Ignition relay Question

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rb25drag
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Hey guys, I have been trying to trace down a short in my car for a few weeks now. I have narrowed it down to the red/Black wire coming from the igniton switch and runs to the fuse panel under the drivers side dash. There is suppose to be a relay some were in between. I am having No luck finding which one it is.

The car is blowing the 30AMP ign fuse in the fuse panel under the hood on the passenger side. When it blows the fuse it is a dead short. You can try bypassing it and it will melt what ever you put to it instantly. But I have noticed if I leave the car alone, Sometimes for days I can go out turn the key on and everything is working back to normal, As if a Relay is sticking and shorting its self out.

I have tested Alternator, Starter, I have pulled all the fuses from all the panels, I have pulled all the relays I can see, I have also unplugged all the plugs I can see and it still shorts out.

Also when it shorts I get No power to anything, So its telling me there is no power leaving the Ignition relay.



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Hijacker
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That relay is on the side of the super multi junction connector. It's not too terribly hard to get to. Just pull the driver side kick panel and unbolt the SMJ and fuse panel from the chassis to get them swinging. Then you can twist the SMJ around to get at the relay.

We just recently had a member having the same issue. He was popping his ignition fuse as well, but the issue turned out to be in one of the coil packs (he had some wires touching causing a backfeed through the Black/Red wire and was shorting the fuse)

Are you popping the fuse with the car on or off?

I'm having trouble thinking it's your ignition relay, because if the draw that the ignition relay draws is negligible. My money is saying your issue lies on the ignition line somewhere. Try removing the coil and the resistor/condensor pack out of the circuit and see if you're still having the issues you have.

Now, if you're correct and the ignition relay is the culprit, the only way I can see that being the case is a collapsed gate that is arcing to the relay coil. There is one circuit that passes through that is driven directly off the battery, but it shares that particular power line with a lot of other stuff. So it shouldn't be able to draw that much power IMO.

It's just hard to pop a 30amp fuse, so I would look at backfeeding possibilities. Typically the only thing with with that much backfeeding potential comes from the ignition system.

rb25drag
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Thanks for the reply. I think I know which relay your talking about and if It is then I have already pulled it and your correct its not it. Dang, I have the Rb25 swap in it, I have unplugged my ignition coils, nothing changed.

I have never had this problem. When it occured the first time I was putting my fenders on my car, my gf was helping me and i was having her to turn the wheels for me, she forgot and left my key on for 30-45 mins, I heard the fuse pop. So I grab a 25amp,(the only one I had at the time) put it in and it popped again. Well I spent all night unhooking things and tracing wires with No results. The next day I come out first turn on the key and bam everything is working again with no problems. It First started with the car not running. It worked for 30-45 mins then it shorted again, Blew another fuse.

I thought it might have been my fuel pump, possibly melted wires together b/c When it finally did come back on the fuel pump was not working. I have the upgraded walbro, Well I re-wired the pump back into the relay and it started working again. Everthing seemed fine for 2 days, I left the car running for several hours and I started it multiple times, 35-100 times, went to start it 2 days later and pull it out of the garage, Bam Blew the fuse again, So now back to square 1. This past weekend, The fuse was working again, I thought I would test the alternator and found it to be in very poor shape, So I unhooked my alternator until my new 125amp Quest came in. Car ran fine again for 2 days, Decided to drive it around the block, I went 1 mile down the road got the car up to temp went to get on it and everything in the car shut down again. Ever since then I have not been able to get it to work again for more than 15-20 seconds before it shorts again.

The only Wire I have Added to that side of the fuse panel is my remote wire for my sylenoid I use to power all my accessories, Such as my Lunch control, shift light, Line Lock, SAFC, Wideband 02, Volt, Oil, Boost, Oil temp, Water temp gauges, boost controller and Electric fans. I have unhooked the sylenoid also and it still shorts so I know thats not my problem either.

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Hijacker
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The ignition relay is the big brown one on the side (assuming you have power windows since that's what you highlighted) Otherwise, it's a green or a blue for the base models

Did this just start up or has is the RB swap a recent deal and you haven't had it running yet?

