91VertT2

Hello, I was checking around for T2's that are running rich and didn't quite find one with my same situation. I noticed that at cold start it some what wants to run right, and a minute later the AFM just hurls to the rich side. It idles fine, but bogs a little bit when running 3500-5k RPM or revving around there. The plugs are showing sign of wear but no sign of crude fuel still sitting inside. I'm thinking it might just be the plugs, so I'm getting some wires and plugs today. Also, the compression is at 100 on both rotors in case some one asks.

List of known Mods:

750cc Secondaries
Stock T2 Primaries
Walbro 255
Fuel cut defender
BOV (don't know the brand)

Aaron Cake

iTrader: (1)

Start with a full tuneup. Plugs, wires, belts, hoses, fluids, TPS adjustment, idle adjustment as per FSM, etc.

Your question was not very detailed.

For example, how are you measuring AFRs?
When does it seem rich? Cruising? Idle? Load?
Have you removed any emissions equipment?

DC5Daniel

iTrader: (10)

These cars are known the run rich when a Walbro or any other upgraded fuel pump is installed on a stock fuel pressure regulator. Coupled with your upgraded injectors and that fact that you're using a FCD leads me to believe you have no real engine management....start with a FPR upgrade and engine management, RTEK for example if you're on a budget and have basic needs.

Evil Aviator

^ Problem right there.

Aaron Cake

iTrader: (1)

Ah, didn't even see the pump in the parts list. Yep, with that pump, fuel pressure will be raised significantly over stock due to the stock FPR not being able to bypass enough fuel.

91VertT2

It's got an aftermarket fuel pressure regulator running at 40 psi. Also, I'm using an autometer digital gauge to measure my AFR. I'm going to start with the basic tune up and see what happens.

Aaron Cake

iTrader: (1)

Is that gauge a wideband?

As mentioned though, with 720CC secondaries and no way to control them, you will run very rich anytime you are on the secondaries (above 3800 RPM and 2" of vacuum).

91VertT2

I'm getting a wideband and as far as the rich, it only does running the primaries. When the secondaries kick on it runs fine. I'm thinking the fuel pressure is too high currently running 42 on idle. Was told 38 is where it should be.

DC5Daniel

iTrader: (10)

There's nothing wrong with running 42 psi as that is right around stock, per the FSM.

91VertT2

Question, can a faulty temp sensor (the one that controls the air and fuel mixture) be causing all this? I read and noticed that there are several, on an FD post it says it's the green one. Can this be the same for my FC? Thanks.

Evil Aviator

...


OK, I'm gonna ask... at what rpm do you think the secondaries operate?

ALT2X2

iTrader: (2)

Have you pulled the spark plugs to check how they are burning? What plugs are you using? Are you running stock ECU? Also, is the T2 an 87, 88, 89??? All those factors count depending on the combination of the injectors vs ECU, etc.

Aaron Cake

iTrader: (1)

Yes, a faulty temperature sensor will cause the car to run rich. Located on the back of the water pump housing.

But I think we need a clearer description of the symptoms. With 720CC secondaries, the car should run too rich once they stage, not the opposite.

91VertT2

That's what I'm confused about. To my knowledge the Secondaries kick on after 3800 right? Well between 1500-3500 It runs like crap until it warms up to operating temp. Could it be flooding? But flooding would be because of running rich, or maybe surprisingly enough a sticky injector?

EDIT: The plugs were just changed, and they seemed like normal wear.

Evil Aviator

Yes!

Next question: The ECU is calibrated for 550cc fuel injectors, but your car has secondary fuel injectors that flow 136% this rate. What makes you think that this is not even remotely related to your over-fueling problem?

So it no longer "bogs a little bit when running 3500-5k RPM or revving around there."?

The engine will not start if it is flooded.

91VertT2

After around 3500 it no longer bogs out. And your probably right about the ECU I haven't touched the car after I bought so I wouldn't really know. What's a good affordable standalone, cause I have a really weird cone for the MAF sensor. Looks like it's constricting airflow.

Evil Aviator

I am 100% certain that the engine will run rich with 750cc fuel injectors if it has nothing but the OEM ECU controlling them. Any other contributing factors to your problems would be difficult to diagnose over the internet, especially for me because I am not a mechanic.

If it's only the air filter that you don't like, it is cheap and easy to install a different one. Just use a tape measure to determine what will fit in your car, and then order an appropriate universal filter. This is one of the few cases in which an oversized part will not hurt anything, just as long as it physically fits.
K&N Universal Clamp-on Air Filters for a Variety of Universal Air Filter Applications

If you want to go the more complex and expensive route of installing a standalone EMS, then see the posts by FCNAred and me in the below thread. It may not be what you expected, but it is the truth. Also, if you are intent on using a standalone EMS, don't buy a new air filter yet because the original AFM (MAF) will be discarded and you may need a different filter size depending on how the inlet is configured.
https://www.rx7club.com/forum/engine...arched-669577/