Are my injectors the Problem?

[tdawg88]

Hello everyone,

I have a concern regarding my 240sx. Seems as though the problem comes from what I thought was an empty tank of gas but Im not certain.

Basically I was driving home one night and my tank was quite low on fuel however the light had not yet turned on. So i kept going home, right as I passed the gas station the exhaust started fluttering as if though I had a massive misfire. I didnt really ignore it but figured I was out of gas, I noticed that my RPM's were dropping immensly and... Well the car died on me and I added some gas yet it still would not start. Figured the lines had air in them and needed to be aired out somehow.
Next day, I went to start the car and ran fine. A day later when I was running out of gas again I felt a similar jump in the engine and a backfire out of the exhaust. I made it home and figured id pump gas the next day. Filled up the tank the next day and the car still bogged out on me. It would not give in.
Seems that it will run ok when it wants to or something like that. I went to Nissan and somewhat explained the situation and they told me it would surely be the injectors because this happens so often on KA24's. Is that the case? If so, is it as easy as changing out the injectors or could I clean the ones on the car now?
I started the car this morning, the engine runs fine past idle but at idle it vibrates really bad.

Any ideas? thanks in advance.

[orion::S14]

Injector failures are NOT the common...but they are a quick-n-easy repair for a dealership, a quick way for them to make $500.

Sounds to me like a vacuum leak...based on your description of "bad idle, runs fine above that".

Eliminate the simple stuff first:

Check for vac leaks.

Makes sure the MAF plug is on tight, and the wires are not rubbed through/exposed.

REALLY dirty air filter?

When did you lat replace the cap and rotor (or when did you last do a tune up?)

- Brian

[steve shadows]

Maybe your gas gauge is broken...

I have had the little level arm break or get messed up after changing the fuel pump in the sending unit way back in the day.

[s13rookie]

did you check the fuel filter? running your tank that low repeatedly will suck the crap from the bottom of the tank

[steve shadows]

could be an ailing fuel pump as well.

[Dream240]

Originally Posted by s13rookie

did you check the fuel filter? running your tank that low repeatedly will suck the crap from the bottom of the tank

Let me dis-spell this one once again. There's no logic to this old fable....the tank is pressurized, hence, the fuel will get sucked up whether it's full or empty. If there's deposits in your tank they will get sucked up whenever. Also there's a little thing called a pick up screen in your tank. It like a pre-filter-filter. Now unless you've got suger poured into your tank, or you dumped some dirt in there, deposits of notable size are not a concern. The old deposit myth I believe is something that came from the old LEADED fuel days where large amounts of depositis are far more common and require a more strict maintenance schedule. Someone confirm this.....

Change your fuel filter, and then check your fuel pressure with the appropriate guage. If you're showing poor fuel pressure readings, replace pump. Then re-check. As far as where to check your fuel pressure from, plug the gauge into the line that feeds your fuel rail. This is after your filter but before your FPR.

This is all of course AFTER you replace the filter and drive it to see if it's still running bad.

As a side note:
I have been having poor acceleration issues and decided to replace the 16 year old, 200k mile pump with a walbro. Car pulls hard now with no hesitation. I also had this problem with my old S14 and my old 86 Accord back in the day....new pump fixed both porblems. Hope this helps.

[tdawg88]

Thanks everyone for your information. I have tried everything except the new pump.

I started out with changing injectors went to a local yard and grabbed some injectors. It fixed the problem temporarily, but not all the way. The car merely drove fine for a few hours.

I noticed once the problem returned, that the hesitation started when the car shook while driving. i.e. on smooth surface road car functions well, however the first bump i hit then the car boggs. I have really stiff suspension so a small bump makes a hell of a shock. So could this be a bad pump? car just turned 160k miles. The last tune up woulda probably been a year and a half ago. Twas a major tune up so I think all was changed including cap and rotor but not dist.

Is the fuel pump really that big of an issue? Could this be the reason im experiencing problems?
My car was towed home last night and the tow guy banged on the fuel tank a bit and the car started with no problems so could that be my issue? if so, since 240s are hard to find at PNP, what other pump could I use temporarily since I cant afford a new pump and dont really know what is fair price for a pump. Thanks