Look at the big plug next to the battery tray for any possible arcing/damage. Also, try unplugging it and seeing if your issue happens when you turn the car to on. The black/red wire passes through there to power the ECU and most swap guides have you tap off it to power the ignition coils. Just make sure that your splicing isn't grounding out on anything or shorting.

rb25drag
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I have had the swap for a few years now. I mostly do drag So I have less than 2k miles on everything.

I recently took my motor out this winter and installed the Gizzmo launch control, I had an issue with the first on I received, Now the second one is fine, I also re-done most of my wiring, its worked for a few years but I wanted to make it neater, I soildered all my connections and heat shrunk all the splices. So the wiring should be better than b/f I have not changed anything other than adding the Lunch control, I Use to have my gauges running off the fuse panel until I upgraded this winter to the Autometer ones, Now I ran all my power from the sylenoid. When I did hook everything back up, My Started remote wire was not working, So I bypassed the original wire and put in a push button start. But other than that everything is the same. If I unhook the red/black wire under the dash, I can get power to everything except the accessories on that wire mainly my ECU/fuel pump. Also with the wire unhooked I can click my ignition as if im trying to start the car and I can hear the relay under the dash click.

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Hijacker
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Like I said, something's backfeeding into that wire. The Black/Red is part of the coil for the relay so if it's backfeeding, it leaves power on to all the accessories associated with that relay.

The relay under the dash you're hearing is the blue accessory relay. It's powered by a Light Blue wire coming off the ignition switch.

I've traced the black/red wire before and it's primary job is to power the ECU, power the KA coil, power the Ignition relay, and power the fuses labelled Eng Cont and Fuel Pump.

Since you redid your wiring recently, just go double check it to make sure your solders are covered up correctly. Especially with the splice for the black/red and blue/red wires.

rb25drag
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Ok ill double check the ECU wiring. Could the Gizzmo launch control cause this? I had a misfire problem with the first one they sent me, Havent had the problem with this one yet. But Im up for any ideas at this point.

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I don't know anything about it or how you had it wired in. But you said you unplugged it and your problem persisted.

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Encryptshun
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Is it possible you pinched a main hot wire with one of the fasteners you used when you put your fenders back on? Dead-shorting to the chassis would certainly blow fuses, and if it was a wire pinch, it might only happen when the chassis was torqued just the right way that it made contact with bare wire.

rb25drag
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Encryptshun wrote:Is it possible you pinched a main hot wire with one of the fasteners you used when you put your fenders back on? Dead-shorting to the chassis would certainly blow fuses, and if it was a wire pinch, it might only happen when the chassis was torqued just the right way that it made contact with bare wire.
That was my first thought, But I took the fenders back off and have looked over all the wires. I see nothing wrong with them. But my harness is tucked in the fender wells with plastic tubbing wrapped around them.
Hijacker wrote:I don't know anything about it or how you had it wired in. But you said you unplugged it and your problem persisted.
The Launch control is suppose to get power and Ground from the ECU, and it has 2 wires for each coil, 1 from the ecu and 1 to the coil. I don't see how it could affect it either, But I unhooked my power wire and it still done it.

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Hijacker
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What wires are you tapping into to make that happen?

rb25drag
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Are you asking how I hooked up the launch control?

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Yes. You say you had to splice into the coil circuit and the ecu circuit. The coils play a part in the black/red circuit that goes back into the ignition fuse. So that could be the culprit. Maybe something in the way it was wired since it's happening when you don't have it plugged in.

rb25drag
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WELL I used the ECU ground wire, Then ran a Power wire from my accessory sylenoid for power, I belive the green was the tach signal and white ran to the Gizzmo shift light. This is all from memory, So the colors could be mixed up. But then the rest of the wiring was spliced between each coil, 6 from the ECU and 6 to the coil.

Both my shift light and launch control have the same ground and power supply.

rb25drag
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5. Red Wire - Connect to ECU ignition positive.Black Wire - Connect to ECU earth.Green Wire - Connect to ECU RPM signal, (light duty)` Blue Wire - Connect to clutch switch.Green Wire / Black Wire - Cut negative and join black to one sideand green to the other (note it doesn'tmatter which side each colour joins to.)Options for installation:Single coil - cut and join to coil negative.- cut and join to igniter negative.Twin coil - cut and join to igniter negative.

This is from the manual.

