1.4 8v KDX wont idle, intermittent miss

[Richie-Van-GTi 72 2 Cars]

Ive just replaced an engine in my daughters mk1 106 1.4 8v, SPI with the KDX engine. Old engine developed a nasty bottom end grumble.

New engine has her original throttle body along with plugs, leads and coil which were all new, as was crank sensor and battery.

The car starts but wont idle at correct speed, only the cold start speed, when warm I have to jam throttle open to around 1200 rpm to maintain idle which the car then tries to bring back down to normal but cant quite get there. Its constantly hunting about but more like an intermittent misfire, can hear it throughout the revs but more prominent at slower rpm.

Everything worked great on old engine and I cant find any obvious air leaks, tried sparying all the joints with carb cleaner but no obvious changes.

Any suggestions?

Edited June 15, 2018 by Richie-Van-GTi

[DamirGTI 342]

I remember TPS sensor tends to go bad on these SPi engines .. certainly seen a few 205 1.4 SPi with bad TPS sensor with similar symptoms .

 

Try to open the TPS and have a look at the resistor strip , if the resistor strip/track is worn out/scratched  .

 

 

D

[Richie-Van-GTi 72 2 Cars]

Thanks, will check that out today

[Richie-Van-GTi 72 2 Cars]

Sorted, gasket underneath was slightly oversize and allowing air through what I assume is a bypass of some sort. New gasket, idles and revs properly. Cleaned it all out while it was off though