# errr' Disconnected plugs on engine wire-harness help please :(



## MrFurious (Oct 30, 2005)

More questions by MrF. I have found a few plugs unpluged under the hood and cant find where they go. 









This one ( ^ ) is under the large intake duct to the throttle body. It is a female plug connector that is just like the one for the O2 sensor that is 6 inches away from it.???









This one is just behind the drivers side headlight. I thought it went to the small head lamp (cause they currently dont turn on). But after looking closer, I dont think it does.???









This one is directly behind the intake manifold. It hangs towards the drivers side. It was taped to the harness with blue tape.???

I have looked everywhere for what is suppose to be on the other ends of these things but cant find them.


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## OK85NA2T (Nov 4, 2005)

MrFurious said:


> I just went out and looked. It has a plug type identical to the O2 sensor that is 6 inches away from it. But it is not to that sensor. Is there only one O2 sensor on this model? I havent been able to find any diagrams of this section of the wireharness, which is called the "Engine Sub-Harness". But have harness diagrams of practicly everything else.
> 
> 
> I have found 3 unplugged connectors so far. I may have to post them cause I cant find what they go to.!!??!!



Man like I said... just chill out.. everyone has open connectors whether they notice them or not. Nissan only made two harnesses, one for turbos, and one for non turbos... that means, all the accessories and options that you DONT have, have open plugs that go to nothing on your engine. So chill out, check your ECU codes. If you don't throw any codes and your engine is running fine, then everything is all right...


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## ICP Sux0rZ! (Jan 10, 2005)

MrFurious said:


> This one is just behind the drivers side headlight. I thought it went to the small head lamp (cause they currently dont turn on). But after looking closer, I dont think it does.???


factory alarm for the hood, its supposed to mount to a sensor on a slide bracket right by your hand but you dont appear to have the sensor, oh well


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## MrFurious (Oct 30, 2005)

heheh' thanks guys... Just it has all the sudden decided not to start so I have been going over everything.


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## OK85NA2T (Nov 4, 2005)

Tells us what it's doing and we'll tell you the problem.

When you turn the key, what does it do?
Nothing at all, no noises whatsoever?
Does it try to turn over?
Do any of the accessory lights come on?
Does the starter click?


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## MaxQ (Jun 3, 2004)

The bottom pic.....that sensor at the back of the intake plenum is supposed to remain disconnected, it came that way from the factory and doesn't affect anything. 

The second pic....is that sensor connected to your TPS? I can't tell from the photo.


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## MrFurious (Oct 30, 2005)

OK85NA2T said:


> Tells us what it's doing and we'll tell you the problem.
> 
> When you turn the key, what does it do?
> Nothing at all, no noises whatsoever?
> ...


It turns over fine, will turn over untill you run down the battery. No odd noises, just turns over. It gets spark too, I just put new plugs in. And its getting gas also... You can smell it in the exhaust. I got it to stumble and try to start for a second by pumpin' on the gas. But that was all, and just once. I thought it may have sputtered because it got a little more air in, giving it enough air to try and start. But I dunno'.

The car was running, it was sputterin' and stumbling but runnung. Did some work on it, got to running better, but still there was a little something wrong. It didnt seem to want to idle at times. I thought it possibly may be the timing belt, but then found that the vacume hose was hardened and cracked on the fuel pressure regulator. Woke up the next mornin' replaced the hose, and it wouldnt run. Just turn over.?. Seems like I suddenly got a new problem over night.


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## OK85NA2T (Nov 4, 2005)

could be a big vac leak, or AFM... or you might have knocked it way out of time..


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## MrFurious (Oct 30, 2005)

Its not timing, I checked that. If it was a large vacum leak I figure I could hear a sucking noise from somewhere when the motor turns over. How can I test the Air Flow Meter? Anyone know of a way?


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## Zen31ZR (Mar 24, 2004)

It's been discussed here a few times, the engine will run without the MAF. Not well, but it will run.


