Need to fix cold enrichment Please help

[turbo84voyager]

Hi all,

I am still having problems with my cal in my 89 caravan. It is a 40+ cal for a 2.5 g-head which is what I am running. The cal runs great when it is warm out but as it is getting colder especially in the mornings it just does not want to go into closed loop and stays running pig rich. The problem starts around 50 degrees and gets worse below. I dont want to remove any fuel when it is warm because above 50 I dont have any problems, just when it is cold. I have been playing with the cold enrichment B table quite a bit and have lowered the closed loop temp to 140. This helped and seemed to lower the problem to start at about 50, but it is still very rich and since it is rich it takes long to warm up and I am worried about washing down the cylinders. The strange thing about the issue is that eventuially when the temp gauge gets to normal operating temp the blue light on my dawes is still lit the entire time. Eventuially it will start to bounce around. My EGTS also show the rich mixture because they are low. It seems sometimes not always, if I turn the engine off after driving a little and restrart it goes into closed loop a little while after. Even if the van does not go into closed loop faster how can I lean it out only when it is cold?

Another note is I have had to make several adjustments ( take out fuel)to the starting fuel (coolant) table and the van starts great, no black smoke and very smooth. The EGTs climb quickly until the o2 warms up ( dawes climbs to blue) and they will sit at 850, Normially on this engine they are between 950 - 1000 at idle. What ever "table" it follows after this point is too rich.

Any help would be grately appreceiated. It is getting coloder out and I need to get this fixed.

Thanks,
Justin

[GLHNSLHT2]

I'd recommend not doing fuel adjustments based on the narrowband O2 sensor. They are highly innacurate. I was off 40% in my WOT curve trying to tune with that thing. WBO2 is the only way to go. Because "rich" might be 13.5:1 at cold idle which isn't really rich. Cylinder washing would be anything lower than 10.5:1 or so. With a Narrowband you don't really know where your at.