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Mike V.
Mike V., Nissan Technician
Category: Nissan
Satisfied Customers: 25667
Experience:  Nissan factory trained and Certified Subaru Technician.
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2003 Nissan Sentra GXE: Cranks..wont start..starting fluid..spark plug

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2003 Nissan Sentra GXE; Cranks but wont start, seems like no fuel and or no spark. I tried starting fluid with no effect, pulled a spark plug it was clean (changed them only 10k miles ago) and I can confirm it is sparking. Had a couple of hard starts last week after it sat for about 24 hours. No check engine lights or any other performance problems prior to it hard starting last week and not starting now, not sure what I should try next or what it might be.
Greetings Sir or Madam and welcome to JA! I will do my very best to assist you with your problem.
HI there! So you have spark? You are sure of this? Did it fire off on the starting fluid for a few seconds?
Customer: replied 6 years ago.
I cannot guarantee spark beyond a shadow of a doubt, I was inside the car turning the key, had a friend watching the plug, he is rather mechanically challenged to be honest. When I tried the starting fluid I just barley got the slightest bit of a rumble from the engine, and I wasn't able to reproduce that rumble a second time.
Ok, fair enough :)
Is the security light on solid when cranking the engine?
Customer: replied 6 years ago.
I'll have to go check to be sure, but I'm pretty sure all lights go off when cranking the engine, except for the seatbelt and break lights.
Ok, also, while you are out there, just check to make sure the check engine light is coming on when the key is on. No sense making 2 trips!
Customer: replied 6 years ago.
Security light doesn't come on at all, oil/check engine/battery lights come on with the key in the 'run' position and go off when cranking, although this time around it seemed like the oil light was staying on longer than it should (might not be anything, could just be me paying attention to it for once...)
Ok, Couple things, first, sounds to me like a possible fuel pump failure. Need to either check spark, or get more starting fluid into the throttle body. Enough so you can hear it fire for a few seconds.
It sounds to me like you did hear it and that would mean there is spark.
This would pretty much eliminate the crank or cam sensors. Injector pulse and spark is run by these.
Also, it may be flooded. Try cranking andholding it to the floor to clear it.
Customer: replied 6 years ago.
I can hear the fuel pump when the key is in the 'run' position, and I know I did flood it at one point while I was tying to troubleshoot this. I am very confident that it is not fuel related, I am a lot less confident about spark however. So until I get another assistant to help me out lets cover all the bases and troubleshoot as though it didn't. Next thing to test would be crank/cam sensors then?
Well, if it is getting fuel,then it should be getting spark. The cam and crank sensors send the signals to the ecm to fire the coils and the fuel injectors.
Have you had any issues with coolant loss?
Customer: replied 6 years ago.
Can't say that I have, last time I had my oil changed they recommended I have the system flushed out (I didn't at the time for financial reasons), but they didn't say anything specifically about my coolant being low.
do you have a volt meter? We can do some checking for the wiring to the coils, the ecm and the cam and crank sensors.
Customer: replied 6 years ago.
I don't have one, but I can get a hold of one fairly quickly.
Ok, go ahead and let me know when you have it. We will do some wire testing to see if we can pinpoint it.
Customer: replied 6 years ago.
Ok, my apologies for taking so long, have the multimeter now. I'm rather inexperienced with a multimeter, how should I have it set up?
Well, right now, it should be put on a 12 volt scale dc, the black lead will go into a plug that should be labeled com, the red lead goes in the plug that should have a V and possibly the ohm symbol.
Then, take it to the battery, put the black lead on neg and the red lead on positive and make sure it is showing you battery voltage.Turn the dial if it isn't until it reads around 12. volts.
Let me know.
Customer: replied 6 years ago.
Ok, so looking at the DCV section on this multimeter it goes from 200m - (points)2 - 20 - 200 - 500. Should I be setting this to 20 or am I looking at the wrong section all together?
Right section, set it at 20 and you should get 12. something when reading the battery.
Customer: replied 6 years ago.
Ok, reads at 12.46
Ok, now, the black lead is always used for ground. So, for example, if you put the red lead on the battery pos, and the black lead on a bolt on the engine, you should still get a 12.46 reading on the volt meter.
with that in mind, with the key on, you should be able to check the green/white wires going to the coils and show battery voltage on them.
Let me know.
Customer: replied 6 years ago.
All came in ~12.25
OK, now, I have to have you check continuity to ground.
To do this, you need to set the volt meter to ohms. It should be on the dial.Then take the red lead and check the black wire on the coils and put the black lead on a ground.
It should give you some type of number.
We don't want OL or infinate there has to be some type of resistance. Check it and let me know!
Customer: replied 6 years ago.
What setting/range in ohms should I set it to?
There is not typically a setting, just the ohms symbol to set the dial to. Some of them aren't auto, so pick a higher number and go with it. Basically we just need any type of reading. If we get OL that means the ground is not grounded. Any number out of there is good other then over limit.
If you do see OL, try all settings.
Customer: replied 6 years ago.
On the lowest setting I got 0.6-0.7 on all of them, on anything higher it either read 0.00 or "i" (I'm assuming for infinite).
Sorry, those are the black/yellow wires you are testing?
Customer: replied 6 years ago.
Yes, center wire in the connector.
Ok,. Good, it sounds like there is continuity to ground.
Next step is to ohm the signal wires since we don't have a scope to see if they are getting signal from the ecm.
To do this, you will have to open the ecm case.
The ecm is in the firewall on the passenger side of the car.Unbolt it and pull it out, then open the case.
Here is a diagram of what the harness will look like when you unplug it from the ecm.
I have highlighted the pins that run the coils.
Coil #1 you want to check the brown wire and pin #62
Coil#2 is the Purple wire and pin #82
Coil #3 is the Blue/white wire and pin #61
and coil #4 is the gray/red wire and pin #80
same deal, we just need some resistance.


