unstable coolant sensor feed after hot start

For discussing how to choose sensors and create a wiring harness for all Bowling and Grippo versions of the MegaSquirt® EFI controller.
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durson1
MegaSquirt Newbie
Posts: 28
Joined: Wed Dec 31, 2008 11:48 pm

unstable coolant sensor feed after hot start

Post by durson1 »

Running MS2 V3 2.89 code on a VW4 cyl. direct coil control.
So reviewing my logs after a cold start my coolant sensor feed is pretty steady along with the intake air sensor. After a hot start though its shakey throughout the log. Intake air sensor stays pretty steady, but coolant temp is a jagged line. I've checked the wiring and the grounds. Anyone have any idea why the output from the sensor is only effected after a hot start.
I've attached logs of a cold and hot start and my msq.
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kjones6039
Master Squirter
Posts: 618
Joined: Sat Jul 22, 2006 7:02 pm
Location: Eureka, Nevada USA
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Re: unstable coolant sensor feed after hot start

Post by kjones6039 »

Not to worry!! :D

Both logs look quite normal IMO. In the first log your clt went from ~66 to ~190 degrees, a difference of ~125 degrees. In the second log your temp only varied ~24 degrees which accounts for the more jagged looking trace spread across the vertical axis of the log.

I have seen this many times and it does not indicate a problem.

Ken
1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
MS2 v3 w/ms2extra 3.4.0 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
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durson1
MegaSquirt Newbie
Posts: 28
Joined: Wed Dec 31, 2008 11:48 pm

Re: unstable coolant sensor feed after hot start

Post by durson1 »

Thats good to know and makes sense. Thanks.
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