KA24DE PROBLEMS please help

[ZOLTAN]

Ok, here's the deal.
On my way home from work yesterday my car started losing power and felt as if it wasn't running on all it's cylinders. About a mile later it started working correctly, and then promptly lost power once again. I got it home and it idled, but very roughly.

Since this is my only functional car at the moment(other car needs new power steering pump) I was forced to drive it to work today.
Again same situation, Power comes, power goes; Doesn't stall, just Struggles.

Any ideas, things I should check?............Thanks....Eddie

[transient]

I'd pull the spark plugs and give em a reading (http://www.pdm-racing.com/features/plugs.html) . That should tell you something.

[scandalcat1]

First, using a compression tester, check all cylinders and make sure that compression is even. 145(low)-185(high) If compression is 20% above or below the above figures for any of the cylinders, time to start looking deeper into thew matter.
Second, check the MAF for blockage and also the AIV so that it is not allowing exhaust air back into the air cleaner box

((Model Dependent))

[kalieaire]

check through some of my old posts, they've lately all been about fuel problems and engines idling rough and stuff.

i'm sure that in my last 20 posts, you can find all the information you need to diagnose your problem.

unless of course you're too lazy to do a search.

[scandalcat1]

Forgot to add
go here:
240sx.org (http://www.240sx.org/faq/index.html)

and search for the poor performance issues
topic

[ZOLTAN]

Thank you for the timely replies.
I'll check the plugs, MAF and AIV in the morning.

My guess is that it is something electrical. Again, it cuts in and out like if it were a bad connection or sensor.
The mass air sensor seems to be a very logical culprit.

"unless of course you're too lazy to do a search."
It's quite difficult and a waste of time to search for something if you do not know what you are searching for. It's far simpler to just ask a question and wait for an answer. And, I fully understand how to use the search feature.
Now, hopefully your statement wasn't meant to be a jab at a "noob" and is just poorly worded, and thus was misunderstood. With that being said I'll check your posts for further insight into my problem.

Thank you all for your help, and keep the information coming.

[ZOLTAN]

Ok, I did a power balance test and the problem is in the 2nd cylinder.
I'm hoping it's just a "leaky injector."

[kalieaire]

leaky injector is a big possibility, could be 1 seals, 2 injector itself.

replacement part can be had for ~50 bux before core charge.

if you check 240sx.org for injectors they'll have a link somewhere for cobra or viper or something remanufactured injectors. I'm using those.

if you look around on the forums, you can get an entire fuel rail w/ the injectors for like 50 bux or less.

------however.

if it's not an injector problem, it would be electrical.

the sources are in two spots, CAS and Injector harness.

to test your CAS, remove the rotor assembly(it's the big thing that you bolt your cap and rotor to) from the front upper timing chain cover.------IMPORTANT------ Remember to mark where the rotor was before you take it off so that you do not affect timing.

Take out the Fuel Pump fuse and turn the rotor. it'll spark and the injectors will click open. Make sure each injector opens. if not, then you have a problem with the CAS or the electrical wiring of the 2nd injector.

if they all the injectors click, then it's just the injector that is leaking from either the o-ring seals or from the injector itself.

simple enough?

[transient]

When you say CAS, are you talking about a crank angle sensor?

[kalieaire]

Yes I am, cas = crank angle sensor. it controls spark via cap and rotor, and injector timing.

[kalieaire]

oh I forgot to mention that you need to have your key in the ignition and set to the "on" position.

if the key isn't in, or set in the acc position, it won't work.

[ZOLTAN]

I just pulled my plugs(they are only a couple months old) to take a look at them, they have a bit of carbon build up on them. So, it's running a little rich.
Could old/worn injectors dump more fuel then they should?
Could the o2 sensor be causing it to run rich?

I did the old screwdriver to the ear trick and listened to the injectors, they all seem to be firing.

CAS test is next, just to be sure.

[kalieaire]

old injectors can have their seals break after years of use. sometimes even just months. this will cause fuel to leak past the seals even after the injector is closed.

an o2 sensor would cause a rich condition in all cylinders, not just one.

[ZOLTAN]

All the plugs were fouled, not just cylinder 2.

[kalieaire]

does your idle go up and down, or does it just idle roughly?

if it idles roughly but the idle is at a stable speed, it most likely isn't a wiring problem. just replace the injector and all should be well.