North American Turbocoupe Organization



87 TC getting no boost
wyattk94 Offline
Junior Member
#1
Hello im new to the forum and i just picked up my own 87 TC 5 spd.

I'm having an issue with my boost, the stock boost gauge will climb to 5lbs of boost in any gear but it wont go past that. with that being said i dont even think the car is making 5 lbs of boost. i think its running solely off the motor as its very sluggish. I removed the IC today and tomorrow i plan on checking the turbo to see if it will spin easily and checking the wastegate to see if that is holding pressure. if anyone has anymore advice or what to do to troubleshoot where the issue is coming from that would help a lot.
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wyattk94 Offline
Junior Member
#2
quick update, i noticed the BCS has two nipples on it and there arent any vacuum lines attached to it. im not sure if they bypassed that or not. does anyone have a vacuum line diagram ( im waiting for my chiltons,haynes manuals in the mail) not even sure if those will show those diagrams
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Pete D Offline
Administrator
#3
http://turbotbird.com/faqs/Vac_Diagram.htm
Check IC hose for leaks also,
Pete Dunham


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anasazi4st Offline
Senior Member
#4
wyattk94 Wrote:does anyone have a vacuum line diagram ( im waiting for my chiltons,haynes manuals in the mail) not even sure if those will show those diagrams
Eventually (even if you get the BCS fixed) you’ll likely want to go with a Gillis Boostvalve for the turbo, much better and replaces the stock unit. It’s $60 and well-spent—Read more here.

Might I also suggest that if you are serious about keeping your TC running well, purchase a set of original Ford shop manuals. There are 6 in total, including Engine and Drivetrain, Body (2 books), the EVTM (Electrical and Vacuum Troubleshooting Manual), a 1988 Update manual, and a valuable volume on Emissions testing.

I have used my Haynes manual quite frequently over the past near-30 years and I do consider it very valuable, but nothing beats the original Shop Manuals. They shouldn’t be that hard to locate (try eBay or post a message in the Wanted to Buy here) and they might be a bit pricey, but I for one would not be without them.

Also—you want the grey Haynes manual, “Ford T-Bird & Mercury Cougar 1983 thru 1988” edition. There was another that came out and included the later models, but it is (IMHO) almost useless compared to the other. It’s too watered-down and tries to cover too many different vehicles. Again, search eBay. I picked up a second copy there for about $7—the binding came apart on my original one years ago, I punched holes in the pages and put it in a looseleaf binder. I keep that one in the car, the other is for my workshop.
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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firebirdparts Offline
Junior Member
#5
2nd the motion here on factory shop manuals. I absolutely would not want to live a day without them.

Welcome to the forum, I am also a bit of a newbie to the club. I always wanted one and bought it less than a year ago.
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Rob H Offline
Junior Member
#6
I was interested when I logged in to see this post. After replacing my wastegate actuator my car now behaves the same as this. I get almost exactly 5 on the boost gauge as well.
If the weather is decent tomorrow I'll be replacing the boost control solenoid with the Gillis valve.
I was told by the guy I got my parts from as far as he knows that is about normal if you have the fuel switch set to normal. He told me if I set it to Premium I should get more boost. When I tested that I did not find that to be true, I don't know if the fact that I'm only running normal fuel in it currently would have anything to do with it or if his information was incorrect.
I'll let you know if there's any change after putting the Gillis valve in
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Jeff K Offline
Administrator
#7
Before putting in a Gillis valve, disconnect and plug all hoses going to the BCS and turbo compressor. Run a line from an unused bung on the vacuum tree directly to the bung on the WGA. This should net you 9 to 10 psi boost in all gears. If you dont get 9-10 psi boost, you either have a big boost leak (split hose, loose hose clamps, etc) or the turbo has internal problems.
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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Rob H Offline
Junior Member
#8
That sounds easy enough. If I understand you correctly I would basically be doing the Gillis valve installation procedure except removing the valve from the equation. The instructions I got with it for installation have a line coming off the vacuum tree to the inlet of the valve and the outlet going to the wga. Testing it the way you're saying rather than go through the valve it would go directly from the vacuum tree to the wga. I would still disconnect the same hoses, as well as plugging and capping where the hoses came off with the parts supplied in the kit?

I'll give this a go once the rain lets up hopefully this afternoon. Also, not sure if you remember Jeff but I was replacing my wga because when I was driving I would have to be careful with my acceleration, boost gauge was going all the way up and I was worried I was going to wreck something. With the new wga in I don't have that problem but I do have the low boost.
Also sorry wyattk94. Not trying to hijack your post, I was having my own problems with my Turbo. Was finally able to get around to replacing some parts and came back on to report the changes to find your post talking about exactly what I I was now noticing with mine. Hopefully the information here will help us both
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Jeff K Offline
Administrator
#9
Yes, hook up vac lines as explained in the Gillis instructions, just dont put the Gillis in.
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
#10
Rob H Wrote:I was replacing my wga because when I was driving I would have to be careful with my acceleration, boost gauge was going all the way up and I was worried I was going to wreck something.
You might not be aware, but there is an OVERBOOST SOLENOID located near the right fender and above the turbocharger. When activated a normally unseen amber lamp will light on the instrument panel (it looks a lot like the amber ABS warning light) and an annoying buzzer will go off. This should happen at 17 lbs boost and above.

The Overboost Solenoid is kind of fragile, especially in its advanced age (and obviously no longer available), so it’s probably a pretty good idea that you DON’T hit 17 psi in your boosts, for this and many other reasaons. Most of us would hope we never see/hear this thing go off.

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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