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Discussion Starter #1
I'm now having a problem (with a '93 240SX) very similar to those mentioned by some here. In my case, as odd as it may sound, the bad part is that the problem sometimes goes away.

The first time it started was a little over a week ago. I got in the car; it started right up and ran fine. The weather had gotten colder and I noticed one of my tires was a bit low so I stopped at a gas station for air. When I tried to leave, the car wouldn't start. The starter motor cranked (and cranked) but the engine wouldn't turn over. I didn't really think it was the problem but I thought maybe it could use a little extra boost -- and as it was one of the only things I could even try at the time -- I got a jump from one of the customers. As expected, it made no difference.

Eventually, having to leave it where it was, I explained to the attendant, packed up some of the car's contents and hit the road. I returned a few hours later to mess around with it and, again, nothing: cranked but didn't turn over. Battery switch, starter, solenoid, etc seemed OK. I figured it either wasn't getting fuel or spark.

I returned the next morning to tow it away. Knowing it wasn't going to start I got in and tried it once again - something one just has to do! As you may've guessed, it started right up without problem. I drove it around that day stopping here and there at different mechanics half hoping it would die again in their lot but it started right up again each time. It did seem to be running a little rough, though.

I don't know how to troubleshoot it without the problem being there consistantly and I assumed if I took it to a garage they'd probably simply replace a few hundred dollars worths of parts and return it to me only to have the same thing reoccur later.

I purchased some fuel injector cleaner which I immediately dumped in and a new fuel filter which I've not yet installed. On the one hand, I feel I should install the fuel filter right away but I read one must change the fuel filter after using fuel injector cleaner.

Q: Should I change it now then put in another later or just wait?

Q: Also, I've been told that this car has two fuel filters. I know of one under the hood on the passenger tower. Is there another and if so, where is it?

Q: Should they both be changed regularly?

If fuel injector cleaner even works, I still haven't run this whole tank through but so far the car's been back to behaving normally. I began to think maybe I just got a bad (watery) tank of gas.

Yesterday, almost forgetting there was any problem, I got into the car to go somewhere but when I tried to start the car, encountered the exact same problem as before: starter cranking away but not turning over the engine. Nothing obvious had changed. We did have a bit of a thaw and had some rain though so I thought maybe wet wires or distributor? I tried to dry off the spark plug and coil wires and popped off the distributor cap but nothing seemed at all damp.

Q: When moisture or oil in the distributor is a problem is it just right under the cap or down inside?

Q: Could spark plug or coil wires be wet enough to cause this sort of problem without appearing at all wet?

In a way I was a little pleased it went down again, but here, where I might be able to do something with it. I got all prepared to work on it this morning but tried to start it again just for the heck of it and, again, it started right up and seems to be running strong.

I've never been a big fan of Russian Roulette and the never knowing if it'll start or not at any particular time could give one an ulcer. I don't know how to troubleshoot it when it's working alright.
Q: What are some other possible suspected causes I might be able to duplicate?

Q: Is it safe to hose down the engine compartment and see if it'll still start up to determine if some wet component is the problem?


I could just put on a new set of wires - they could probably use replacing anyway - and maybe even throw on a new coil but I never really liked the idea of replacing parts helter-skelter (especially at over $40.00 and about $120.00 respectively). I like to know if what I'm doing really addresses the problem.

Q: If the problem is a plugged fuel filter, bad coil or air flow sensor wouldn't the problem be continuous?

With intermittent problems like this that aren't caused by some obvious change (like only after the car has warmed up or only when the temperature drops, etc) I usually automatically suspect electrical problems like loose connections.

Q: Could that be the case here; fuel pump? If so, how can I test or confirm this?

Q: What other causes would follow this on and off again pattern?

Sorry if this is a bit lengthy; I'm only trying to be compehensive. Answers to any of my questions or any other help, suggestions, ideas are all very much appreciated. Thanks in advance for any help.
 

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Sup Mod keeping the peace
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Actionclaw said:
Q: Should I change it now then put in another later or just wait?

Q: Also, I've been told that this car has two fuel filters. I know of one under the hood on the passenger tower. Is there another and if so, where is it?

Q: Should they both be changed regularly?

Q: When moisture or oil in the distributor is a problem is it just right under the cap or down inside?

Q: Could spark plug or coil wires be wet enough to cause this sort of problem without appearing at all wet?

Q: What are some other possible suspected causes I might be able to duplicate?

Q: Is it safe to hose down the engine compartment and see if it'll still start up to determine if some wet component is the problem?

