94 XE wont start

Bullitt · Jan 27th, 2006, 05:36 PM

Ok, i have done a ton of searching, what happened is gas mileage was suffering, so i got instructions on some basic stuff. When I went to reground the MAF, my helper misread the wiring diagram, and the power wire (orange one in the middle i think) was grounded to one of the two bolts on the passenger side of the intake plenum. I have checked several things, and am about out of options. The MAF sensor wire inside isnt broken, i have spark, havent checked injectors (checking tomorrow morning) but i have fuel at the top of the filter, computer is a code 55...all fuses check out OK...everything else on the car works. When i turn the key, all it does is spin over. Any help is greatly appreciated, this is my DD.

nastynissan · Jan 27th, 2006, 10:27 PM

Quote:

Originally Posted by Bullitt

Ok, i have done a ton of searching, what happened is gas mileage was suffering, so i got instructions on some basic stuff. When I went to reground the MAF, my helper misread the wiring diagram, and the power wire (orange one in the middle i think) was grounded to one of the two bolts on the passenger side of the intake plenum. I have checked several things, and am about out of options. The MAF sensor wire inside isnt broken, i have spark, havent checked injectors (checking tomorrow morning) but i have fuel at the top of the filter, computer is a code 55...all fuses check out OK...everything else on the car works. When i turn the key, all it does is spin over. Any help is greatly appreciated, this is my DD.

Im thinking you have probably FRIED your Maf.. If youve got spark then at least weve got somewhere to start. The CPS (Cam Position Sensor) signal tells the ECM when to fire the injectors as well as the Coil. So the fact that youve got spark means the Dist, Coil, Ign Module, and "Probably" ECM are good. Do the injector test tomorrow... One of the injector leads should have 12v+ whenever the key is on. I dont remember which offhand, check the FSM or a Haynes/Chiltons. Or get a Noid light and plug it into one of the injector connectors. If it pulses while turning over the engine then your good to go.

You could go ahead and do a compression test...... But if it was running before then I DOUBT sincerly thats the isssue. You probably just fried the Maf. I'll try to find testing "Specs" for you.

BTW*****I meant to reply to your other post but lost IP Service for a couple days.****

Bullitt · Jan 27th, 2006, 10:47 PM

thanks man, thats what i needed to know. so the only way to tell if the MAF is fried is to switch it out with one, or is there an electrical test i can do? BTW i figured i might be able to get more response in the GA16 section. Thanks for your help

nastynissan · Jan 28th, 2006, 05:16 PM

Quote:

Originally Posted by Bullitt

thanks man, thats what i needed to know. so the only way to tell if the MAF is fried is to switch it out with one, or is there an electrical test i can do? BTW i figured i might be able to get more response in the GA16 section. Thanks for your help

There is a test you can do... I meant to get that info for you last night but....

..... And thats the rest of the story....

Let me do some research and I'll get back to you...

PM me with your e-mail so I can send you the info. Ive got. Tis in PDF form and is a B!#%H to get online.

GA16DE200sx · Jan 30th, 2006, 06:29 PM

There is no way you can fry the MAF if you take the power wire away from it and ground it you would blow a fuse.

Bullitt · Jan 30th, 2006, 08:52 PM

The only thing that i have come across is that my injectors arent getting power, which also makes me think that it was a fuse, but i cant find one at all that is blown, or for that circuit.

GA16DE200sx · Jan 30th, 2006, 10:43 PM

Find a wiring diagram for the circuit and find out where the injectors are getting power from. If the B+ for the MAF was grounded the a fuse had to have blown. Unless it uses a fusible link, which I'm not sure about but I'll have an answer tomorrow when I can get to school and use MotorAlldata.

GA16DE200sx · Jan 31st, 2006, 09:54 AM

I need to know the exact color of the wire that was grounded. was it Orange/yellow or orange/lavender? Where did you unhook it? Also how did you test the injectors? Take a paper clip and back probe the injector B+ and then take a test light and touch the paper clip and it should blink.

Bullitt · Jan 31st, 2006, 10:46 AM

i cant remember the exact color, im looking at the FSm for the self diagnostic on the Air Flow Meter, it labels the wire as OR, same as the first wire, but it is the third from the left, which appears to go into the ECCS relay, i tested the relay by switching it with the fuel pump relay, and it seems to work fine, it engages(audible and i can feel it click). from the relay, there is no more OR wire, a W/G wire runs to connection 4 in the ECCS control unit, or 2 white wires run from the relay to (on the diagram F34 -> M36) the main harness. From there to the SMJ, then to the fuseable link and fuse box. Runs through a BR (im not an electrician...) breaker i assume, then ultimately from the battery. I have about 30 pages from the FSM printed off, and just cant line up anything.

GA16DE200sx · Jan 31st, 2006, 05:02 PM

BR means for brazilian models. The injectors get their power from a fusible link. It's the same fusible link that gives power to the MAF sensor. I'd say find the fusible link and see if it melted.

Twiz · Jan 31st, 2006, 05:42 PM

I'm sure OR stands for orange and BR for brown not brazilian lol. Here's a quick test you can run with a voltmeter.

Bullitt · Jan 31st, 2006, 05:49 PM

well the engine wont start, so i cant test the idle voltage, plus i dont have a voltmeter, but i do have power on the orange and blue wire, which is the one i spliced the new ground into. and the "BR" is the "flowpath" if you will through the engine bay fuse box and fusible link box, but unless it is hard to tell if one is bad, they all look the same

Twiz · Jan 31st, 2006, 05:55 PM

Quote:

Originally Posted by Bullitt

well the engine wont start, so i cant test the idle voltage, plus i dont have a voltmeter, but i do have power on the orange and blue wire, which is the one i spliced the new ground into. and the "BR" is the "flowpath" if you will through the engine bay fuse box and fusible link box, but unless it is hard to tell if one is bad, they all look the same

Set the ignition to ON and test if you have battery voltage on that ORANGE/BLUE wire. Why would you ground the power supply to the sensor? Anyways if it's got battery voltage then it's good enough. Your car SHOULD be able to start with the MAF electrical plug disconnected however the ECU will set an error code.

Bullitt · Jan 31st, 2006, 06:10 PM

i had an extra hand out there who...supposedly...knew how to read a wiring diagram, need i say more. so the original power wire still had power, while being grounded, tried to start the car, and it wouldnt. The body of the car shocked me worse than normal when i got out, so needless to say i took the new ground off...then tested the voltage on that wire, and it had power.

GA16DE200sx · Jan 31st, 2006, 09:38 PM

Quote:

Originally Posted by Twiz

I'm sure OR stands for orange and BR for brown not brazilian lol. Here's a quick test you can run with a voltmeter.

Have you even seen the wiring diagram for the circuit? I have the nissan diagram in my hand right now. The brazilian models get source voltage for the injectors from the ignition switch while the non brazilian models get it from the fusible link. Besides there is no brown wire on the MAF.