Expert: Rob Painter - 2/8/2010

Question
QUESTION: Hello,

I have a 1985 Cadillac Sedan DeVille it has the 4.1L V8. When I go to start it, it takes a few tries and it does start but when I push the gas pedal down it dies. It's like everything stops and the car wants to die and most times it will but other times I'm able to nurse back into running. And when i let it go(run) it dies within a few seconds. It does have a throttle body on it and i don't know if maybe the throttle body is inhibiting it from running or if there is something other then that that is wrong. It had been sitting for about a month when i got it. And from what i can see there is a vacuum leak going into the cab of the car and goes to the E-Brake, there is another leak from a 1/4" vacuum line running along the valve cover, and there is a plugged line coming off of a T from the diaphragm. I know they have a little bit to do with the problem but I don't see as how they could be the whole problem. It seems like there is a bigger problem. Any help you can provide to me would be greatly appreciated and if you have any questions just let me know.

ANSWER: Hello,

You state there is a vacuum line broken at the E brake. One very big problem for you is that the E brake is totally mechanical and does not use vacuum. Now, there is a sizable diameter hose that has vacuum that goes to the brake booster. If that hose is broken, the engine probably won't stay running especially if there are aditional broken hoses.

Change the broken hoses before doing anything else. You already admit you have a number of hoses broken or disconnected so they need to be changed. You state that it hard for you to believe that the vacuum lines would keep the engine from running.

In stead of guessing, it is more important to repair the known problems first.

If you have more than one vacuum hose bad, you better change them all because conditions were right for thos decay. Its a cheap fix that just takes some time. See if the engine will run then and thats when you can get backvwith me.

Rob

---------- FOLLOW-UP ----------

QUESTION: I read in a service manual that there is a vacuum actuator at the parking brake assembly that uses a vacuum line from the engine's vacuum system. I think this is the line and i connected all the lines and i already did the vacuum line going to the booster. Could it be a bad throttle body?

Answer
Hello,

The problem is that I am in Texas and I don't know where you are. Without eliminating many different things, you are strictly guessing.

I don't see where a throttle body would get gunked up after sitting for only a month. Put some goggles on and have someone try to get it running good enough that you can spray WD-40 on and around the intake, on and around the outside of the throttle body. If the RPMs raise, you will find your vacuum leak if that is what it is.

Is the exhaust clear? Could a rodent gotten inside the exhaust. I had a Jeep in the fall in my garage. It sat for about a month. Could not keep it running, so I babied it down the road and slowly but surely put more gas in. Then all of a sudden, I had lots of power after I saw the family of dead mice come out the exhaust!

Of course, I can't give you the solution without being at the vehicle, but I am trying here.