93 J30 severe shaking

[bukelian]

i got a 93 J30. It vibrates severely even in parking, the engine drop to around 1000 rpm several seconds after I start it. At driving, when i add gas, it vibrate too, especially around 65mph,like a small earth quake. But when it runs up to 4000 rpm, the vibrating disappears. What possible reason could it be??

Brought it Carx and the guy there told me one of the injector is clogged and need to replace at around $900, parts plus labor. Is this money stealing or just acceptable price? Have tried to seafoam the engine, but the shaking still exist, maybe I didn't do it right. Any suggestion?

[yodawill2000]

Welcome to Nico.
If the injector is just clogged you may try a bottle of Redline SL1 in a half tank of gas.
Pep boys carries it here in Tx.
You should also ohm test the injectors , they should be in the 14 ohm range if good.

And 900 is outrageous for a single Injector.
Maybe he meant all 6 ?

[bukelian]

thanks for your reply, yoda
$900 is only for one single injector replacement. They ask for $200 for the parts and 5.5 hours labor. Also they told me to replace the injector, they will have to remove and replace the upper intake gasket set, which they ask for $125 and I don't really understand what they are referring to.

is redline sl-1 a kind of fuel system cleaner? I tried other brand already, not really helpful. Even add seafoam in the tank, not obvious improvement either.

[yodawill2000]

Redline is the strongest out there now.
I bought Injectors for about 110.00 and replaced them myself.

http://www.fuzzycats.com/docs/j30_fuel_ ... cement.pdf

[bukelian]

i will try the omhtest first, and see if they are telling me the truth. Thanks, yoda

[yodawill2000]

If they all Ohm in spec then its either a clogged injector or a Spark Plug or coil gone bad.
Does the Check engine light come on ?

[driverdriver]

The ohm test range for a good injector is 10-14 ohms. Anything below or above indicates failure. With the type pf shaking your describing, I'm fairly certain that you have 1 or more failed injectors. It's a very common age related issue.

[bukelian]

will do the Ohm test in the weekend. The check engine light doesn't come on when driving, what will this indicate?

[yodawill2000]

If a cylinder is Mis-Firing it should throw a code and Check engine light.

[bukelian]

Hi yoda, I have a new observation. The engine does have a unstable idle, can feel the shaking. I put it in parking gear, and gas it up, the engine runs smoothly except small vibration around 1700rpm. Then I drove it on highway, and found out the fierce vibration around 65mph is most likely coming from the steering wheel. What is possible reason for the wheel shaking? Plus the engine checking light doesn't come on, could be mean it might not be the injector problem?

[bukelian]

Hi yoda, I just finish the Ohm test, and one of the 6 injector has 0 resistance, bad one?
Unfortunately, it is the one closet to the driver seat, the most difficult one to replace? But how come the engine light doesn't come up and it only vibrate at certain speed?

[driverdriver]

CEL never came on for me when one of my fuel injectors failed. Its a rare occurance for the CEL to come on for injector failure.

[yodawill2000]

Mine did.
When it started it ran uber rough till I got it up to speed.
Then all 6 were firing and the CEL light went out.
A few days later it went out completely.
iir it was the cylinder misfire code.