Car woes (2002 Nissan Sentra)

nightcrawler335 · June 2008

Okay, I'm just trying to find some help with this problem so I figured I'd post here and hope for the best. Two nights ago I was getting ready to leave my apartment when my car died. I had just backed out of my parking spot and started to drive when the engine died. As of now, the car doesn't start. It's a 2002 Sentra with a manual transmission.

Here are the dirty details. The engine turns over but does not start. I haven't had any problems with this car until now, and I bought it about 3 and a half years ago, so it isn't something from a pre-existing problem. From the research I've done and people I've talked to, it seems that the fuel pump is a likely candidate for the problem, or possibly the fuel pump relay. Can anyone tell me how I can verify if this is the problem and how easy/expensive it would be to fix? I've heard that there is an access panel to the fuel pump that you can get to by removing the rear seat, which is supposedly very easy to do. I would prefer not to take it to a mechanic because it would cost me ~ $400 to get the fuel pump replaced at one. So, does anyone have any info/advice that would be helpful to me, someone who knows very very little about how to fix a car?

Thanks in advance for your help guys!

RUNN1NGMAN · June 2008

Might be something in the fuel system, but not necessarily the fuel pump. Could be a clogged fuel line. Could be something completely unrelated to the fuel system, like your distributor. Unless your fuel pump just up and died (which would be pretty rare in a 2002 car) you would have noticed a problem in your fuel system.

Unless you're a technician, you verify the problem by taking the car to one. Paying to fix it once is usually less costly than paying to fix the wrong problem 2-3 times before you find the right one.

Gonmun · June 2008

Well, the problem with a mechanic is that you would either need them to come to where the car is, or get the car towed to where a mechanic is, both of which costs money depending on who you know, etc. Most times you can get a mechanic to look at it for a small fee or nothing at all if it's just a matter of them hooking up their computer and reading the sensor report to find out. With all my car troubles though engine or fuel pump wise I'd always take it to a mechanic, especially since it very well could be an issue with the lines as well or any other number of things to do with the fuel system.

Aurin · June 2008

nightcrawler335 wrote: »

Okay, I'm just trying to find some help with this problem so I figured I'd post here and hope for the best. Two nights ago I was getting ready to leave my apartment when my car died. I had just backed out of my parking spot and started to drive when the engine died. As of now, the car doesn't start. It's a 2002 Sentra with a manual transmission.

Here are the dirty details. The engine turns over but does not start. I haven't had any problems with this car until now, and I bought it about 3 and a half years ago, so it isn't something from a pre-existing problem. From the research I've done and people I've talked to, it seems that the fuel pump is a likely candidate for the problem, or possibly the fuel pump relay. Can anyone tell me how I can verify if this is the problem and how easy/expensive it would be to fix? I've heard that there is an access panel to the fuel pump that you can get to by removing the rear seat, which is supposedly very easy to do. I would prefer not to take it to a mechanic because it would cost me ~ $400 to get the fuel pump replaced at one. So, does anyone have any info/advice that would be helpful to me, someone who knows very very little about how to fix a car?

Thanks in advance for your help guys!

Go to your local auto parts store and get a Haynes or Chilton's manual. There's your start. Usually those books also have basic troubleshooting sections, and they'll show you how to take things apart. Before you go ordering parts, make sure that you have the proper tools and understanding of how to swap things. Fuel very flammable, etc.

Sometimes, depending on what the problem is, and just how hard it is to get to (or how much the tools cost!)... it's easier and cheaper to just go to a mechanic. Either way, if you get a mechanic to diagnose the issue and tell you exactly what it is... and you don't agree with the price, you can shop around, though I'd imagine the tow bill would get irritating.

Good luck!

Also, for easy troubleshooting online:

Have you ever done any maintenance on the car? Tune-ups, oil changes, etc?

1ddqd · June 2008

Your fuel pump will probably be mounted inside the fuel tank (mine was, 2003 Chevy Cavalier) - they do this to keep the pump cool when fuel is in the tank. If you make a habit of driving the car with less than 1/4 of a tank, I've been told this can burn out the pump sooner.

