Truth,? In truth all you can do is TEST or guess. (change parts till it runs right)
if the engine is good we attack EFI. (good vacuum good compression tests) no vacuum bounce nor reverse acting vac with melted CAT and blocking exhaust path.)
This car is not 1996+ so driving and logging all inputs sensors and all DTCs live, is not possible. with OBD1 1995 here.
That means only connecting a wire to each ECU pin 1 one at a time to a portable scope can find the sensor that drops out; is the only way, in school they teach about break out boxes.
If all inputs are good and the spark fails, at the coil minus lug, (ECU out) that means the ECU is bad.
If all ECU inputs are good and any out put of ECU is bad then the ECU is bad.
this is true on all computers made those the phrase GIGO, garage in ,Garbage out. mantra.
NO LIE intermittent problems can be a horror to find. for sure hot and for sure only driving or only under load or only wot ,etc.
I even have digital meter here DMM that has USB port and I can log data (voltage) to laptop, and test sensors driving.
It (meter above link) is slow to find changes but is far cheaper than any good scope. and does have software that has slow mode scope.)
cheers and happy trails.
if the engine is good we attack EFI. (good vacuum good compression tests) no vacuum bounce nor reverse acting vac with melted CAT and blocking exhaust path.)
This car is not 1996+ so driving and logging all inputs sensors and all DTCs live, is not possible. with OBD1 1995 here.
That means only connecting a wire to each ECU pin 1 one at a time to a portable scope can find the sensor that drops out; is the only way, in school they teach about break out boxes.
If all inputs are good and the spark fails, at the coil minus lug, (ECU out) that means the ECU is bad.
If all ECU inputs are good and any out put of ECU is bad then the ECU is bad.
this is true on all computers made those the phrase GIGO, garage in ,Garbage out. mantra.
NO LIE intermittent problems can be a horror to find. for sure hot and for sure only driving or only under load or only wot ,etc.
I even have digital meter here DMM that has USB port and I can log data (voltage) to laptop, and test sensors driving.
It (meter above link) is slow to find changes but is far cheaper than any good scope. and does have software that has slow mode scope.)
cheers and happy trails.
http://www.fixkick.com