smurphs_s13

Ok so with the car running like absolute crap.. we figured hey.. lets replace the ECU to see what happens well now there is no spark.. i want to know if anyone knows if the two ecu's are compatable.. (btw my old ecu was corroded and rusted to hell from a nice leak i have) the one we took out has the big number 29 on it and the new one is a 28 both from a dohc motor...

Joel SX

No.1) Yes they are from 26 trough 29
2) Replacing the ECU doesn't do anything, it might even give you less HP
3) B/C you have bad iddle you should just go "Hey I got an idea right off the bat: Its the ECU" and replace one of the most delicate things in the car
4: If your ECU was rusted to ****, who knows what else (wirign ,conectors, relays, fuses, cables might be toasted, etc.)
5) Try looking for codes

smurphs_s13

No we tried everything before replacing the ecu.. but along with the no idle at all.. not a bad idle there was no signal to the fuel pump relay etc etc.. and if you read my other post about vaccum problems... and we checked all the wires to see if there was a possiblitiy for a loose/bad ground.. pinched wire somewhre in the harness everything.. its not like replaceing the ecu was a huge deal... weve got spares...

Joel SX

Yeah well I guess in the conditio nthat the ECU was, I think it was apropiate to replace it. I got spares too (2 automatic ecus and 1 auto/trans ecu).

Put your old ECU back and see. Also try testing for signal at the igniter coil. Do you have the FSM? I'll check mine to see

smurphs_s13

ok so i talked to one of my guys at Nissan and he said that the computer may be from the same year car and same engine but may not be compatable.. so there is my probablem probably.. in my old ecu i had power to the igniter coill.. in the new one i do not.. in the old ecu i opened it up and you can see that the prongs on one of the chips is coroded

Joel SX

Well I know that when I swaped the ECU's on mine (from a 93, to a 91, to a 92, and back now with my old 93) they all worked. One thing I noticed is that with the old 91 computer it ran at higuer revs and smoother. but I'll se numbers on the one's I have, try to see maybe i can sell it to you 10 bucks. Its auto ECU, so I'll get rid of limiter. Aslo try this:

Try getting some kind of soft metal brush, like the plastic pad to clean ovens with, then apply alcohol to the rusted corner of the Chip. After you remove as much rust as posible, then either heat it and aply soldering over it if its a big pin, or if its a small one, get some acid from radio shack and heat it. I'll cause the metal to get bared. then cover with electrical glue (also at radiochack) or silicone and let it dry before you use. I did that with a motorola radio and it worked.

Either way, its am atter of time before it fails I guess.

smurphs_s13

yeah the one i need has the big number 29 on it... i swapped it one with a 28... but now i have no spark.. no fuel pump signal nothing.. so.. we will see what happens.. if i cant figure out somthing soon.. i think it might be time to join the crowd and go with a swap