So I just bought this 87 TC 5speed and it has only been getting to 6psi in all gears. I installed an after market boost/vacume guage and I get a perfect 20lbs of vacume but I still only get 6psi. Last night I was driving with the heater on high and noticed that when the motor builds positive manifild pressure the heater would lose pressure and then build up again. Very odd... I'm going to check all the intercooler hoses in the morning. Any ideas?
What exactly do you mean by "heater would lose pressure"? My guess is maybe you've got some cracked vacuum hoses. Inspect your vacuum lines and replace any that look suspect.
^^^^ +1
Explain "heater looses pressure".
id say the check valve on the passenger side for the heater is toast and thats your problem...try doing the same thing again and ill bet the heater is transfering from the front vents to the defroster when it happens.....
^ 4cammer72; that is exactly what the heater is doing this morning. I pulled the check valve and it works with just my lung power but as soon as the part stores open up im gonna grab a new one.
I replaced the check valve that 4cammer72you suggested but it did not rectify the issue. It is still only producing 6psi on a new aftermarket gauge. I checked all the hoses and they are all in good shape. The only thing I found wrong is my pcv valve has blow by on the intake side. I do have a small puddle if oil on the turbo compressor intake tube. Would that cause my boost issue?
When you blow through your PCV valve to simulate boost, do you fill anything on the lower side (i.e. the side going TO the crankcase)? If you feel even the smallest amount of air, replace the valve with the Ford part only or install a check valve... preferably both. ]
I don't see that affecting your heater, but it could affect you low boost pressure.