Customer: replied 6 years ago.
Pins all come back with numbers, couldn't fit the tip of the tester into the harness to check the wires...
Ok, we aren't checking the pins, we have to check the wires. Get a sewing needle and push it into the wiring harness on the back of the connector, then retry the test.
I use quilting pins for this, but most folks don't have them laying around.
Customer: replied 6 years ago.
I'm having a hell of a time getting anything out of this harness, I managed to get something out of numbers 80,81,61, but not 62, however I think this is because I can't get good contact with it...
Ok, fair enough, plus if it wasn't firing one coil, you would still run.
Seems all is good for the coils to fire.
As long as it is out, check pins #119 and #120 for power with the key on and let me know.
Customer: replied 6 years ago.
The diagram you linked only goes to #81?
Sorry!! This is the smaller section of the ecm harness!
Remember, key on for this one.
Looking for voltage again set the dial to 20 dc
Customer: replied 6 years ago.
There appears to be no contact in #119 for anything... Of these I was only able to get a reading on #116.
119 and 120 are both red wires with green stripes. They both need to show power. they are the power supply for the ecm.
You are checking the wires, not the ecm. These tests are to be done on the wire side of the harness and not the ecm itself.
Customer: replied 6 years ago.
I can't see the wires, they're all bundled and taped up. Here's a pic of my harness, tested all of these, the only one that has power is #116[email protected]/5547624492/
You are going to have to open it up just enough to see the wire colors.
It's important, if you have no pwer to the red/green striped wires, we have probably found the problem.
Just open it enough to see if those pins line up with the correct wires., If not then something is amiss here for sure.
Good pic btw!
Customer: replied 6 years ago.
I don't have the right socket to pull it off the firewall, my buddy is going to bring over his more complete set - he'll be here in like 20-30 minutes. In the mean time I pulled back the tape a little, I can see that there are actually 3 red/green wires, I can see one goes to #115, can't see where the other two go.
Ok, those other 2 are the ones we are after.
I can wait until you get things apart to be sure and we will go from there.
Let me know when you are ready, I'll be here!
Customer: replied 6 years ago.
Pulling it off the firewall doesn't help any, still can't tell where the wires go, but the #116 is still the only one with power.
Just to be sure here, you have the ecm out of the firewall and the case opened correct?

