Hello! I've been out of the forum for a while and had a lot of problems with my car, some of you may remember me, I was ripped off by a so called "mechanic" who did an engine swap and tranny rebuilt but returned a non working car, car had very bad acceleration so took it to a tranny shop and problem wasn't the tranny.

Thanks to the help of many of you (especially capedcadaver and wiking) I was able to figure it out that I had a plug swapped, inhib switch to the front 3 injectors (forgot at the moment the number of the plugs) after figuring this out I test the compression of all 6 cylinders and they seem to be great.

Then this problem showed up, my idle started to jump from 1.5k to 2.5k RPM and then some white smoke was coming out from under the engine, I start disconnecting the o2 sensor (as some of you suggested) but nothing changed, then I recently figure it out that the cable from the battery is getting incredible hot, there a small plug connected to the positive terminal, that cable get so hot that starts coming smoke out of the whole cable.

I'm not sure why but when this happens I disconnect this cable and then the erratic idle stops and it stabilizes for a moment, then after a few minutes it starts again, I suspect I have a mayor wiring issue that I'm unable to spot due my lack of knowledge about the electric system.

I've drive the car just for a minute on the alley and it seems to be strong, however I can't keep it on for so long because I'm afraid I'll damage something if I have a short somewhere, I need your help where to to start and how can I trace this problem.

I'll appreciate if you can help me about this, this problem has become very frustrating, so frustrating that I have to give it up for a coupe of months since last time I posted here, I know the problem will never go away just leaving it like that but I also call another mechanic and even he said he had over 30 years of experience he wasn't able to figure the problem, he said he'll try to research a little more on my problem but he haven't called back, so I guess he give it up but I don't know.

I know it's hard to diagnose from thousands of miles away but at least if you could point me in the right direction I'll give it a try, I want to have this car back on the road because what really **** me off is paying insurance, registration, etc for a car that it's just sitting on my parking lot.

Well Thank you very much in advance to everybody.

 

did you ever get your money back from the mechanic that hooked your harness up wrong and messed everything up?

and can you show us which wire? the one that goes to the starter?

 

No, I could never get a single cent back from this A$$hole I asked advice from lawyers but all told me can't be an 100% win case because I just have my word, and after all the time had passed I figure it out that is not worth my waste of time, money (money I'll spend with lawyer if I didn't win) and anger with this kind of people, after all that I learned my lesson, I should never EVER pay anybody in advance without a receipt or a paper signed by him and prefered with a witness.

I'm not sure about the wire, it seems to be the only one that plugs into the + terminal to the battery about 3 inches awat from the + connector, I'll upload a picture in a couple of hours, I'm glad you're still around caped

 

This is why I do all my work myself despite not knowing enough about what I'm doing

This wiring mess may be difficult to sort out, I know almost nothing about the wiring in our cars.

 

haha me too.

 

I always try to do most of the mechanic stuff myself but living at an apartment complex without garage won't help much on DIY jobs.

Besides I don't know much about mechanic/electrical too, but I've learned many things here on the org, very smart people here and very patient with a noob like me.

I never thought I could do compression tests, injector check, read ECU, trace an air leak, replace plugs, check MAF, maybe basic things but I never thought a noob like me could have done that and here I'm.

Just the engine swap wasn't a job for me, neither tranny rebuilt which I knew for sure without a garage and at least one experienced mechanic I never could have done that myself, but probably if I tried I'm sure I could have done a better job that this retarded mechanic who hooked up incorrectly the plugs and vacuum hoses all wrong.

 

i'm going to go look at my car to see what wire you are talking about. did you verify all your fusible links are ok, and importantly, that every fuse is the proper rating?

 

Well, the cable it's the that powers up everything, I mean if I disconnect that cable, belts are off, dashboard is off, courtesy lights off, but the car can start normally, the mechanic that came to check on the car trace that cable continuity to the fusible links, the ones below drivers headlight and the ones behind the battery, he found continuity from this cable to the... hold on, I thought those were solenoids? I forgot who mention that, I might be wrong. just curious, what are those? the ones that say: engine control, fog lights, rad fan, I never replaced or removed anything from there, however some spots are empty, now that I think about it, the plug swap could burn any of these right? I will take pictures of those either and upload in about an hour or so.

In any case, how do I test them? just like a regular fuse with continuity but I remember they have more than 2 connectors... I rather check them out and post when I'm sure, and about the ratings... do the FSM have that information? or how do I know if I have the right ones.

 

My point exactly

 

perhaps unplug everything on the engine harness and and undo all the vac, and just run that s**t yourself

relay is the term for the big ones. the clear-window little ones, those are fusible links. plus the one on the battery cable that i've never taken out before.