Q: Could that be the case here; fuel pump? If so, how can I test or confirm this?

Q: What other causes would follow this on and off again pattern?
There's no need to replace the fuel filter just because you're running injection cleaner through the system.

Only one fuel filter to replace every 50,000 mi.

If you've got moisture inside the distributor cap, it'll be almost impossible to start the motor.

It's a bad idea to hose down the engine compartment; if water gets into the electrical harness connectors, you'll just be compounding your problems.

When the motor fails to start up, check to see if you have spark or fuel. An easy way to test the fuel pump and filter is to disconnect the fuel hose from the top of the fuel filter and insert a long length of spare hose into the top of the fuel filter with the other end draped over the fender going into a catch can placed on the ground. Now turn the ignition key to the run position but DO NOT START THE ENGINE. You should see fuel going into the can at a good rate.

A good way to check the ignition is to get a spare spark plug; test each ignition wire by unplugging it and plug it into the spare plug then lay the plug on the valve cover; have someone spin the motor while you watch for a spark.
 

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I had a friend whos car would randomly shut off and not start. We routed the problem back to his fuel pump harness. The harness leading directly to the pump would be dirty and provide to weak of a signal to energize the pump. We ended up just cutting and spicing the wires directly together.

The fuel pump is in the trunk. Just pull up the carpeting where the spare tire is. The pump is underneath the sheilding to the right. I would recommend checking the connection.

But other than that, just do what Rogoman said, check the fuel pressure, and check the spark. I hope things work out
 

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Discussion Starter #4
Thanks for your input so far, guys.

An electrical problem of some sort, possibly in connection to the fuel pump was one of the things I suspected. I will look into this further. It's about 10 degrees out there right now and I'm not too anxious to be working on cars. In the meantime...

..does the wiring to the fuel pump run under the car (and possibly damaged) or inside the passenger compartment?

..is there a fuel pump relay and, if so, does my problem sound like it could be a dirty, sticking relay?

Thanks
 

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Actionclaw said:
Thanks for your input so far, guys.

An electrical problem of some sort, possibly in connection to the fuel pump was one of the things I suspected. I will look into this further. It's about 10 degrees out there right now and I'm not too anxious to be working on cars. In the meantime...

..does the wiring to the fuel pump run under the car (and possibly damaged) or inside the passenger compartment?

..is there a fuel pump relay and, if so, does my problem sound like it could be a dirty, sticking relay?

Thanks
if its a hatch like mine, then underneath the trunk carpet, next to the spare, there is a tan cover, with a wire running to it, youll need a philips, and a 10mm socket, then you can get to the fuel pump.
 

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Discussion Starter #6
I've been searching around and found that several others that had reported very similar intermittent starting problems eventually solved them and attributed it to faulty solder connections on the fuel pump relay.

Sounds like a good lead. I'll report back whatever I find later.
 

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Discussion Starter #7
Update: the problem continues

Well, it sounded good but in my case, I no longer think the relay is the problem.

It happened again. Another of the relays is identical (labelled "EGI pump relay" and "EGI") so I swapped them and there was no change.

- I installed a new fuel filter. It needed a new anyway. Slight improvement but the problem continues.

It now seems to be more consistant. It will start and run pretty much OK. Then if you shut it off it won't start back up again. A few hours later or the next day the same thing again.

I read the fuel pump is controlled by both the fuel pump relay and the oil pressure sending unit depending on if the car is just being started or already running. Could it be a bad oil pressure switch?

A mechanic told me the fuel pump itself is the problem. I kind of hope it is since I know how to get to it and replace it but, if it were, why does the fuel pump function alright the first time the car's started and only fail when being restarted?

(I do realize the first and obvious thing to do is check if it's no spark or no fuel but - especially when this happens unexpectedly out on the road alone - it's difficult to be in the car turning the key while under the hood at the same time. I have tried!)

Thanks again for any input.
 

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Actionclaw[INDENT said:
(I do realize the first and obvious thing to do is check if it's no spark or no fuel but - especially when this happens unexpectedly out on the road alone - it's difficult to be in the car turning the key while under the hood at the same time. I have tried!) [/INDENT]
Thanks again for any input.
Just like anything electrical, the fuel pump has a small electrical motor, the motor could be old and worn out causing it to:
A: Overheat and get sticky like a starter does.
B: Could have bad grounds, or something in that department.

If the fuel pump is shot, it just gives you all the more reason to upgrade to a 255lph fuel pump as an upgrade, that will make you one step closer to preparing for a turbo if that is your thing!
 

