stumbling and choking after 5,000 rpm?
#63
Boost Czar
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,490
Total Cats: 4,079
If could be how the fuel is being delivered and not necessarily how much. Although the quantity would certainly make a difference.
If it was a coil pack why does he see the problem at WOT (building boost) and not at 1/2 throttle (no boost)? Same with plugs? Wires? Afm? Not talking about a large amount of boost.
It looks to be boost related, and the one thing that is directly refrencing boost is the Vortech unit. Now a vacuum leak might show up at higher boost levels for sure, but it sounds like he's having the problem right at cross over to positive manifold pressure. Just went the FPR starts to clamp down on the return.
Car was fine (I assume) NA. So what did he change? A turbo (duh) and a whack load of extra fuel.
I'm not being argumentitive, I just don't want to poor bastard to go and replace plugs/wires/coils only to find out the FPR is label backwards or some ****.
Start with the basics, confirm what you've changed.
If it was a coil pack why does he see the problem at WOT (building boost) and not at 1/2 throttle (no boost)? Same with plugs? Wires? Afm? Not talking about a large amount of boost.
It looks to be boost related, and the one thing that is directly refrencing boost is the Vortech unit. Now a vacuum leak might show up at higher boost levels for sure, but it sounds like he's having the problem right at cross over to positive manifold pressure. Just went the FPR starts to clamp down on the return.
Car was fine (I assume) NA. So what did he change? A turbo (duh) and a whack load of extra fuel.
I'm not being argumentitive, I just don't want to poor bastard to go and replace plugs/wires/coils only to find out the FPR is label backwards or some ****.
Start with the basics, confirm what you've changed.
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?
#64
Senior Member
Thread Starter
iTrader: (1)
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
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??
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??
#65
Supporting Vendor
iTrader: (33)
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,659
Total Cats: 134
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?
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 still running with the linear AFPR, took out the vortech
#68
Senior Member
Thread Starter
iTrader: (1)
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
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?
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?
#72
Senior Member
Thread Starter
iTrader: (1)
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
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.
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.
#73
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.
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.
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.
#76
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.
#79
Senior Member
Thread Starter
iTrader: (1)
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Gessus!!
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!
Thanks everyone for their comments and time!
My Miata is finally boost smoothly! CHEERS to everyone!
Stephen
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!
Thanks everyone for their comments and time!
My Miata is finally boost smoothly! CHEERS to everyone!
Stephen