North American Turbocoupe Organization



no boost ?
vfast Offline
Member
#1
for some reason and all the sudden car has no boost...if I rev it up it will flash about 4psi..what is the black thing by the vane that has 2 vac lines going to it and a electric connection? could that be the problem?
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Ryan H Offline
Posting Freak
#2
That would be the boost control solenoid, and I doubt that is the problem. At the least, you should be getting 9 PSI (the default wastegate setting).

Some things to check:

- Check the codes!
- Gauge accuracy
- Vaccum/boost leaks
- Cam/crank timing alignment

These are the easiest things to check for IMO. If all of these are alright, I would check the actual wastegate and make sure it is still attached to the flapper arm on the turbo, and that the spring isn't weak.
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Jeff K Offline
Administrator
#3
Are you just free reving it sitting in the driveway? If so, you should see very little, if any, boost (unless you hold it at WOT and let it bounce off the rev limiter, which isnt a good idea). Boost depends on engine load = exhaust flow. Free reving puts almost no load on the motor = very little exhaust flow.
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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vfast Offline
Member
#4
no boost when driving either..timing is 12 degrees as I just installed a new timing belt...the flapper arm is attached and isn't frozen....tubro doesn't leak oil either..does have a small exhaust leak but had that when it had boost of about 7-8 psi. I have replaced most hoses as there were a few leaking but no changed...
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Pete D Offline
Administrator
#5
When did the problem start. Was there anything that was changed just before the problem started (like the cam belt??)
Pete Dunham


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Ryan H Offline
Posting Freak
#6
When you say the flapper arm isn't frozen, are you implying that it moves freely? If so then that is a problem. The flapper arm shouldn't move more than just enough to tell with the eye that its moving. It should be very rigid.

Also like Pete said, what else have you changed? Did you actually check the marks again, or are you just going on where they were positioned after you did the belt? The belt could have jumped a tooth or two by now, so you would need to actually check it again.
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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vfast Offline
Member
#7
as for the belt I checked it 3 times car idles great, timing is correct. marks line up. so that part is all good.... the no boost was happing before belt broke....as for the flapper it's not that easy to move and you can actaully hear a vacuum like sound. the only problem with car is the vain, if pluged in idle isn't very good so I unpluggged it and it idles and runs fine to a point..I'm waiting on the replace vain to come in....only thing I think is the peller have hit the housing??????so maybe try replacing the actuator first????? I have a used turbo coming
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vfast Offline
Member
#8
?????
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Ryan H Offline
Posting Freak
#9
If you can hear a vacuum like sound, you probably have a leak there. Whether or not this is affecting your boost I don't know, but it sounds like there could be a problem. I would bet on the vane airflow meter being the culprit. If you don't have it plugged in, your car can't meter the air properly. Wait until you get the replacement in.

For future reference, it does help to list things like this when posting the problem.
'88 TC Smile Walbro 255HP, Stinger FMIC, PIT BOV, Pro 5.0, Kirban, RR cam, FRPP strut tower brace, T3
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Pete D Offline
Administrator
#10
Are you saying the turbo impeller has defintely hit the housing?? Can you see witness marks on the inside of the housing? If yes, then that could explain where some/all the boost loss is. Like Ryan said, get the Vam thing straightened out first.
Pete Dunham


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