ECU failure, and VSS issue. - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

*NemeGuero* · 03-31-2006, 03:06 PM

So my ECU is retarded. I can turn off the ignition and the car still runs. Its the ECU, because I had a spare I swapped out and the ignition turns off with the other one.

My question is, what could lead up to the failure of my ECU? A bad ground? How did it go bad?

Question 2: My speedo no longer works and I measured the resistance on it per FSM specs of ~250OHMS. That resistance was pretty much continuous all the way up to the connector near the starter.

So why doesn't my speedo work? Is it a problem with the guage itself?

I hate electrical........................
-Evan

!Zar! · 04-01-2006, 01:38 AM

It's either your VSS, or you might have burnt your cluster. take your cluster out and check to see if any of the traces are burnt or cut.

Is your fuel guage/tripometer working?

NIK90s13 · 04-01-2006, 06:41 AM

My stock speedo went out as well, I checked every thing out, it turned out to be the speedo itself, I Swap it, and it was good to go.
Sorry to hear about the ecu, its not stock, right? I was following your other thread, I'd hoped it was the ignition tumbler. I do'nt have a clue, just saying it sucks!!

*NemeGuero* · 04-01-2006, 12:00 PM

Yah, well I guess I can replace the speedo. More $ and time... argh..

and I'm buying another ECU that I'll have to resolder the BikiR0m into...
Hopefully its not a short somewhere that'll make me eat through ECUs like potatoes.

*NemeGuero* · 04-02-2006, 06:39 PM

No Zar, the trip meter and odometer are also not working.

Zesty · 04-03-2006, 08:58 AM

If your car is reading a code 14, vehicle speed sensor circuit is open, would my speedo still work?

I ask because I got the code 14, yet my speedo still works. Took it to the shop and they said that if the sensor was messed up, my speedo wouldn't be working.

g6civcx · 04-03-2006, 09:03 AM

If the speedometer is working properly, i.e. displaying correct speed, and you're showing a code, there is a problem with your ECU wiring. The VSS wire goes to the odometer first before going to the ECU.

Zesty · 04-03-2006, 09:25 AM

^Thanks, I think I may have a "bad" ECU.

!Zar! · 04-03-2006, 10:19 AM

Quote:

Originally Posted by NemeGuero

No Zar, the trip meter and odometer are also not working.

I had the same problem and it tured out that I had fried part of my cluster.

But I knew it happened because my wheel cut through my harness.

In your case you arn't sure why it's happened...

*NemeGuero* · 04-03-2006, 10:30 AM

Yah, but how? I hate electronics.

g6civcx · 04-03-2006, 10:53 AM

The engine harness runs underneath the left front fender. If your car is lowered, the tyre will eat through that harness. Pull out your fender and reroute that harness through the engine bay rather than right on top of the tyre.

*NemeGuero* · 04-03-2006, 11:21 AM

I'm not that low though... but I'll check it out.

Would the VSS wiring run through there?

g6civcx · 04-03-2006, 11:42 AM

Yes, that harness you see there with the blue zip ties originally ran right on top of the tyre. I unplugged the junction box and pulled it through the fender. Then I fed it back in on top of the strut tower like so.

Your VSS signal runs right through there. It meets up at the junction box and goes to your speedo.

Just run your finger up on it and feel to see if you chewed through the loom. Sometimes if you hit a bump hard enough it will compress the front wheels and cut right through it.

*NemeGuero* · 04-03-2006, 01:28 PM

I think I still have the fender liner, could it eat through the wires without messing up the fender liner?

Anyway, the VSS signal comes up by the starter.. why the hell would it go over that fender instead of just straight to the Ecu? Oh, 'cuz it goes to the cluster first....

heh, ok, well I'll double check that.

Thanks for the pics.

