Fuel pressure reading's very depending on the system your in our vehicle, but most throttle body injection cars (TBI) are between 13 psi and 17 psi. and most (DPI) direct port inject systems are between 40 psi and 55 psi. To find out your vehicle system fuel pressure consult a repair manual. If little fuel pressure is present the fuel pump needs to be replaced.

C. Plugged Fuel Filter: A plugged fuel filter can cause an engine to surge. The fuel system supplies power to the engine through combustion, if fuel can not be delivered it will cause inconsistencies in performance. To check for this condition remove fuel filter and inspect, replace with new unit and recheck.
D. Check Engine for Vacuum Leaks: If an engine vacuum leak is present it will cause the sensor input readings to the ECM to be incorrect causing an engine surge. The system is programmed to work at prescribed value. When a vacuum leak is present these readings are incorrect causing the engine to surge under power and idle rough. Inspect the air intake boot for tears and vacuum feed lines to all accessories. Replace torn or dilapidated hose with a new hose and recheck system. Also an IAC (Idle Air Control) valve bypass hose it can develop tears/holes mid way through the hose, inspect thoroughly (common problem on Ford trucks and SUV's) Sometimes a vacuum leak can be detected by opening the hood, start the engine and allow to idle, then listen for an audible whistling sound. Then inspect that area of the engine compartment to locate leak.
E. Check for Plugged Exhaust System: The exhaust system in your vehicle is designed to release exhaust gases from the engine to the rear of the car. This system is designed to have about 3 pounds of exhaust backpressure under full throttle. This means the engine should not have to push more than 3 pounds of pressure to release the exhaust at any given time. If a catalytic converter plugs or breaks apart it will plug the exhaust system causing an engine surge.



F. Test for Weak Ignition Spark or Failing System:. A weak ignition system can be a sign of a failing ignition component and cause the engine to surge. Remove spark plug wire and insert an extra spark plug into end of wire, attach spark plug to engine ground then crank engine. You should observe blue spark between spark plug gap. If a yellow spark is observed, your ignition coil is weak and needs to be replaced. Also the spark should flash in a constant rhythm, if the spark is inconsistence suspect the crank angle senor, ignition coil or ignition module.
G. Check for Automatic Transmission Clutch Slippage: When the clutches inside a automatic transmission start to wear they can malfunction. This condition will deliver a surging or a tugging sensation to the driver. Without taking the transmission apart it is impossible to check the wear of the clutch discs. But there are tests that can help you in the repair diagnosis, first remove transmission dip stick and inspect the condition of the fluid, if the fluid has a burnt smell and is dark color instead of the normal red color the fluid is burnt. The transmission fluid is a hydraulic fluid that when extreme heat is applied to the fluid condition becomes burnt and smelly. The extreme heat is generated from the clutch discs slipping. Sometimes a transmission service will help the operation by removing the burn fluid and replacing it with new.

H. Check for Standard Transmission Clutch Slippage: When a clutch assembly starts to wear it can cause a engine surge sensation. This is caused by the clutch pressure plate loosing tension and allowing the clutch disc to slip against the flywheel. The clutch assembly is a normal service item and need to be inspected between 60,000 and 80,000 miles. If the clutch peddle is at the top of its travel with no free-play this is a sign the clutch assembly is worn out needs replacing. When servicing a clutch disc always replace the clutch disk, pressure plate, throw out and pilot bearings (note: some transmissions do not use a pilot bearing). The flywheel is the component the clutch assembly bolts to, the clutch disc is in direct contact with the flywheel and clutch pressure plate.

Thanks

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