My situation was very similar; it would die at speed on the highway, or simply just click like crazy when I tried to turn it on. Fuel pump + labor + lifetime warranty was $900.

Good luck, oh, and +1 to the Haynes manual idea.

nightcrawler335 · June 2008

Thanks for the advice so far.

I could have it towed to a mechanic for free because I do have a AAA membership which includes towing, but this would just be a huge hassle for what it's worth at present time. I hear that I can essentially "borrow" an OBD II tool from Auto Zone or a similar place for free with a security deposit on it. Now, I did talk to my mechanic that I goto from my hometown, and he told me that this tool wouldn't get to the root of the problem, and that I would need to get a test light to check if the fuel pump is getting any power. If it is, he said it's going to be the fuel pump itself, and if not then it'd be the fuel pump relay or maybe something else. He also told me that with my car, the fuel pump is accessible right underneath the rear seats, which is probably why the local auto shop I called for a price estimate told me that there wasn't much labor involved. My mechanic, knowing how little I know about fixing a car, told me that this job is something that could be tackled by me with the help of a friend who is mechanically inclined. However, I am still looking for opinions on what else could possibly be wrong. I would rather figure it out with the help of others than pay an over-priced mechanic to do it.

I have managed to find a copy of the repair manual for my car online, which will be handy if I figure out what the problem is and decide I can tackle it without going to a mechanic.

Also, Aurin, I haven't done any maintenance first-hand on the car, but I have had routine oil changes done as well as tune/check-ups before long trips and winterizing before the winter hits.

Aurin · June 2008

Yeah, the OBD II tools are mainly for just giving you a good point of reference. If you've got a 'Service Engine Soon' type light on, then the tool will tell you what generally is causing the light to come on. If you don't, then there's no point in trying it.

Also, if your mechanic really thinks it's the fuel pump, I guess that'd be a good place to start. Can you remove the pump and take it to him to check it out?

And the tune-ups mean that it's probably not the distributor/electrical things, since they should be changing the spark plugs/wires during the tune-up. Most newer cars don't have a distributor anymore, IIRC.

But, seeing as how you were able to move the car, then it probably is a fuel-pump or relay related issue. Your best bet would be to go with the cheapest part first, and see if it fixes your problem.

nightcrawler335 · June 2008

Aurin wrote: »

Yeah, the OBD II tools are mainly for just giving you a good point of reference. If you've got a 'Service Engine Soon' type light on, then the tool will tell you what generally is causing the light to come on. If you don't, then there's no point in trying it.

Also, if your mechanic really thinks it's the fuel pump, I guess that'd be a good place to start. Can you remove the pump and take it to him to check it out?

And the tune-ups mean that it's probably not the distributor/electrical things, since they should be changing the spark plugs/wires during the tune-up. Most newer cars don't have a distributor anymore, IIRC.

But, seeing as how you were able to move the car, then it probably is a fuel-pump or relay related issue. Your best bet would be to go with the cheapest part first, and see if it fixes your problem.

I live 1100 miles away from the city my mechanic is in, so that's not really an option. I'm only in this city until September, which is why I don't have a mechanic down here. I explained to him over the phone what happened, and he agreed that the fuel pump or relay is a likely candidate, and told me that using a test light will point out to me if it's the pump itself or the relay. He also said that switching out the pump isn't extremely difficult or anything, but you just have to be sure to remember to put everything back in the same way so as to not cause a leak or anything. I think as of right now I'm probably going to pick up the circuit tester tool from an auto parts store as well as borrowing the OBD II tool, because I would imagine the OBD II tool would tell me if it's a problem related to the fuel pump, or at least something to that effect.

