The unanswerable question this far

[240sxcl50]

Ok here's the story so far, last year i had Ma motorsport straighten out my car (sr20det) they tuned the power fc replaced fuel pump all new fuel lines car ran great until two weeks ago. The car started breaking up at 5k rpm would idle fine and run great until 4500-5k so i got the car home and parked it and now it won't start. So i checked every thing i could think of ignigtor chip coil packs spark plugs checked the gap the injectors are spraying the chain and sprockets for the cams are snug the battery is good and the motor cranks it just wont start. so i had the crazy idea lets bump start it, well I caught it in gear and sure enough it ran, ran smooth except still breaking up around 4500-5k I was able to shut it off and it would fire right back up, next morning wont start again.

Im just at a loss can any one answer this for me?

[PapaSmurf2k3]

Almost sounds like what happened on my miata when the cam angle sensor and crank angle sensor had too much disagreement. It would start under certain temperatures, and not in others.
Are there any check engine lights on?

[240sxcl50]

Will it throw a check engine light with a power fc because I don't have a check engine light showing

[240sxcl50]

Is there and easy way to check either of those sensors

[PapaSmurf2k3]

Well, I'm not familiar with the power FC, but in the case of the Miata I actually had to datalog the 2 signals with my stand-alone ECU to see that they were out of sync. Normally the ECU will do that for you and throw the check engine light if anything is off, but if the Power FC doesn't do that, then you're SOL.
You can probably double check your valve timing just to make sure everything is kosher there and you didn't skip a tooth or something.

I'm also not deeply familiar with the SR20, so I can't suggest things that could alter your timing, etc. Do you have access to a wideband O2 sensor (just so you can rule out a fueling issue)?

[240sxcl50]

I do have a wideband and it fuels just fine and as far as timing skipping a tooth it's a chain and it is snug so I kinda ruled that out

[PapaSmurf2k3]

Might be worth checking the cam positions just in case. Usually it doesn't skip/misfire at higher RPMs at that point (it just sort of trails off and has no power), but you never know.
What are your air fuel ratios during break-up?

[240sxcl50]

That I will have to get back to you on I'll bump it tomorrow and check again can't remember the number

[240sxcl50]

Ok we have a break through car will start but only if I turn the key to prime it 7 times or so still breaking up at 5k could a bad fpr be the cause

[ca18det_boy]

Do you have the L-Jetro or the D-Jetro? What FPR/pressure/injectors/pump are you running? On the sensor check screen of the commander what values is it giving for your sensors?

[240sxcl50]

Ok I have an aeromotive fpr Tomei 750cc injectors and the l jetro which values should I look at