K-Series low idling problem - any suggestions?

[Norman]

Hi all, 

Recently my 1998 1.6 K series Supersport has started to idle really poorly - the revs are down at around 500, and whether hot or cold, it will basically conk out if I don't give it some throttle, even when pulling up to traffic lights. 

In the 2 years I've had it, it has always idled low on startup, and needed some throttle until it warms up. I thought this was normal, but am told it shouldn't need any throttle. 

I'm aware it could be the ECU, or fuel lines / filter, residue in throttle bodies or timing or air filter blocked... 

I should mention I'm a bit of a newbie with this, and not very engine savvy!

I have an Emerald ECU (serial no. 42148)

I also have a DVA supersport kit with TBs, cam timing etc.  

I've read on other posts that the throttle position sensor can be reset on stardard ECUs by turning ignition on, pushing and releasing throttle 5 times, then ignition off. 

I've tried looking elsewhere if this will work on my Emerald, but not found anything. Will it?

thanks for any help - I need to get her running sweet in time for the Taffia Fish & Chip Run in a few weeks!

[SM25T]

How is your battery. Mine won't start without throttle application when battery is dying. New battery sorted it.

[Jonathan Kay]

"I've read on other posts that the throttle position sensor can be reset on stardard ECUs by turning ignition on, pushing and releasing throttle 5 times, then ignition off. 

I've tried looking elsewhere if this will work on my Emerald, but not found anything. Will it?"

Full search of the archives... the truth is out there...

Jonathan

[Jonathan Kay]

If you want to test your battery I suggest measuring the voltage:

1. At rest
2. Minimum during cranking
3. At 3,000 rpm.

Jonathan

[SLR No.77]

Norman, originally your car will have had a Rover MEMS ecu with a plenum and single throttle body that included an IAVC (idle air control valve), this enabled the ecu to control what was going on at idle. Your DVA setup will no longer have the IACV and idle is controlled within the mapping usually by small advances in ignition timing.

With this setup the first thing you need to do is plug the ecu into a laptop (still in the car) to enable the TPS (throttle position sensor) to be reset, this is effectively what is being done with a standard Rover MEMS when the throttle is repeatedly floored as you mentioned. This resetting enables the ecu to know the limit points of the TPS, from idle to wide open throttle and will align the map with these values. If you're not sure what you're doing, just ask around locally, there'll likely be someone with experience doing this that can help out.

If this doesn't solve it, it gets more complex, but always start with a TPS reset, it's a mechanical component and over time small changes can occur.

Stu.

[revilla]

Unfortunately I don't think a lot of that is relevant here. Yes a low battery can leave a K struggling to idle on startup, but that's because of the way the standard ECU recycles the IACV and only persists for a few seconds. The OP mentions throttle bodies, in which case I guess there won't be an IACV to cause this issue. The reset process you mention is also only applicable to the standard MEMS ECUs and not an Emerald. I'm afraid I'm not sure of the correct idle setting procedure for an Emerald with TBs, so don't want to make suggestions that could do more harm than good!

[revilla]

Looks like my post crossed with Stu's! At least we agreed as far as my knowledge went. Stu's fills in all the details.

[TomB]

I needed to tweak up my idle on my K / Emerald / SLR TB combo.  It wasn't as lumpy as above, but was hovering about 900rpm at idle and a bit chuggy, and about 2-300 below where it should have been in the other settings.  I reset the TPS from the laptop, and also adjusted the maximum trim advance for ignition at idle condition.  This is a setting that limits the degrees of advance at idle to a selected maximum value to help idle control - nudging this up (I cant remember the value I selected, but I think you cant go about 25degrees) increased idle much closer to where it should have been.      

[Norman]

Thank you all for your suggestions. After buying the Emerald comms cable I've now got the laptop and software hooked up to the ECU successfully, but not sure which setting I need to change to alter the RPM at idle. If anyone who has done this, has any screenshots of their settings, I'd love to see them. 

Also, can someone point me to where I reset the throttle position sensor in the software? I can't see a button or option anywhere which mentions this! 

thanks