bad idle on the TR

What engine family? F113A, F113B, F113A040, F113A046, etc...?

 

Yes it is necessary to know what year and type of fuel system his TR has. Is it an early car with Warm-Up Regulators? Is it a later car without...? Need more info....

 

This wouldn't be my first choice as a suspect. The cold start injectors' function is to aid initial cold engine start-up, and your friend's TR seems to be doing that OK (even if the subsequent cold-running is poor). Also, if the cold start injector(s) was(were) doing something wrong (like continuously spraying fuel), then the warm-running wouldn't be OK.

Since he has a F113B (KE-Jet without Lambda), the two things that I would do are:

1. Confirm that the resistances of the thermistors (that "tell" the injection ECUs what the engine temperature is) are OK both cold and warm. It's probably unlikely that these are the problem (as usually a "bad" one would make both cold-running and warm-running bad), but it's a fairly easy measurment to make:
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2. Confirm/deny if there is +12V power present on the "red wire":
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You don't mention if things were OK for both cold-running and warm-running, and then, suddenly, only cold-running became bad. One "problem" with the KE-Jet system is that, if this +12V power on the red wire is lost (for example, because the 10A fuse on the protection relay is blown, or if the protection relay itself is bad), by tweaking the FD mixture screws, the Mechanic can make warm-running sort of OK, but the cold-running will remain bad. If your friend's history was that both cold-running and warm-running got bad at the same time, but then a Mechanic was able to make warm-running OK, but cold-running was still bad, then this would be a strong clue that "no +12V on the red wire" was the real problem and the Mechanic "fixed" the wrong thing. Of course, if your friend now doesn't have +12V on the red wire, but restores that, then the manual mixture screws will most likely need to be retweaked. But this is getting ahead of ourselves so best to just make the red wire voltage measurement to confirm/deny.

Good Hunting! (and I actually hope your friend's TR fails one of these tests as I would be a little unsure what to do next if he passes both )

 

Olá "portogts",

Primeiro e um teste muito simples... desligar o sensor de temperatura de água com o motor a funcionar, se se notar uma quebra grande na regularidade, ainda que precária, do funcionamento do motor então o sensor está a funcionar no entanto os valores de resistência do mesmo podem já não ser os indicados. Mas não seria só po isso que o "relanti" não estaria regular...
Se não for notada nenhuma alteração quando se desliga a ficha então temos um sensor avariado.

Cumprimentos

 

Hello Steve

I am the owner of the Testarossa in England that my friend in Portugal 'portogts' posted a question about with low rpm idle when cold. You were very kind in replying and I wanted to thank you for your time. The car should be fixed sometime soon and I will let you know exactly what the problem was. I am now a new member of FerrariChat.com today because I wanted to get this message to you personally, and I will now actively get involved on this site.

Many thanks again

Jonathan '288 GTO'

 

Welcome to FChat Jonathan -- glad to have you with us.