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## Zen31ZR (Mar 24, 2004)

Pull the cam covers and make sure they both line up with the heads properly and with the crank TDC mark . If you have spark and fuel, the only thing missing is air. 

How did you test for spark and fuel, just curious.


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## MrFurious (Oct 30, 2005)

Zen31ZR said:


> Pull the cam covers and make sure they both line up with the heads properly and with the crank TDC mark . If you have spark and fuel, the only thing missing is air.
> 
> How did you test for spark and fuel, just curious.


The only way I know how to check the cam timings is by taking off the timing belt cover and looking in there.

You can smell the gas from the exhaust pipe. And I just put brand new plugs in, so I just took an extra plug I had and connected it to the plug wire and watched it spark. And I had air, I dunno what could have happened in a few hours while the car wasnt running.


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## MrFurious (Oct 30, 2005)

and the Air Flow Meter is plugged in...


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## Zen31ZR (Mar 24, 2004)

Pull off the distributor cap, make sure the rotor is actually rotating in there.... Sounds dumb, but I had a distributor shaft pin sheer once and it kinda did the same thing as you are describing. Might as well eliminate that as a suspect. If the cams are lined up as they should, then that leaves the MAF and the ECU. The FPR might possibly be bypassing most of the fuel pressure, but I'd think you'd still get some sputtering out of the engine, at least. Try swapping in a known good MAF. Also try swapping in another ECU. Random elctrical discharges can take those out in a heartbeat, but if that's the case that also means you have grounding issues......


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## Zen31ZR (Mar 24, 2004)

There's always the good old cylinder head temp sensor problem. This may also do what you are describing. Can't find any test procedures in the FSM, however. Doesn't mean there aren't any, just means I can't find them right now.


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## OK85NA2T (Nov 4, 2005)

Zen31ZR said:


> There's always the good old cylinder head temp sensor problem. This may also do what you are describing. Can't find any test procedures in the FSM, however. Doesn't mean there aren't any, just means I can't find them right now.



The engine will run without a CHTS alot easier than it will without a MAF. CHTS seems to be everyones cop out response... it's tired.


You need to do more diagnostics before you start rummaging through and replacing stuff in your engine.

Get a timing light and check your ignition timing.
Check ALL of your wires (you can do this with a timing light as well)
Close the hood almost all the way in the dark and see if you see arching anywhere.
RUN ECU DIAGNOSTICS AND CHECK THE CODES.
Smelling fuel out of the exhaust is not a check of the fuel system. There are tons of remnents of fuel in your exhaust system.
When you replaced the hose on your FPR, which hose did you replace? Where did it go to and from?
You aren't trying to start the car with just the TBody open and no MAF are you?

Come back after this is done


















^^^You've hooked ALL of this back up when trying to start it, correct?^^^


P.S. Whenever you get time, get some decent plugs (Nothing but the cheap NGK's)


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## Zen31ZR (Mar 24, 2004)

I think we've covered just about everything that might cause a problem with starting, however.  And that's the important thing. Whether something is a "cop out" or not is not for anyone to say, it could still be the cause of the problem. I might suggest that when posting, leave the attitude on the other side of the keyboard.


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## MrFurious (Oct 30, 2005)

Yes the motor is put back together. I said the vacum hose on the FPR. I just did the timing when it was running, so it shouldnt be off. And I did check to see if it got knocked way off, and it hasnt.


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## OK85NA2T (Nov 4, 2005)

MrFurious said:


> Yes the motor is put back together. I said the vacum hose on the FPR. I just did the timing when it was running, so it shouldnt be off. And I did check to see if it got knocked way off, and it hasnt.



Where is your vac hose from the FPR running, is it going to the selenoid on the engine compartment wall or have you moved it to attach directly to the plenum?


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## OK85NA2T (Nov 4, 2005)

Zen31ZR said:


> I think we've covered just about everything that might cause a problem with starting, however.  And that's the important thing. Whether something is a "cop out" or not is not for anyone to say, it could still be the cause of the problem. I might suggest that when posting, leave the attitude on the other side of the keyboard.



