Throttle Body and Idle Control Valve Fix

[Z-Kev]

Hey

As some of you may know I recently had a issue with my VR4 hesitating on light throttle and almost stalling, you could force it through this by using more throttle but it was quite bad the way it would stall. How I fixed this was with a throttle body change but was able to point my finger at the Idle Control Valve being the culprit, here is a guide to the sensors on the Throttle Body and tear down of the ICV and fix which worked on my valve.

TB 1.jpg

A quick guide to the sensors on the throttle body of a TCL
Yellow : Throttle Position Sensor
Blue : Idle Control Valve
Red : Pedal Position Sensor/TCL Throttle Position Sensor

OK now onto the Idle Control Valve

TB 4.jpg

In the above picture remove these Green highlighted bolts ( 6mm hex ) from the ICV to remove it from the Throttle Body, be aware there is a o-ring behind the ICV sitting inside the Throttle Body.

TB 5.jpg

In the above picture on the electrical connector I have highlighted the pins on both the top and bottom rows, check the resistance from the centre pin to the outside pin on each row, it should be in the region of 28-33 ohms, if it is outside these parameters you will need a new valve, if like mine it was well within these its time to take the valve apart by undoing the three highlighted Red Screws.

TB 6.jpg

This is what should happen when you start to pull the valve body apart , it may be seized like mine with corrosion so it will help if you rotate the body around the insert slightly to help it separate, the electromagnet inside may try to separate due to corrosion, be careful of this and try to ease it apart without pulling the core apart.

TB 7.jpg

Hopefully this is what you will end up with.

TB 8.jpg

Be aware inside the core there is a spring which will drop out.

TB 9.jpg

This is the spring I was talking about.

TB 10.jpg

This is the extendable nib which is used for idle control , it extends by spinning the magnetic spindle inside the body.

TB 11.jpg

Nib extended.

Now you need to clean off both the core and the magnetic spindle, I used Isopropyl Alchohol for the cleaning and liberal amounts of WD40 for lubrication of both the core and the body, working the nib in and out to make sure it was well lubricated, I also removed corrosion off the spindle with wet and dry until the two half's slide back together without any friction. Re-assembly is the reverse of Dis-assembly remembering to make sure you put the spring back in the core and also make sure you have wound the spindle so the nib is fully seated retracted into the body .

This fixed my Idle Control Valve and hopefully may help some of you out there if you want to take a look at yours.

If you have any questions feel free to contact me , I also have investigated the correct way to set up the Pedal Position Sensor and Throttle Position Sensor if you need help with this.

Hope this helps.

[hbkuk1]

I've got to replace my tps tomorrow info on that would be cool or testing it

[Z-Kev]

If its the rear Pedal position sensor on a auto then put a .5mm feeler gauge between these two plates, these split apart and i believe its for the TCL control.

TB 12.jpg

Once you have done this loosen off the sensor mounting bolts put a multimeter on pins 3 and 4 and set it to ohms or continuity

TB 13.jpg

rotate the sensor all the way anticlockwise then rotate it again untill the multimeter shows no continuity, thats the spot you want to retighten the fastening bolts, remove the feeler gauge and make sure you have continuity again with the throttle closed, slowly start to move the throttle and it should lose continuity again showing that the throttle is open.

If its the front one TPS adjustment is by checking the output of the TPS on the sensor on the front of the throttle body , should be 580mv to 690 mv with the throttle closed and the ignition on ( black wire and white/black wire) if its not in that range loosen the bolts and move it till it is, then tighten up, you can check its functioning right by moving the throttle fully open and the voltage should climb cleanly all the way to just around 5 volts.

[Nick Mann]

Nice article! Thank you. It needs copying in to the articles library. LIBRARIAN!!!

[Z-Kev]

thanks Nick, just trying to give something back as the forum has been so useful to me over my first year of VR4 ownership

[hbkuk1]

Cool cheers