I have a 90' GTU turbo that was done by the previous owner. It hasn't idled since the day after i bought it.. The throttle is rough when i get on or let off the gas especially at low speed. Ive also blown 2 rear main seals.
The car runs fine except for the idle; so I just heel toe around town
A mechanic i took the car to to have my hydraulics replaced had told me it was because of a Vacuum leak/crack in my intake hose..

I found the ECU list on the forums the other day, and while i was fixing my door handle this afternoon I decided to just give mine a peek to make sure the guy that did a half-*** job on everything else didn't **** that up too..
Little to my surprise I discovered i have a N351 (89 NA)

Needless to say i will be replacing that shortly, but i was wondering what else I should look for now that you know that..

 

You need to find out if the sensors on your engine are NA or turbo (boost sensor & AFM primarily). The turbo and NA versions have different resistance/voltage values and will not be compatible with the opposite ECU (ie turbo sensors w/ NA ECU or vice versa). Is this a turbo engine (4-port) in the car, or a modified NA engine (6-port) w/ turbo? To run under boost you should have ALL turbo sensors and an N370 ECU (US-spec S5 TII). If you have mixed and matched electronics, trouble under vacuum (idle / low throttle) would not surprise me.

 

So far this is what I have:
N351 ECU = N/A
N350 Pressure sensor = N/A
N326(T) & N327(L) Coils
N350 AFM
Some Bosch O2 sensor
H271?
and N32? its very worn but i think its a N326 which is N/A also

So it looks like he left all the N/A stuff and just slapped a turbo on there..

Ive put close to 10k on this car with this setup before checking the ECU but it still runs the same.

Can I get a run down on the worst case scenario? Rebuild?


P.S. after I blew my first rear main, I went back to the guy and collected another 13b; and now I'm waiting for a friend to bring me back my impact(he moved to school and took my tool box from his old house w him), or borrow a breaker bar to tear it down..
Should be done with that by Christmas.

 

The ECU, pressure sensor & AFM are the ones that matter. Coils and 02 sensors are irrelevant and interchangeable. You need to replace the three with S5 turbo versions, and in the meantime either stop driving the car or take the clip off the wastegate arm (open all the time = no boost). Just how much boost has the car been making? The problem with the NA ECU & pressure sensor is that they have no way of seeing positive pressure, so timing will not be retarded much under boost & fuel will not be delivered properly either. If the engine has blown yet, it's miraculous. Poor idle is a sign of low compression, but only when you have serious power losses as well.

 

When I got it I would say it was around 10lbs, but had it turned down to around 5..
So if I get the ECU, pressure sensor, and AFM, everything else will be compatible?
Its all plug and play correct?