Sup guys.
My g/f's car is having hesitation problem.
Here is the problem.

about 1 month ago, I took her eclipse and do some maintainance for her.
Changed oil, took of the upper intake manifold for cleaning, clean the IAC, etc.
I changed the fuel injectors also with my RED eclipse's fuel injector. since my red eclipse's fuel injectors were taken off at 60K miles, and hers is like 120K now.

After everything is done, I gave the car back to her, and after 1 week, her car SHAKES like SHIT! engine light flash, CELs... etc..
And everytime it shakes badly (BADLY), we smells GAS!

we read the CODE, misfire in cylinder 3 & 4 and injector open circuit 3 & 4.

So I changed all 4 spark plugs (doesn't help) (still CEL)
Then I changed all 4 spark wires (doesn't help) (CEL)
Then I changed the coil pack (doesn't help, then I return it) (CEL)
Then I swap back the original fuel injectors (and it helps alot!) (NO MORE CEL)

But it is still a rough and shake. but 10x better then before. and the CEL DOESN"T comes back anymore. so I buy the coil pack again, and put it in, and thought it will fix it. but NUP. same thing...

THE ONLY improvement is, it doesn't shake as much as using my fuel injectors, and doesn't smell gas anymore and no more CEL.

What can it be?
please help!
Gil

The shuddering you experienced is the cylinders loading up on fuel, snuffing out the spark, and basically trying to compress liquid. Thats fine, if you've got the cylinder temps and compression ratio of a diesel. The code you pulled means exactly what it says, you have an open in the injector circuit. Meaning, no ground. This would leave the injector constantly on, which explains your problem. I'd check the connector and the little pins inside the connector for some damage. Also, make sure there are no breaks in the harness. Also, could be internal damage inside the injector. Its nothing more than a small solenoid and some coils, it can go bad like anything else.

But as I said, I changed the injectors back to the original one.... but you really think is the injectors? or can it be the ECU?
Gil

check the ECT sensor ( big one below the thermostat). If you engine thinks it's running cold it'll dump fuel in. Damn electronic choke. As a matter of fact check all your sensors, after you do the injectors. These poeple know what the hell they're talking about. most of 'em any way

Originally posted by gilee_8
we read the CODE, misfire in cylinder 3 & 4 and injector open circuit 3 & 4.

circuit = wiring

Originally posted by gilee_8
But as I said, I changed the injectors back to the original one.... but you really think is the injectors? or can it be the ECU? Gil

Not injectors, the wiring/plugs that goes to them. Test the wiring harness and plugs for the injectors. How? I dunno, but that's where I'd start.

you can get a test light, plug it at the end of every connector in the injector harness (one at a time) to see if the injectors are getting a fire signal.

Originally posted by whodatt1
you can get a test light, plug it at the end of every connector in the injector harness (one at a time) to see if the injectors are getting a fire signal.

Just because theyre getting power, doesnt mean theyre working. Injectors are a ground controlled actuator. To test the wiring, find the connector from the injectors to the harness. You really need a multimeter. You're checking for an open in the circuit, the meter will read OFL, or out of range or infinite.

OK, so bascially you guys think it's the "4 plugs that go to the injectors and where it RECONNECTS to the adapters under the THROTTLE body right"'s wiring is not good??

I will unplug all 4 injectors' adapter and the adapter under the throttle and use the multimeter to check it.

But why will it just NOT work? weird!

Edit: I am thinking...can it be the ECU?
About cold, the gauge shows it's at normal temperature. so it shouldn't be the choking.. and also, engine light BLINKS, so it's misfire.

(one funny thing. it only HAPPENS after it is FULLY HOT)
Like driving for like an hour, then it will happens, and it ONLY happen at SLOW SPEED. (at least more noticable at slow speed)
when on highway, or above 30mph~, it is alot less noticable or gone.

When you're checking the wiring, check for resistance through the wires as well. Resistance values will change significantly with temperature and loads. For example, you could have an ignition coil that operates fine at startup, but after underhood temps have risen, it starts to misfire. Just make sure all your resistance readings are next to nill. The wire and connecter itself should have next to no resistance, like .02 ohms or less. Also, check them after you've been running the engine for a while and compare the cold/hot readings.