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Re: The cold start flooding saga continues Posted by Saana88 [Email]  (#207)  [Profile/Gallery]
(more from Saana88) on Wed, 21 Dec 2005 15:40:44
In Reply to: The cold start flooding saga continues, Will, Wed, 21 Dec 2005 10:10:52 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Hmmmmmm...... 85, 85, 85. Our first 900 in the family.
The way the system works is it'll hold a fixed pulse rate until the initial couple o'minutes' warm-up period expires, then it's up to the oxygen sensor and the pre-set mixture to regulate fuel flow. If the internal diaphragm inside the airflow assembly was leaking, you'd be rich all the time (moreso when cold as the cold start injector is active).
In '85 your FI thermoswitch is in the head (between cylinders 2 and 3 on the intake side) and it should be closed (5 ohms or less) for a cold engine (coolant temp below 100 Fahrenheit, 38 celsius). It should be a resistor (140 ohms between pin 1 and ground) on a hot engine (above 110 Fahrenheit). Measure between pin 1 and ground; pin 1 supposedly has a green wire. Bentley says there should be battery voltage at pin 2 when cranking a cold engine; this activates the heating element.
About ten minutes after reading all this, I decided I'd had enough and ordered a replacement from TSS. It's not just a thermostatic switch that fails with age, it's got a heater in it too? It's sixteen years old? Out it goes! Twenty bucks or something like that; I replaced it when the coolant was drained anyway. If you don't want to drain the coolant, just pull it out in a big hurry and slap the replacement in, mop up what spilled, and refill the reservoir. With the bleed screw open, of course.
My best guess at your predicament is that the cold start injector may be stuck open/leaking/have its sensors shorted or grounded which means the car starts great when cold but as the CSI is supposed to cut down then cease functioning after warm-up it's making you go hyper-rich. With a cold engine, the CSI should spray a few seconds and then stop. It may operate up to twenty seconds or something like that if it's colder than cold outside.
What does your oxygen sensor say? What does it say in the warm weather versus the cold? Has it been changed in the past decade? Is your venturi plate stuck off-idle? CI is supposed to be a closed-loop system after it warms up, simply regulated by the O2 sensor, the lambda pulse valve, and the constant stream o'fuel from the distribution block.
Good luck, and if it doesn't get better, post about it again.
, Wed, 21 Dec 2005 15:40:44 <-- Viewing This Message
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