Tricky-Ricky Posted October 1, 2008 Share Posted October 1, 2008 OK I'm going to start a new thread, as this is a different approach, but still related to my "Misfire" and "CAS" threads, I guess I'm looking for input from people who map and understand ECUs like Ryan etc, As my mis/pop only occurs when the engine is warmed up/hot i need to look at the cold start parameters for clues. If my Supra is started from cold, it will not miss until the AFRs start to go to stoic and temp is over 30c, so what i need to find out, is what other things are used in cold start other than 1/ water and intake temp, my understanding is that if there is a problem with either of these, ECU will run a rich AFR through hot closed loop? so although i checked these a little while ago, i would expect to notice if something was amiss! 1.5/ more air entering engine due to ECU control of idle during cold start. 2/ is the ignition advance adjusted for cold running? 3/ As during cold stat/warm up, lambda feedback is not used, and as AFRs are fine when hot its not a lambda problem, i have also swapped them to check. So is there something i have missed that could have an influence? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 2, 2008 Author Share Posted October 2, 2008 Anyone? Ryan? Quote Link to comment Share on other sites More sharing options...
bondango Posted October 4, 2008 Share Posted October 4, 2008 My understanding of the TCCS is that on iniaital start the ecu recieves an STA signal. On this THW is referenced in regards to cold start. AIT is not used as part of a cold cranking enrichment. If THW is above a certain temperature then the ecu sets a longer pulsewidth to the injectors for a short time when seeing the STA signal - cranking enrichment, and on a UK/Euro if above a certain temp, Fuel pressure up VSV is activated. Cold start routine is via a basic lookup table referenced via THW. The table data contains a refererence value for idle motor stepper, injector pulse width, and ignition advanve at a specific temp. So bascically as the water temp gets warmer, Ignition advance, injector and idle motor pulse width are reduced until the engine is hot enough to switch to Closed loop control. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 4, 2008 Author Share Posted October 4, 2008 Thanks for that, its pretty much as i thought, except i wasn't sure about whether ign timing was advanced, So i guess that the only thing other than that which might have any effect on my symptoms is AFRs being rich, will have to see if i can disable closed loop and richen things up and see if it still pops during idle. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.