North American Turbocoupe Organization



Solved: High idle and stumbling on throttle?
DR1Pilot Offline
Member
#1
[video:youtube]https://www.youtube.com/watch?v=PbZIF-AC_Hg&feature=youtu.be[/video]

I cannot figure out what the problem here is. Idles high and has some pulsing too. Almost sounds like misfire or possibly running on only 3 cylinders? Stumbling under throttle.

A little background, just got done replacing the head gasket and some mild gasket matching. EGR housing cracked so I just deleted it all together.

Started up and ran like crap so I checked for fuel in the rail, set the timing to 10 deg BTC, checked that the header was tight, checked for possible locations of vacuum leaks but I'm not sure beyond checking for cracking or loose hoses where to look.

Any ideas or thoughts? Any aid is appreciated.
Project 88 T-Bird 74k original miles
and a Loud Moped
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Jeff K Offline
Administrator
#2
Check fuel pressure and check for vacuum leaks again. Consider pressurizing the intake to find vac leaks or do a smoke test.

Stock IC? If so, it is easy to not get the turbo to IC hose seated correctly resulting in a bad vac leak.

Are you 100% sure the cam timing is correct? What is the idle vacuum?
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
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DR1Pilot Offline
Member
#3
I was going to do the propane test for checking vacation leaks. My brother suggested it.
As for fuel pressure... not liking the price on those testers. Any diy solution you guys suggest? Found a few online but nothing I can get locally.
Project 88 T-Bird 74k original miles
and a Loud Moped
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Jeff K Offline
Administrator
#4
Many auto parts stores will loan you a FP gauge for free with a $100 or so fully returnable deposit.
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
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DR1Pilot Offline
Member
#5
Got the car to run a little better. Still idles high even with the TPS set to .95V. Throwing a CEL if left on for a minute so I'm going to try and run a self test
Project 88 T-Bird 74k original miles
and a Loud Moped
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DR1Pilot Offline
Member
#6
Should I be able to blow any air through the Idle Air Controls valve when it is not active?
Project 88 T-Bird 74k original miles
and a Loud Moped
Reply

Jeff K Offline
Administrator
#7
Be sure to run the complete self test..... KOEO, CM, and KOER.
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

DR1Pilot Offline
Member
#8
SOLVED! The high idle was related to the TPS being slightly off (over 1V).
The occasional misfire and stumbling on WOT kicks was either the distributor cap and rotor or ignition wires.
Luckily that was the first thing I checked that actually cost me any dough. But at least now the injectors and VAM are clean!
Project 88 T-Bird 74k original miles
and a Loud Moped
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Not B Anymore Offline
Administrator
#9
Excellent news! Thank you for posting the solution as well.
Brian Leavitt
'86 TC 5-Speed -- MS2x w/COP | 83 lb. injectors | T3/T4 50 Trim Stage 3 .63AR | Full 3" Exhaust - No Cat | Motorsport FMIC | Ranger Roller | Ported E6 | Walbro 255HP | Kirban | 20psi | 120-amp 3G | 8.8" 3.55 rear | '03 Cobra Wheels
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