North American Turbocoupe Organization



Help ****FIXED****
Littlehoe Offline
Junior Member
#1
Ok so I have the timing right, new cap rotor plugs. Car will idle with iac unplugged set idle, and tps. Plug in iac and the rpms drop and the car stumbles and dies. If I crank up the idle stop the car will idle fine at 1300 rpm and up. What should I check next?
1987 Turbo Coupe, Auto and running... Yippeee
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boosted chicken Offline
Senior Member
#2
How old/gunked up is the IAC? They are pretty picky about being able to move freely inside.
88 TC#1 Boport stg 3 alum dport head, PT6466, Boport header, CP pistons, Crower rods, MS2xtra
88 TC#2 drag car project(someday)
88 TC#3 parts car (just needed the header panel...bought the whole car, lol)
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goldwing Offline
Senior Member
#3
I sprayed carb cleaner in mine then worked the spring a few times. I also spray cleaner in the little port on the intake.
I had to do this twice in a 3-4K miles period one time. Its been working perfect the last 7-8K miles.
T.C:87 5 speed
HOLSET(HE341/HY35W type-D),255 Walbro, No intercooler yet,8lbs boost,Timing @ 9,Low& C.C Plates & SN-95 Bumpsteer Kit, KYB-AGX Struts,Belt driven fan,Custom oil cooler feed,Relocated ECT,Relocated TFI,N/A Hood, showing 178K
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Littlehoe Offline
Junior Member
#4
I have had it off and cleaned it out about 3 times now. it moves freely inside. Unless the motor part of it is hooched.
1987 Turbo Coupe, Auto and running... Yippeee
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Littlehoe Offline
Junior Member
#5
well it runs, Went out for a drive, anything off idle is great, nice and smooth, lots of power, making good boost. but when I come to a stop it runs rough, sounds like it is missing a bit on idle... it even stalls from time to time when it is sitting on idle. But there are no codes at all, no check engine light. I really don't know...

Could it be an egr?
1987 Turbo Coupe, Auto and running... Yippeee
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Pete D Offline
Administrator
#6
Sounds like an air or vacuum leak which could include the EGR if it's dirty enough to be holding it partially open. The EGR does not normally open at idle. If you can put a vacuum gauge on it you should see 18-22" at warm idle. Less than that would indicate a leak. Start looking for cracked vacuum lines or disconnected lines.
Pete Dunham


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w60 Offline
Senior Member
#7
is there a diode in the IAC? If the diode is bad will the IAC function correctly? Not trying to hijack the thread, I've read that there is a diode and wonder if there really is one and what happens if it is bad.
http://www.mycoachonline.com
White 88 TC Auto Trans
White 04 Honda CR/V
Blue 74 Honda Trail 70
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Jeff K Offline
Administrator
#8
Diode is in the harness. Its there to protect the EEC from the inductive kickback voltages generated as the IAC pulses on/off. (IAC is a PWM modulated solenoid). Open diode just puts EEC at risk of damage, shorted diode = no IAC function at all. Partly shorted diode could cause idle problems I suppose.
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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Dan S Offline
Administrator
#9
+1 on Pete's comments above.

Did you go through the steps in this write up?
http://turbotbird.com/techinfo/Idle-TPSa...e2005.html
Dan S
Custom 88 TC, Mandarin Copper Pearl Metallic
http://natomessageboard.com/ubbthreads.p...5#comments
1972 Ford F-100 SWB Styleside
2015 Lincoln MKC 2.3 EcoBoost AWD
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Littlehoe Offline
Junior Member
#10
yes I followed that to a T. I have now hooked up a vacuum gauge to the tree and it is only showing about 10 when the car is idling with the miss. Add some throttle and the vacuum goes up but still not to the spot it should be.

Could it be that I don't have the cam timing set properly, that is the only thing I can think of now... maybe one tooth to late? I know I was having issues lining up the crank mark with the tc and then getting the cam marking to the middle of the three tabs. It appeared a little ahead or behind, never exactly where I thought it should be.

So in your guys opinions should I attempt to advance the cam one tooth and try it again that way?

Also I am only getting about 9 psi boost. is that normal for a stock auto?
1987 Turbo Coupe, Auto and running... Yippeee
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