205 over revving

[Gregg1980 0]

Hi guys, thanks for taking the time to read this.

 

Ok, so I purchased my 205 1.9 gti a couple of years ago, it came running megasquirt, but wasn't set up properly, so decided to back to original. As the car had been stored for a fair while my mechanic had a good look over it and decided it would be best to change all tge usuals over, next belts, pumps, pipes etc.

 

The engine was dropped and lots of parts replaced - new ECU, new AFM, new wiring loom, temp sensor, timing belt and pump, thermo, gasket thermo, ego sensor and so on.The car runs cold idle start, no sad.

 

So, the car starts up and idle is a little rough, but nothing drastic, can leave the car idling and will be fine, can rev the engine and will drop back to about 6-700rpm, but, as soon as I take her out for a drive and come to a halt it revs up in the region of 2100rpm!! 

 

My mechanic has tried tinkering with the setting on the throttle body etc but same old. He's checked for air leaks, and says there's defo none. We've tried different afms and ecus. We've cleaned them all out before trying. The distributor cap does have a crack in it, getying replaced next week, but don't tjink that's the problem.

 

In Australia, so it's not the sort of car mechanics have much knowledge with.

 

Any ideas??

 

Thanks guys

[petert 588]

Sounds like the TPS isn't set correctly, or it's a dud. Especially if it's a DKZ.

[welshpug 1,661]

"new"  or just old parts off another 30 year old car?

[DamirGTI 342]

I'd say SAD valve not closing up completely .. thus bumping the revs up after driving .

 

Go for a spin , drive for a while , and stop when the idle goes up till 2100rpm ... leave the engine running/idling , open the bonnet and with your fingers (or use some long nose pliers) pinch the SAD hose which connects on the main air hose to the TB (opposite the blue oil breather hose , black one next/under the PAS reservoir)

 

If the idle drops down while you pinch this hose means the SAD is not closing after warm up ... usually wiring to the SAD heater element breaks down thus lacking +12v supply to the SAD heater element to fully close the bimetallic disc inside the SAD , also the connector to the SAD heater could be disconnected , dirty/oxidized , or even mixed up with the ECU temp. sensor connector .

 

 

D