fuelish · July 2008

Before you pull the pump you should jack a fuel pressure guage in to the fuel rail and see what the numbers are. There is ususally a schader style fitting to hook the tool into. A manual will have the right numbers. For a real backyard test you can spin the motor over for a few seconds and then pop the valve to see if there is any pressure in the rail. This will let you know if there is zero pressure. Be sure to protect your eyes and don't do it with a lit cigarette dangling.
Then you still want to check some other(cheaper) things: Fuse, bad line, clogged filter, bad pressure regulator before you pull the pump. Even once all those are eliminated it could be something as simple as a feed line to the pump, inside the tank, has come loose. I had that happen on a Jeep one time, that was a fun to find.
There are also a bunch of other things that will cause your problem. Jumped timing(cambelt slipped), ignition issues(Bad coil wire, blown ignition fuse, failed cap/rotor.

In conclusion, you need three things for the motor to run: fuel, ignition, compression. You need to be able to check all of these and from there you can figure out the exact issue. Don't just leap to the fuel pump(probably the biggest bitch of any to repair just because the pump is hard to get to)

1ddqd · July 2008

If you're getting a noise when you turn the key, it's trying to turn over. Scratch (temporarily) ignition issues. Most likely, unless there was a huge asplosion, I doubt you have a compression issue. Primarily, it will be a fuel pump issue.

Also, check your fuses. Just to be sure

Some cold start troubleshooting info

Donovan Puppyfucker · July 2008

Did the engine die instantly, or did it cough and splutter before it went down? Basically did it behave like you had run out of gas in the tank, or like you had switched the key off? Because if it just went from running to dead like you hit the key, it's more than likely not a fuel problem. If you pull the sparkplug leads off and the plugs out, you can check for a spark in each cylinder by putting the plugs back in the ends of leads and one at a time, holding the insulated part of the lead, gently hold the metal side of the plug against a metal part of the engine and winding the motor over with the key. if you have a spark at the plug, then your ignition is probably o.k. The timing could be out for some reason, but to check that you'll need a timing light and a manual.
If you're getting a noise when you're turning the key, that has nothing to do with the ignition, that's the starter solenoid clicking, which is totally separate from the ignition circuit.

fuelish · July 2008

Ignition has nothing to do with the motor turning over. It will even turn over faster with no ignition.
If you have enough juice in the battery and the starter works, you can spin the motor over like a madman. Ignition is the actual firing of the plugs via the coil and distributor at the proper moment before TDC in order that the fuel will be ignited causing rapid heating of the air in the cylinder and its following expansion, pushing the piston back down and on and on.

The motor spins when you turn the key. Next you need to ignition(including timing), compression, fuel.

So first you could buy a cheap ignition testor, which will replace one of the blugs in the boot and have a lead off of it to make grounding easier. Then you spin the motor over to see if it arcs the gap. Next I would check for fuel pressure because it is easy, if you have the guage. Then I would do a compression check, also easy if you have the right guage. If the compression was off I would line up the cam timing marks to make sure it had not jumped time. After that it starts gettting more complicated.

Donovan Puppyfucker · July 2008

You sound like quite an experienced and knowledgeable guy fuelish! I'm not sure if nightcrawler has pressure test gauges though...

fuelish · July 2008

chrishallett83 wrote: »

You sound like quite an experienced and knowledgeable guy fuelish! I'm not sure if nightcrawler has pressure test gauges though...

Probably true. But if you want to fix stuff yourself you need some tools. I beleive you can pick up a fuel pressure guage from the local parts store pretty cheap. It is barely more than a schrader guage. Some tools like a OBDII scanner, they will let you borrow(Altho I don't remember him saying the check engine light came on)
There are so many things that can cause the problem he has(out of gas, bad crank sensor, fuel pump, blown fuse, etc) that investing in a few daignostic tools is a far more economical strategy than the aproach of shotgun parts replacement.
I used to be a commercial equipment mechanic(retired from that, now I fix bikes.

), and I really enjoy trying to figure solutions to the tech problems posted.

nightcrawler335 · July 2008

First off, thanks a ton for all of the helpful advice, you guys rock!

