Buzzing sound from the engine bay!? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

808hellyea · 07-12-2012, 09:25 PM

I have a 93 240sx that won't start. Cranks over but seems like no fuel or spark is getting to it.

I've researched for weeks trying to figure out what it is but still nothing... It's a stock KA on coilovers. Rubbed through a little bit of the harness and found two wires that were exposed so I taped them up and tucked it more.

The buzzing sound is coming from the intake manifold side/ firewall, I take the ign switch fuse out and it stops. I step on the gas pedal and it stops. Already replaced the battery with a brand new one today and got it to run but the buzzing came back and the car won't start again . My fuses are all good too...

My terminals are good and clean, fuses are good. What else should I be looking for? I checked te main grounds to the motor but what else grounds should I look for?

Any help is appreciated!

Prozac · 07-12-2012, 09:42 PM

Any way you can get a video up , I understand thats your saying its an electrical buzz. Place your recording device next to where you think its coming from , rinse and repeat till you zone in on the area and then it will clarify what it might be.

JFoxx · 07-12-2012, 09:53 PM

is it a relay buzzing? if it is it means its not gettin sufficient power.....

808hellyea · 07-12-2012, 10:25 PM

Weird thing is it started again and I drove it and left it running for 15-20 mins and started back up fine? Idk if it was the battery needed to juice up the motor or what. Or if there's a loose ground that keeps loosing contact.

But the buzzing does sound like a relay. But coming from right below the intake manifold where the alternator is.

808hellyea · 08-25-2012, 12:54 PM

Update... Still didn't fix it... Thought the battery would've solved it but didn't. Blew another fuse I think it was the egi fuse. Did a little more research and found out it might be a fried ecu, pulled the ecu out and checked the pins for any burnt pins or any smell of being burnt and nothing buzzing sound is still coming from below the intake manifold. I'm going to check my grounds today they have a bunch of caked up oil on them so I'm going to clean them and see what that does. Anything I should be looking for that can be making that sound there?

jvega · 09-07-2012, 08:00 PM

its one of the relays. Re-check those wires that rubbed out, check the lower harness too (connects to starter, alt, battery).
My friend had a similar issue in his 240sx, but his lower harness was all hacked up, along with some wires that rubbed out on the wheel well both sides.. We rewired the wires on the wheel wells and the buzzing continued, then we installed a good lower harness and the buzzing stopped

hope this helps

07-12-2012, 09:25 PM	#1
808hellyea Join Date: Sep 2011 Location: Tacoma, WA Age: 34 Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	Buzzing sound from the engine bay!? I have a 93 240sx that won't start. Cranks over but seems like no fuel or spark is getting to it. I've researched for weeks trying to figure out what it is but still nothing... It's a stock KA on coilovers. Rubbed through a little bit of the harness and found two wires that were exposed so I taped them up and tucked it more. The buzzing sound is coming from the intake manifold side/ firewall, I take the ign switch fuse out and it stops. I step on the gas pedal and it stops. Already replaced the battery with a brand new one today and got it to run but the buzzing came back and the car won't start again . My fuses are all good too... My terminals are good and clean, fuses are good. What else should I be looking for? I checked te main grounds to the motor but what else grounds should I look for? Any help is appreciated!

07-12-2012, 09:42 PM	#2
Prozac Leaky Injector Join Date: Aug 2011 Location: Ky Age: 43 Posts: 89 Trader Rating: (3) Feedback Score: 3 reviews	Any way you can get a video up , I understand thats your saying its an electrical buzz. Place your recording device next to where you think its coming from , rinse and repeat till you zone in on the area and then it will clarify what it might be.

07-12-2012, 09:53 PM	#3
JFoxx BANNED Join Date: May 2008 Location: SD & OC Posts: 722 Trader Rating: (3) Feedback Score: 3 reviews	is it a relay buzzing? if it is it means its not gettin sufficient power.....

07-12-2012, 10:25 PM	#4
808hellyea Join Date: Sep 2011 Location: Tacoma, WA Age: 34 Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	Weird thing is it started again and I drove it and left it running for 15-20 mins and started back up fine? Idk if it was the battery needed to juice up the motor or what. Or if there's a loose ground that keeps loosing contact. But the buzzing does sound like a relay. But coming from right below the intake manifold where the alternator is.

08-25-2012, 12:54 PM	#5
808hellyea Join Date: Sep 2011 Location: Tacoma, WA Age: 34 Posts: 13 Trader Rating: (0) Feedback Score: 0 reviews	Update... Still didn't fix it... Thought the battery would've solved it but didn't. Blew another fuse I think it was the egi fuse. Did a little more research and found out it might be a fried ecu, pulled the ecu out and checked the pins for any burnt pins or any smell of being burnt and nothing buzzing sound is still coming from below the intake manifold. I'm going to check my grounds today they have a bunch of caked up oil on them so I'm going to clean them and see what that does. Anything I should be looking for that can be making that sound there?

09-07-2012, 08:00 PM	#6
jvega Leaky Injector Join Date: Nov 2010 Location: arizona Age: 35 Posts: 133 Trader Rating: (1) Feedback Score: 1 reviews	its one of the relays. Re-check those wires that rubbed out, check the lower harness too (connects to starter, alt, battery). My friend had a similar issue in his 240sx, but his lower harness was all hacked up, along with some wires that rubbed out on the wheel well both sides.. We rewired the wires on the wheel wells and the buzzing continued, then we installed a good lower harness and the buzzing stopped hope this helps