1.4 K series supersport idle problem

[rkanaga]

So I had a curious idle problem with my K-series car and thought that I should share the fix.

The car is a 1997 1.4 K series supersport which I bought from Damian and Anthony at GP Sevens. I built an almost identical car whilst in med school and always regretted selling it so it was great to find an almost identical 6 speed to drive again, differing only in having cycle wings, which I actually now prefer.

 

The car developed a curious problem, initially stalling at idle when hot. After a replacement TPS which Damian kindly sent me to avoid a trip back to Sevenoaks, and cleaning the oily residue from the throttle body (from the oiled K&N filter) the symptoms changed to now stalling at idle when cold, and then as the engine warmed up the idle speed would rise and rise to as much as 3K. Doing a manual TPS reset helped but only for a few minutes, and I was curious because whilst you could hear the stepper motor chattering when you did the TPS reset, it did not appear to move at all.

I dropped the car back to them, and Chris there very cleverly worked out the problem, dry solder joints on the feed to the stepper motor (the board is inside the motor housing). A quick resolder and it is now working perfectly. The car has done 33,000 miles so presumably just the result of vibration over the years as I  think 1997 was before the use of lead free solder?

I've seen a few other threads about K series idle problems and I do wonder if any of them actually had this fault. Because the fault is intermittent it results in very inconsistent symptoms and so you might actually find that fiddling with other parts of the system might work temporarily only to induce other issues later. The clue in my case was that stalling at idle and then running fast when hot implies running both too lean and too rich which points to a sensor or actuator fault I suppose. You might even think the ECU was faulty I imagine.

 

Anyway, thanks to GP Sevens who have been fantastic in sorting this out and are great guys to buy from, and of course for getting me back in a 7 again!

All I need to do now is stop planning upgrades and just drive it! (iIve even bought some noise-cancelling headphones for long trips..)

 

Robin

 

 

[SM25T]

Good story and service from GP7. Not sure notice cancelling headphones work well in this environment ? We use Peltor Optime 3 ear defenders with speakers built in. You could use in ear headphones under them.