stumbling and choking after 5,000 rpm? - Page 4 - Miata Turbo Forum - Boost cars, acquire cats.

Welcome to Miataturbo.net   Members
 


Prefabbed Turbo Kits A place to discuss prefabricated turbo kits on the market
Sponsored by:
Sponsored by:

Reply
 
 
 
LinkBack Thread Tools
Old 01-13-2007, 11:03 AM   #61
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,438
Total Cats: 84
Default

Just another thing to check. If your plugs and wires are good, gap your plugs down to about .035"
olderguy is offline   Reply With Quote
Old 01-13-2007, 03:34 PM   #62
Junior Member
 
Join Date: Jan 2005
Location: United Kingdom
Posts: 255
Total Cats: 0
Default

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.
tabs604 is offline   Reply With Quote
Old 01-13-2007, 04:45 PM   #63
Boost Czar
iTrader: (61)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 72,872
Total Cats: 1,790
Default

Quote:
Originally Posted by jayc72 View Post
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.

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?
Braineack is offline   Reply With Quote
Old 01-14-2007, 11:49 AM   #64
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

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??
Mimime is offline   Reply With Quote
Old 01-14-2007, 12:01 PM   #65
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

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?


Quote:
I am still running with the linear AFPR, took out the vortech
Ben is offline   Reply With Quote
Old 01-14-2007, 12:53 PM   #66
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

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.
Mimime is offline   Reply With Quote
Old 01-14-2007, 12:56 PM   #67
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,438
Total Cats: 84
Default

The Vortech is connected to the fuel hard line coming up into the engine bay where? Forward, or toward the fire wall?
olderguy is offline   Reply With Quote
Old 01-14-2007, 02:20 PM   #68
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

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?
Mimime is offline   Reply With Quote
Old 01-14-2007, 02:27 PM   #69
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,438
Total Cats: 84
Default

Quote:
Originally Posted by Mimime View Post
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?
olderguy is offline   Reply With Quote
Old 01-14-2007, 04:20 PM   #70
Ben
Supporting Vendor
iTrader: (33)
 
Ben's Avatar
 
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,689
Total Cats: 99
Default

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
Ben is offline   Reply With Quote
Old 01-14-2007, 11:20 PM   #71
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

Olderguy, the actuator was never touched nor tempered with.
Mimime is offline   Reply With Quote
Old 01-17-2007, 11:45 PM   #72
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

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.
Mimime is offline   Reply With Quote
Old 01-17-2007, 11:53 PM   #73
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,438
Total Cats: 84
Default

Quote:
Originally Posted by Mimime View Post
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.
olderguy is offline   Reply With Quote
Old 01-18-2007, 12:21 AM   #74
Elite Member
iTrader: (14)
 
Join Date: Mar 2006
Location: Edmonton, AB
Posts: 4,921
Total Cats: 0
Default

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?
jayc72 is offline   Reply With Quote
Old 01-18-2007, 12:46 AM   #75
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

the FP reads fine, since I took out the Vortech and running a linear AFPR. At 0 atmostpheric the FP gauge is reading 55psi.
Mimime is offline   Reply With Quote
Old 01-18-2007, 01:01 AM   #76
AFM Crusader
iTrader: (18)
 
olderguy's Avatar
 
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,438
Total Cats: 84
Default

Quote:
Originally Posted by jayc72 View Post
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?
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.
olderguy is offline   Reply With Quote
Old 01-18-2007, 01:11 PM   #77
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

OK...! just spent 20 mins.. prep up for the O2 clamp. Testing session at sunrise...crossing my fingers!
Attached Images
File Type: jpg O2 clamp.JPG (168.1 KB, 21 views)
Mimime is offline   Reply With Quote
Old 01-18-2007, 11:08 PM   #78
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

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

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

Any clue?
Mimime is offline   Reply With Quote
Old 01-18-2007, 11:59 PM   #79
Senior Member
Thread Starter
iTrader: (1)
 
Join Date: Sep 2006
Location: Hong Kong
Posts: 523
Total Cats: 0
Default

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
Mimime is offline   Reply With Quote
Old 01-19-2007, 12:02 AM   #80
Elite Member
iTrader: (14)
 
Join Date: Mar 2006
Location: Edmonton, AB
Posts: 4,921
Total Cats: 0
Default

Glad to hear you got it sorted out! Bruce is great. He gace me a similar eureka moment with my old EMB setup!
jayc72 is offline   Reply With Quote
 
 
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
My solution for Oiltemp and Oilpressure input into Megasuirt (MS3) Zaphod MEGAsquirt 41 01-24-2016 01:25 PM
Low oil pressure after 1.8 swap and new turbo setup JesseTheNoob DIY Turbo Discussion 15 09-30-2015 03:44 PM
Are my coils failing? viriiguy General Miata Chat 5 09-28-2015 08:39 PM
The "other" spool question stefanst DIY Turbo Discussion 44 09-28-2015 08:16 PM
6ULs for Sale in Green Bay JStoops Miata parts for sale/trade 0 09-28-2015 06:35 PM


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -4. The time now is 11:05 PM.