'91 Sammy runs rough

[fixkick]

Here is a shot of the case tag. B50
Also a shot of the board number, might be able to verify with that.


Soldering a 10k resistor to the connector pins would be child's play and fortunately the pins are clearly numbered on the board.

So. a 10K resistor between A16 and A17 then? Is that the trick to eliminate the EGR error code 51?

Thanks,

Jim

yes,  if the harness is gone so is the EGRT connector
the hack here is simple, the ECU
some newer ECU set code 53 that means if powered on scan it sees the EGRT missing, (infinity ohms)
the early ECU many do not do this test, I think also that is  CALIF test. code 53.
51 is a  live engine running test. (hot engine and never at idle)
but is DUMB as a brick.
it fails to do the real 2 test test. and does only the 1 test. (I call it the expectation test)
In 1996 they do test A and B, and is mandated by EPA law to do so. but not here.

It expect the EGR to be flowing now, test. At cruise .
and if is reading about 10,000 ohms it sees that magic current flow as at spec, EGR is good.

yes,  this is how it works see on my EGR page

some cars around this year, use the MAIN MAP sensor vacuum drop test. and had no EGRT at all. my 91 had this and up to 1993 maybe.
some cars have used EGR main using wrong EGR valve and the new owner does not know that  this car does not need the EGRT at all,  
seeing the EGRT there is not any proof at all after 30 years. (swaps happen)
only the ECu matters.!

and there is no way to fool the , MAP sensor drop test. at all. (aside from a custom complex processor box to fool it, with a dynamic vac leaking device)

your ecu is 94/95.
not sure if it is MAP test  or EGRT version,  I do not  know. (I guess EGRT)
using the resistor there will prove it.

i think yours is EGRT ECU.  using the thermo sensor probe to prove it works. at cruise.
good luck