 

Here are some pictures:






The first picture points the cable that gets extremely hot that you can't touch it without get burned

second and third pictures are the relays, are they ok? I mean by the color they can be known if the rating is correct or I don't know.

fourth picture this cable get very hot too, not like the first one but you can actually feel it that it's not normal, actually is the same line but all the way to the bottom, I can see amoke around this one too.

fifth and last is a picture from the connector under the PCV valve the insulation looks cracked but cable seems ok, but is this cable only one line or should be two? because the other pin doesn't have any cable.


Relay is the term caped, that's what someone told me not solenoid, you're correct, about running the cable and vacuum lines, if you can help me I can surely try, I have nothing to loose the car is just sitting there, but again I have no experience removing a lot of stuff and please remember that if I need to take apart a lot of stuff I just can't because of the apartment complex rules, I mean if it's gonna take a while or maybe I can do a little bit one day and then close the hood and a little bit next day, I know sucks not having garage and freedom to work on the car but that's just my situation.

 

as far what i can judge from these pics...ur power cable looks faulty....did u try to change it? it should be minimum 4 gauge recommended 0 gauge (size)....and plus where is ur ground located?....but eh its electric...could be other things.....

 

it's not a terribly huge amount of disassembly really. just unplugging connectors and removing vac lines. the very last pic is only supposed to have 1 wire

the relays aren't the things that are rated. the fuses and fusible links are. anything that's 10A 15A 20A whatever... verify that all of the match what the caps say should be in that slot. all that is in pic #2 and inside the cabin by the driver door.

 

disconnect the wire that gets hot and see what features on the car don't work anymore. that will give you an idea of where to start looking for issues.

 

Fuses and fusible links seem to be all right, but don't know about the relays, how do I test them?

Already disconnect the cable and as mentioned before the dashboard turns off, automatic belts turns off, courtesy lights off, etc. also the idle changes.

I can start disconnecting, but how will I know if I'm reconnecting correctly, unfortuntely I don't fully understand the FSM, maybe everything is there, could you tell me which plugs involves the whole harness, I think you mean that right? disconnect and reconnect the whole harness and vacuum lines.

 

as many as i can remember are (from firewall to end, in *very* rough order)
a/c clutch
alternator
power transistor
ignition coil
distributor (CAS)
coolant temp sender
coolant temp sensor
knock sensor
02 sensor pre-harness
injector 1
ground
injector 3
injector 5
ground
oil pressure sensor
vehicle speed sensor
tranny valvebody control
tranny inhibitor switch
other random tranny harness plug or two
brake fluid resevoir sensor (amirite? or is this on the other harness?)
egr solenoid
powervalve solenoid
MAF
drop resistor
iacv
2-4-6 injector subharness
tps hard
tps variable

k guys so go ahead and fix the list (VG auto) unless it's already right. no butthurtness taken.

http://i164.photobucket.com/albums/u...g?t=1217345969
the harness dragging the ground is the one i'm listing connectors for, except yours will have a few more connectors b/c the picture is of an m/t car.

 

Ok, Thanks caped great picture, is it possible to take the whole harness out without removing any mayor parts, I would like to inspect the whole harness carefully or if possible replace the whole thing because I know many of my cables are in really bad shape.

Vacuum lines are also confusing for me, last time I had only one broken and I wasn't able to figure it out where it supposed to go, I'm talking about those hoses around EGR, but that was because I had some hoses connected wrong, and FSM won't help me that much.

 

you don't have to remove any parts. that stuff just plugs in onto the sufrace of everything.

 

Ok, that sounds very easy, I'll try to do that, at least I'll disconnect everything from where it is right now, the problem will be how to recognize if something was connected wrong, and actually put it back correctly.

I'll check and try to get as many info as possible from the FSM, and BTW haven't check the harness but is there any main plug from the firewall, also I think I'll better start looking for a harness that is in betten shape than mine.

 

there is a main plug that goes into the firewall..... but that's about all i know about it. i'm guessing it goes into the rubber grommet there, and kinda.. travels back across the car behind the dash and goes to the SMJ.

 

Ok, Yesterday I unplug almost everything from your list caped, from coolant temp sensor all the way to the bottom of that list, I didn't continue disconnecting because everything there seems that there's no way to plug in incorrectly.

I didn't find anything crushed, pinched, or cracked as bad as it won't work, I don't know if it was correctly connected or not but I guess the only plugs easy to get confused are the ones they messed up already.

Besides no cable get as hot as the one on the first picture, but I took out the intake tube, battery and the base tracing that cable and it's connected to something in the transmission, I took pictures but they are at home will upload later, I mean this connection looks like a ground but hey, this is the positive terminal! and there's one more plug that goes just about 2-3 inch aside this connection, are this connections ok? if I'm not clear please check the pictures a little bit later, I just want to update with this information in case it could be important.

Also took a minute video of the RPM while idle. and BTW the smoke is not as bad as before, and it's only coming out from that cable now, before it was coming from around the intake plenum but not anymore, Thanks.

