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Old 05-01-2010, 01:10 PM   #1
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Default Injector issue?

Hey guys.. Finally got a chance to work on my car. School definately takes alot of time out of it and besides the fact my miata is a few hundred miles away..Anywho, I keep running into different problems with my car. First the mspnp with a shoddy previous owner (which was repaired thanks to diyautotune!), arcing coil packs leading to bad misfires and now with my current injectors 305cc (not the 550ccs I have listed on my sig).

I fixed the first two, but now I'm getting weird fueling problems. Okay, I'm trying to get it running right before I install the MSPNP and then the 550ccs. It certainly beats throwing everything together and praying for no problems.

So with the stock ecu I should be idling fine with 305's correct? I saw a few threads where guys with band-aid setups without any computers to compensate idle for larger injectors ran fine, a bit rough but it wouldn't stall out and die outright.

Basically when I try cranking the vehicle with my turbo kit minus MSPNP (oem in place) and with the 305 injectors it won't fire because its overfueling, but when I take away power to the injectors it will fire up and run for a while perfectly. I guess due to the overfuelling it still provides enough power for combustion. But while I run the vehicle on the excess vapours or whatever and apply power to the injectors one at a time it just bucks up and dies.


So with the above in mind my questions are.

Should I be stalling with stock ecu, with 305cc's with no secondary fuel regulator? I'm 90% sure the FPR's kick in under boost.

Or should I just slap the mspnp in and adjust the cranking p/ws and control the injectors and hope it will be okay?
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Old 05-01-2010, 01:11 PM   #2
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Yes, just adjust your cranking pw's, and req fuel.
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Old 05-01-2010, 01:24 PM   #3
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Ok cool. Just thought it was weird how others could have idled "fine" on my setup and I'm just having troubles.
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Old 05-01-2010, 01:46 PM   #4
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It's not weird.My stock ecu idled my 305cc injectors but I had to crack my AFM and adjust it. Your stock FPR only increases fuel pressure up to atmospheric (0 vacuum). It will not compensate for any boost.

If it were me, I would put the MSPNP in, tune it for the 305ccs because it will be easy to get a stable idle and base map, then add the 550ccs afterwards. It's easier to change one thing at a time. If you have a problem, it's easier to diagnose what caused it when there's less possible causes to choose from. GL!
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Old 05-01-2010, 03:29 PM   #5
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okay a quick little update: I installed the mspnp and quickly plugged in another users similar crank settings (so I would just fine tune it later ).

It eventually flooded. Took off my plugs and yep.. filled to the top of the spark plug hole. I tried another quick test of turning the power on to prime the pump and...watched the cylinder **** out fuel. So I guess my fuel injectors are stuck open thats why it would flood majority of the time.
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Old 05-01-2010, 03:53 PM   #6
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So..... reduce cranking pw's you can use math to figure it out. It is outlined to some extent in the manual for your ms. Oh... don't forget to adjust your req fuel.
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Old 05-01-2010, 03:55 PM   #7
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Quote:
Originally Posted by aphongt View Post
Took off my plugs and yep.. filled to the top of the spark plug hole.
WHAT!?! I filled my dish up before but the whole cylinder.

I guess shes a little rich.
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Old 05-01-2010, 04:15 PM   #8
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Quote:
Originally Posted by lordrigamus View Post
WHAT!?! I filled my dish up before but the whole cylinder.

I guess shes a little rich.


I was going to just leave the fuel pump primed so it would spew out of my cylinder but figured it wouldn't that be that great of an idea.

I think ill just throw on my 550cc's after I get em cleaned and then ramp down the crank settings furthur.
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