North American Turbocoupe Organization



88 TC 5 Speed Low Boost (IHI turbo)
88Slowbird Offline
Junior Member
#1
I've got a 5 speed 88 TC that's only getting 9-10 PSI with the premium switch on

pulls 19-20 vacuum at idle

I have an aftermarket Autometer boost gauge that shows vacuum and boost up to 30 PSI

Haven't found any vacuum leaks, has a new air filter if that matters

where should I look next?
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Jeff K Offline
Administrator
#2
BCS or fuel switch relay may have failed or you may have a wiring issue.

Do yourself a favor and pitch the stock boost control system and get a Gillis manual boost controller which will let you set max boost to anything you want. Plus you will get max boost in all gears and boost will come in quicker.
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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anasazi4st Offline
Senior Member
#3
(12-06-2019, 02:13 AM)Jeff K Wrote: BCS or fuel switch relay may have failed or you may have a wiring issue.

Do yourself a favor and pitch the stock boost control system and get a Gillis manual boost controller which will let you set max boost to anything you want. Plus you will get max boost in all gears and boost will come in quicker.

^^^^ +++++

I’ve done that and I’ll never go back to the BCS.
Another proud dues-paying member.

1987 Turbo Coupe w/T5OD, 8.8 axle, grey smoke; most options. Got it in 1991 with 41K miles: 3 turbos, 2 heater cores, 1 T5OD full rebuild, 5 clutches, 1 head gasket, 2 Teves II ABS units, etc. later....
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Kuch Offline
Member
#4
Slowbird, I had a similar issue with my 88 TC after checking multiple things I found that the wastegate actuator road was seized up on the flapper on the turbo. It looked like it was somehow welded to the pivot and I had to pry it off and then sand it down and re-install. As it wouldn't pivot and close, it was only building low boost, if you have a vacuum tester, something like a mightyvac you can hook it up to the wastegate and put some air pressure on it to check movement. just something else to check out
1988 Turbo Coupe, Black/Black, 5 Speed, Moonroof,  T3/T4 50 trim, ported E6, 255LPH, BBK AFPR, 3" DP dual 2.5" w Hooker Maxflows, MGW shifter, K&N, Gillis valve, RR cam
1964 Ford Galaxie 500XL, 390 6V, 4 Speed, Vast and fast
1960 Ford Starliner, 292 Y Block, 3 Speed, slow and low
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