Thrasher

Holy **** this is a trip, I am having the exact same problem on my na/turbo swap in get this an 89GTUs. I bought a halfcut that ran great when I bought it, 2 weeks later I drop it in my car and it acts like its running on one rotor!? Iam ordering that chip but I would really like to know what the specs are on it, what does this chip do exactly and why does it need to be replaced if the engine ran great 2 weeks prior in the jdm halfcut?! I swapped nearly everything from that halfcut too, coils, maf, fuel pump resistor realy trying to get this thing working right thinking my n/a stuff was bad. BTW I'm using my n/a harness too. This would not have anything to do with the little black box attached to the ecu that the jdm car uses but the us one dosn't would it?

Anyways I hope this solves my problem too.... but please do explain more!

Thrasher

ohh also what are the "right tools" to desoder the oem chip and put the "performance chip" in
I really wanna know what is differant about that chip!

scottfetsh

the black box is the knock sensor module mines not hooked up and by now you have the chip(been away buliding a new car) right tools are a real 40watt iron ,desolder wick ,solder that does not come from home depot and good eyes simple!
ps car is still running fine on a quote "fu**ed" ecu
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QUOTE=RETed]Geezuschrist, your N374 ECU is *FUCKED*.
Is that the straight answer you're looking for?

I've messed with N374 ECU's, and they work identically as US-Spec N370.
I think someone already said that.

Can you put two and two together now?

Your N374 most likely came from a JUNKYARD.
The cars get treated like dirt...literally.
I put money your N374 ECU is BAD, or more accurately...your rear rotor injector driver is FUCKED.


-Ted[/QUOTE]
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even injector drivers can be replaced cheap thanks for your support RETed. glad you have more money than sense

RETed

I would've went Haltech a long time ago instead of ******* with that stock ECU crap...


-Ted

xrotaryguy

I am having the same problem with an N374 ECU. Actually, I am on my 3rd N#&$ ECU, and they have all exhibited the exact same problem. The car is an S5 NA, the harness is a modified S5 NA, and the engine is a j-spec S5 TII. Both of the S5 NA ECUs that I have run the car perfectly. I think I am going to swap this ecu into someone else's car just to make double sure my wiring harness is not the problem.

Click here to view more details about this swap.

RETed, take it easy man, after all, it's not like Haltecs are problem-free either.

rotawhat

iTrader: (1)

very similar problem

The problem
The car does not want to start, and when it does finally start, it backfires, runs really rough and as soon as u let off the gas, it dies.

The project
89 GXL with an S5 TII swap, running the TII tranny with the mazda trix driveshaft.

What Ive done
Just put in an 89 TII motor from a front clip, I am using the J-spec harness, I took the rat's nest out and put block off plates, the car has a walbro 255, 3 inch down pipe, FCD, koyo radiator with electric fan, greddy rs BOV kit, new NGK plugs, new 7mm wires

What I know so far
that im getting fuel to the fuel rail
that im getting spark on leading and trailing
that i have good compression over 100 psi on both front and rear
that the timing is right
swap inj with other s5TII 550 no help
swaped harness to n/a still runs like crap
swaped tps with other s5 TII tps still runs shitty

HKSpoweredFC3S

thats kinda funny rotawhat, i have a '90 gxl with everything you have exept the DP and radiator...i have the n374 right now and as of tomorrow, my bov kit is coming in and ill be able to crank my car...ill let yal know what happends though, everything seems to check out other than my bov kit...

drift13b88

iTrader: (1)

Thread revival anyone ever figure out the problem i have the same bs going on but i have a ks rom tuned n374 ecu, na harness, 90 gxl, s5 turbo motor swap.

could it be i have no knock control box also by the ecu there a box to the right that reads n351 or n350 dont remember with 2 back plugs not plugged in, in the spot were the atmosphere pressure sensors sits in a s4 n/a i guess you can say behing the fender, should those be unplugged?

j9fd3s

iTrader: (3)

the S5 has no external knock box, the knock sensor goes straight to the ecu.

the pinout of the US ecu and the JDM ecu are going to be slightly different, the US ecu has AWS, and an extra valve on the ACV, since the JDM car may use those pins for something else, speed limiter, they should be unplugged for a start.