!Zar! · 04-03-2006, 01:34 PM

There isn't any way for your tire to cut through the harness without cutting through your fender liner first.
Cluster~

g6civcx · 04-03-2006, 01:36 PM

I don't know. Nissan does some weird stuff. AFAIK it's only used for the top speed governor. There's nothing else the ECU does with the VSS signal.

If you still have the fender liner it could still damage the harness. If you hit debris hard enough, the wheel could come up so hard it would sever the harness and chew right through the liner in the process.

!Zar! · 04-03-2006, 01:58 PM

But he would have more than just a dash cluster problem, now wouldn't he?

*NemeGuero* · 04-03-2006, 02:08 PM

You mean, like also an ignition failure?

!Zar! · 04-03-2006, 02:52 PM

No. Like a cluster. I had the same problem, my speedo, odo,trip,fuel, all wouldn't work. I eventualy took my cluster out and had a burnt trace. Went to the yard and was raped $70 for a new cluster. Then once I installed it all was good.

g6civcx · 04-03-2006, 02:56 PM

It's a possibility. It depends on which wires get damaged. You won't know until you check.

*NemeGuero* · 04-03-2006, 03:00 PM

It'll be at least 2 weeks.. I hate not having a garage while I'm at school... or tools.

rsxrcr87 · 06-16-2006, 08:43 PM

on my s14 the odometer trip meter and gas guage all dont work... i need one of those so i dont have to top off the tank every couple of days could this be all one problem? i swapped the clusters out both clusters acted the same.

03-31-2006, 03:06 PM	#1
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	ECU failure, and VSS issue. So my ECU is retarded. I can turn off the ignition and the car still runs. Its the ECU, because I had a spare I swapped out and the ignition turns off with the other one. My question is, what could lead up to the failure of my ECU? A bad ground? How did it go bad? Question 2: My speedo no longer works and I measured the resistance on it per FSM specs of ~250OHMS. That resistance was pretty much continuous all the way up to the connector near the starter. So why doesn't my speedo work? Is it a problem with the guage itself? I hate electrical........................ -Evan __________________

04-01-2006, 01:38 AM	#2
!Zar! Post Whore! Join Date: Nov 2004 Location: North Korea Posts: 14,579 Trader Rating: (27) Feedback Score: 27 reviews	It's either your VSS, or you might have burnt your cluster. take your cluster out and check to see if any of the traces are burnt or cut. Is your fuel guage/tripometer working? __________________

04-01-2006, 12:00 PM	#4
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	Yah, well I guess I can replace the speedo. More $ and time... argh.. and I'm buying another ECU that I'll have to resolder the BikiR0m into... Hopefully its not a short somewhere that'll make me eat through ECUs like potatoes. __________________

04-02-2006, 06:39 PM	#5
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	No Zar, the trip meter and odometer are also not working. __________________

04-03-2006, 10:30 AM	#10
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	Yah, but how? I hate electronics. __________________

04-01-2006, 06:41 AM	#3
NIK90s13 Zilvia Junkie Join Date: Jan 2006 Location: texas Age: 58 Posts: 471 Trader Rating: (0) Feedback Score: 0 reviews	My stock speedo went out as well, I checked every thing out, it turned out to be the speedo itself, I Swap it, and it was good to go. Sorry to hear about the ecu, its not stock, right? I was following your other thread, I'd hoped it was the ignition tumbler. I do'nt have a clue, just saying it sucks!!

04-03-2006, 08:58 AM	#6
Zesty Leaky Injector Join Date: Nov 2005 Location: Central Coast California Age: 41 Posts: 74 Trader Rating: (0) Feedback Score: 0 reviews	If your car is reading a code 14, vehicle speed sensor circuit is open, would my speedo still work? I ask because I got the code 14, yet my speedo still works. Took it to the shop and they said that if the sensor was messed up, my speedo wouldn't be working.

04-03-2006, 09:03 AM	#7
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	If the speedometer is working properly, i.e. displaying correct speed, and you're showing a code, there is a problem with your ECU wiring. The VSS wire goes to the odometer first before going to the ECU.

