617G

iTrader: (6)

car is an 03

KPierson

iTrader: (1)

Unless someone changed one of your fuses a wire will NOT burn from 'overload'. I would ask to see the wire that they repaired. I would also expect future problems, unless they find out exactly what caused the wire to 'burn'. Simply replacing the fuse and the wire won't fix the problem.

Looking through the '04 G35 service manual I found that the ignition wire is white/blue (pin 109, like you had previously said). The same white/blue wire powers the fuel injectors. I'm guessing that this is the wire that they are working on.

What I would be more concerned about right now, though, is how two perfectly good fuel injectors failed at the exact same time.

I wasn't trying to put down the technician that is working on your car. I was simply pointing out that most performance shops struggle when it comes to electrical wiring. You had posted several 'flags' and I just wanted to bring up that possibility. In the end, only you can determine if he did the 'right' thing because you are the one paying him.

Good luck!

KPierson

iTrader: (1)

I don't have the '03 manual on my laptop. From what you are saying about the fuse layout I'm assuming that the IPDM changed from '03 to '04.

Audible Mayhem

iTrader: (48)

that white/blue wire actually runs a lot of places if i recall, it is the main power for a lot of things...

617G

iTrader: (6)

Yes, you're both right. They changed the fuses in 04 and that 12v white/blue wire powers a lot of things.

Well, that wire was replaced (some parts were melted to bare metal), but still no luck. Same issue as before.

We did find something interesting, though. If the intake pipe is off the car, creating a vacuum leak, the car runs and has a little throttle. But, with the pipe back on, there is no throttle control and the car doesn't start...doesn't make any sense.

Anyone have any ideas of what else the problem could be? Right now we're waiting for someone with a consult, but until then, I'm not sure what else can be done

617G

iTrader: (6)

No harm, no foul...thanks for the help!

617G

iTrader: (6)

still no luck...the shop (which has an electrical engineer on hand) checked and rechecked every wire and still no luck. The one 12v blue/white wire that looked "burnt" (basically the insulation melted like it was carrying too much current) was replaced and everything put back together and the same issue persists...

Does anyone have any other ideas? I'm not sure what else can be done without a consult to plug into the ECU and find out what's going in...

Thank you everyone for all your suggestions thus far! It's been 3 loooong months and my engine/twins are finally finished, but this stupid problem is preventing me from enjoying it

shushikiary

What type of battery was it? If it wasnt a fiberglass foam matt battery like the optima's but a pure lead acid battery and it died like you said, plus the fuse blowing I would say you had a serious short in the system.

Somethings tells me that you have a low impedance issue somewhere... Like damaged insulation, etc. Also, because of the damage done to the blue/white wire you are talking about it is possible that even though you fixed all the "other" issues it may have blown some electronics that you dont know have blown yet. If you arnt 100% sure that the ECU/e-manage blue is fine then try swapping them out temporarily with a unit you know is good to see if that's the problem.... though BE CAREFUL because if the problem that happened before happens again it could blow the test unit if that's what cause the original problem... If you have one put a current limiter between the blue/white wire and the new test ECU, etc.... a simple current limiter can be made with a large coil of wire (the more turns the better) and a high power low resistance resistor and a fuse, and if you have one a zener diode (if it's DC)... best option is to opto-isolate it but I doubt you'll be able to do that.

Also make sure they pull the alternator and run a test on it to see if it's voltage regulator is good, AND that there arnt any shorts in the coils on it. If it gets too hot and melts through the enamel insulation on the windings it can some serious shorts and voltage spikes depending on where the enamel melted off. I dont know if it will work on this car but a quick check to see if it's the alternator is to just unplug it so everything runs off the battery.


If the shop has an oscilloscope make sure they put an inductive sensor on the injector wires and see what is going on there. Also check the grounds to the motor and make sure they are all good, if the grounds are not good it is possible to get a charge build up on certain parts of the car which may cause it fry like it is (unlikely but possible).


That's about all the advice I can give you without being there, hope it helps if at all!!!

taurran

iTrader: (18)

Possibility of a blown ECU? I've heard of a handful of these and they always exhibited strange activity like listed here. Then again, finding out WHY it blew would just open another pandoras box of questions.

This kind of issue sucks. One of the toughest to troubleshoot on these cars, imo.

617G

iTrader: (6)

the battery was crappy...i dont remember the type as it was in the car when I bought it and it's not a nissan battery we found that the battery lost one of its cells...

all of the piping anywhere near the alternator has been heatwrapped and the alternator was checked.

the main problem we're having is the APP sensor. The wires were tested and the output is fine, but the input has weird voltage readings, I believe...

thanks for the help

617G

iTrader: (6)

my thoughts exactly! i COULD just buy an ECU and that might fix it, but I would rather find out WHAT caused it instead of just replacing parts and hoping it works

shushikiary

Yes do this, and you're right just as I said above. Danget, I could just build you a current limiter so you could test without fear but I'm not there!!! lol Without the proper electronic tools fixing electronics is a game of replace, test, repeat.

You could try to get a used ECU from a junk yard so if you let the smoke out of it it wont be so costly.

If the white/blue wire melted it's insulation it either was next to something too hot or you pulled too much current... find out WHY... it is possible that if the cell in the battery failed horribly it could have been the cause for all this. If you still have the failed battery and didnt recycle it (and have no plans too) then take it appart and check the cell that is bad for any shorts, it could very well be your problem.

