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Discussion Starter #1
So last Friday I visited a fellow Alfista who recently acquired a turboed Giulia 2.0. It's running FI on Diktator management.

The car runs well when cold but after some driving, the engine starts losing power and almost dying but can be persuaded back to pulling okay by tapping on the petrol pedal.

Any idea of where to start troubleshooting? He doesn't know the engine well.

 

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It sounds like a fueling problem. He should get an AFR (lambda) sensor to see if it goes lean / rich when running into this problem.

Stand alone ECU's have enrichment profiles based on the water / air temp. I'm guessing it is tuned while the enrichment is high (read choked). The alternative is that it could be tuned with TPS value and not MAP sensor - bad for a turbo motor, also not best for N/A :alien:
 

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Discussion Starter #3
That's what my untrained mind thought as well. Thanks, Gertie.

Sent from my SM-G925F using Tapatalk
 

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Difficult to answer without knowing more about his set up. Is it running MAP or TPS inputs for fueling? Former is more likely. If the car is responding to being given more fuel then perhaps there is a problem with the fuel pump. One assumes that its running some sort of rising rate fuel pressure regulator but if it also has a fuel pressure gauge (sometimes on the fuel regulator itself - it should be making 2,5 to 3bar) and the problem arises when the car is warm and you see a fuel pressure drop - stationary obviously then you'd know that the problem is fueling and this could be a number of things in the fueling chain starting with the pump (they do get gunged up) and then the regulator itself and the plumbing. The other could be the programming when the car is warm - diktator has cold start and then normal (warm) running mode and maybe there is an issue with the latter although this seems unlikely. Lastly, is it intercooled? The temperatures get so hot under the cramped engine bay of a Giulia/Junior it melts paint work (bigger Alfetta and Giulietta engine bays mitigated this problem) and without intercooling you may have an air charge that is just getting too hot (and that is being temporarily cooled by a dab of fuel). Very difficult El - He probably needs to go to a diktator tuner with a dyno and my understanding is that in the Cape tooth fairies are more easily found than reliable diktator tuners. Seems Kaapies like Gotech.
 

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Discussion Starter #5 (Edited)
Thanks, guys. Wish I could provide more info. It is intercooled. The nose was modified slightly to accommodate the intercooler.
 

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I think GTAR has touched on a possibility. Often stand alone systems come factory programed to enrich for idling(cold signal from the engine) and to lean out when hot. The tuner should cancel these programs, but often just carry on tuning in his cool temp workshop and when the car is used outside and a "hot" signal is received, the ECU change the program. Often a VW temp gauge is turned into a nut and fitted against the head to get the temp reading when hot. There can be a problem with the sensor or the position it sits in. (air flow influence)

A fuel pressure regulator can also cause similar problems, some great looking units let the fuel pressure drop under pressure. Fit a fuel pressure guage to check.

I had similar problems once, but some power just dissapeared.
 
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