whats causing the ecu to short? s13 blacktop. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

mixedwell · 04-22-2005, 11:27 AM

this is the second ecu ive used on my car in the past 6 months. this is very frustrating.. yesterday i couldnt get the car to start becasue the mafs plug wasnt plugged in. i plugged it in and the car started. about 20 mins after driving it, the car died and wouldnt start anymore. all it would do is just crank and crank. when i towed it home, i went and checked the usual, the wires were matched and everything seemed to be in order. when i went to check the ecu for fault codes, i noticed that the little bulb wasnt working. fuck. so i took out the ecu and check with a test light if it was getting power. the spots in the ecu harness plug for the fuel and others were getting power so i concluded a dead ecu. i checked the harness by the battery plug and everything was fine except the Black/ white stripe wire. this is the ecu main power wire. the back up power wire had power through it but still no light to the ecu. im thinking the ecu is getting fried some how.

remember- i started the car before and it worked fine. it just died all of a sudden and now wont start. just cranks all day long. the coil packs arent getting power as well.

whats causing this? im running out of cash for this project and im thinking of just selling it. i really dont want to do that and part with it. can someone please help me out? im confused as hell and i cant find anyhting on zilvia about this. thanks.

-

quick mod list-
91 240sx coupe SE RED 5 speed
96 s13 SR20DET
s14 kouki turbo
custom exhaust manifold
HKS FMIC
HKS dump pipe
HKS sqv BOV
Apex'i intake kit
RS*R Gold exhaust
BONUS! JDM folding mirrors!

possibly for sale if i cant figure this out.

mixedwell · 04-22-2005, 03:22 PM

so.... im the only one huh?

240trainee · 04-22-2005, 06:13 PM

Alternator. I went through 3 CA18DET ECU's because of a bad alternator. didn't show up bad when tested, just randomly it would spike, and blow ECU's. Everyone told me it couldn't be the alternator, hence why I blew 3. But it was. And your symptoms sound exactly like my CA18 car.

mixedwell · 04-22-2005, 08:38 PM

ok i kno this sounds dumb but i havent been running the car with a battery.... i mean i've been jump starting it with one of those portable juumper thingys. why? i couldnt get the battery in the trunk to mount properly. and when i have to stop and restart, i just pull the jumper from the trunk. could this be the reason?

and if the light on the ecu works.. .tjhe ecu should too right??

-

240trainee · 04-23-2005, 11:10 AM

Not necessarily. Thats why the guy I bought my engine from was stumped, I kept turning the little knob tring to get the lights to flash, they never did. I even have taken the things apart, and they show no signs of burning. But thats what it is. and I would definatly be running a bettery, that can't help.

jlinder · 05-10-2006, 09:43 PM

I have had the same problem, with an ECU. I am running a E5 ECU. Anyway to get my car started I had to jump a wire across the black\white and the red\black wire located near the battery. You have to turn the key to the ON position and then jumper the wire. You will hear a click followed by the fuel rail filling, then remove the wire. BUT, by doing this your ECU will not shut off until you disconnect the battery for a second. Pain I know, but it will get you going. You need to install a battery, Because your alternator will sense a lack of voltage and put out max power. I had an alternator putting out 15.4 volts because of a dead battery. You may have over powered your ECU.
Josh

jlinder · 05-10-2006, 09:55 PM

Here is a picture of my ECU

nsrracing · 05-19-2006, 12:56 AM

Just my 2 cents but first your never supposed to use a regular test light on an ECU because they are usually low impedance and that itself can short out the ECU. U must use the expensive test lights, the one with L.E.D.s high impedance. Second I think its safe to safe you need a battery because the battery is your ground for all electrical systems, wiring and such. Obviously it looks like your grounding out the ECU with a short to ground directly on the ECU. Put a battery in, permanetly and that should take care of the rest.