04-03-2006, 09:25 AM	#8
Zesty Leaky Injector Join Date: Nov 2005 Location: Central Coast California Age: 41 Posts: 74 Trader Rating: (0) Feedback Score: 0 reviews	^Thanks, I think I may have a "bad" ECU.

04-03-2006, 10:53 AM	#11
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	The engine harness runs underneath the left front fender. If your car is lowered, the tyre will eat through that harness. Pull out your fender and reroute that harness through the engine bay rather than right on top of the tyre.

04-03-2006, 11:21 AM	#12
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	I'm not that low though... but I'll check it out. Would the VSS wiring run through there? __________________

04-03-2006, 11:42 AM	#13
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	Yes, that harness you see there with the blue zip ties originally ran right on top of the tyre. I unplugged the junction box and pulled it through the fender. Then I fed it back in on top of the strut tower like so. Your VSS signal runs right through there. It meets up at the junction box and goes to your speedo. Just run your finger up on it and feel to see if you chewed through the loom. Sometimes if you hit a bump hard enough it will compress the front wheels and cut right through it.

04-03-2006, 01:28 PM	#14
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	I think I still have the fender liner, could it eat through the wires without messing up the fender liner? Anyway, the VSS signal comes up by the starter.. why the hell would it go over that fender instead of just straight to the Ecu? Oh, 'cuz it goes to the cluster first.... heh, ok, well I'll double check that. Thanks for the pics. __________________

04-03-2006, 01:34 PM	#15
!Zar! Post Whore! Join Date: Nov 2004 Location: North Korea Posts: 14,579 Trader Rating: (27) Feedback Score: 27 reviews	There isn't any way for your tire to cut through the harness without cutting through your fender liner first. Cluster~ __________________

04-03-2006, 01:36 PM	#16
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	I don't know. Nissan does some weird stuff. AFAIK it's only used for the top speed governor. There's nothing else the ECU does with the VSS signal. If you still have the fender liner it could still damage the harness. If you hit debris hard enough, the wheel could come up so hard it would sever the harness and chew right through the liner in the process.

04-03-2006, 01:58 PM	#17
!Zar! Post Whore! Join Date: Nov 2004 Location: North Korea Posts: 14,579 Trader Rating: (27) Feedback Score: 27 reviews	But he would have more than just a dash cluster problem, now wouldn't he? __________________

04-03-2006, 02:08 PM	#18
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	You mean, like also an ignition failure? __________________

04-03-2006, 02:52 PM	#19
!Zar! Post Whore! Join Date: Nov 2004 Location: North Korea Posts: 14,579 Trader Rating: (27) Feedback Score: 27 reviews	No. Like a cluster. I had the same problem, my speedo, odo,trip,fuel, all wouldn't work. I eventualy took my cluster out and had a burnt trace. Went to the yard and was raped $70 for a new cluster. Then once I installed it all was good. __________________

04-03-2006, 02:56 PM	#20
g6civcx Post Whore! Join Date: Apr 2004 Location: Virginia, USA Posts: 5,764 Trader Rating: (5) Feedback Score: 5 reviews	It's a possibility. It depends on which wires get damaged. You won't know until you check.

04-03-2006, 03:00 PM	#21
NemeGuero No more nissan. Join Date: Jan 2003 Location: RAIN, Washington. Age: 40 Posts: 8,132 Trader Rating: (10) Rides Gallery: NemeGuero Feedback Score: 10 reviews	It'll be at least 2 weeks.. I hate not having a garage while I'm at school... or tools. __________________

06-16-2006, 08:43 PM	#22
rsxrcr87 Leaky Injector Join Date: Feb 2004 Location: louisiana Age: 37 Posts: 102 Trader Rating: (0) Feedback Score: 0 reviews	on my s14 the odometer trip meter and gas guage all dont work... i need one of those so i dont have to top off the tank every couple of days could this be all one problem? i swapped the clusters out both clusters acted the same.