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Topic: Vacuum Diagram anyone? (Read 860 times) previous topic - next topic

Vacuum Diagram anyone?

I just got a free (hooray) 1985 Cougar 3.8 w/3spd auto. The thing runs like it's stuck in molasses, all boggy-like, and gets around 8mpg. I took a look, and quite a bit of the OE vacuum equipment is missing/capped off, so I was curious if anyone had an ACCURATE (no chilton, ick) Vacuum diagram for the '85 base model Cat with the 3.8, speed density injection. I'm going to start with replacing the O2 and water temp sensors, then possibly the MAP sensor, but even so, the vacuum issues are something that will need to be adressed.

Thanks,
Andrew

Vacuum Diagram anyone?

Reply #1 –
Quote from: Lupinestarfox;202231
I just got a free (hooray) 1985 Cougar 3.8 w/3spd auto. The thing runs like it's stuck in molasses, all boggy-like, and gets around 8mpg. I took a look, and quite a bit of the OE vacuum equipment is missing/capped off, so I was curious if anyone had an ACCURATE (no chilton, ick) Vacuum diagram for the '85 base model Cat with the 3.8, speed density injection. I'm going to start with replacing the O2 and water temp sensors, then possibly the MAP sensor, but even so, the vacuum issues are something that will need to be adressed.

Thanks,
Andrew


Andrew.  To get the best you need an emissions book that covers that model.  Try the library.  Or, to get just a diagram you can get those on line at Auto Zone.  They are pretty hard to interpret compared to the emissions book when you're trying to identify parts.  If most are capped off you may be missing some other bits too.  There's a row of vacuum modules underneath the radiator overflow tank that controls the EGR.  There's also a bunch of vacuum parts along the right side of the engine behind and underneath the alternator and smog pump.

It can be quite complicated.  Believe it or not having all the emissions equipment installed and working will net you a gain of 12mpg over what your getting now.

Good luck.
Armed Forces Car Club
Eastern Sierra Chapter, California
WEB:  armedforcescarclub.com

Vacuum Diagram anyone?

Reply #2 –
Take codes so you kinda know where to look for problems.
someone on here can post or send a diagram.
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +

Vacuum Diagram anyone?

Reply #3 –
Yep, I am pretty much assuming that many modules, tanks, and hoses will be completely missing. I'll check out Auto Zone to see if they have anything. I figured the car -should- be getting around 20mpg under ideal conditions. There are no emissions requirements in my state, but in the 80's, so many sensors and intake things depended on the entire emissions system to be working, as you all surely know :P

Hopefully there will be junkyard finds for me in the future, as I don't intend to spend much money buying new vacuum solenoids/modules/tanks, but at least a diagram could give me an idea what i do and do not have.

Thanks,
Andrew

Vacuum Diagram anyone?

Reply #4 –
Take codes,if you don't know how search.
Old Grey Cat to this.88 Cat, 5.0 HO, CW mounts, mass air, CI custom cam, afr165's, Tmoss worked cobra intake, BBK shorty's,off road h pipe, magnaflow ex. T-5,spec stage 2 clutch, 8.8 373 TC trac loc, che ajustables with bullits on the rear. 11" brakes up front. +

Vacuum Diagram anyone?

Reply #5 –
not to sound like a know it all but there isnt a vac line on the 3.8 i have not seen or deleted.

In my diy link there is a write up on smog delete which will define all color lines near and far end terminations.

you should have 5 colors, black, tan, green, orange and red.

The shop manual has a better illustration on the 3.8 vac layout but the evtm does not so i wont post it.  any ole 3.8 motor with CFI will be the same configuration from 84 to 87, 83 was a lil different but not "exactly" like yours.

just keep in mind, when your talking about a vac leak, explain why you think there is one.

Another good idea is to check the CFI for carbon buildup per my diy link as well.

just post up the color vac line and ill reply when i get time or someone else will jump in.

8mpg is a sign of major issues, that much fuel being dumped into the cc leads to bad bearings and rings.

Since the car was free, you have one  helava budget to place on new items for repairs.


If there has been someone under the hood taking things out and whatnot, I will bet pulling codes is fruitless.  It does not take much for the 3.8 eec to go directly to code 11 and remain on open loop.
 

Vacuum Diagram anyone?

Reply #6 –
There should be a vacuum diagram on the fan shroud. This is a logical diagram and does not tell where things are physically located.
If you need help figuring out what the abbreviations mean, or where things are, post them.

When you put the ignition in run without starting the car, you should hear the fuel pump run for a second or two then shut off.
If it runs continuously you have an EEC problem.

What do the plugs look like?
How is the compression?
Check the fuel pressure for 39 psi. Does the pressure hold after you shut down? If the pressure does't hold the injectors may not be sealing and dumping in excess fuel.