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flightlead404 flightlead404 is offline
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Join Date: May 2015
Posts: 767
Cold Start Observations

OK, now that I've got power wired to the delayed action relay my hot start issues seem to be gone. Cold starting is a different story. Here are my observations, and a log attached.

Cold start attempted with outside air temp around 60*f, engine completely cold soaked.

Caught and died on the 1st two attempts, started on the 3rd turn of the key. But, a very low and lump idle, around 450 rpm for a few seconds then suddenly kicked to a smooth idle around 950rpm.

After that it crept quickly to 1,150 then more slowly up to 1,400 as the engine warmed up. It did not show any sign of stopping that slowly increasing rpm.

During this time the Control Pressure was significantly higher than target. Example data point on the control pressure curve that mimics the WUR curve, target was 190, actual pressure was 290. During this entire time the eWUR duty cycle was pegged at 90% (the max I've set), with the frequency valve duty cycle at 49%. None of guages (CP, eWUR DC, FW DC) seemed to change much during this time.

When the WUR curve hit a target control pressure above 290 the eWUR DC started to reduce and the CP started tracking the target. Idle stayed high. FV DC didn't appear to change much.

Seems the eWUR injector can't get the CP below 290 and the FV is not helping at all during this phase.

As soon as I blip the throttle it goes right to a ~950 rpm idle relatively smoothly.


Last edited by flightlead404; 01-05-2017 at 08:48 AM..
Old 01-05-2017, 08:36 AM
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