e30 325i running with 320i ecu!

[madmax1410]

ive been thinking of getting a chip for my ecu and i found one that sounds good so i checked the number for the ecu it suits online with the one in my car and it end's with 172

from looking up on the net this seems to be a 320i ecu were as the 325i one ends in 173 so i done a bit of research and apparently the inner workings are all the same bar the chip!

so this might explain why my car could never be got to run right!

has anyone else had a 320i ecu in there 325i how does the engine behave on tick over acceleration fuel economy ect is it very noticeable or not? either way im changing the ecu for the time been till i get a chip for my own!

[HairyScreech]

Best to check the chip, 320 ECUs can be fitted with a 325 chip.

[madmax1410]

ive had the cover of and it looks like it was never opened i also have another 172 ecu here out of my parts car to compare them inside to see if anything has been messed with but it all looks right so far anyway!

the number on the chip inside the ecu out of my car is 1 267 355 793! were as the number on the chip in my spare 320i ecu is 1 267 355 518

[Speedtouch]

Yes, a 320i will run on a 325i ECU and vice-versa, but the ignition timing and fuelling maps will be way out, which does the engine no favours in the long run!

[madmax1410]

Yes, a 320i will run on a 325i ECU and vice-versa, but the ignition timing and fuelling maps will be way out, which does the engine no favours in the long run!

this might explain the fact its sometimes hard started! on occasion it needs to be turned over more than once so its not getting enough fuel!

it also has high idle at 1000rpm or slightly over this could be from the 325i afm and throttle body been larger than what its suppose to be there for letting in more air?

[Speedtouch]

Check that your 325i actually has a 325i AFM and TB - it's quite possible that they may have been swapped for 320i items!

[madmax1410]

Check that your 325i actually has a 325i AFM and TB - it's quite possible that they may have been swapped for 320i items!

the throttle body is correct as its got the single bored hole for servo and seen as the rubber boot fit's tight on the afm aswell i suspect its correct also but i will check to make sure! as soon as i get an ecu it will be interesting to see the difference!

[madmax1410]

well to update this i got another ecu this time a 380 chipped with an alpina 2,5 191hp and the car seems a good bit more powerfull after 3000 rpm plus its got a new rev limit of 6900/7000 rpm

but the car still idles over 1000 rpm so i went about looking for vacuum leaks and i think there is a little one where the icv connects into the throttle body and were the servo pipe connects.

i also checked the afm against a 320i one i have here and the diameter of the round end on both of them are the same but the part number ends in 83 on the 325i one and 82 on the 320i one is that correct?

one last thing i have no pipe on the air box to the plastic cover behind the headlight at the moment which is getting a lot of hot air from the engine bay because of the rad fan would this be affecting the idle and power much compared to cold air?

[Speedtouch]

The Alpina 192 chip has a standard 900 rpm (approx.) rev limit programmed into the idle map, which will explain your high idle.

[Brianmoooore]

Without the corresponding Alpina mods., your new ECU will not be suitable for your engine.