"Turbo Warning Switch" ???

[Sick Puppy]

I just had a guy call me looking for a "turbo warning switch". He said the smog dude told him there was supposed to be two and he was missing the lower one. Does he mean the overboost buzzer switch? I'm lost because in my SVO race car all that stuff is long gone and I never owned a stock one that ran.

I'm going out now to look at my (non-running) parts junk to see if I can figure this out. :confused:

Thanks, Paul

[brownsvo]

There is a buzzer/light that ive never seen light up even when pegging stock boost levels... it shouldnt be required for smog test unless all lights in dash must work.

[Mike S]

There is a pressure switch (over boost) next to the EGR valve on the back side of the PS strut tower. It has a vacuum line feeding it. It is only a warning light and has nothing to do with emissions. The EGR solenoid valve on the other hand does. You need to get clarification of the exact failure.

[Sick Puppy]

After some investigation I found the '84s have the two solenoids behind the strut tower. The top one is EGR and the bottom is overboost, does this sound right?
I guess my '86s only have one (EGR) as the over boost is under the dash...
I'm going to call this guy back and get some more details.
Thanks for the responses,
Paul

[MikeFleming]

The SVO has the EGR solenoid, two hose connections, on the top of the bracket and the OverBoost switch (set to 17.5 +/- 0.5 PSIG) on the lower bracket. When that switch is triggered it simultaneously illuminates the red O'BOOST lamp (varies by year) on the left side of the instrument cluster and the buzzer.

My apology for all the red.
1799


For the NON-SVO turbo 2.3L OHC cars pre-1987 there are two Overboost switches. One of them switches at 0.5 PSIG and higher and illuminates a green "Boost" lamp on the dash (no boost pressure gauge). The other switches at 11.5 PSIG (+/- 0.5) to activate the Overboost buzzer and a red overboost indicator on the dash.

From the training manual reprint that everyone should have (for the non-SVO):
1800

Note there is a bulb/buzzer test in crank mode.

In my experience most of these switches get melted by the close proximity of the exhaust system and stopped functioning decades ago.

[Sick Puppy]

You guys are awesome. Not only did you answer/verify my SVO question, you gave me valuable info that I can use for my '84 GT Turbos.
Thanks for the visuals Mike! I must be lucky, all the lights and buzzers in my 'vert still work! I have the boost valve set at 14psi so when I hear the buzzer it's time to shift!
ps: nothing wrong with red, my SVO is red, my GT turbo 'vert is red, my Focus SVT is red, my '83 GT is red, both my F-250s were red...

[MikeFleming]

Refer to the wiring diagram above - Yes, there is a fuse (unfortunately the diagram above does not ID the specific fuse). That is different from the Boost Control Module fuse on the early cars (which is behind the dash).

If the previous owner was complaining of low boost, then the wastegate actuator can probably needs to be replaced. As it gets exposed to heat over time, the spring weakens and the base boost level drops accordingly. Look up the test procedure for the wastegate actuator - should be open 0.015" with 10 PSIG (+/- 0.5PSIG) applied. If it's like 0.250"+, then it needs to be replaced.

Be sure to verify any other boost control mods again after replacing the actuator. Things will change quickly.

[8T6 SVO]

Here are the part numbers:
1984 - Boost Control Valve - E3ZZ-9D474-B
1984 - Boost Switch manifold pressure - E4ZZ-10D883A
They are impossible to find.

[escogt]

Sorry to bring up an old thread, but where is the exact location of the 'overboost buzzer'?

[MikeFleming]

With the seat belt buzzer behind the passenger dash directly behind the fuzzy dash panel on the right. Iirc there's a key buzzer, a seat belt buzzer and the o'boost buzzer.

I have some pics of the panel that mounts the buzzers at home.

[escogt]

With the seat belt buzzer behind the passenger dash directly behind the fuzzy dash panel on the right. Iirc there's a key buzzer, a seat belt buzzer and the o'boost buzzer.

I have some pics of the panel that mounts the buzzers at home.

Thanks Mike. Pics would be great!!

[MikeFleming]

Here's a few pics from an 86 dash showing the normally rusted mounting plate that holds the buzzer thingies. There's three different ones. Remove the glove and you can contort your hands and arms up there to access them around/between/behind the air handling ducting. having two (or more) swivel joints between your wrist and elbow helps a bunch. Naturally it's pretty easy ot access with the dash out and on the bench - hence the pics.

78717872787378747875

[Sick Puppy]

Thanks Mike, this will help me too when I swap the harness in my 2R this winter.
I have those same rusty brackets in my car, they must come from the factory pre-rusted...;)

[escogt]

Thank you Mike!!!