The truth about the N338 ECU!!
08-05-04, 09:22 AM
#1
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The truth about the N338 ECU!!
Ok folks, we're gonna rid the community of this rumor once and for all. I'd completed my TII swap a few weeks back and have been breaking Kevin Lander's motor. The swap was done w/ an N338 ECU since the rumor was that it has internal switching to sense whether you run an NA or Turbo car.
The first time the car was boosted, I gave WOT in second gear for a couple of seconds. Curiously, the car had some pretty severe hesitation @ 4K rpm under moderate load. This occured more often in first gear though it had happened in others. When it did happen, the car would break up then eventually rev past the hesitation point. With lighter load, sometimes it would rev out smoothly and sometimes it wouldn't. I decided NOT to boost any further until we could get things sorted. Another curious feature was fuel cut - according to my peak hold GReddy boost gauge, I never hit it
The car made 10 psi.
My installer and I checked the TPS, it was fine. We checked the secondary injectors and they were fine. Pressure sensor? Also fine. We both thought the ECU was our problem so I drove the car easily until my N332 with the rtek7 1.5 chip was shipped to me from digital tuning (www.pocketlogger.com).
I installed it last night and took it for a test drive. Upon startup, the car settled to a MUCH smoother and slightly higher idle (900 rpm). The N338 idled @ 750 (what we set it to) and although it held idle well, it was always a bit lopey. Now, it's super-smooth. On the test drive I drove @ light load without hesitation until about 6K. I fed in boost smoothly and the car just rocketed forward. No hesitation, no argument. I made no other adjustments to the car, just swapping computers. I drove it all last night on the way home making a lot of transitions to on/off boost and never got that hesitation back.
I am sending the N338 to Henrik to crack open so he can get us the truth about this ECU once and for all. His opinion is that it isn't possible - what could the ECU use to determine what car it is running? Correct me if I'm wrong, but all it knows it voltages.
So, that is my experience - I'm pretty sure that the N338 is just another NA ECU, even though it looks different internally than other NA ECU's. I think it is programmed to run an NA car w/ NA fuel and timing. Once Henrik gets this ECU, he'll let us know for sure I suppose.
My mods are as follows:
-Rotary Resurrection S4 TII motor, streetported
-Walbro fuel pump & stock injectors
-Rtek7 1.5 ECU upgrade
-HKS downpipe, Apexi dual N1
-Stock turbo, ported wastegate
-GReddy FMIC, K&N cone filter, stock TID
-GReddy boost/EGT peak hold gauges
-Unorthodox racing crank pulley
-RB aluminum flywheel, CFDF clutch
-NA tranny/Rear
-Removed A/C and P/S
The first time the car was boosted, I gave WOT in second gear for a couple of seconds. Curiously, the car had some pretty severe hesitation @ 4K rpm under moderate load. This occured more often in first gear though it had happened in others. When it did happen, the car would break up then eventually rev past the hesitation point. With lighter load, sometimes it would rev out smoothly and sometimes it wouldn't. I decided NOT to boost any further until we could get things sorted. Another curious feature was fuel cut - according to my peak hold GReddy boost gauge, I never hit it
The car made 10 psi. My installer and I checked the TPS, it was fine. We checked the secondary injectors and they were fine. Pressure sensor? Also fine. We both thought the ECU was our problem so I drove the car easily until my N332 with the rtek7 1.5 chip was shipped to me from digital tuning (www.pocketlogger.com).
I installed it last night and took it for a test drive. Upon startup, the car settled to a MUCH smoother and slightly higher idle (900 rpm). The N338 idled @ 750 (what we set it to) and although it held idle well, it was always a bit lopey. Now, it's super-smooth. On the test drive I drove @ light load without hesitation until about 6K. I fed in boost smoothly and the car just rocketed forward. No hesitation, no argument. I made no other adjustments to the car, just swapping computers. I drove it all last night on the way home making a lot of transitions to on/off boost and never got that hesitation back.
I am sending the N338 to Henrik to crack open so he can get us the truth about this ECU once and for all. His opinion is that it isn't possible - what could the ECU use to determine what car it is running? Correct me if I'm wrong, but all it knows it voltages.
So, that is my experience - I'm pretty sure that the N338 is just another NA ECU, even though it looks different internally than other NA ECU's. I think it is programmed to run an NA car w/ NA fuel and timing. Once Henrik gets this ECU, he'll let us know for sure I suppose.
My mods are as follows:
-Rotary Resurrection S4 TII motor, streetported
-Walbro fuel pump & stock injectors
-Rtek7 1.5 ECU upgrade
-HKS downpipe, Apexi dual N1
-Stock turbo, ported wastegate
-GReddy FMIC, K&N cone filter, stock TID
-GReddy boost/EGT peak hold gauges
-Unorthodox racing crank pulley
-RB aluminum flywheel, CFDF clutch
-NA tranny/Rear
-Removed A/C and P/S
08-05-04, 09:54 AM
#3
Former Moderator. RIP Icemark.
Sounds like the N338 you have has a couple blown transistors... hopefully Henrik will find them.
FYI, I ran a S4 13BT fine for 6 months using a N338 and turbo boost sensor (so I suspect that either your harness was incorrect, or it was a bad ECU). And remember the N338 will not run one of Henricks turbo chips. The two fuel map chips are different than any other ECU mazda made (of course you would have seen that if you opened it up).
FYI, I ran a S4 13BT fine for 6 months using a N338 and turbo boost sensor (so I suspect that either your harness was incorrect, or it was a bad ECU). And remember the N338 will not run one of Henricks turbo chips. The two fuel map chips are different than any other ECU mazda made (of course you would have seen that if you opened it up).
08-05-04, 10:08 AM
#4
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Supposedly, it has internal switching to sense whether you run a turbo or NA motor since all verts were made in the same place in Japan and mazda thought they might bring a turbo vert to the US. I'm fairly sure that it's an NA ECU though since my problems are totally solved.
08-05-04, 01:50 PM
#5
Lives on the Forum
I dunno about internal switches, but we've also run it successfully in the past.
Again, we got this tip from Donnie Peters from the now defunct Sun Auto about the N338 working in Zenki FC turbos.
I dunno if you know this, but the N332 (1987 US-Spec Turbo II) has different ROMs than the N333 (1988 US-Spec Turbo II), and I suspect the N338 ROMs are also totally different than the N332 and N333 ECU's.
You cannot swap mod chips between the N332 and N333.
This probably means Henrik needs to almost start from scratch to dechiper this N338 chip(s).
-Ted
Again, we got this tip from Donnie Peters from the now defunct Sun Auto about the N338 working in Zenki FC turbos.
I dunno if you know this, but the N332 (1987 US-Spec Turbo II) has different ROMs than the N333 (1988 US-Spec Turbo II), and I suspect the N338 ROMs are also totally different than the N332 and N333 ECU's.
You cannot swap mod chips between the N332 and N333.
This probably means Henrik needs to almost start from scratch to dechiper this N338 chip(s).
-Ted
08-05-04, 08:35 PM
#6
Former Moderator. RIP Icemark.
Originally Posted by RETed
You cannot swap mod chips between the N332 and N333.
This probably means Henrik needs to almost start from scratch to dechiper this N338 chip(s).
-Ted
This probably means Henrik needs to almost start from scratch to dechiper this N338 chip(s).
-Ted
And then if Henrik does decode the chip... then I am sure any replacement chip he makes would need to be either Non turbo, or Turbo rather than both.