04-22-2005, 11:27 AM	#1
mixedwell Zilvia Addict Join Date: Sep 2002 Location: SOuth Cali Posts: 892 Trader Rating: (0) Feedback Score: 0 reviews	whats causing the ecu to short? s13 blacktop. this is the second ecu ive used on my car in the past 6 months. this is very frustrating.. yesterday i couldnt get the car to start becasue the mafs plug wasnt plugged in. i plugged it in and the car started. about 20 mins after driving it, the car died and wouldnt start anymore. all it would do is just crank and crank. when i towed it home, i went and checked the usual, the wires were matched and everything seemed to be in order. when i went to check the ecu for fault codes, i noticed that the little bulb wasnt working. fuck. so i took out the ecu and check with a test light if it was getting power. the spots in the ecu harness plug for the fuel and others were getting power so i concluded a dead ecu. i checked the harness by the battery plug and everything was fine except the Black/ white stripe wire. this is the ecu main power wire. the back up power wire had power through it but still no light to the ecu. im thinking the ecu is getting fried some how. remember- i started the car before and it worked fine. it just died all of a sudden and now wont start. just cranks all day long. the coil packs arent getting power as well. whats causing this? im running out of cash for this project and im thinking of just selling it. i really dont want to do that and part with it. can someone please help me out? im confused as hell and i cant find anyhting on zilvia about this. thanks. - quick mod list- 91 240sx coupe SE RED 5 speed 96 s13 SR20DET s14 kouki turbo custom exhaust manifold HKS FMIC HKS dump pipe HKS sqv BOV Apex'i intake kit RS*R Gold exhaust BONUS! JDM folding mirrors! possibly for sale if i cant figure this out. __________________ silvia... my love ::

04-22-2005, 03:22 PM	#2
mixedwell Zilvia Addict Join Date: Sep 2002 Location: SOuth Cali Posts: 892 Trader Rating: (0) Feedback Score: 0 reviews	so.... im the only one huh? __________________ silvia... my love ::

04-22-2005, 06:13 PM	#3
240trainee Post Whore! Join Date: Jun 2003 Location: Richmond, VA Age: 38 Posts: 3,861 Trader Rating: (1) Feedback Score: 1 reviews	Alternator. I went through 3 CA18DET ECU's because of a bad alternator. didn't show up bad when tested, just randomly it would spike, and blow ECU's. Everyone told me it couldn't be the alternator, hence why I blew 3. But it was. And your symptoms sound exactly like my CA18 car. __________________ Team Pterodactyl SHARK ATTACK!!! LookoutDrift

04-22-2005, 08:38 PM	#4
mixedwell Zilvia Addict Join Date: Sep 2002 Location: SOuth Cali Posts: 892 Trader Rating: (0) Feedback Score: 0 reviews	ok i kno this sounds dumb but i havent been running the car with a battery.... i mean i've been jump starting it with one of those portable juumper thingys. why? i couldnt get the battery in the trunk to mount properly. and when i have to stop and restart, i just pull the jumper from the trunk. could this be the reason? and if the light on the ecu works.. .tjhe ecu should too right?? - __________________ silvia... my love ::

04-23-2005, 11:10 AM	#5
240trainee Post Whore! Join Date: Jun 2003 Location: Richmond, VA Age: 38 Posts: 3,861 Trader Rating: (1) Feedback Score: 1 reviews	Not necessarily. Thats why the guy I bought my engine from was stumped, I kept turning the little knob tring to get the lights to flash, they never did. I even have taken the things apart, and they show no signs of burning. But thats what it is. and I would definatly be running a bettery, that can't help. __________________ Team Pterodactyl SHARK ATTACK!!! LookoutDrift

05-10-2006, 09:43 PM	#6
jlinder Join Date: Nov 2005 Location: Central FL Age: 48 Posts: 32 Trader Rating: (1) Feedback Score: 1 reviews	I have had the same problem, with an ECU. I am running a E5 ECU. Anyway to get my car started I had to jump a wire across the black\white and the red\black wire located near the battery. You have to turn the key to the ON position and then jumper the wire. You will hear a click followed by the fuel rail filling, then remove the wire. BUT, by doing this your ECU will not shut off until you disconnect the battery for a second. Pain I know, but it will get you going. You need to install a battery, Because your alternator will sense a lack of voltage and put out max power. I had an alternator putting out 15.4 volts because of a dead battery. You may have over powered your ECU. Josh Last edited by jlinder; 05-10-2006 at 10:26 PM..

05-19-2006, 12:56 AM	#8
nsrracing Join Date: May 2005 Location: hercules Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	Just my 2 cents but first your never supposed to use a regular test light on an ECU because they are usually low impedance and that itself can short out the ECU. U must use the expensive test lights, the one with L.E.D.s high impedance. Second I think its safe to safe you need a battery because the battery is your ground for all electrical systems, wiring and such. Obviously it looks like your grounding out the ECU with a short to ground directly on the ECU. Put a battery in, permanetly and that should take care of the rest.