 

whenever you get a shot at posting the pics let's see them. and the video.

don't quite get what you meant about the one looking like a ground connection tho....

 

Here are the picts:




Those cables came direct from the positive terminal, I don't know if they are feeding voltage there or what exactly are the purpose of those cables.

 

Here are the videos:



The first one is the rpm needle which behaves like that after 5 minutes of the car being on, no need to say that I don't touch the gas pedal or brake while this happens, car is on P and the the more I keep it running the faster the needle keeps jumping.

I tried to capture the smoke on the second video but it was impossible, at least you can hear the idle.

BTW, when this happens no matter how much I play with the IACV screw it won't have any effect.

 

that's part of the starter circuit... perhaps you have a shorted starter solenoid that keeps pulling juice through when it shouldn't. does the idle still jump around even when you unhook the starter? and i'm guessing you unhook that wire on-the-fly right? since otherwise you souldn't be able to start the car

is your CEL still on?

 

The starter, That's what I thought, but wasn't sure because from top I wasn't able to recognize it.

So that mean the positive terminal is correctly connected there since it's the main terminal to juice the starter, and yes the cable I just disconnected to inspect it and I pictured that way, and so I put it back to start the car.

The idle stabilize when I disconnect the cable from the battery (the first picture on post #13) but so all lights on the dashboard goes off.

Yes, unfortunately CEL is still on

 

yeah it all seems connected properly. I've never dug into my + cable, so i don't know what plugs do what off the cable, except the one for the starter. i think the one that is 3" down the line from the battery post is the fusible link, and the other 2 connectors i assume go to the relay box.

what code(s) are showing at present?

 

Hello, I'm new here. I've recently rebuilt the motor on my 240sx and am currently looking for a new project. I've been researching gen3's and gen4's looking for a possible sporty sleeper sedan to turbo. Anyways that's why I'm browsing around.

I was having a similar problem with my 240 after the rebuild with its idle. Turned out I had some corrosion in side the little box that comes off the positive battery terminal. I sprayed it with battery cleaner and it solved it. The problem keeps coming back and I spray it again and it goes away for a few weeks. I'm going to replace it this weekend and I think the problem will be solved for good.

You have to give it a good tug but that black connector will come off and you can clean it good. It's just so tight in there that it is hard to clean it fully out. I haven't gotten at the connectors with a wire brush since I'm replacing it anyways.

Another thing to check is your alternator connections. I'm not sure where it is on a maxima or if it is accessible but if you can reach your hand around back of it and make sure the ground wire is connected. That is a simple thing to not do on a rebuild/ engine install. I should know, I've done it.

Couple of Q's
Any batteries die on you recently? Is there a big change in idle when you flash your highbeams?

 

Hello Komete, first, welcome to the org

I can just say one thing! OMG!!! I thought the beams will have nothing to do with this but I just decided to try and I'm glad I did.

I just went to check my codes from ECU and like I said I turn it on and decided to check if the high beams will make any difference.

Well, when I turn the car on I turn my low beams on and wait for the problem....5 min....10 min... nothing... "ummm I guess this thing is crazy" I said to myself then I turn my beams off and then the idle start to jump exactly like the video, so Im like "WTF!!!" so turn them on again and the idle stabilize at 1200 this time the car feels much better, no shaking at all.

So, in conclusion, now I'm 100% sure my problem is electric, right? so the question is where and what is malfunctioning. Yes my positive terminal in incredibly corroded and I clean it some time ago but.... will it better to replace the whole thing, I guess just the plug right? honestly the whole cable looks so messy.

To answer your question Komete, no, no batteries had died recently, I use an Optima yellowtop since 2006 without any issues.

Caped, my list codes just add up, before I got 33 & 34 but now is also giving a 35, so, exhaust gas temp sensor have a problem also right? well I guess I should take care of the electrical problem first.

Thanks, now where do I start? OH! almost forgot I tried to take a picture of my alternator but it's too dark and couldn't reach it, here it is anyways I'll try to take a clearer picture later:

 

it could be CABLE, BATTERY, VOLTAGE REGULATOR, AND ALTERNATOR...OR bad ground....

edit: or something is drawing too much current that wen u turn ur lights on it gets stable and wen u turn ur lights off its get unstable? dont only look at ur positive terminal...pay attention ur Negative too....I HAVE THE SAME problem cuz wen i push the brake pedal it needs more current right so my rpm drops or if i turn on my lights my rpm drops very LIL....i have alternator problem i know and i m gonna change any time soon...but ur problem is opposite compare to mine...ur rpms drops if u turn off high beam and mine drops wen i turn on...