Don't start this I'm better than you bullshit already, you replied to my post about the AFM in the exact same tone.


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## Zen31ZR (Mar 24, 2004)

OK85NA2T said:


> Don't start this I'm better than you bullshit already, you replied to my post about the AFM in the exact same tone.


Nobodies started anything but you.


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## Spongerider (Nov 18, 2002)

PM each other you guys are fighting like girls? 

Remember we are here to give each other help from different *perceptives*. 

I will delete my own post at the end of the day.


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## MrFurious (Oct 30, 2005)

All vacum hoses have been checked, and double checked. Found another one with a slight crack and fixed it. Anything to do with timing has been checked (except for looking to see if it has jumped time, but that wouldnt be an overnight problem). You can start to smell gas at about the fourth time you try cranking it over. I looked at the AFM and saw that it has already been replaced once. I doubt that is the problem. Here are the error codes I get from the ECU

23 = Idle switch circuit
31 = Load signal circuit or ECU (One of the load signal [air con, power steer, or radiator fan] circuitsis open or shorted)
41 = Fuel temp sensor circuit. 

I dunno where the Idle switch is to check it. My Haynes manual doesnt say. Thats probly why I had probs idling. As for the 31 code, my air doesnt work. The guy I bought it from said it stopped working when the radio got ripped out. And I have checked the fuel temp sensor. Looks fine, just old. But if my FPR is faulty, that might be why I am getting that code huh'?


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## Zen31ZR (Mar 24, 2004)

Idle switch circuit is the TPS itself. In fact, on the non-auto cars, that's the only function it performs. To tell the ECU if the throttle is open, or shut.


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## ICP Sux0rZ! (Jan 10, 2005)

Zen31ZR said:


> Idle switch circuit is the TPS itself. In fact, on the non-auto cars, that's the only function it performs. To tell the ECU if the throttle is open, or shut.


maybe he needs a new one?

go to the junkyard, pocket (or buy whichever you prefer) like as many as possible and plug and play until the code goes bye bye


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## Zen31ZR (Mar 24, 2004)

As far as I know, they can not be repaired.


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## ICP Sux0rZ! (Jan 10, 2005)

Zen31ZR said:


> As far as I know, they can not be repaired.


hence the junkyard run, hes gotta be able to find at least one thats in good shape, hell if he can't i'll go and get 6 and mail them to him


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## Zen31ZR (Mar 24, 2004)

That one plug hanging over by the intake piping... I'd bet money on that being plugged into the A/C, maybe that's his load sensor fault.


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## ICP Sux0rZ! (Jan 10, 2005)

Zen31ZR said:


> That one plug hanging over by the intake piping... I'd bet money on that being plugged into the A/C, maybe that's his load sensor fault.


so he may need the TPS with the extra plug? worth a shot, although mine isn't hooked up and mine works fine


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## Zen31ZR (Mar 24, 2004)

Fuel temp sensor circuit, most times the plug on those gets corroded inside, or the wire between there and the firewall gets cut or crushed and grounded. If the sensor itself is ok, check the wiring, if that's ok then the sensor is bad. Should be testing details in the FSM.


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## Zen31ZR (Mar 24, 2004)

ICP Sux0rZ! said:


> so he may need the TPS with the extra plug? worth a shot, although mine isn't hooked up and mine works fine


No, that extra plug may go on the A/C compressor itself. Too bad I threw mine away, so I don't know for sure.


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## ICP Sux0rZ! (Jan 10, 2005)

Zen31ZR said:


> No, that extra plug may go on the A/C compressor itself. Too bad I threw mine away, so I don't know for sure.


theres no plug on the ac compressor










it doesn't plug into anything if you have a manual, i think his TPS is shot


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## Zen31ZR (Mar 24, 2004)

ICP Sux0rZ! said:


> theres no plug on the ac compressor
> 
> 
> 
> ...


 I'll accept that. :thumbup: I'm just wondering where he's getting the load sensor fault from. And if it was before or after he removed the A/C.... The code itself may not be important, but it might explain one of his missing plugins.


