low boost?

Topic: low boost? (Read 861 times) previous topic - next topic

low boost?

March 26, 2012, 12:41:50 PM

Hi i am a 'new guy' thanks for having a great forum!
have a 88 tc/auto, it only seems to get about 4lbs of boost, the car has 150k miles and otherwise runs well. what should these boost to? is the turbo or wastegate bad? i have never owned a turbo car before. so this is all new.
thanks in advance for any help!

low boost?

Reply #1 – March 26, 2012, 05:07:52 PM

Welcome to the forum! Feel free to make an introduction thread and tell us more about yourself and your car(s)

I think the 87-88 auto cars are supposed to make around 10 psi. I would make sure all your clamps are tight. You may just have a boost leak. Also make sure the wastegate actuator rod isn't stuck open. Is the car terribly slow? I can't imagine 4 psi being fun...

low boost?

Reply #2 – March 26, 2012, 08:40:08 PM

thanks for the reply. I have a couple pics of the car, and need to load them in,

yes the car feels like a non turbo 2.3. the previous owner said something about the wastegate being sticky. so thats possible. what does that take to 'unstick it? thats assuming i know what a wastegate is or where to find it. i assume its next to the turbo impeller?

low boost?

Reply #3 – March 26, 2012, 08:54:55 PM

If the wastegate is stuck open the exhaust is bypassing the turbine and not letting it build full boost. Here is a pic of the wastegate actuator. It is the goldish part on the left with the rod coming out of it. The rod attaches to the flapper arm. If the rod is binding or rusted it may not shut properly. Also attached is a video of how the wastegate actuator should snap shut.

http://static.photobucket.com/player.swf?file=http://vidmg.photobucket.com/albums/v648/Loaded87IROC/CIMG0462.mp4

low boost?

Reply #4 – March 26, 2012, 09:08:22 PM

so i should unhook the arm and see if the flapper has full travel and snaps back? if it doesnt, is there anything i can do to free it up without taking off the turbo? i suppose i should check and see if the actuator holds vacuum too.

low boost?

Reply #5 – March 26, 2012, 09:38:12 PM

Hi, welcome to the forum!

The 87/88 auto TC is indeed suppose to boost 10 psi. The low boost could be several things. If it has been sitting I would start with a good tune up, plugs, wires (use Motorcraft plug wires), cap, rotor, fuel filter, oxygen sensor, and check for vacuum leaks.

The factory boost controller could be bad. It is the small, black, round, sensor looking thing mounted to the passenger side inner fender that has two vacuum hoses and an electrical connector coming out of it. The factory boost controllers are obsolete, but many of us run a Gillis boost control valve. You can get one from here.
http://www.boostvalve.com/ford.html

Here is an install guide for it.
http://www.turbotbird.com/techinfo/GillisValve/GillisValve.htm

Also the factory boost gauge has been known to be very inaccurate, but if the car feels like it is a non-turbo 2.3, then that probably isn't the case.

On a side note here is a list of beginners mods for more HP, but beware that the A4LD doesn't like the extra power!
http://www.turbotbird.com/techinfo/Mods/Mods01.htm

Edit: The wastegate may be stuck, but out of the multiple TCs I own none of them have had a stuck wastegate. Not saying it isn't possible, just that I have not personally run into that yet.

low boost?

Reply #6 – March 26, 2012, 11:06:23 PM

wow thanks for the tips. once its daylight again, i will try and check the actuator rod. is there a test for the factory boost solenoid? i assume the aftermarket BoostValve kit makes the boost adustable past 10psi? its cheap enough to try i suppose. I also will check all the clamps and hoses.
the car should get a fuel filter and some plugs at least. the wires are fairly new, although not motorcraft. the car has been sitting and only started and idled occasionally for a couple years. when i test drove the car the first time last week, the boost did seem to get up to maybe 8 or 9, but only on that first drive. since then i put 10 gallons of fresh premium gas in it. also if it matters, when i test drove it, the fuel switch was on regular, now since then i have switched to to premium, but still has low boost.