Does adjusting the idle speed affect the TPS voltage?

[CycleSi]

The idle speed is a little low on my 2002 R300 1.8K with roller barrels and an MBE ECU.

When hot it is currently around 800/850 rpm but it seems happiest around 1050 rpm. If I simply increase the idle speed  on the roller barrel linkage will it affect the TPS voltage? I ask because I recall being told if you adjust the idle speed then the TPS will also need resetting.

Thanks in advance.

[brianjhall31]

Correct. The TPS is directly affected by the idle setting.  Dynamic (engine running) idle should be set at 1000rpm+ or - 50rpm and then engine switched of and TPS set to 0.45ohms between pins 1 & 2.

Here is the full K Series Throttle Body and TPS set up instructions:

K Series Throttle Body and TPS set up_0.pdf

[brianjhall31]

Don't think the file uploaded properly. Send me a PM with contact email so I can send direct

[Jonathan Kay]

The upload worked, and the resolution is great. But it's a pdf and we know that some browsers won't render them when others do. The next post is the same as a JPEG. 

If anyone can't see it well enough please let me know.

[Jonathan Kay]

[John Vine]

You can view the Minister guide here.

Btw, I think there's a typo in that doc.  The 0.45ohms should read 0.45Kohms.

JV

[CycleSi]

Thank you both for this.

My issue is that I can do the mechanical adjustment to the idle speed screw, but I cannot reset the TPS as I don't have Easimap or a meter.

Are you saying if I increase the idle speed it will throw the TPS out and run like a bag of nails?

[John Vine]

No, it won't run like a bag of nails because you're not changing the fixed TPS relationship between voltage and throttle site.  All you'll be doing is (possibly) picking up a slightly higher site (with corresponding fuelling map) than the normal idling one.  At throttle openings above that, it will behave just as it did before.  Think of it as though you were easing your foot down a little on the pedal to keep the revs up. 

However, the best solution would be to reset the RBs.

Some years ago (when I had a 1.8K SS-R with RBs), CC sent me Workshop Notice 373, which says:

"Firstly, Set the balance of the two pairs of barrels as closely as possible. This is achieved by unlocking the small 6mm lock-nut on the throttle operating lever and adjusting with a allen key.

Secondly, set the air intake flow rate. This is done by unlocking the 7mm lock nut on the idle adjusting screw (nearest the engine – the other one is for full throttle). At idle (900 – 1100 rpm) the Roller Barrels must draw in 5 kg/hr per cylinder. If all the cylinders are not drawing in the same amount of air then they should be set so that each pair draws in 10kg/hr i.e. if cylinder 1 draws 5.5 and cylinder 2 draws 4.5.

Lastly, the throttle potentiometer can be set. This is achieved by fitting the in-line adapter harness and connecting a multi-meter to the provided ports. Set the potentiometer to between 0.43 – 0.45V by releasing the lock screws and rotating the potentiometer body."

When I asked CC about the "adaptor harness", this was their reply:

"We don’t do a harness but all you need to do is this:

Get a voltmeter and with the ignition on put the probes to the wires that go in to the TPS sensor.  Loosen the bolts holding the TPS on and turn the sensor until you get between 0.43-0.45 Volts.

And that’s the TPS set up."

JV

 

[oilyhands]

Maybe.. but that assumes the TPS alignment was correct in the first place. My experience is that they seldom are. Borrow a meter or buy a cheap one from ebay, that will allow you to test the alignment. It's a lot cheaper than paying to have it done.

Oily