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## MrFurious (Oct 30, 2005)

The idle control is the TPS. Thats good to know. I have been searching through manuals trying to find an idle control switch. I have found some test procedures with a multimeter for it. So I will test that. I have a compressor on my car. Because he said it quiet working when his stereo got pulled. I was thinking that it was the wiring behind the dash. I have glanced in there and have seen some cut wires. I just need to get back there to check what is what. But I was wanting to get the car running first. And when looking at engine codes is the VG30E the manual car, while the VG30ET is the automatic?


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## Zen31ZR (Mar 24, 2004)

MrFurious said:


> The idle control is the TPS. Thats good to know. I have been searching through manuals trying to find an idle control switch. I have found some test procedures with a multimeter for it. So I will test that. I have a compressor on my car. Because he said it quiet working when his stereo got pulled. I was thinking that it was the wiring behind the dash. I have glanced in there and have seen some cut wires. I just need to get back there to check what is what. But I was wanting to get the car running first. And when looking at engine codes is the VG30E the manual car, while the VG30ET is the automatic?


The "T" designation denotes whether the engine is turbo or not. Has nothing to do with the transmission.


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## MrFurious (Oct 30, 2005)

just an update... I checked the TPS, it needed adjusting. After adjusting, everything checked out fine on it. I havent got the codes again from the ECU, will do that in the morning. But I suspect that the #23 code wont show up again. But the car still didnt start.  ah' T for turbo


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## Zen31ZR (Mar 24, 2004)

Have you listened for the fuel pump whine when you turn the key on? (Sorry if this has already been asked) It's actually more of a low hum. 

We can possibly rule out the ECU as the difficulty. I say possibly because I had a similar ocurance in another vehicle, and while diagnostic mode worked fine, the ECU was shot otherwise......

Have you tried starting fluid yet? It's a bit hard on the engine though, gas in the TB works much better.


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## MrFurious (Oct 30, 2005)

I can hear the fuel pump turn on then shut off when acheiving the desired pressure. And starting fluid wont help, the motor isnt even struggling to start. If I didnt see the fact that I have spark, I would think I wasnt getting any spark.


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## Zen31ZR (Mar 24, 2004)

That's why I'm suggesting a bit of gasoline, though. It may work or it may not, but it may go a little way towards determining the problem. If it doesn't even cough or try to start when you do that, then you know you have other problems. I'm suspecting maybe the injectors aren't working, which is why I'm suggesting this approach. 

Here's another one for you, have you tried starting it while holding the gas pedal on the floor. Not pumping it or opening and then closing it, but just holding it on the floor. If it is flooding, that'll help some. 

Pull a couple other plug wires randomly, make sure you're getting spark out of them, too. I've seen stranger things......

Do a compression check. It's not as hard as you think, you can get to all 6 plugs without using anything other than standard tools and without moving anything but some wiring (the bundles on the sides of the intake mani). This will let you know if the engine even has useable compression to create combustion. At or above 160 psi (on the nonturbo engine) should be adequate.


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## OK85NA2T (Nov 4, 2005)

I've never had my fuel temp sensor hooked up, and a TPS wouldn't bother it as far as starting... I believe it is fuel as well. You can clean the pins on the TPS connection, sometimes they get corroded and won't make the connection that they need, but I believe there are other problems. None of the codes listed will have any effect on it starting. If you have a test light, you can test the injector connections... but I doubt something happened to an entire set of injectors and compression all over the board in one night... All it would need to try to start is 1 good cylinder, you said it was running previously, so I doubt the whole engine went to shit over night.. What all did you do to it the day before you found out it couldn't start? pull the return hose off of the fpr and put a bucket or something up to it, turn the key to on and see if fuel comes out... if it does, enough is getting to the injectors and its' not your fpr. My guess is that something was left unplugged/unhooked up


Take some current close up shots around your engine bay and post'em up


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## Zen31ZR (Mar 24, 2004)

_Run_ on 1 cylinder? That's pushing it a bit, I'd think. Though it'd cough and sputter at least. 

