I recently had my head gaskets replaced by the local speed shop. Unfortunately, they didn't know how to put the vacuum system back together properly. Now the cruise control system is out and I'm having idling problems.

The problem stems from the arrangement of vacuum tubes leading from the two ports, one over the other on the left side of the intake manifold.

Can anyone with a '95 or '96 advise, 1) to which port, (upper or lower) the t-valve is attached, and 2) where the total of 3 vacuum tubes lead ?

Thanks,

Brian

 

not sure if this will be of any use, but this is a shot of the passenger side vacuum routing on my old '95 LT1. But T-valve goes on top for sure.

 

Thanks - That is a help. Any advice from anyone on where those three vacuum tubes go?

Brian

 

The single tube coming off the bottom nipple goes to the fuel pressure regulator. Off the top of my head (not home at the moment) I think the two coming off the tee go inside the firewall to the HVAC system.
There should also be a vacuum routing diagram sticker on the driver side of the radiator housing near the top.

If no one else chimes in I can look around under hood on my '95 after work this evening and report back.

edit: also, be sure to check the opti vent tube assembly where it connects to a vac nipple on front of intake directly underneath the throttle body-- even if it looks like its on good, make sure the rubber is still soft and stretchy so it grips good.

 

Thanks Ranger - It would be a huge help if you could identify where those two from the tee go. The existing diagram on the left front of the radiator housing do not speak to those pieces.

Brian

 

I have to apologize. I got involved in another project after work and did not look at my '95 as agreed. I will pop the hood tomorrow as I plan on stopping by home for lunch.

 

I understand about life! Thank you for the help.

 

Okay, I took a good look, but don't know if it will help much. As can be seen in MikeC4's photo the two lines coming off the tee go into the wiring harness. They are buried in it. But, it is apparent that one of them, which one I don't know, comes out of the harness underneath the battery and runs to a tee for the cruise control. The cruise control tee has three nipples: one goes to plastic vac line from the vacuum reservoir up in front left fender in front of wheel (vac line goes into wiring harness but exits and connects to the reservior on bottom of reservior-- make sure this vac line is securely attached to bottom of vacuum reservior, but be gentle else risk break off vac nipple on reservior = BAD). Other one goes to the vacuuum line I just traced coming out of the wiring harness, the third one goes to the smaller (thinner) of two rubber vacuuum lines that come off the cruise control module. The larger of these two rubber cruise ctrl lines is marked 7/32" and it goes through the firewall and up into the under dash area about four inches away from and parallel to the steering column and into a module that you can feel but not see (not without a dental mirror or something).

Referring back to the photo from MikeC4 the other line that goes into the wiring harness I cannot locate it coming out of the harness, so I have to assume it must enter the firewall with the harness somewhere. The most likely place is where the harness Y's off just behind the passenger side cylinder bank-- it goes into what looks like an HVAC (heater/AC) module on the firewall, and the other part of the Y runs along the firewall behind the engine and when following you can eventually find the one I described in 1st paragraph that comes out of the harness where the harness is down under the battery.

No way to tell which one coming from the tee near the intake on passenger side goes to the cruise ctrl and which one is going to the HVAC module on firewall, without pulling the wiring harness apart. That is, we know two go into the wiring harness but we see only one coming out (under battery and then into cruise ctrl tee), and we assume the other is going into the HVAC module on firewall (near HVAC blower assembly). But we can't say for sure where the unseen one really goes with hacking up the harness. And we don't know which of the two that bury into the harness comes out under the battery, but it has to be one of them.

I hope this isn't too confusing, because it sounds confusing when I proof read it.

 

If I didn't already mention, the tee valve attaches to the top nipple and the fuel pressure regulator vac line attaches to the bottom one.

 

Thank you for your help. I truly appreciate that you spent the time to poke around for me. I'll dig in with a print out of your note in my teeth this weekend. I will put this back together!

Thanks again,
Brian

 

No problem. Let me know in this thread this weekend or by PM if you need any photos.