Customer: replied 6 years ago.
I didn't open the case, going to do that now. I'll also note that when the harness is disconnected the check engine light doesn't come on when the key is in the 'on' position, which implies power even if I'm not getting it so far...
Well, I am not sure what you have unplugged at the moment,but you need to open the case to unplug the ecm. Hence the reason you aren't getting any power. I need you to plug whatever you have unplugged back in and then disconnect right at the ecm.
Then check your pins.
then let me know!
Customer: replied 6 years ago.
The small wiring harness was all that I had disconnected, I have the whole ecm out right now but I can't get the case open, is there a trick to it?
Just remove the ten mm bolts and it should open. Should be a plastic case with the wires going into it. It is sealed so it might seem tight, but if the bolts are out, it will open.
Then you should see the actual ecm, steel box with the 2 harnesses going to it.
This will get us back on track.
Customer: replied 6 years ago.
Thats exactly where I'm at, except no plastic, all steel/aluminum, and no bare wires, the harnesses go straight into the steel box.
Ok, this is what you see right now?
Customer: replied 6 years ago.
Yea, got it right here :)
Ok, lets check the pins 119 and 120 on that and see if there is power.
also, on the bigger plug, recheck continuity on the signal wires.
let me know!
Customer: replied 6 years ago.
According to the numbers on my ecm pins 119 and 120 are registering 0.2-0.3 (before they were at 0), and #121 is the one getting power. which wires did you want me to check on the large connector?
Ok, this is with the key on? Don't worry about the big connector yet. If you only have that many volts with the key on, we are finding the problem.
Customer: replied 6 years ago.
Yes, key was on.
ok, you are going to love this, remove the glove box and locate the ecm relay.
It has 2 white/blue wires going to it. Check them for power.
Should have battery voltage with the key on.
let me know!
Customer: replied 6 years ago.
both wires tested good, ~12.30 on both
Ok, stupid question but was the harness you previously had disconnected,reconnected before you checked for power at the pins?
Customer: replied 6 years ago.
No, it was still disconnected, should I have reconnected it?
Yes, plug it back in, plus,I think you need to back probe the wires at 119 and 120. The ecm is suppose to ground the relay and give you power on those wires.
Customer: replied 6 years ago.
What do you mean by back probe 119 and 120?
I mean plug the connector back into the ecm, the come in from the wire side to check for your power.
if ecm pin #111 doesn't send a signal to ground the relay, then you won't see any power on the pins.
Customer: replied 6 years ago.
Ok, with everything connected we have power on 119 and 120, as well as the relay wires.
Ok,l sorry I got lost there for a bit.
forgot about the connection.
Ok, the ecm is powering up so thi is good. Can you recheck for spark at the coils yet? Do you have an assistant that can crank while you look for spark?
Customer: replied 6 years ago.
Yes, and will do
Thanks, XXXXX XXXXX know,it looks like it should have spark based on the wiring.
Customer: replied 6 years ago.
It does indeed have spark
Ok, this is good, so try some starting fluid and see if it pops off for you. It won't run, but it should at least fire for a few seconds.
Let me know!
Customer: replied 6 years ago.
Absolutely nothing....
Odd as heck!
Ok, try unplugging the mass air flow sensor. Then try starting the car holding your foot to the floor. Crank it for about 30 seconds and then stop, then repeat, see if we get some life out of this thing!
let me know!!
Customer: replied 6 years ago.
Got the faintest bit of a rumble 2 or 3 times, first signs of life I've seen out of this thing since last Wednesday!
Ok, I think it is flooded, probably from all the trying to start.
Need to remove the fuel pump fuse and continue onward trying to start it.
When it starts to start, you won't be able to accelerate with the maf unplugged. It will or should idle on it's own however.
We get this thing idling, then shut it off and put the fuel pump fuse back in and plug the maf back in.
We are almost there I am sure.

Customer: replied 6 years ago.
No go, still the most I can get is a rather pathetic mumble from the engine while cranking, and it's not improving.
Ok, lets plug the maf back in then and see. Keep the fuel pump fuse out still though.
Customer: replied 6 years ago.
Ok, will do.
Worth a try...
Customer: replied 6 years ago.
No change
WEll, ok, I think the only choice is to get a check on the fuel pressure. It seems to have injector pulse and spark. If there isn't enough pressure, it might be the problem.
You could try it again with the fuel pump fuse in, maybe if it was flooded it is cleared out now.
If not, I really think the fuel pump pressure has to be the next step.
Customer: replied 6 years ago.
Ok, fought it's way to life with the fuse in, now I have a check engine light, I'm gonna take it somewhere to pull the code(s).
Great news!!!!!!
and please, let me know the codes for sure.
Customer: replied 6 years ago.
Will do, I'll be back in a bit.
I should be here, if not, reply, I will get it. Have to break for dinner at some point!
Customer: replied 6 years ago.
Two codes, P0113 IAT sensor circuit high input, open or short circuit condition, faulty IAT sensor.

P0550, Power Steering pressure (PSP) sensor circuit, Open or short circuit condition, Faulty PSP sensor.

Also the car was running way quieter than normal, other than that the car seemed to run normally, granted it was a very short trip.
Ok, the IAT sensor is part of the mass air flow sensor.
It sort of makes sense because if it is reading the wrong intake air temp, then it will change the fuel mixture.This code however might be there from running the car without the maf sensor plugged in. I would clear it and see if it comes back.
If it does, then you will have to replace the mass air flow sensor.
The PSP sensor is on the power steering high pressure hose. Make sure it didn't get bumped off when doing all the things with the computer today.
Glad to hear the car seemed good.
Customer: replied 6 years ago.
Can't find the PSP... Would the MAF being bad cause my car to run quieter than normal?
No, it wouldn't run quieter, but if the air box wasn't on tight or the hose to the throttle body, it would be louder.

Customer: replied 6 years ago.
I'm going to wait till the engine cools down before I reach my arm back there to check that one. I'm going to wait till tomorrow to take the car back to get the codes cleared, I will update you tomorrow afterwards if you're interested. I appreciate all of your help time and patience, you've been awesome!
I would like to know what happens of course! You can post even after you accept, I'll be here!
Mike V. and 3 other Nissan Specialists are ready to help you
Customer: replied 6 years ago.
Cool, I'll let you know what happens then! See ya later!
sounds good!