What could possibly be unplugged on the engine that wouldn't throw a code but would keep it from running? That's why I'm kinda tending to think a mechanical problem.....


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## MrFurious (Oct 30, 2005)

I thought that it may be getting to much fuel thats why I was thinkin' FPR, or possibly not enough. "but I doubt something happened to an entire set of injectors and compression all over the board in one night... All it would need to try to start is 1 good cylinder, you said it was running previously, so I doubt the whole engine went to shit over night.." my thoughts exactly... And because the motor was running the day before, I dont think it is compression. It would atleast stumble like you said. And this is what I did the day before.
~plugs
~plug wires
~distributor cap & rotor
~timing
~fuel filter
~air filter
~flushed motor
~new oil filter
~flushed radiator

I have double checked everything I have done that would affect starting the car. But after I did all of this I drove the car out then back into the garage. Pulled out the keys then went to bed. And sense then I have more than likely fixed my two problems that I had before it wouldnt start. 1)Idle trouble = TPS needed adjusting 2)Stumbling (sometimes) lack of power at high RPMs = Vacum hose on top of FPR. BUT NOW IT WONT START!!! AAAAH!!! :crazy:


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## RocketRodent (Jun 21, 2004)

Have you checked the FPR, not the hose but actually the FPR itself. I had a FPR fail and the car would crank as decribed but would never fire. The diaphram might have been punctured/ruptured once you hooked up the vacum line. Just a thought.


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## MrFurious (Oct 30, 2005)

I havent yet, I was just about to go out and do that though.


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## OK85NA2T (Nov 4, 2005)

Zen31ZR said:


> _Run_ on 1 cylinder? That's pushing it a bit, I'd think. Though it'd cough and sputter at least.
> 
> What could possibly be unplugged on the engine that wouldn't throw a code but would keep it from running? That's why I'm kinda tending to think a mechanical problem.....



Hmm, that's funny, I don't think anywhere in my response I said it could or would run on 1 cylinder... but whatever.

MrFurious... if you think it's the fpr, do like i said and pull the return hose off of it, put something up to it, and turn the car (fuel pump) on, not trying to start it, and see if fuel comes out... if it does, then fuel is getting to the inejectors... If it's getting too much fuel, it would atleast stutter a little bit... If you can't get any of this info to help your problem, find someone with a Z in your area to come take a look at it. It's hard to fix something uncommon with advice over the internet. where are you located?


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## MrFurious (Oct 30, 2005)

I put a cup under the return hose. Gas came out as fast as the fuel pump could pump. Makes me wonder though. Because I thought iw would atleast take a second to pressurize the system before the return started pouring out gas. I really need to test the pressure in the fuel lines, but there isnt a shrader valve on these things. So I dont quite have all of the stuff needed to check it.


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## Zen31ZR (Mar 24, 2004)

OK85NA2T said:


> Hmm, that's funny, I don't think anywhere in my response I said it could or would run on 1 cylinder... but whatever.





> All it would need to try to start is 1 good cylinder


That's where I got that from. What I get for posting after being up for 30 hours.....


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## OK85NA2T (Nov 4, 2005)

Zen31ZR said:


> That's where I got that from. What I get for posting after being up for 30 hours.....



Yea, said that but didn't say running...


Also, MrFurious... there is always going to be fuel in the lines... what do you think happens to what's in the lines when you turn off the car.. think it magically disappears? okay so you're getting fuel. get a multimeter and check the connectors on your injector harness. If they're showing proper voltage then you can eliminate fuel because all of your injectors didn't lock up overnight


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## MrFurious (Oct 30, 2005)

I just installed a pressure guage in the fuel line, and it shows that the pressure is where it is suppose to be. So fuel all the way to the injectors is not a problem. And its probably not the injectors but I will try to test one tomorrow. I am still getting the same 3 error codes though. And whats funny is that the error codes should usually repeat over and over. But sometimes one code wont repeat, just flash once. ???