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Hijacker
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Cool. What year is the RB25 out of? I'm only slightly familiar with how they're wired up, so I don't know if different generations had any huge wiring differences.

rb25drag
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Not sure exact year, its a series 2, I think 94-97 model. The only difference between the s1 and s2 is the s1 had an ignitor chip and mine does not.

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I found the online manual at gizzmousa.com

http://gizzmousa.com/file-copi...l.pdf

From the looks of it, you need to power the launch control using the black/white power source (assuming the RBs use the same wiring coordination I've seen in pretty much all the 4 cylinder Nissans I've worked on) It's the power signal that comes from the ECCS relay. On the KA/SR ECUs, it would be easy to accidentally use the backup power wire (Red) that is always hot. But all of those are powered by the brown ENG CONT fuse, not the green IGN fuse.

Now, the part of the unit that intercepts the coil signals is on a direct line with the coil pack main power supply (Blue/Red), which you should have tapped straight off the Black/Red which travels back to the IGN fuse.

A quick what's what on our coils is that they use the jumping energy principle of two closely wound coils. Basically, you charge a primary coil and there's a secondary coil wound in parallel to the primary. The primary is charged at all times, but when you cut the ground suddenly, the charge jumps to the secondary coil and the secondary coil is connected to the spark plug. The jump also causes a huge jump in voltage.

Anyways, the power routing should look like this:battery -> 30a fuse -> ign switch -> coil -> gizzmo -> ECU. Normally, the ECU is protected by the ignitor chip. The ignitor chip, from what I gather, is basically a resistor to prevent the ECU from getting accidentally fried by the possibility of the coils arcing funny. Nissan later designed the ECUs with an internal ignitor (S15 SRs are known to be like this). The Gizzmo unit seems to be designed to be on the low power side of the coil signal wire as the manual says it's supposed to work on an external ignitor chip system and to be placed between the ignitor and the ECU.

Normally when I see these fuses popping, there's something arcing high voltage back onto the either voltage supply or signal wires for the coil packs. The most recent one was some exposed wires at coil 1 on an SR were touching. One was the ground on the head that is connected to the secondary coil while the other was the 12v supply to the coil. The 40,000+ volts from the secondary coil were backfeeding the supply wire and popping the fuse. Given that you had to muck with a supply wire and all the signal wires, which are directly connected to the 12v supply wires, you may want to isolate your search to the launch unit's wiring and see if there's something arcing funny down there. You mentioned that the IGN relay was acting like it was stuck open, it would only take a 12v constant to make that happen. Also, that would trick the ECU to staying on, which would keep the power going to the launch unit just perpetuating the situation.

That's all theoretical, though. Since I really don't have any experience with the gizzmo unit

rb25drag
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ok I got most of that. But wouldn't cutting the power completly from the Gizzmo unit act as if I completly unhooked the unit from the ECU?

I have taken the ECU out and unplugged the power wire on my gizzmo unit and it still arcs. Ill re-wire the ECU back to Stock if I have too but I just don't see the launch control causing this feed due to the 12volt power source. But I could be wrong, Thats why im asking questions.

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Hijacker
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If you cut the power to the unit, but left it in you would still have arcing issues if the interals have had damage done to it. It's hard to say if the 12v power supply was causing the issue or if it's the signal lines themselves that have been arcing the whole time. I'm wondering if the unit can't be used on an internal ignitor ignition system.

What I would wire back to factory and see if your problem continues. If it does, then you know the launch unit was at fault. But so far, that's all I can come up with to being your issue.

However, you say you removed the ECU, which would prevent the ECCS relay from powering up the launch unit. Hmm...now I'm at a loss to think of any other possible problem. Diagnosing electrical issues over the internet is a grade A b1tch

rb25drag
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ok thaks for the help. Ill re-wire the unit tom and see what happens.

rb25drag
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Well I re-wired my ECU so the launch control is not hooked up at all, But its still shorted. Also Pulled the IGN relay and it Still sparks. Any more Ideas?

rb25drag
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Well I took my dash out last night and traced the red/black ign wire out underneath the engine bay to the passenger side fuse block. I can take out the 2 fuses it runs and it still shorted. So Im thinking there is a problem with that wire. Im going to run a new wire today and see if that fixed my problem.

Fighter15
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Soooooo did you ever figure this out?? Kinda left everyone hanging. Totally understand the whole reving the old post crap but when people do a search and look for stuff to fix their own problems kinda throw a wrench in things.


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