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Old 10-10-2006, 09:50 PM   #1
boxoftj
Scooby Newbie
 
Member#: 120944
Join Date: Jul 2006
Chapter/Region: South East
Location: Fort Bragg, North Carolina
Vehicle:
2004 STi
Aspen White

Unhappy Hydra, car starts, bad idle, dies under throttle

Just completed a 2.5l swap, stock WRX heads. mods are as follows:
gp moto headers w/ up-pipe.
bosal DP
gutted main cat
HKS cat-back
intake resonator elim mod w/ K&N drop-in
stock injectors
stock turbo
rear 02 sensor mounted in front bung pre-turbo (i dont plan to use this sensor, really, bu since hydra doesn't use front o2 sensor, Phil said it'd be cool to put the rear one up there)
WB 02 in rear stock location, inside cat.
besides mods, the rest of the car has 81k miles, heads, sensors, injectors, etc.
new parts: crawford S2 short block
NGK plugs included with install kit, heat range 11
coil packs (replaced because i thought this was the issue to begine with)

with that taken care of, here's the problem.
I decided to start running the hydra with the 2.0l map, but in closed loop mode from 800-4500rpm, because i figured the closed loop mode would automatically decide the injector pulse-width. it started up, no problems other than the idle being a little lumpy, prolly just need to tune the PID for the IAC. ran great for about 60 miles, i wasn't hard on it, nothing above 4k rpm, no boost, no throttle above 50%. i thought i had complete my first engine build with no trouble. i stop the car to let it cool down and rest. and i come back to it to start it and now all of a sudden i've got a horrible misfire (sounds like). replaced coil packs, used a spark plug sand blaster to clean the plugs. started up again, same problem. idle is REALLY lumpy, oscillates up and down, and when you give it gas it stumbles, rpm doesn't really rise and it sounds like its missing. i've checked each plug, and each is firing. fuel pressure checked out. could one of my injectors be sticking? really, it almost sounds to me like the MAP sensor is jacked, but its brand new and inside the hyrda, checked the vacuum hose, no kinks. checked all the connections around the map sensor hose/FPR, any brittle hoses i've replaced so i doubt there's any cracks in the hoses and everything is hooked up. I'm not really sure what i should be watching for on my laptop while i'm logging data and whatnot, so any pointers as to what i should look for would be appreciated. I've shot an e-mail to Phil as well, and he usually always e-mails me right back unless he's busy or out of town, so i'm guessing that's the case now. what does anyone else think? also, my crank and camsaft sensors are mounted tight and plugged in, anyone think one of these might have gone bad? appreciated the help, sorry for the novel post. just trying to get all the info possible out there.

Thanks
Matt.
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Old 10-11-2006, 03:30 AM   #2
WhiteKnight
Scooby Newbie
 
Member#: 56133
Join Date: Feb 2004
Vehicle:
2004 Euro spec Sti
Black - Rotated gt3037s

Default

It can be a dumb question but i want to ask as a reminder,

Did you calibrate your TPS ?
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Old 10-11-2006, 10:40 AM   #3
x99percent
Scooby Specialist
 
Member#: 27108
Join Date: Oct 2002
Chapter/Region: MWSOC
Location: Detroit-ish, MI
Vehicle:
2004 STi
2004 A4

Default

Quote:
Originally Posted by boxoftj View Post
NGK plugs included with install kit, heat range 11
Ummm... What plugs did they give you?

If the part number ends in "-11", that's not the heat range, that's the gap... as in 1.1mm, which is WAY too large for your car. You *can* gap them down to the normal .028-.032", but it's not recommended by NGK.

Quote:
Originally Posted by boxoftj View Post
I decided to start running the hydra with the 2.0l map, but in closed loop mode from 800-4500rpm, because i figured the closed loop mode would automatically decide the injector pulse-width.
If you've got the Hydra configured to use the wideband, don't use closed-loop at idle. I think the narrowband might be able to deal with idle + closed-loop, but I've never tried it.
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Old 10-11-2006, 05:07 PM   #4
Element Tuning
Former Vendor
 
Member#: 54918
Join Date: Feb 2004
Chapter/Region: MAIC
Location: Gaithersburg, MD
Vehicle:
673 WHP Element
Tuning Pro Comp Engine

Default

Turn your closed loop off at idle, ie just leave the lower and upper limits where I set them in the base map. Also are you sure your plugs are heat range 11? They should be 6 or 7 at the most or they will be too cold and will foul very quickly.

Also letting us know what your AFR at idle is and under cruise would be very helpful to determine if this is a tuning issue. Your Hydra also shows you all the parameters you need to know such as boost or vacuum to check for normal running.

Thanks,
Phil
www.elementtuning.com
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Old 10-11-2006, 08:50 PM   #5
boxoftj
Scooby Newbie
 
Member#: 120944
Join Date: Jul 2006
Chapter/Region: South East
Location: Fort Bragg, North Carolina
Vehicle:
2004 STi
Aspen White

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i've been busy at work so i haven't had another chance to look at it but i'll get back to everyone. Yeah, i've calibrated the TPS, it did run great for 60 miles, remember.
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