2G Cylinder 4 missfire only with FIC injector

[DUDUCD]

Guys, I'm having trouble finding the root cause of the problem and I'd like to check if this has happened to any of you or if you have any suggestions.

I have an original eclipse 95 with standard measurements. A few months ago, I made the entire exhaust in 3" stainless steel and a K&N air filter, later checking it on a dynamometer where we had a result of 185whp and 29kgfm, with the engine running without problems.

Moving on to the second part of the project, I acquired a B16G turbine, AEM 225lph pump, FIC 950cc, grade 7 spark plugs and ECM link.

All items were installed with the exception of the injectors. The Car works normally.
After installing the injectors and adjusting the globalfuel, the car starts but it is noticeable that there is 1 cylinder with missfire.

We tested cylinder compression, pump pressure, changed the position of the injectors, changed the position of the spark plugs, changed the position of the cables... the problem always persists in cylinder 4. The ECU with ECMlink was tested on another car and worked perfectly.

in the functions of the ECMlink, when turning off cylinders 2 and 3, the car weakens. When turning off cylinder 1 the car also weakens, but less than 2 and 3. When turning off cylinder 4 there is no difference. When doing the same test with rpm above 3k, you can notice a difference when turning off cylinder 4.

We have already adjusted deadtime individually for cylinder 4 but still there is no improvement.

Has anyone had a similar problem or have any suggestions for further tests to be done?

 

[pauleyman]

Check the cylinder 4 coil tower for cracks, corossion etc

 

[curt-s]

Check the wiring all the way from ecu for injector 4 to the injector itself. Check the metal tabs in the connectors as well. Continuity tests are helpful here as you jiggle the wires about.

Since you're disabling the injector firing via ecmlink on 4 and seeing no change even whilst swapping injectors in that position, I'd bet a small amount of money it's a wiring issue. Cracks and breaks in the wiring at injector plugs are not uncommon

 

[pauleyman]

Check the wiring all the way from ecu for injector 4 to the injector itself. Check the metal tabs in the connectors as well. Continuity tests are helpful here as you jiggle the wires about.

Since you're disabling the injector firing via ecmlink on 4 and seeing no change even whilst swapping injectors in that position, I'd bet a small amount of money it's a wiring issue. Cracks and breaks in the wiring at injector plugs are not uncommon

Yeah this is a good idea. I've seen harness corossion 8 or 9 inches up the harness from.the connector. Aren't 30 year old fuel injected cars fun?

 

[curt-s]

Yeah this is a good idea. I've seen harness corossion 8 or 9 inches up the harness from.the connector. Aren't 30 year old fuel injected cars fun?

Makes me all sentimentel just thinking about it.

It's one of those things where it worked fine before, but as soon as you touch the wiring for changing injectors, something breaks. Maybe now that wire is down to the last strand and even that's corroded. Many don't realize that copper will corrode exactly as you say, or a foot or more up from the connector. They get brittle and snap inside and you have no idea where until you start testing for continuity under stress/movement conditions.