KPierson

iTrader: (1)

It would be almost impossible to pull too much current through the wire, as the fuse would have blown before the insulation melted. I would do much more research in to the wire itself.

Any chance you can post a pic of the burnt wire? If it was burnt from an excess of current it should have noticable discoloration through it. Like I've said, the fuse should have blown long before the wire got hot enough to actually melt the insulation.

Who is paying for all this troubleshooting? I know you have faith in your shop, but there is a chance that you will never find out what happened, if it is their fault and they want to cover it up so that they can charge you for their time. Just something to think about.

The APP sensor should be easy enough to test. It should have three wires, one source (5vdc constant) and two signals. Measure the signals with the pedal up, halfway down, and all the way down. If you get 'weird' signals then disconnect the signal wires from the ECU and perform the test again. If you still get 'weird' signals replace the APP. If the signals are normal on this second test then replace the ECU, as something in the ECU is causing the signal to change to an unacceptable level. It's very possible that whatever happened damaged the internal power supply of the ECU which would cause all your 5vdc sensors to quit working.

You've got a lot of strange things going on here, and a lot of suspicious blown parts (two fuel injectors, your battery, a stretch of wire, and possible either the ACC or the ECU). It is very unlikely that all of these these would fail at the same time. Automotive components are designed to live through crowbarring the battery and every other 'stupid' thing that people can do to a car.

You can't simply swap out the ECU, unfortunately. You will NEED a consult at that point to register the new ECU to the car (as well as the keys). You might as well do what it takes now to get your hands on a Consult and someone who knows how to use it thoroughly.

merlin3

iTrader: (4)

umm yeah what he said

KPierson

iTrader: (1)

Get back in your hole!!!!!

lol

3 more hours till track time....

617G

iTrader: (6)

Thanks guys...let me explain and paraphrase this as best I can seeing as I'm a thirdy party just trying to relay information.

The battery lost a cell, the fuse blew, and yes, that 12v wire looked like it had too much current running through it. The wire has since been replaced and yes, it was discolored. I've hadd issued with the battery before, but I forgot to replace it during the build, i.e. it has died on me several times (Yes, I know...stupid of me not to replace it). My guess is that it is a snowball effect of the battery going bad. That wire feeds a lot of sensors, and could have caused them to go bad when it "fried." Only two of the injectors has weird readings, so they popped in new ones just in case free of charge atm to illimate that part.

Kpierson, I think you may be on to something...

The shop already performed the APP sensor test and found some odd readings. The output is fine at 5v, but the input is reading 7v...at least that's what I remember being told...It seems like they have been doing a lot of the things that have been mentioned, but I have been relaying this information incorrectly due to my lack of knowledge in the field.

If we had a consult, we could easily find out the issue and have one readily available program the ECU. Does anyone have a consult they could rent my shop???? I'll pay for the overnight shipping and rental fees.

As far as money, I know some of you are concerned that I may be getting ripped off, but fwiw I am not being charged for the troubleshooting. The money situation will be worked out on a personal level later and I am not being billed by the hour. But thank you for looking out.

shushikiary

If the fuse is a slow burn fuse and/or behind any kind of energy holding device such as a capacitor or inductor such as a dc-dc converter or other things that I'm sure are in the ECU, then it is entirely possible to burn the wire before the fuse blows. Especialy if the overall phase delay from the electrical components is greater than the time it takes to overheat the wire, which dependent on the amount of current the short caused and impedance of the wire is entirely possible.


oh you're right about the ECU, i forgot that these cares use the chip in the keys to validate it... darn.... lol I'm so used to dealing with the older ECU on my mx6 as it has tons of electrical problems..

KPierson

iTrader: (1)

The fuse is an automotive 15A fuse. They are fast acting, and at 20.25A the fuse would have lasted 1/2S, not near long enough to heat up a length of wire to the point of melting it.

The ECU typically supplies the (-) side of the circuit, so with a blown fuse most of the circuits wouldn't be complete, so even if there was a VERY large cap it wouldn't be able to discharge. There are no current storage devices on the battery side of the switch.

That being said, it sounds like somehow the wire did pull more current then it is capable of handling, so you'll have some other questions to answer.

Honestly, I wasn't talking about you getting ripped off, I was simply stating that IF the shop did something wrong they might try to cover it up so that they can recoup some time.

I looked at the diagram for the ACC and I was wrong, it has 6 wires (not 4). I didn't realize that they grounded each sensor, and each sensor uses a dedicated supply feed (Makes sense since it is fail safe). Both feed wires should be 5vdc. With the pedal pushed all the way down one sensor should read around 2.25vdc and the other should read about 4.2vdc. If any of these readings are off then that will be a starting point.

617G

iTrader: (6)

I know the pedal has been tested and without going into detail and making myself look like a fool by saying something incorrect, there are def. strage voltage reading on those wires. The question is: is it the APP sensor or the ECU that's causing it?

MIAPLAYA

iTrader: (3)

I wish I could say there was a Consult you could use but at $4000 a piece you are not likely to find one. The UpRev software pack I believe has all the functions of the consult though. Its only a few hundred and maybe worth it to buy in this case.

http://www.uprev.com/products/cipher_NI.html