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## OK85NA2T (Nov 4, 2005)

listen, don't worry about the error codes right now. Worry about them later. and I'm not telling you to test your injectors, I'm telling you to test the connectors for the injectors on the wiring harness to see if it's giving proper voltage to the injectors. This will rule out any wiring/ECU/fuel problems


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## Zen31ZR (Mar 24, 2004)

Hopefully he has a DVOM with long leads, or a helper. Since the engine must be cranking to fire the injectors.....


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## ICP Sux0rZ! (Jan 10, 2005)

Zen31ZR said:


> Hopefully he has a DVOM with long leads, or a helper. Since the engine must be cranking to fire the injectors.....


could get a starter button and hook up the batt + to the starter


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## Zen31ZR (Mar 24, 2004)

ICP Sux0rZ! said:


> could get a starter button and hook up the batt + to the starter


I tried that once, not as easy as it sounds. The starter, the oil filter, and the knock sensor (well, he doesn't have one of those) all kinda fight for position right there.


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## ICP Sux0rZ! (Jan 10, 2005)

Zen31ZR said:


> I tried that once, not as easy as it sounds. The starter, the oil filter, and the knock sensor (well, he doesn't have one of those) all kinda fight for position right there.


lol oh well, but then again hes not blown, so maybe its not as crowded


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## OK85NA2T (Nov 4, 2005)

it's not that hard to have someone lend a hand for a few minutes, that's all I was suggesting.


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## MrFurious (Oct 30, 2005)

Update... I went ahead and pulled a spark plug that I had just put in the day before. Some how all 6 plugs were fouled overnight, go fugure... So after I cleaned and put them back in I turned the car over and it sounded worse than before, this time more like the timing was off. No clanging, just umphin', and not wanting to idle. The ditributor is in place (sounded worse than the timin just being set to low, sounded off). So I plan on changing the belt and tensioner. :banana: Anyone know of a high performance belt for the SOHC Z31? Greddy makes a belt for ZX's, but only for the DOHC ZX's.


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## MrFurious (Oct 30, 2005)

12345678910


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## Zen31ZR (Mar 24, 2004)

MrFurious said:


> Does anyone know where to find their IGNITION MODULE
> 
> 
> 
> ...


It's next to your coil.


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## RocketRodent (Jun 21, 2004)

That module is the little round thing that is connected to the same bracket that your coil is on.




MrFurious said:


> Does anyone know where to find their IGNITION MODULE
> 
> 
> 
> ...


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## Zen31ZR (Mar 24, 2004)

MrFurious said:


> Update... I went ahead and pulled a spark plug that I had just put in the day before. Some how all 6 plugs were fouled overnight, go fugure... So after I cleaned and put them back in I turned the car over and it sounded worse than before, this time more like the timing was off. No clanging, just umphin', and not wanting to idle. The ditributor is in place (sounded worse than the timin just being set to low, sounded off). So I plan on changing the belt and tensioner. :banana: Anyone know of a high performance belt for the SOHC Z31? Greddy makes a belt for ZX's, but only for the DOHC ZX's.


The stock belt is more than sufficient. I saw a belt made of Kevlar a while back, I forget by who, but you could buy about 5 stock belts to equal the price on that one. Just get genuine Nissan parts and you'll be fine.


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## MrFurious (Oct 30, 2005)

RocketRodent said:


> That module is the little round thing that is connected to the same bracket that your coil is on.


Yeah' thanks, I found it just after I posted.


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## MrFurious (Oct 30, 2005)

*UPDATE* 








This open connector is for the TPS on a automatic, it is for the "Full Throttle Sensor" function.


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## ICP Sux0rZ! (Jan 10, 2005)

MrFurious said:


> *UPDATE*
> 
> 
> 
> ...


we told u that already, we never said exactly waht is did, but we told you its for the auto trans


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## MrFurious (Oct 30, 2005)

All I got were guess's. One guy said it was connected on his but never said if his car was an auto or a manual.


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