: 1977 deville, and the 425

09-27-04, 05:37 PM
Im finnally driving my 77 deville, but it is the gutless wonder. Sure, it does actually push me back in the seat from a stop sign, but i have to give it 1/2 to 3/4 throttle up small hills to keep at 25.

The only time this car burn rubber was when the transmission went into neutral when i was crusing through a parking lot at 5mph. I slowed a little for a stop sign, then gave her about 1/4 throttle for a turn... The engine roared up without moving the car, and i heard a clunk, then RERRRRRRRCH.

The timing is at 12 degrees BTDC, the sticker on the fan shroud says it needs to be 18 degrees BTDC. would this have much of an effect on the hill-climing power?

also, the engine idles like a drag car (exhaust popping and glugging) with the engine throbbing on the mounts. I figure its a carburetion problem, since the car heasitates when i go from crusing at 10mph to 1/4 throttle, and then onto 1/2 throttle.

Now this is a fairly fresh engine (about 1,000 miles), so it isnt a problem of worn-out parts. Is my car just a gutless wonder from the factory, or should it at least have the balls to power-brake one wheel?

And finnally, if i unhook the vaccume advance, will the car still run normally or not? (car idles a bit better with it off, using 92 octaine gas)

09-27-04, 08:14 PM
Put the vacuum advance back on! The Idle might be too high, try to turn it back to the point where the lever is resting on the little rod thing it should rest on at idle. Get a timing light and adjust it to 23-degrees at 1600 rpm. It should be bouncing around a bit, mine does too('79 coupe deville w/425+q-jet) Test the choke pull-off to the left of the carb(from front) and see if is hard to push back. If its sloppy replace it. The part is only like $23. Make sure to get the carb. number on the right side of the carb. Next, there are two small screws on the left side almost underneath of the carb that need to be pulled out, these are very hard to see. I have no Idea how far, a good mechanic did it for me, and unless you know what you're doing i'd suggest you do the same. After you've done all this check the timing once more. Try it out. Mine lagged a whole bunch too, and I too though it was the carb. The only carb part it was happened to be those two screws and the choke pull-off. The choke pull-off isnt really a big part of the problem though. If you know any genious mechanics ask them. They'll probably know more than I do.

10-03-04, 07:44 PM
You need a new fuel pump! I had the same problem with mine...no balls at all... found out from an old school tech that there was a problem with a malfunctioning check ball that returns excess fuel at idle...essentially starving engine for fuel when stuck open...replaced mine, and it screams now!

Night Wolf
10-03-04, 10:23 PM
something I noticed with my 425...

... if i am going 10mph (say after making a turn onto a road0 then give it 3.4 gas... it'll stay in 2nd, and run on 2bbl and accelerate... but sluggishly.... now to an unspspecting person, they may think that their foot is almost to the floor, and there i no power.... but if I put my foot to the floor at 10mph, she'll downshift into 1st, adn the secondaries will open, it'll put me back in the seat and accelerate nicly...

...although it sounds like there are some other issues going on with your enigne... the fuel pump may be a good idea...