just to convince more people that the obd1 protocol is useful even tho it is slow..
Diagnostic capabilities on stock ecus are way better than error codes will ever allow.
It helped me make the day for an ST165 guy on the 26th dec. Solving an issue he inherited from the tuner guy that installed his ST205 engine last summer WITHOUT even looking at the car wiring itself.
here is the exact post from my facebook toyobd1 user groups.( https://www.facebook.com/groups/1505898572959292/
Never overestimate someone else`s engine swap wiring job to be right.
adding engine issues that no one could suspect diagnose or correct...
ST205 swap into an ST165 celica, stock ecu,stock everything.
fuel consumption ranges from 20l/100km while crusing to 87l/100km under acceleration, no power, ignition cannot keep up with the amount of fuel to burn under acceleration. no meaningful error codes helping to diagnose.(code 12 crank sensor problem)
Here`s a hard one that I got to solve using TOYOBD1.
Let me start by saying I never even got to look at the wiring itself, finding the problem only by looking at data. the solution is explained at the end of the post,
After a data logging session with toyobd1 here are the things that surfaced.
-no missing sensor
-there is nothing wrong with the rpm signal so the error code IS misleading.
-igition locked at 5deg btdc all the time.
-heavy use of the IAC valve all the time
-always in open loop.
-heavy fuel consumption is confirmed
-ox sensor (fuel trim) is at the maximum value for rich mixture all the time
THERE is ONE more fact that explains everything tho!!!
-STA is on all the time
-when the starter is running STA is on
-when staring the ignition is about 5deg btdc
-when starting the IAC valve can be used to make things easier
-when starting there is fuel enrichment, seems like base fuel map * a large %
-when starting the ecu is probably in Open Loop
OK so WHY is STA on all the time??
Because the guy that did the wiring job wired STA to a constant 12v source due to a lack of knowledge and the ecu thinks it is always starting, regardless of engine speed,temperature or load...
solution was to correctly connect the STA wire like in the wiring diagram..
here is the data log from that session.(when STA was always ON)https://www.dropbox.com/s/t2a2fax6gdwdr ... 9.csv?dl=0