Just another thing to check. If your plugs and wires are good, gap your plugs down to about .035"

got new wires 8mm magnecor wires (supposed to be the best for the MX5 in the UK)

After fitting them and a short drive...I have no hesiation or missing. that was with a warm engine.

remains to be seen if the cold start mising is still there tomoz.

I've driven in my car with massive amounts of fuel...enough to cause black smoke and flames out of the tail-pipe.....no bogging or said symptoms, just not as much power.

I've driven in a miata with a lack of fuel in boost and you could feel it chough/hesitate/lag/sputter, etc. just at 4-5k.

FPR appears to be installed correctly.

Disconnecting the vacuum line will disable the Vortech, and you can test that theory....otherwise clamp a FP gauge on there and see how it reacts during said problem.

Wire/Plugs/Coils will cause both idling and sputtering/hestation problems

Ballooning/leaking crossover have been know to only leak in boost, but be prefectly fine in vacuum. If a slight leak is there, then that could explain idle issues.



Minime, search for "vacuum leak test". It involves pluging the intake port of the turbo and pressuring it through a shrader valve with a bike pump or similar....then you can listen for any leaks.

you also mentioned before you knew what pressures you were getting. while you were clamping down on the rail was it a continued 120psi?

when you turn off the car does it stay at around 30psi for a while?

in boost when siad symptom occurs, what happens to your fuel pressure? does it drop off?

Thanks again for the all the advice, I hope to test my fuel pressure as soon as I could get a guage T into the my fuel syste.

I feel also is definilty lack of fuel in the system during that range. It almost feels like something is cutting fuel at the point.

I've also check engine code: CODE #17 IS ON!! I think that is the O2 sensor.

I will check tomorrow if its a vaccum leak once in boost that is activating the AFPR and OEM FPR.

?? Can both FPR run with different Vaccum source, or dose it have to be in series??

LMK if I interpreted your posts correctly....
You're running your oem 1:1 fpr, and you've removed the vortech 12:1 fpr?
And you wonder why it's lean at 3 psi?

I am running another AFPR.. that is a linear rising rate with 1.7:1.
I the lean problem happened once the Vortech is attached in the system first.

The Vortech is connected to the fuel hard line coming up into the engine bay where? Forward, or toward the fire wall?

The Vortech (center fitting) is connected to the hardline FORWARD (return line).

Could this be a symtoms of injectors failure? If so, I could go back with my 1.6 injectors and test. But will the Vortech 12:1 and Walrbo 190hp be too much pressure on the 1.6 injectors?

Not at a boost pressure of 5 psi.

You have only barely tightened the wastegate? And the line is going from the compressor housing to the actuator? And you didn't turn the rod on the actuator when you were adjusting?

Well 1.7:1 ain't gunna cut it.

I was able to get 7psi (with a 8-9psi) spike safely with a vortec 12:1, 190lph hp, and blue 1.6 injectors

Olderguy, the actuator was never touched nor tempered with.

After further testing and inspection: As many has advice for me to put T in an fuel gauge... well here is what it reads. @ PRIME MODE!

125 PSI constant when the return is clamp shut!!
42 PSI constant once released.

Road testing:

hesitation presist aorund 4500-5000 rpm, than no problem after till 6500 rpm.

You know, we might have all been chasing something that you can correct with the O2 clamp you have finally received.

We think of the transition point from closed loop to open loop as being at 4000 rpm. Maybe your ECU holds onto control longer, and therefore pulls fuel as you are trying to add it until a higher rpm. Go ahead and put in the clamp and try it.

Bruce,

He doesn't have the problem when not in boost. If it were purely RPM related wouldn't it happen in and out of boost?

What is the FP at the point you hesitate?

the FP reads fine, since I took out the Vortech and running a linear AFPR. At 0 atmostpheric the FP gauge is reading 55psi.

What I'm thinking is that it is a lean tip in condition as he adds fuel mechanically under boost and the ECU is trying to pull it out at a level that is higher than we normally think of the ECU going to open loop(4000 rpm) Like maybe the ECU isn't going to open loop until a much higher rpm.

OK...! just spent 20 mins.. prep up for the O2 clamp. Testing session at sunrise...crossing my fingers! :cool:

Road test!! WORKED.. no hesitation on the 2 tries.

BUT MY CAR REV is not coming back down.. .its holding at 3000rpm! ?????

Any clue?

Gessus!! :bowdown:

Olderguy!!

AFPR $ 100
Fuel Pump $ 85
O2 Clamp $ XX

Olderguy support = PRICELESS!

Thanks for all the help from Olderguy!! It was the stupid thottle cable, I guess it was too fast, there was a soft rubber Ring fell out and got stuck with the pulley! :sadwavey:

Thanks everyone for their comments and time! :bigtu:

My Miata is finally boost smoothly! CHEERS to everyone! :eek5:

Stephen

Glad to hear you got it sorted out! Bruce is great. He gace me a similar eureka moment with my old EMB setup!