engine management issue

[x_christ0n]

hey guys i got a smallport with stage 2 crow cams in my car but the wiring isnt exactly a1 i bought the car and been trying to clean/fix it up and after chasing all these smallport wiring diagrams i finally found my problem i found a diagram for a "ae92 bigport" on google with the ecu im currently running Its got yellow plugs as well if that means anything. should i chase up a smallport ecu loom and stuff?

[Skylar]

I read that like 5 times and still don't get what you're saying.

You have a smallport. It's not running right. You think the problem is because an ECU pinout for bigport AE92 you found matches your loom. Since AE92 /= smallport, it is a problem?

What exactly is wrong with it? Does it even run?

[x_christ0n]

yeah it runs lately its been running rich as and yeah the problem is i have a smallport with bigport management i want to know if i should look for a smallport loom and ecu or should i leave it as a bigport ecu and loom because of the cams. i dont know how to explain how my car runs at first it was fine i wouldnt pick a pronlem althought it was rich my o2 sensor hasnt been hooked up i been trying to clean up the wiring slowly and now im starting to run into issues its misfiring and what not runs super rich like leave Black rings on the concrete my cats now melted from it being so rich

put simply

should i change to smallport management?

if it helps this is what my ecu pinout was meant to be

[Skylar]

Not that I've done it but I heard of many people running big port ecu on small port fine. The question is, do you have big port or small port injectors?

If it's running rich, I'd check the plugs to see if they haven't fouled up and is causing your misfire.

[x_christ0n]

Well it's running okay but do you think I should swap to a small port one

[xero]

do you want to borrow mine to test it on?

[70XIN]

Didnt know a cat could melt from richness. Quite the opposite actually.

And skylar, bigport & smallport injectors run on a totally different impedance. Wouldn't they have burnt out/not run at all if he was using the wrong ECU?

[slydar]

your issue is more likely to be the your factory ecu set up not being able to compensate for your cams.

a small port will run on big port management fine.

a small port engine management system is no more likely to be able to run an engine with cams any better than big port.

if you change to small port engine management, which i dont think theyres any need to. then youll need to change your distributor and injectors too.


give us some specs on the cams. if they seem like they not too crazy, then servicing you current engine management system and a new set of plugs etc should do it.

if not you might need to go to programmable management.

[Skylar]

Seamus, Cats melt from being rich. When you run them lean, they just get hot. Running super rich causes fuel to get caught in the honeycomb stuff and when you gun it, it gets hot and burns as there's combustible material there.

The ECU will run low-impedance injectors even if designed for hi-z. The problem is with less impedance more current goes through the injector (and the ECU) and causes them to run rich. It's to do with the PWM damping and the electrical circuitry behind it. The engine won't run spot on but it will run.

chist0n, what injectors are you running? I don't know with those ae92 big ports, I think they got some goofy injector or ran a resistor pack. Nikkojoe, Halp!

[x_christ0n]

hey lol i just noticed that the pinout i put up was for the airflow meter version mines map sensored oops but yeah its still definitely not a smallport ecu lol and cheers for the help guys