North American Turbocoupe Organization



Sputtering under boost
grevels Offline
Junior Member
#1
I'm new to the board but have been poking around for awhile, doing research. I've got a 100% stock 85 TC that is having a problem under boost. When it gets to about 10 PSI it begins to sputter and will not pull until I back off and let the boost drop. I have replaced the FPR, the fuel filter and EGR, It is a 5 speed car. I haven't pulled any codes yet. I have tried disconnecting the various sensors to see if they were bad but no noticible difference. The exhaust is not clogged, thought it was but it isn't.

I suspect it is a fuel delivery problem, but with the stock injectors do you think the fuel pump would be running out of fuel or fuel pressure under boost?

I will try to check the idle fuel pressure in the morning.

Also, would going to a carb with a hat be worth the effort? I can get all the parts I need pretty reasonable to do the swap if it will help with this problem or would it be more of a pain to tune than what it is worth?

thanks
Gordon
Reply

Pete D Offline
Administrator
#2
Hello and welcome.

I would recommend you run the complete fuel system diagnostics including at boost since that is where the problem is. Fuel pressure at idle does not tell you what fuel pressure under boost is. It is thouht that the stock fuel pump may lose capacity with age.

Pulling the codes is always a good idea. Also how old is the tuneup and what brand(s) of parts do you have in it. old or weak parts may succum to the additional stress of boost.

http://www.turbotbird.com/techinfo/Fuel_...ostics.htm
http://natomessageboard.com/cgi-bin/ulti...0;t=000004
Pete Dunham


Reply

grevels Offline
Junior Member
#3
Tune up less than 500 miles ago using Motorcraft parts or parts recommended from this as well as other turbo sights. I believe I will try and after market FPR made by kirban as soon as I find the sight again.

I will eventually need a better one anyways because I plan on boosting it up a bit over time.

Thanks
Gordon
Reply

Pete D Offline
Administrator
#4
http://www.jdsperformance.com/index.asp?...e=all&pg=4
86 to 93 Mustangs - KIR5005.
Pete Dunham


Reply

grevels Offline
Junior Member
#5
Thanks

Gordon
Reply

Crawdaddy Offline
Member
#6
How much gap did you put on the plugs? Too much and you will get missfires under boost.
86' 5.0/AOD K&N, MSD, Headers
88' TC T-5 Speed pro forged pistons, Lunati turbo cam, Racer Walsh Valves Intake 1.89" SS Exhaust 1.59" SS 1470 Springs 1476A Retainers, PST front and rear, MM Caster/Camber plates, BBK Pressure regulator, Gillis Valve
92' SC stock
95' LX 4.6/AODE stock
Reply

grevels Offline
Junior Member
#7
I started with 32 but backed it down to 26 without any change.

BTW, I live abour 20 minutes east of Knoxville Crawdaddy.

Gordon
Reply

Pete D Offline
Administrator
#8
Quote:I started with 32 but backed it down to 26 without any change.
You shouldn't have any problems at 0.032" with a basically stock set up, even if you turn up the boost some.
Pete Dunham


Reply

Jeff K Offline
Administrator
#9
An AFPR like the Kirban isnt going to help you now if the fuel pump cant keep up at current boost levels. A fuel pressure test under boost will rule in or rule out a weak pump, plugged filter, etc.
Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 24 psi, forced air IC, water injection, BPV, Ranger cam, subframes, etc., etc.
86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP N2O, ignition, gears, suspension, etc., etc.
05 Taurus SEL Duratec daily driver
04 Taurus Duratec (wifes car)
02 Pontiac Grand Prix GT
95 Taurus GL Vulcan winter beater
67 Honda 450 Super Sport - completely customized
Reply

Crawdaddy Offline
Member
#10
I will come take a look at the car if you would like. My name is James Crawford.

Email: [email protected]
or call me 423-494-0098
86' 5.0/AOD K&N, MSD, Headers
88' TC T-5 Speed pro forged pistons, Lunati turbo cam, Racer Walsh Valves Intake 1.89" SS Exhaust 1.59" SS 1470 Springs 1476A Retainers, PST front and rear, MM Caster/Camber plates, BBK Pressure regulator, Gillis Valve
92' SC stock
95' LX 4.6/AODE stock
Reply





Users browsing this thread:
1 Guest(s)



Theme © iAndrew 2018 - Software MyBB