 

Sorry for being late to the party . You definetly have an electrical problem. Your idle jumps as a consequence, so I wouldn't worry about it for a moment. The cable which was getting hot was obviously drawing too much current. All electrical circuits in the car are fused to prevent exactly this situation - fire from some wire going from positive terminal somewhere. Unfortunately, in your case the short happens to be somwhere before fuses, otherwise you'd blown one already. It also seems to be related to the headlights which eliminates simple short of that wire around firewall. I'll take a look at FSM to see if I can figure this out based on your information. I wouldn't bother with alternator or engine harness or whatever as you already localized problem to the headlights circuit.

 

When you mention the wire gauge, I thought you was confused with my problem because I've had this cables the same way always and 4 gauge cable is huge and don't mention 0 gauge, I only have 0 gauge for my audio system, even the ground cable seems to be like 8 gauge.

But it makes sense that this little cable is not holding up for the amps flowing through it. so my guess is when I draw more current for another part of the car this cable gets a relief, because all I know about this little cable is that if I disconnect it the dashboard goes off completely, besides if my idle is jumping and I shift to D or R, the problem seems to go away, however I don't want to drive it like this.

isn't there a chance that the haedlights are misdirecting the real problem by just drawing more current and making the idle stable, will it happen with anything else that draws more power? I think I'll try turning the AC on today.

I also tried disconnecting my audio system but that had no effect at all, I did check the ground terminal and looks ok, I'll check more carefully today my cables that goes to the fusible links and headlights to see if I found anythin unusual. Thanks

 

Sorry, this is not the case - if you draw more current to some other part of the car this patricular cable won't get it easier unless another part draws so much that it brings the voltage in the system down considerably. What does happen I think, is that when you turn your headlights the circuit which draws high current gets disconnected. I'd take out your lighting switch to see if anything is wrong there, like melted insulation or wires getting hot when you turn lights off. Don't waste your time on idle problem - get the electric one solved, a lot of other things might behave strange.

 

ibhisstupidholdmechaniccausedtheelectricalproblems inthefirstplace

dunno if you saw the other thread, Max5gen, but a VG auto engine harness allows for transposition of the injector/iacv plug pair for the trans inhibitor plug pair (both have a 2x3 plug and a 2x2 plug). meaning that connections will be made that should not be made. possibly messing up the car's wiring.

 

Pardon my ignorance but, what do you mean by taking out the lighting switch, you mean from inside the car? the switch from the steering wheel?

Now talking about the swapped plugs, is it possible this swapped plugs (was it F16 to F21?) caused this? I think is very likely but it just doesn't make sense for me, if something was short circuited, well it's burned and damaged, but after plugging it back it shouldn't work, and everything seems to work except for a hot damn cable which causes inestable idle.

Now, for me, the million dollar question is, why this never happen with the front 3 injectors unplugged? but well I'll have planty of time to ask those questions after fixing my problem, right now all I need is get this lady on the road again.

BTW, exahust still stinks like hell! but that I guess is gonna be related to my CEL codes.

I'll be checking very carefully the cables this evening. does autozone sell universal battery terminals? I really want to get rid of the posibility of poor contact on the + terminal,.

 

Sorry to be slow and all but, when exactly high beams come into play?
Letme recap, you turn on your lights and the problem isn't there. But you turn off the lights, and you get a problem?

My guess is that since a circuit closes when you turn on your lights, dividing the current, that means something is possibly parallel to that light circuit is causing you problems. I'll check there.

The schematics on the MAX in the Chitons manual are hard to read. But since someone wired your car wrong, it may not be of help.

 

I saw that. I also think that it takes some skills to mess up wiring by plugging to the wrong socket, melting wire insulation and not blowing any fuse in the process. Unless, of course mechanic put a piece of wire instead of actual fuse in the process being tired of fuses blowing on him ... As I said - some skills.
Realistically speaking though I'd assume that those circuits survived and try to analyze the problem at hands. What he is saying about headlights is very encouraging as it localizes the problem to somewhere around the headlights switch: the original wire supplies current to almost everything in the car and it would take some time to identify which path draws abnormal current. If this can be stopped by just turning on headlights (make sure, please, that this is the case) then it eliminates all other paths and leaves only those around the switch. I'd look very close at that switch first. Some of the wires going into it must become really hot when the lights are turned off.

 

the code 35 will be related to this item:
http://i164.photobucket.com/albums/u...sorharness.jpg

 

well they fit perfectly... it's just ignorance to not take a second glance and notice that one of the 2x2's has 3 pins and one has 4.... yet the mechanic swapped them backwards (iacv was hooked to PRND2L switch, and injectors were hooked to PN switch.... vice versa)

 

Yes, I assumed you turned your headlights by using that switch, correct? Could you please make sure that this is the case: when you turn your low beams on - your original wire going from the battery doesn't get hot anymore. If it still becomes hot like hell - please forget everything I said about lighting switch, the problem is elswhere. Don't do this for too long as well - just long enogh to notice the high temperature. Smoke is the least thing you want to see.