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Discussion Starter #9
I was just about to replace the fuel pump but it seemed it was working. I tested again and found that I am getting both spark and fuel -- yet it still won't start! I thought maybe I was doing something wrong, pretty much gave up and took it to a shop.

Got a call back today confirming that it is getting both spark and plety of fuel pressure yet it still won't start. He doesn't know what the problem is either; only that it's probably computer related. He doesnt want to just start swapping parts (got to give him credit for this) and suggests the Nissan dealer would be better equipped to test it. I really, really don't want to take it to a dealership if I'm able to avoid it.

Has anyone else experienced anything like this?

Is there more than one electronic control or ignition module? Might it be worth it for me to just replace it?

If not the computer itself what else might make it not function?

Any ideas, anyone?
 

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Tarmac Terrorist
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Actionclaw said:
I was just about to replace the fuel pump but it seemed it was working. I tested again and found that I am getting both spark and fuel -- yet it still won't start! I thought maybe I was doing something wrong, pretty much gave up and took it to a shop.

Got a call back today confirming that it is getting both spark and plety of fuel pressure yet it still won't start. He doesn't know what the problem is either; only that it's probably computer related. He doesnt want to just start swapping parts (got to give him credit for this) and suggests the Nissan dealer would be better equipped to test it. I really, really don't want to take it to a dealership if I'm able to avoid it.

Has anyone else experienced anything like this?

Is there more than one electronic control or ignition module? Might it be worth it for me to just replace it?

If not the computer itself what else might make it not function?

Any ideas, anyone?
If you have checked all relay's and fuses, my suggestion would be to check the ECU, for errors, and then maybe the Electrical relay, it is located on the passenger side behind the armrest in the back seat, have to remove the seat, panel and stuff, that unit may be shorted out in one way or another.
My reason for suggesting checking this is because all rear wiring runs through this unit...Might want to pick up a used one from a donor car just to test em!

Good Luck!
 

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another thing...I believe the previous poster said the solder connections on the relay connectors were bad...meaning the relay is fine...but the electrical "welds" called a solder is what was bad.

In testing my stuff I've noticed bad connections in that very spot.
You should def. should invest in a good wiring diagram, soldering iron, and ohm/voltmeter.
 

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LUCKY SLIDES 2 2/25/06
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Actionclaw said:
I was just about to replace the fuel pump but it seemed it was working. I tested again and found that I am getting both spark and fuel -- yet it still won't start! I thought maybe I was doing something wrong, pretty much gave up and took it to a shop.

Got a call back today confirming that it is getting both spark and plety of fuel pressure yet it still won't start. He doesn't know what the problem is either; only that it's probably computer related. He doesnt want to just start swapping parts (got to give him credit for this) and suggests the Nissan dealer would be better equipped to test it. I really, really don't want to take it to a dealership if I'm able to avoid it.

Has anyone else experienced anything like this?

Is there more than one electronic control or ignition module? Might it be worth it for me to just replace it?

If not the computer itself what else might make it not function?

Any ideas, anyone?
if its getting spark and fuel then the ecu is fine because you are getting all necessary components to start because the only fuel related thing the ECU controls is the injectors and it gets feedback from the timing to know when to fire the injectors. the fuel pump is just connected to the ignition switch and when you turn it to the on position you should hear the fuel pump kick in which is proving you are getting fuel. but i cant really diagnose without seeing this for my self

Don
 

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i have a 92 maxima with a vg30e diffrent moter but i have the exact same problem try puling the fuel pump fuse next time itl start right up then put the ruse back in and itl run fine
 

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Is that a temporary fix or will that have to be done repeatedly?

If you've got spark and fuel...then all you need is suck and squeez...getting air in? Getting the air squeezed? Maybe bent valves? No compression no bang.
 

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Sup Mod keeping the peace
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Actionclaw said:
Is there more than one electronic control or ignition module? Might it be worth it for me to just replace it?

If not the computer itself what else might make it not function?

Any ideas, anyone?
The crank trigger module may be malfunctioning; it's located on the distributor body down below the cap. Try reseating the harness connector. The crank trigger tells the ECU what injector to fire according to piston stroke.

To check the crank trigger:
1 - remove the distributor; the trigger harness connector should remain connected.
2 - disconnect ignition coil harness connector.
3 - turn ignition switch to the RUN position but DO NOT START THE CAR.
4 - rotate the distributor shaft by hand and listen for each fuel injector to make a clicking sound.
 
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