robsterzallan`

I drove my car up on ramps, shut it off, and took the whole exhaust system out besides the manifold and O2 sensor. I welded a new exhaust out of 4 inch piping, away from the car, not under it, and put it all in. When i went to drive the car off the ramps, it wouldent start. So i messed around for a bit trying to figure it out and what not. First, the fuel pump wouldent start up when you turn the key on, then i checked for spark, none, so i checked the coil, and it was bad, so i replaced it. still had all the problems, so i turned to the computer, but the computer lights dont even turn on when i turn the key on. So i have no idea what the deal is. Bad computer? but i dont know what could of happened to it? i recently chiped the IAT sensor, but that couldent hurt the computer could it? any help would be great. Thanks!

BenStoked

iTrader: (7)

have you checked your fuses, yet?

robsterzallan`

yea all fuses are good,

shiloh51933

iTrader: (5)

Did you go threw everything that you disconnected first to see if you forgot something. If the car drove up the ramps then it's obviously something you did. Check all your sensors.

BenStoked

iTrader: (7)

okay, lets start from the beginning:
remove the "chip"

you turn the key; does the engine turn over, or not?
fuel pump wasn't humming; did you fix that, or is it still not starting?
no spark; how did you test the coil?
computer; did you verify you put it in diagnostic mode first?

Matt93SE

iTrader: (44)

http://www.youtube.com/watch?v=G-tCIRJH9p0

Greeny

iTrader: (43)

robsterzallan`

Only thing i did was took the O2 sensor out, and it tested good.

robsterzallan`

Yes the motor turns over with and without the chip, and it was running fine with the chip before the exhaust job. I cant figure out whats wrong with the fuel pump, i tested resistance on the coil, and when you turn the key on the computer lights should light up anyways, but yes no matter what you do the computer lights dont even turn on.

BenStoked

iTrader: (7)

went, double checked, you are right.
I am still suspect of a blown fuse; does anything else not work?

robsterzallan`

Um on the turning directional lever, you spin the end once for gauge lights and parking lights, and then 2 clicks for headlights. The gauge lights and parking lights dont turn on on the first click, but the head lights work on the second click, but thats about it, other then the fuel pump and computer, but i tested for the power to the coil, and when you turn the key on the coil gets power, but dont send out spark. What fuses should i check? Ill double check tomarrow. All inside and all under the hood, i dont know of any others.

Greeny

iTrader: (43)

Check the big fusible links in the black box under the hood....

1-6.... look at the silver strip inside the top window of the fuse..replace the one thats broken.

robsterzallan`

Yea i know that, ill check now.

robsterzallan`

Nope all fuses are good. I have no idea other then the ECU. what do you think?

robsterzallan`

Anyonee have any other ideas?

chrome91

iTrader: (1)

are all of your grounds good?

ColombianMax

iTrader: (7)

have you tried getting rid of the 4 inch exhaust and installed the stock size yet?

So let me get this straight.

-Battery is fully charged?
-Engine does crank but does not start?
-Does it put put or make a sputter sound as it "attempts" to start like a backfire?
-Have you checked the ignition cables to make sure they're all connected at the distributor as well as on the coil?
-When engine turns over, does it crank REAL fast compared to before?

LvR

You totally honest when saying you never welded on the car itself?

Seen many a fried ECU as a result of bad welding practices................

1991Maxima1991

iTrader: (3)

^^^ Yup welding on the car WHILE the Battery is hooked up could verywell result in a fried ecu, from what ive experianced it will ruin the alternator aswell....im just wondering about the 4" exhaust???? y 4 inches rly? 3 is for turbo's wdf is 4 for? Anyway i would put it back to the way it was before you tinkerd with it and see what happons...Still think ur ecu is toast tho..

LvR

The exhaust is not the problem ............... you can remove the whole thing and the motor must still start and run.

robsterzallan`

Yes, i redid all of them when i had the other problems with it

robsterzallan`

Fully charged.
It cranks but dont start
No, just turns over like theres nothing there.
Yes everything is tested and good.
Nope turns over regular.

and why would i putt the other exhaust on?

robsterzallan`

i swear on my life i dident weld on the car, im not the dumb. and is all but welds, theres no way its even posible under the car

robsterzallan`

Just made sure i wouldent have any back pressure

robsterzallan`

Yupp ive had the car running before with no exhaust, or O2 sensor.

shiloh51933

iTrader: (5)

Just doesn't make any sense, car was running, you drove up ramps and now no start. I would check junk yards for ECU, you can find used ones for cheap sometimes and install that one to see if you ride will start up. It sound like that is where your problem is coming from if everything checks out like you say. Even if you didn't fry it by welding, it still might have overloaded with all the mods your trying to run on her and fried ECU. I would look there, it can't hurt.

maxmaxima91

No restriction here.... haha... At the time i could do 4 inch cheaper than 3.5..

robsterzallan`

Haha, yea you bought yours for your car, i just bought the pipe and welded it together, then just put two 90 degree bends in it and ran it strait back and took the sway bar out.

robsterzallan`

Thats what im thinkin, but if thats the problem as soon as i plug in the new one that will be junk also?

ColombianMax

iTrader: (7)

So we've narrowed it down to there being AIR, and FUEL, just simply no SPARK... is that correct?

khemraj1999

iTrader: (2)

the ECU lights should turn on when you put the ignition on..

sounds like a fried ECU? ..no crank signal receiving..no spark?

shiloh51933

iTrader: (5)

Your not gonna fry another ECU, you fried it during whatever you were doing. Make sure all fuses/relays are good, disconnect your battery terminals and cover them with something that can't pass electrical current and install used ECU. There cheap enough used at most junk yards, if you've checked everything else like you said then your ECU is DEAD. Just try it, if it don't work or let's say you do fry it, then bring back to wreck yard and tell them it don't work. Good wrenching.

chrome91

iTrader: (1)

yep just get a JY ECU, the junkyard here will let you bring anything back but you just get credit

khemraj1999

iTrader: (2)

+1 does he have to match any numbers on the ECU? or just any 3rd gen works?

chrome91

iTrader: (1)

i would imagine is its from the same engine/tranny its fine. i dont even think the tranny matters because some people with turbo VG's use the Z31 turbo ECU, and Z31 of course have VG30E but a different tranny

maxmaxima91

No no.. made with my two hands

1991Maxima1991

iTrader: (3)

Your exhaust looks very nice and it tucks up under there well, i also like your crossmember up front did you make that your self? looks nice and tough...

maxmaxima91

Thanks.. yea i made everything myself. it double as a down pipe/flex guard/speed bump destroyer.. its 1/2 inch solid steel and wins against everything it hits. Sorry robster... i didnt mean to thread jack.

ColombianMax

iTrader: (7)

I believe the ECU is year specific... I remember I once thought my ECU was bad on my 93GXE and I did some research and only a certain ECU was compatible. Make sure you do your research before spending money or wait til' someone else chips in with more info...

sup_mario

Are you sure that fuses are still good?