nicorsts1

Its been running on a S2 ECU since i bought the car, i had it set up at Nobles to be on the safe side because it was hesitating under boost, sometimes just holding back. (mainly when the air temp was warm) They never said anything about the ecu being wrong but i was told on here by a few of u guys that the S2 ECU which is Blue Red Black won't allow the engine to run right.
Well today i finally got round to fitting a blue red blue ECU, it seems ok but sometimes rarely whilst boosting the power just drops right off . I wondered whether this might be a faulty ecu or will the car need setting up again. Both ECU's are standerd, never been chipped but somethings not quite right, it does'nt hesitate like it did on the S2 ecu so do i just need to take it to a tuner or should it have been just a straight swap?
Whats the diffrence between em apart from the later S2's having the knock sensor?

Thanx in advance for any help...

GrimmeRS2K

could be amal valve if running one, i thought a s1 ecu were just silver and had no colour coded on them

nicorsts1

Been out this mornin and found that in 4th and 5th gear between 3.500 - 4000 rpm the revs just drop right off, happens so quick i'm not sure if it drops right below the 1000 mark or if its just cutting out completley for a split second. So far its not done it in 2nd or 3rd gear. Any ideas, anyone else had a simlar fault....?

db

I am pretty sure what is happening to your S1:

the boost is set too high and the ECU cuts the ignition when you go higher than the max allowed boost. That's why the revs drop for a moment.

This does not happen in 2nd or 3rd, because you do not get to max boost.

Have the boost turned back to a level that will not trigger this safety system. I experienced the same with my S1 when I tried to adjust boost pressure, simply turning back the boost solved the problem. Of course the trick is to end just before the safety kicks in.

A blue red blue ECU should be OK for a S1. I also heard from a Dutch tuner that not all S2 ECU's work in a S1. Only 86 versions seem to work in a S1.
I assume it has something to do with the knock sensor (not all S2's had one????) electronics.

I have a 86 blue red blue ECU from a S2 at home as a spare, but not tried it yet, should work though.

Cheers.

nicorsts1

Thanx guys, db i'll get it checked out, see if the local tuner can sort it. Lost a bit of faith in Nobles... not sure whether to try somewhere else....