Re: [20v] ‘91 coupe quattro cold start problems

[theringmeister]

My suggestions would be leaky injectors washing the cylinders and loss of compression, fuel pressure regulator, although that would probably lead to some flaky running and idling conditions as well regardless of operating temperature, and that coolant temperature sensor which you unplugged. I'm trying to recall the resistance values but I'm not sure unplugging it would fake the ECU into thinking the engine was cold and setting the mixture accordingly. Have you pulled codes since your last issue to see if anything's in the fault memory?




-------- Original message --------From: Christopher Gharibo <cgharibo at usa.net> Date: 1/23/19  6:56 AM  (GMT-05:00) To: quattro at audifans.com, 20v at lists.20v.org Subject: [20v] ‘91 coupe quattro cold start problems 
My ‘91 CQ cranks fine but has difficulty starting when cold. Once it starts the subsequent cold starts and warm starts are fine. About eight hours later, cold starts are a problem again. 

I changed the 20 year old fuel pump and multi function temperature sensor without improvement. All the vacuum lines seem fine. I unplugged the coolant temp sensor behind the block without improvement. The fuel injectors are 034 and about 15 yrs old. 

The car runs and accelerates fine otherwise. 

Any other ideas would be greatly appreciated. 

CG 
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