Now, on to business. Here are some more details. When I went to work on the car yesterday, when we pushed it into an area with enough space, I decided to try and start it for the hell of it, and it started. I immediately fueled up because I was a little under a quarter of a tank (I had 1.5 gallons at least in the tank) and had no issues after that between yesterday and this evening. It got me around last night, to work today, to/from lunch, but decided to not start again when I went to leave for the evening. The problem is that the fuel pump is not priming up when I turn the car on. I do not hear it kick on. So, in light of that, a buddy of mine from work and I took a stab at doing some diagnosing tonight. Luckily, with my car, the access to the fuel pump is underneath the back seat, which is relatively easy to get to. So we took the seat out, pulled the power from the fuel pump, and probed it with a test light but did not see it light up once on any pins. However, when we plugged it back into the fuel pump and turned the car on, it primed up and the car started. This is when we were stupid and turned the car back off, and as you can imagine, it didn't start again after that.

In short, here is what we checked out today:
Battery
Every fuse and every relay (all checked out okay)
We checked all of the fuses and relays because when we started we didn't have the manual so we just checked all to be safe, and there weren't any issues with any of them.

What happens:
When the fuel pump primes up, the car starts with no trouble. However, it doesn't prime up at the moment.

Fuses/relays can be checked off the list, so the problem is somewhere else. I do not have any of the specified tools/gauges, but can always pick them up from Auto Zone if they aren't too pricey. My friend thinks that it might be the ignition coil going bad, does this seem likely? What is the next step that is relatively easy to do in a parking lot where I do not have access to a wide variety of tools, and what tools will I need to purchase to do that?

Sorry for the long post, and thanks again for all of the help.

fuelish · July 2008

When you key to "run" the pump works sometimes. Also sometimes when the line is at full pressure you will not hear the pump prime up. It should hold pressure for at least a short time after shutting the motor off.. This indicates that the pump is probably not the problem. More likely there is an intermitent electrical issue(Which is a real pain in the ass). It could also be a regulator issue if it has one that cuts the pump when it hits max pressure. Do you have a manual with a decent wiring diagram that will let you check voltage in the harness without needing to get to the pump? When you get the no start you need(with a freind helping) to check the wiring for the starting system including a simple spark check to make sure the ignition is firing(I looked around and saw some crank position faliures as a problem, but I think that would kick a check engine light).
The absence of OBD codes makes me think this is some odd wiring issue because OBD codes pop up for just about everything(Usually in some cryptic manner that will keep you from passing inspection without providing enough information to easily solve the problem)

In a pinch you can check for fire by pulling a plug wire and jamming a screwdriver into the boot. Then have someone turn the motor over while holding the metal part of the screwdriver close to the block. The ignition should be able to throw a nice bright blue spark about a quarter of an inch. Be sure you are not the conductor, use a screwdrive with a nice plastic handle, don't ground your self to the car while doing this. Disclaimer: Be careful, a modern ignition throws a hell of a spark, as much as 40,000 volts(with low amperage). It will not hurt a healthy person but can cause an issue if you have heart trouble and it grounds thru you right. It hurts at any rate.

Donovan Puppyfucker · July 2008

Sounds like a bad earth on the pump circuit... Don't just check for feeds, check for continuity throughout the circuit as well.

nightcrawler335 · July 2008

I do have access to the repair manual, as well as wiring diagrams via http://www.shopkey5.com which my neighbor back home has an account for. I can check voltage at the pump no problem, it's easy to get to since all I have to do is remove the back seat (2 screws total).

Fuelish, I will show your post to my buddy who is helping me out with this (he's much more knowledgeable about cars than I am) and I will let you know what he thinks. Thanks.

update: We are going to check the voltage/ground at the fuel pump today after work with a multimeter (which we didn't have yesterday, we just had a crappy test light), and if the pump is not getting power, we might try and wire it directly to the ignition relay or something in order to try and get the car started so I can drive it to Auto Zone or a mechanic or something. I will let you know how it goes.

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