If I have the wrong ecu hooked up to the motor, what are some of the symptoms to let you know? I currently have installed my swap but can only get the motor to rev up to 2500 RPM's. Now I have already replaced the MAFS and the car still runs like crap and almost like it only runs on 2 cylinders but when you first start it up it runs smooth for a few minutes and there is black smoke puffing out the tail pipe? What is causing all this? Also all the vacuum lines are connected in the correct location.

 

2500rpm is the magic MAFS number. This is the engine rpm limit when it can't find the MAFS. It runs really rich so that you don't blow it up, which is what is causing all the black smoke.

Now to the ECU. You can start off by listing the motor type (redtop, etc), the large number on the ECU cover, and who did your harness. The fact that it runs means that you atleast have an SR ecu (or atleast, not a KA ecu). You can go one step further by putting the ecu in diagnostic mode. To do this, flip the ecu around and find the hole that you can stick a screwdriver in to. This is the potentiometer. It'll either accept a large slotted screwdriver or a very small phillips. Turn the car to ON (not started), turn the potentiometer completely clockwise, pause 2 seconds, and then turn it back to counterclockwise. It will start flashing a code to you in long and short blinks. The code is 2 digits. Long blinks make up the first digit, short blinks make up the second digit. There may be multiple codes, so write them all down. Once it starts to repeat (or stops), that's all of them. Turn the potentiometer clockwise and back to return to normal mode.

So, post all the ECU info and codes, and we'll point you in the right direction.

 

I have a Kouki S13 SR20DET Black Top, the ECU does not have a code in it because the sticker has been removed. I did the harness my self and had a guy look at it for accuracy and there were no flaws detected. I soldered all connections and shrink wraped everything. I will try the ECU code and see what happens.

 

Perhaps you wired up the ecu wrong? Since after all you got a new one, you may have just wired it up wrong again?

 

Well the reason that I ask about the harness is that the first step is: extend the mafs wires 2 feet.

 

well if you have a kouki S13 motor, than your ecu code should be J4. the pinouts are different between kouki and not.

 

right but would other ECU's hook up to the harness? all plugs have been extended and converter properly so lets rule out the harness for now, what else could the problem be? just the MAFS or could it be the ECU as well. The car will idle most of the time but the throttle response sucks and if you open it too fast it will bogg down and stall. I check all the coil packs for power and there all good.

 

Taylor, it depends on your definition of "kouki". Could be J4, could be E5.

In the mean time... If the engine is running on all cylinders (idle considered reasonable under ANY condition), then your ECU matches your harness. J4 and E5/62 have a few pins connected differently at the blue plug. The most noticable are that ignition for cylinders 1 and 2 are moved. Trying to run an early blacktop with a J4 will have your car imitating a Subaru or dying lawnmower.

It could be just the MAFS. As soon as the ECU doesn't see the MAFS, it goes into limp mode. Instantly. It's like flipping a switch labled "old jalopy mode". Just to let you know, as long as the car starts and fires on all cylinders, the ECU is fine.

Again, check the codes. It doesn't get any simpler.
"hey car, what's wrong with you". <turns screwdriver>
"bliiiink, blink blink".
"oh, maybe I should fix that".

 

Thanks for the useful info I will try this tonight. one question though. I hooked all the wires up to the ECU from the directions found: http://www.nissanperformancemag.com/march04/240sr/ so will the ECU still flash the code?

 

Oooh, I wasn't specific about that part in my original post. The codes will flash via an LED right next to the potentiometer on the back of the ecu. So, it doesn't matter how you wired it. Come to think of it, some blacktop ecus don't have an LED. Check yours out and report back.