what is going on. UCL installed**

95MkViii

Dedicated LVC Member
Joined
Dec 28, 2010
Messages
1,018
Reaction score
2
Location
Fairfax Co
ok i know how hard it is the pin point a vacuum and even harder when you cant see the car. but yesterday i replaced the UCA on the drivers side. and now i have a major vacuum leak.

i removed the master cylinder (i disconnected the hose going to the vacuum booster and plugged it, that didnt solve my problem)
dropped the air shock to remove the bolts holding the UCA in place.
and broke my cruse control cable (anyone have one :shifty:)

but dose anyone one have any idea where my vac. leak could be. things to check?

my car is idling high! (2k rpms)
and when i rev it, it takes for ever for the rpms to come back down.
 
You mention you broke your cruise cable. Did you disconnect it from the TB? If not then its probably just a kink in the cable causing the problem. Same thing happens when a throttle cable starts fraying.
 
There is an oring between the MC and the booster... You may have dropped it.
 
How is the t-fitting in the back? Behind the throttle body. Maybe when working the boost line you moved a few other lines and that t-fitting finally gave up. Its probably the number one location for Gen one leaks.
 
take the master cylinder back off and properly put it back in to the booster, i garauntee you, that when you slid it back in to the booster the rod didnt go in where it was supposed to. you have to make sure you put the master back in dead straight and slowly. i did this when i put derek's motor back into his 97 mark i couldnt for the life of me figure it out, then i realized he had the master off before the car came to my shop. well that was it, i took it off and slid it back in making sure the rod was straight going into the booster and WALLA problem solved. i gotta ask though, why the hell did you take off the master to do a control arm. jesus some of you guys make upper control arms so difficult, and then you end up with 4 more problems when you are done. whats the problem changing uppers???
 
No idea how the :q:q:q:q I'm going to get the bolts out with a mc in the way.

The MC is I stalled correctly l. But for arguments sake I took it off again and still it idles at 2k.
 
Take a small propane torch and spray it (no flame) around the intake with it idling. Where the engine speed changes is where the leak is.
 
Just for fun, take the vacuum hose off of the brake booster and plug it. See if you still have your problem.
 
Already did that.

Turns out when my dad was tighting the nuts he rubbed the pos wire going to the fuse box and fried my PCM. :(
 
Anyone got a PCM for a 95 with trac?

Or a hotter PCM out of a 93 with trac?
 
Not sure I buy that one... Not that I think this is your problem, but IACs do that when they are bad. You either have a vacuum leak or something is holding your throttle plates open. A "fried" PCM will cause a lot more than a high idle. Are your 2 marks both the same PCM code by chance? I would bet money it's not the PCM.
 
Turns out when my dad was tighting the nuts he rubbed the pos wire going to the fuse box and fried my PCM. :(

i don't believe that.
either something else is wrong, or you have a bigger problem, and something else is wrong.

have you verified that comp. is dead?
switch it out, i know you have another car.
 
well. i spent 8 hours up with my ford guy. he is dumb founded. trased the problem to the MAS. we unplug it, its run. runs ruff but it runs at 800. plug it in and it runs at 2k (it dies if i unplug it with motor running) where getting 12 volts to the power of the MAS. no leaks PCM is good. IAC's good, everything is good. we checked everything on the top of the motor. even unplugged the vac lines on the intake manifold and plugged them. still ran at 2k...

switched the PCM with the one out of my other 95. DZA1 same pcm
switched the MAS with the one out of my other 95

any ideas? i have no idea at this point....
 
I'd say bad TPS also. Had a 96 lsc that did the same thing. I would swap the whole throttle body off the other car. Easy to change.
 
IF your iac is bad, unplugging it alone will not make it close. If it is open, then it is stuck open...
 
Try hitting the iac with something when it running.
Sometimes it will free up and you know the problem.
 

Members online

Back
Top