Hi Guys !
Have a 1988 Camaro 305 TPI manual that had some issues the last two years.

Started with it stalling from now and then , had to wait a minute or two then it ran again.

But last year the OBD-I port stop working so when shortcut the terminals to ask for thje SES lamp to blink codes, nothing happends, even though the lamp is working as normal.

So , decided to buy a new ECM, did so and installed it, and same problem continued.

Finally it stopped for good, wich was well enough bcs I thought it would help in finding the problem.

So, last weeks I have replaced the Injectors with Bosch III, all sensors around the TPI is replaced, incl EGR.

Then it flooded directly, so I made a LED Cable so that I could actúally see whats going on by the injectors, and it shows that when going into crank the coldstart extra injector works during crank , wich is fine.
The Injectors are pulsed for like 5-6 secs then the go fully open constant, read , the ECM port D16 and D15 goes fully Earth instead of pulsing.

I measured the OBD-I port, the A: GND is OK, The B: ECM diagnostic request should be 5V+, but is zero, the M: 8192 serial data should be 5v+, but is zero.

so, any ideas of what to replace ?

Best // Bo
answer if you like to bo@tacticalheadsets.com