Engine Shake -Continuing problem...help!

[alex4]

This is a problem I have been chasing for a while, I have tried doing what searches recommended. Kinda getting stuck...

Originally, the whole front end would shake real bad after starting the car about 1-2hours after driving it. It would shake under 1500rpms until it would just randomly start working wonderfully. I would have greatly reduced power, but then somethign would just start working and it would be an instant power boost. Wouldn't do it from a cold start or turning the car back on right after turning it off.

I took the car to Chek-Ups because they will diagnose your problem for 65$. They said it was leaky intake manifold gasket. The intake manifold gasket was a little leaky, plus the last owner had RTVed all over it trying to seal it (but failed). I spent forever getting all that manifold crap off, and when I finally finished, it still didn't run right.

After using the search button like a good little NiCO member, I did all of the easy possible fixes I found from past threads.I tried running premium gas with no ethanol.I tried putting in lots of super concentrated fuel injector and fuel system cleaner.Today, I put in beck/arnley remanufactured fuel injectors (Why would nissan put phillips head bolts on something so tight and important like injectors? Lame. Now it has hex bolts in muahah.)

NOW it shakes all the time, but only when not moving. It's as if it runs fine until some idle-control thing turns fuel flow down to save gas while sitting still, and that makes the injectors sputter. It drives fine, and under any load it doesn't shake. Also, the new shake is not as violent.

The only thing I can think of now is that since I bought the cheapest injectors, some idle control thing is calibrated to work with better injectors with tighter clearances.Is there any way I can disable some idle control things like that to see if that will cure the problem? I know it would slightly decrease my gas mileage, but that isn't the end of the world- I just want to keep the wheels turning.

I guess I could try to get AdvanceAuto to take my fuel injectors back and give me a refund, then I could try new fuel injectors.

Or also does anyone have any other suggestions about diagnosing the problem?THANK YOU AHEAD OF TIME, OH 240 GURUS!!

[-RJ-]

sounds like injectors to me. just goto the junkyard get some injectors there

[drugsbunny666]

Check the engine mounts maybe once you start driving the vibrations are getting to hard and shaking the whole engine up.

[liquid_cool]

hay bro...interesting issue your having!....some things come to mind rite off the bat...motor mounts!...to see if this is your issue...have the engine runnin g with the hood open and look with a flashlight at your mounts...nissmo mounts blow cum man..they waste easy...if that is not it..check to see if all your cylinders have spark..if your motor had a missfire..it would do that allso.....if thats not it...injectors..and if thats not it..possibly knock sensor..or even a bent crank...at least ya now have somewhat a direction to look in..hope this helpd man..good luck..keep us posted.

[liquid_cool]

any updates on the issue alex?.

[Vegascorbin]

In addtion to the motor mounts etc be sure to check your grounds. If you have loose grounding it can cause intermitent problems.

[-RJ-]

run your car and pull each fuel injector plug 1 at a time. if you notice that nothing happens when you pull one of them, then theres your problem.

gotta try the free stuff first

you could also have a vaccum leak somewhere, my friends car would run fine til it sits at idle, i found out that his brake booster went bad

[alex4]

I replaced the remanufactured injectors with brand new BWD injectors $100 a piece. It ran beautifully the first time I started it up- I was ecstatic. I drove it around, parked at home for 40 minutes maybe, still ran great, drove it to the state park (couple fun curves), running great.After a 3 hour hike, got back to the car and it would barely start. It shook like hell the whole way home. Horrifically reduced power and sputter throughout the power band, and the same old shaking at idle.I gave it a day of rest, and from a completely cold start, it still barely starts, and it still shakes and sputters. I then went down the row unplugging the fuel injector harnesses one at a time. The first (furthest forward) cylinder is the dead one- the others are fine. The spark plug has mild sooty deposits on it.

[liquid_cool]

ok...im thiunking fuel system is cloggd up..something in the fuel delivery is out of whack for shure man...if you were running fine for hours then all the sudden nothing..i think you might have a debris in the tank/fuelfilter problem or bad fuel pump..ither way..its a pian to fix.

keep us posted.

[alex4]

I ran lots of fuel system cleaner and it didn't make it any better.I replaced the fuel filter like 100 miles ago.Should I put in a new fuel pump? A walbro hi-flow fuel pump kit from nico ($84.95) is actually cheaper than any fuel pumps from advance auto ($100-480). That will work ok with stock injectors and FPR rite?Why would my first cylinder only work with a brand new injector?

My friend said he messed up his KA24DE by running regular gas (87) in it, and he had to get an ECU retune. I don't usually put premium in my car (though I have been using top notch gas since these problems started). I don't see how regular gas would mess up the ECU, especially when the owner's manual says 87 is fine.

[liquid_cool]

you might have particles in your fuel system clogging your flow rate..but id definitly upgrade a fuel pump.

[alex4]

If there were things clogging the fuel system, why would the first cylinder be the one not working, when all the ones after it work fine? Also it seems like a problem in one specific cylinder would rule out the fuel pump....

[480sx]

When thats happening, get a Noid light and make sure your injector is receiving a signal.

[liquid_cool]

When thats happening, get a Noid light and make sure your injector is receiving a signal.

i miss read..happens...480 is correct..if its only one cylinder..then it might be electrical in nature.

[alex4]

It ended up being a cracked O-ring. The original injectors were held in with phillips head bolts, so I had a shop get them out (for fear of completely ruining the heads and never being able to get them out). I usually am a DIY guy because it's cheaper and I trust my own work. It turns out when they put the remanufactured injectors in, they cracked an O-ring, which is why new injectors made it worse.MORAL OF THE THREAD: Do your own work, and replace o-rings when you replace injectors (even if Advance Auto says you don't need to)!