misfire

[Gavyjoe]

Hi, my race car has developed a misfire only under heavy boost/load and ive noticed when the misfire comes inn the water temp on my toucan drops like a stone, if i then back off the temp rises back up to normal ? The car idles and runs fine untill it hits say 4th and is under load. Ive already replaced the fuel pump and filter, got the injectors cleaned, new plugs and coils, checked all the air/vacum pipes etc and its still there ! Hopefully someone can put me out of my missery lol

[johnfelstead]

We need more information to help.

What is the ECU?
What temperature drop is seen?
Is the missfire after the temperature drop?
Do you have any data logs you can show us?

[Gavyjoe]

Ecu is a syvecs s6 with jti loom and sensors, ive checked and it hasnt stored any faults and ive not done any loging, im not overly confident around an ecu tbh. Water temp will rise and sit around 85-90 on the toucan, but then and only when under heavy load the missfire appears and with it the water temp drops immediately to around 70 degrees, then when i back off boost the water temp will rise back up to normal again ! If it had of been the other way around id say a head was lifting but its going the opposite way. Ive also an oil temp gauge that behaves erraticly, spiking up and down but this has been the case for a while now, long before my current issues, which ive put down to a possible interference, even though the wiring has been checked multiple times, but possibly linked ?

[johnfelstead]

If you send me your Cal file and your log config file I'll take a look at it and then send you a datalog definition file to load so you can take some useful logs to then send over.
The Syvecs is a great ECU for this kind of thing.
I'll PM my email address.

[stevieturbo]

you need to datalog.

But if the coolant temp is dropping substantially, it implies a wiring/sensor related fault. Because coolant temp sensors are extremely slow, and will never register a very fast change.