Okay, I think it is the injector's needing to be cleaned. I just want a second opinion. When I am driving around and I get up around 3-4k rpms it seems like it just studders. It is alot like hitting fuel cut when you reach too much boost and you don't have an fcd. But it isn't -as- harsh. It worsens when I am going up hills and what not (ie. putting more load on the motor). It happens most when I am giving it about 1/3 gas to about 1/2 gas. If I punch it, it will get up to about 5500 rpm before the fuel cuts out. So do you guys all think it's the injector's aswell, or could it be something else. Keep in mind I do have a fcd, and it's really non boost related from what I can see.

Oh, and also, is their any chance I could run say 720cc secondaries without a piggy back computer, and still be able to use my car as a daily driver, and not hurt gas mileage that bad?

Thanks,
-Mark

 

Bump^^

 

Someone has gotta have some input.

 

It sounds to me that maybe you are haveing the 3800 rpm hesitation. Have you regrounded the car yet? If not I would try that first. I think there is a good write up in the archives. If that doesn't work go with the injector idea.

As for running 720's in the secondaries w/o a piggyback, I think the answer is no. I also have that same question. I know that you cannot use a HKS F-CON with larger injectors, but I was thinking maybe a S-AFC. Can anyone shed some further light on this??

Tim

 

Sounds like TPS to me... have it checked.

 

I am almost positive it is neither of them, I can guarantee you its not the 3800 rpm hesitation. I really don't think it is the TPS either, because I have driven the car without the tps plugged in at all, and it just runs really rich and backfires, but still drives. I am thinking maybe the fuel filter... what does everyone else think?

 

If neither of any of those, I would say your fuel filter needs to be replaced or maybe your fuel pump is going bad. What modifications do you have? Looks like you need a dual alt. pulley if you've taken your air pump off.

As for running 720s w/o a piggyback, yes you can run 720cc secondary injectors without a piggyback, S-AFC, or F-CON. But you should AT LEAST re-wire your fuel pump or get a larger pump (walbro 255). That only problem is that your fuel economy will go down if you're mashing on the gas a lot, and you will be misfiring/shooting flames a lot (depending on your mods).

 

All of my mods are in my sig.

 

Watch out for that walbro..... If your injectors are old, it'll cause 'em to leak down and then flood out the car when you park it (ask me why i know,,,) Mazdatrix makes a fix for it though.

If you know somebody with a widenband, you could tell if its a fuel problem cause it'll lean out (or richen like hell depending on the problem) right before it stutters.

Check your entire Vaccume system and all your intake gaskets.. you could have a leak somewhere let the car idle and start spraying suspect parts with carb cleaner, if it dies after spraying a connection.. BINGO!

Make sure you check around your custom TID, especially after the MAF, it you have a leak between the MAF and the turbo, it'll screw everything up. Also check to make sure the BOV isn't popping open, especially if you are still using the stock one.

My car did something like that one and it turned out to be a loose connection on the leading coil pack's wiring connector.

My advice.. Change the fuel filter... always a good idea.. then look for vacuume/gasket/TID leaks.. then check all your wiring, especially at the coils and the injectors,,, and get a ground kit for your engine if you don't have one.

Finally, , If you are going to run 720's, you can do it, i agree with KenshineFC, but you really should have a SAFC and tune it with a wideband or its just going to be a big pain in the ****...