Installed 1.8 injectors.. running lean?
 

I noticed when I hit 4k rpm my car starts to run lean (wideband reading 16-19). I installed 1.8 injectors because I read it's not safe running 1.6 injectors even with an FPR. The O-rings and rubber grommets are all replaced. After replacing them, I took it out for a drive and it did the same thing. I am currently running a Begi FPR and it's set at 50psi. When I blip the throttle, it drops to 47psi. Not too sure if that's normal. At idle it's reading 13.4 - 12.8(when car is warmed). What could be the problem? Fuel pump going out? Possibly injectors? Replace fuel filter? Lmk asap..

The 1.8 injectors are from a 99 miata,

Red injectors
260cc
#195500-3310

what fpr?

begi fpr

Just replaced the Fuel Filter and did a test run. Still have the same problem.

50psi fuel pressure at idle?

it sounds like youve tuned the FMU incorrectly and you dont have an o2 clamp.

Installed incorrectly? Isn't it the first line from the fuel rail goes in the "IN" section and then from the begi to the upper hardline? Then the 2nd line from the fuel rail to the lower hardline and gauge?

and yes..I don't have an o2 clamp.

This is weird cause I never did have this problem before when I had the 1.6 injectors installed

So you've got the megasquirt that you're not going to tune...yet you're tunning the crappy bandaids?

I need to use my Miata to get around to pick up a few parts, then I noticed it was acting weird. I was curious so I posted it up on miataturbo. I'm still tuning the MS, just need to learn more on the spark, coolant related air density, and acceleration. lol

i said tuned, not installed, but now that you mention it. I'm not quite sure how you're saying you connected it.

There are two hardlines coming up. First, the hardline towards the firewall should go into the front of the fuel rail, then form the fuel rail off the FPR, the fuel line should go to the IN on the FMU, then form the OUT port it shoudl go to the hardline towards the rad.

Fuel pressure should be closer to 35psi at idle and around 45-50psi with no vacuum line connected.

If you need to use the miata to get around, pull the bandaids and undo the wastegate as i told you. This will revert your car back to stock and running properly instead of at 12afr.

I'm surprised you havent fouled half the sensors yet.

It's installed correctly. I double checked it. I set it to 37 at idle. When I removed the vacuum line it rose up to 39. The Begi instructions said to loosen the nut and set it up 48/50 if it's not around that range and so I did that. My wideband is reading 12.7. I'm also running the red 1.8 injectors too. hm.. must be doing something wrong?..

There's usually a larger difference than 2 inches of vacuum between full droop idle and static/base.

no reason you should be that rich with those injectors...

The red injectors are 240cc. The stocker 1.6 injectors are 230cc so you should definitely be in the 14.5 range.

I guess set it back to 35?

It isn't 260cc? Well according to this website.. Fuel Injectors - Miata Turbo FAQ

we'll you should be 35psi with vacuum at idle, and 50 psi with no vacuum at idle.

ok so 256cc. Our other wiki says 240. Anyways. 25cc isnt much. At the most you should be in the low 14s.

Whats the dead times of the 2 injectors? I ran .6 on my stockers. Are the 1.6 stock injectors any less? Doubt thats the issue.

Wait did you install the maf and all the other stock fuel controlling parts on the car the stock ecu needs to function?

I take it all you have is the FPR and the NBa injectors?

Yes. Stock ecu, maf, fpr, and nb injectors. I fixed it though. At idle it's at 37psi. When I blip it, it jumps to 49psi. Without the vacuum line it's at 50. My wideband is reading 14 - 14.5 (exactly what you said).


I took it for a drive, it seems fine when I'm not hitting boost (even when the rpm is past 4) but when I hit boost (pedal to the medal) it starts to lean out.

Sounds like you just need to send it in for a tune...is the boost level the same as it was before?

well I turned it down to 3psi from 6. I was using my stock ecu. I have a mspnp that I'm still tweaking on (when I have spare time).