Cold start problem

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Dioclese - 20 Dec 2007 14:10 GMT

Symptoms:
When left overnight engine off, followed by cool/cold weather the following
morning: The engine starts right away as it should. But, it chugs and
sputters, if you will, until the cold start cycle is complete some 30
seconds or more later. Then runs fine.

Did the drip test on the cold start valve, not leaking by. The auxiliary
air valve is obviously cycling off per the approximate 30 second timeout.
The thermo time switch is obviously working as the car starts (actuates the
cold start valve), and doesn't run rich after the approximate 30 second
timeout. Idle speed is around 900 rpm. Differential pressure regulator
current is approximately 10 mA.

88VW Fox, 1.8L, CIS-E. Going by the Bentley manual.

Signature

Dave

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dave AKA vwdoc1 - 22 Dec 2007 02:17 GMT

check out your Coolant Temperature Sensor for the fuel injection.

> Symptoms:
> When left overnight engine off, followed by cool/cold weather the
[quoted text clipped - 10 lines]
>
> 88VW Fox, 1.8L, CIS-E. Going by the Bentley manual.

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Dioclese - 22 Dec 2007 15:34 GMT

Was thumbing through the Bentley manual this morning. Big Ole basic
schematic view of the Digifant system on one page. Coolant sensor is one of
the key players feeding the control unit, with the control unit at the
center of the schematic. Sensor is at bottom of the cylinder head coolant
outlet.

Backtracking in the manual, there's a schematic view of the CIS-E fuel
injection system. Rather than feeding the control unit here, the coolant
sensor leads to what they call the oxygen sensor control unit. The oxygen
sensor control unit then feeds the differential fuel regulator. I don't
know if they mean the oxygen sensor, or the control unit. My guess it they
mean the control unit, using oxygen sensor input, controlling the
differential pressure regulator. One of many mystery description terms in
the Bentley manual.

Signature

Dave

> check out your Coolant Temperature Sensor for the fuel injection.
>
[quoted text clipped - 12 lines]
>>
>> 88VW Fox, 1.8L, CIS-E. Going by the Bentley manual.

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Dioclese - 24 Dec 2007 05:45 GMT

Opposite of what I expected. Zero ohms/continuity. Both mulitimeter probes
were only contacting each terminal on the temp sensor. Checked 3 times for
my piece of mind. Replacement on its way via UPS.

Thanks, and Merry Christmas.

Signature

Dave

> check out your Coolant Temperature Sensor for the fuel injection.
>
[quoted text clipped - 12 lines]
>>
>> 88VW Fox, 1.8L, CIS-E. Going by the Bentley manual.

Reply to this Message