Relay problem.

[Doya]

So, one of the realys next to my ECU( there are two and I think that they both go to it) was buzzing and vibrating. So I replaced it with a new one and it is still doing the same thing. My car won't start, none of my dash lights come on, and I don't think my ECU is coming on. Since I already replaced the relay and that didn't work, I think I might pull the dash and trace the wiring back to were it goes and see if I find anything wrong with the wiring. Does anyone have any suggestions.

[zerepdivad]

Does the car even turn over? What's your battery voltage with it just sitting there? What about while trying to turn it over?

[Doya]

Does the car even turn over? What's your battery voltage with it just sitting there? What about while trying to turn it over?

Yeah, the car will turn over but it won't start. My battery volts are good with it sitting and when it's turning over.

[OutToWinPAHC]

Sounds like one of the ignition control relays. Best thing to do is first check all the fusesin the car and under the hood, then check the socket for damage, and then check the relay socket for the correct voltage at the right slots.

[Doya]

Alright, the relay that is making the buzzing sound is the eccs relay located right next to the ecm. I found out that relay is tied into a fuse in the engine bay. It's a 7.5A fuse and it say EGI on the fuse box cover. Everytime I turn the key all the way forward, that relay starts to buzz and that EGI fuse blows. What does it mean when a fuse keeps on blowing like that.

[OutToWinPAHC]

Means there is a short, or high current draw in the circuit and the fuse is doing its job

[Doya]

Ahhh, so how can I fix that.

[OutToWinPAHC]

On the relay box, what is the name of it and whats the exact location. Also the same for the fuse, I'll take a look at the prints and point you in the direction.

[Doya]

On the relay box, what is the name of it and whats the exact location. Also the same for the fuse, I'll take a look at the prints and point you in the direction.

For the fuse box under the hood it's a 7.5A fuse, and its for the EGI. The relay is the ECCS, and thats right next to the ECU, but you can't see it unless you remove it.

[OutToWinPAHC]

Hmm no photos of the boxes in the S14 FSM. Is there a fuse number on the diagram or fuse block?

[Doya]

Hmm no photos of the boxes in the S14 FSM. Is there a fuse number on the diagram or fuse block?

My FSM said the fuse # is 43

[OutToWinPAHC]

Check the harness near the fuel rail, injectors, MAF, Evap canister and distributor. Also check the ECU harness connector, and the relay harness / socket where it plugs into. See if any of those are burnt, or pinched or rubbed through.

[OutToWinPAHC]

If you don't find anything then unplug. the MAF, TPS, IAC, distributor (harness connector), injectors, evap, Cam position sensor, Knock sensor ETC. And try with a new fuse turning the ignition on. If it doesn't blow, plus each on in one at a time until you pop the fuse.

[Doya]

I forgot to mention that I have a few aftermarket gauges. I spliced off of the ignition switch wire for a 12v power source for those gauges. Is it possible that those gauges are too much for it and could that be the reason why that fuse keeps on blowing.

[OutToWinPAHC]

Did it start right after you put these gauges in? According to the prints this is ignition to the ECU, but can be affected by a short on the sensors.

If you spliced into this ciruit its possible.

[Doya]

My car did start after I put the gauges in but all of these problems started a few days after. I'll unhook all of the gauges tomorrow and see if that makes a difference.

[Doya]

Alright, I unplugged all of my connectors. The one right on top of the upper radiator hose, attached to a bracket on the intake manifold, is the one that when I unplugged it the buzzing stopped.

[OutToWinPAHC]

try starting it with that on connector off and see if it fires. If it does the problem is with that sensor / device, or along the wires the the device is completing the connection to.

[Doya]

try starting it with that on connector off and see if it fires. If it does the problem is with that sensor / device, or along the wires the the device is completing the connection to.

Alright, I'll do that now.

[Doya]

I just tried starting it with that connector unplugged, and nothing. It just kept cranking.

[OutToWinPAHC]

post a pic please.

[Doya]

Hold on and I'll go take a pic real fast.

[Doya]

It's the plug right in front of the intake manifold. I had to use a old pic because my camera wasn't working.

[OutToWinPAHC]

That is the F50 to F23 connector which connect to

4 injectorsTPSCTSKickdown switch (auto)EGRWiper MotorECUECCS relay..........DIODE Check this, this can hinder the relayEngine groundand Front 02 sensor. (check for melting)

Plus that back in, check the diode, really check this harness, then unplug a these items (minus the relay and ECU one at a time and see if you can get her to fire up.)

Page 199

http://www.nicoclub.com/FSM/240sx/1995/EL.pdf

[Doya]

Ok, so I should unplug the 4 injectors,TPS,CTS,Kickdown switch (auto),EGR,Wiper Motor and plug them back in one by one and see if it starts. Also, what should I DIODE check.

[OutToWinPAHC]

Yeah unplug each of those one at a time and try starting (as in one injector, not all 4).

And to check the diode you need a meter. Should have very low ohms one way less then 1 ohm, and should be open the other way. Or if the meter is half decent it will have a diode check funtion on it.

[Doya]

I just tried what you said, and nothing I tried unplugging almost everything on the harness. I've come to the conclusion that my car simply hates me The only thing that I didn't unplug was the IACV Regulater, IACV AAC Valve, and the IACV FICD Soleniod Valve because I couldn't locate them in the engine bay. Since those things come off of the F50 connector, could it be possible that one of those things are bad. I mean, those were the only ones left on the harness that I didn't unplug. What do you think.

[dfddfd2]

The symptoms you describe with the ECCS relay "buzzing" sounds like a daughter board, or other ECU problem. What ECU are you using?

Dave

[Doya]

Stock '95 auto ecu.

[dfddfd2]

Sounds like you may have a toasted ECU. One of the first things the ECU does is turn on the ECCS relay, so it's getting that far, but if something goes haywire in the ECU and it quits running, it resets itself, which turns the ECCS relay off. After the reset, the ECU turns the ECCS relay on again, but craps out again, resets again, etc. etc. etc. It all happens very quickly so you hear the relay turning on and off rapidly, thus the "buzzing" sound. First try re-seating the ECU connector. If no go, open up the ECU and look and smell for any burnt areas on both sides of the board. I hesitate saying to try another (borrowed maybe) ECU until you know if/and/or why the problem started.

Dave