# ka engine problem???



## 240sxstud (Sep 20, 2005)

Car was running great today but I went to start it up about 10min and it idles very roughly now. When I press on the accelerator the car runs smooth but as soon as I let the RPM's back down, it idles roughly again. The engine moves side to side hard, I have no clue what this could be. I'm a little low on fuel but I don't think it's that b/c when I press the gas it runs smooth. Oil and all the other fluids are fine as well. Any help would be appreciated, thanks.


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## yangs13 (Oct 15, 2005)

It's probably one of your fuel injectors. I had the exact same problem. i changed the spark plugs, distributor and rotor, but it was still idling rough. i took it to a local mechanic and he found that it was a bad fuel injector.


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## 240sxstud (Sep 20, 2005)

Yea, I went ahead and took it for a run, and it lost a great amount of power, and sounded like crap anytime I tried to accelerate. I think I'm going to replace the injectors and fuel pump, how much do the injectors run?


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## Loki (Jan 12, 2004)

240sxstud said:


> Yea, I went ahead and took it for a run, and it lost a great amount of power, and sounded like crap anytime I tried to accelerate. I think I'm going to replace the injectors and fuel pump, how much do the injectors run?


brand new about 100 each.....


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## Rephlex (Mar 7, 2005)

have your timing checked too, mine used to run like that.


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## 240sxstud (Sep 20, 2005)

well I saw some on ebay for like >100 for all four, lol, I think I'll go used. I'm going to replace the filter first, and hopefully that'll fix it, if not I guess I'll go for the injectors.

It does seem like a timing problem, but I don't think it would of been thrown off that quick...I ran it like 100 miles earlier today, turned it off for like 30 min and then I go to start it back up and it acts like a completely different car...


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## 240sxstud (Sep 20, 2005)

Put on a brand new rotor, cap, and fuel filter. The rotor and cap were completely tore up, so I figured that would be my problem...nope, it runs with a little more power but it's still shaking and "sputtering" pretty bad. Still has it's rough idle. I have no clue on what I should do, I'm out of ideas, probably taking it to get a diagnostic monday, if you have any other ideas, let me know.

BTW, spark plugs are fine, checked those as well


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## yangs13 (Oct 15, 2005)

It's a bad fuel injector. my car only had one bad one though and that was the only one i had the mechanic replace. i dont think u need to replace all of them, but my car only has 93K on it.


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## BoostedSE (Jun 26, 2005)

Its not even the whole injector, its the lower o-ring, its worn out so its flooding the cylinder at idle, since so much fuel is leaking in. Simple fix.


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## 240sxstud (Sep 20, 2005)

BoostedSE said:


> Its not even the whole injector, its the lower o-ring, its worn out so its flooding the cylinder at idle, since so much fuel is leaking in. Simple fix.


Is there a way to purchase just the injector o-ring? I have a friend that'll so a free diagnostic anyway, so I think I'll go ahead and take it there but check the injectors as well, thanks for the input boosted, the oring will probably be a lot cheaper than the entire injector.


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## BoostedSE (Jun 26, 2005)

yup, napa, VIP, carquest practically anywhere will have the kit, it will most likely have to be ordered but for the $5 its worth it, before swapping an entire injector. I actually keep a few extra o-rings on hand.


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## 240sxstud (Sep 20, 2005)

I'll keep an update whether or not it fixes the problem, but I've talked to 3 other mechanics and they agreed that my (boosted's) diagnoses is correct


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## 240sxstud (Sep 20, 2005)

Ok, so the orings were in perfect condtion, as are the injectors. I found a big vacuum leak so I was hoping that would fix the problem...improvement but it still vibrates badly when idling...wtf is the problem? Spark plugs are gapped correctly, new rotor and cap, new fuel filter, and fixed vaccum hose...the ONLY other thing is a possible bad spark plug wire? I have no clue I'm taking shots in the dark now, is there a way to test the wire? Thanks.


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## BoostedSE (Jun 26, 2005)

pull each spark plug out one at a time with the wire plugged in and look for a spark on each when you try and start the car (you might want to pull the fuel pump fuse so you wont dump fuel into your motor without sparking it) just make sure each plug is firing, if opne isnt an they're new plugs then a wire might be your issue.


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## 240sxstud (Sep 20, 2005)

Thanks, I'll try it out, I can't wait til I get out of school for the summer, this bitch is getting a rebuild asap, these things are becoming a pain in the ass, one thing after another...if you all have any other ideas let me know

I just haven't taken it to get a diagnostic yet b/c my buddy just started to put a new roof on his house so he's out of the garage for another week; my luck


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## rogoman (Dec 16, 2004)

240sxstud said:


> Car was running great today but I went to start it up about 10min and it idles very roughly now. When I press on the accelerator the car runs smooth but as soon as I let the RPM's back down, it idles roughly again.


There still may be a vacuum leak. To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. A good place to connect to is the charcoal canister. There should be three hoses connecting the carbon canister. Two of the hoses go to a purge valve that's built into the canister. The second larger hose off the purge valve should be your vacuum line. With the motor fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg.

If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.

I posted the following suggestions to another guy on this forum that was having a similar problem; here it is:

Several things to check:

1 - Check your idle speed; adjust if necessary. If you can't adjust it to spec, then the IAA valve may be dirty; disassemble to clean. 
2 - Fuel injectors may be dirty; run some good injection cleaner through the system like Techron or Redline SL-1.
3 - Spark plugs may be dirty.
4 - Check fuel pressure.
5 - Check the O2 sensor.


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## 240sxstud (Sep 20, 2005)

Coil in one of the injectors were bad, so I'm just getting a new injector...there goes 100 bucks...


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