North American Turbocoupe Organization



rev limiter
Ricky03 Offline
Senior Member
#1
I noticed that if I rev over 6k that my car starts to miss like it's hit the rev limiter. It will continue to miss for a minute or so then everything is O.K. It's almost like I flowed a lifter or something but no tapping. I did install a new Walsh stage #2 cam and lifters a few months ago. I didn't have this problem untill I did the 5 speed swap. I still have the auto computer in the car. Should I change to an LA3, I already have one just didn't change it. I did add a new 255 Walbro fuel pump but it didn't help.
It's an '88 Turbo Coupe. Other than this everything is great. It's still pulling hard at 6k and should rev higher. What should I do??????????
88TC :5 speed swap,255 walbo fuel pump, 3" down pipe with 2 1/2"duals, Ported upper and lower intake, ported E-6, Kiben adjustable fuel pressure regulator,T-3 turbo,Forge BPV,Steeda Tri-x shifter,Autometer gauges,Racer Walsh stage #2 cam, Spec stage 3 clutch,Stinger FMIC
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Joe F Offline
Posting Freak
#2
The rev limiter in 87/88 TC is set to 6,250 rpm to the best of my knowledge. The only way to raise it is to (1) go totally aftermarket (such as SDS or similar) or (2) get an EEC tuner. The way it limits rpm is to cut off fuel flow once the limit is reached, so yes it would miss and stutter.

I don't know what the limitation of the stock valvetrain is but I suspect you could bump it up to 6500 or so with no problem. The LA3 won't help you here since it has the same rev limit.

Hopefully someone a little more knowledgable will jump in here.

HTH.


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Be Cool,

Joe

JR's Place - My 87 TC

[This message has been edited by JoeCool (edited 10-27-2004).]
JR's Place - My '87 Turbocoupe
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Pete D Offline
Administrator
#3
When the engine hits the rev limit, the EEC cuts off fuel supply, like hitting a brick wall. As soon as rpms drop, fuel is restored. At least that is the way it has worked on mine and I've bounced the rev limit more than once. If your have problems for several seconds or longer after onset, I would guess that something else is going on, like lash adjuster pump up
Pete Dunham


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Jeff K Offline
Administrator
#4
There is a little bit of hysteresis, or "play" in the rev limit..... fuel shuts off at 6250, and isnt restored until 100 - 200 RPM or so lower than the cut off RPM. Thats what gives the characteristic "chug - chug - chug" feel when you hit the rev limit.

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Jeff Korn

88 Turbo Coupe: Intake and exhaust mods, T3 turbo at 21 psi, forced air intercooler, water injection, bypass valve, Ranger roller cam, subframes, etc., etc.. // 86 Tbird 5.0 (original owner): intake, exhaust, valvetrain mods, 100 HP nitrous, ignition, gears, suspension, etc., etc.... // 91 Escort: Bone stock winter car // 02 Taurus Vulcan(wifes car)
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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