Megasquirt - Engine Dies At 71degs?

[madspikes 41 1 Cars]

I've just tried to run the new engine up to a good working temp, but it dies when the coolent sensor read 71C! I cant find any settings that are enabled that could be causing it. If the sensor is unpluged the engine runs fine.

 

I'm running the same setting and ECU as last year. Could the MS memory / code got currputed as it hasnt been used for a year?

 

HELP! Mad.

[pugpete1108 62 1 Cars]

thats an odd one? wish i could help you out buddy but i know feck all??

 

it dies at exactly 71 every time? dodgy sensor cutting out at 71 degs and causing ms to shutdown maybe?

 

you tried an new sensor?

[madspikes 41 1 Cars]

thats an odd one? wish i could help you out buddy but i know feck all??

 

it dies at exactly 71 every time? dodgy sensor cutting out at 71 degs and causing ms to shutdown maybe?

 

you tried an new sensor?

 

Its a new one on me to! The data logs look normal, it gets to 71 and then then engines dies very quickly after. Not spikes, rpm just drops off!

 

Its a right bugger, so pass another beer!

 

 

Mad

[Mad Professor 7]

What idle control are you running?

 

As a guess without seeing your current MSQ and a log of when the problems happens is that at 71deg your idle valve stops working or turns off (closes) dropping your idle below stall speed.

[sideways danny 0]

measure what the voltage does as the temp hits 71. My guess is the sensor is faulty and giving the ECU some very incorrect readings

[madspikes 41 1 Cars]

I solved this problem the other day.... The issue was that I managed to connect the idle valve transistor to the fuel pump transistor. With the default idle mode set (on till 71c, then off) I killed the fuel pump transistor and so the fuel pump only came on with the idle valve... and off again at 71c.

 

Now that I have replaced, and reconnected both transistors, I now have a working fuel pump and working idle valve.

 

 

mad.