View Full Version : Big, Weird Problem 76 DeVille

DopeStar 156
09-16-08, 12:26 PM
Well, I decided to go outside today and just check up on my rides. I went over to my 76 DeVille and wanted to check out the condition my spark plugs were in since I've never looked at them before. I pulled the wire on the plug directly in front on the passenger side, unsure which cylinder that is. When I pulled the wire off the electrode on the end of the wire stayed on the plug.


So I removed the wire and brought it into the garage and with a pair of pliers and a flat screwdriver, put it back together. When I reattached everything and started the car up, the idle speed was through the roof. The car even after dropping the fast idle was still really high.


09-16-08, 09:01 PM

vacuum leak (knocked a vacuum line off)

secondaries sticking from sitting too much, sometimes they will stick open a little, see if you can push the secondary linkage forward with your finger.

DopeStar 156
09-18-08, 10:19 PM
Well I fixed it. Replaced the broken ignition wire and doused the carb in Gumout. Runs fine.

09-19-08, 11:47 AM
Good call on the carb spray down. Now that so many of us are used to FI, we often forget how gummed up a carb can get, especially on a hobby car that sits around a lot.

DopeStar 156
09-19-08, 06:12 PM
It runs and drives ok but it's very hesitant, sluggish (for a 500) and my poor fuel economy light is always on, even at idle. I was thinking fuel filter since it ran outta gas while I was running it a while ago or maybe something's still stuck and wore out my pedal return spring or something......

09-19-08, 06:40 PM
Fuel economy lights and gauges are always vacuum-based. If that light is on at idle, something is wrong. You need to get at it and figure out why the vacuum is low. A full tune up is in order. New cap and rotor, plugs and wires, set timing, and check all the vacuum lines. Fresh filters (air/fuel). New breather and PCV. You can't adust the mixture on that carb, but doing everything else should help.

Get the vacuum up, that light will go out, and the car will run better. A plugged cat is a possibility, too. Do you have to get it checked in NJ? If not, probably not a bad idea to replace it with a pipe. I would never suggest this on a daily, but on an occasional use car it won't make much of a differnce to the planet.

DopeStar 156
09-20-08, 05:22 PM
Jay you're right again....

I was snooping around and noticed a vacuum line coming from the firewall that went to a T intersection. It was disconnected with a 1 inch piece of dried up, disintegrating vacuum line at the bottom of the T. Going back up it then connected to the underside of the air cleaner. I noticed a vacuum connection behind the carb on the top of the engine. I chipped off the old dried up line and replaced it all with fresh new rubber and reconnected everything. Started the car up, the green economy light came back on (well it would have if the bulb wasn't burnt out) and the engine ran much smoother. Still feeling a slight studder when I first press the gas though, got a new fuel filter going on tomorrow, maybe that'll help. We were all sold out of PCV valves for my car at work so I didn't pick one up on my way out today.

I also changed the air filter and noticed the old one was filthy, a little wet, and reeked of gasoline. Dirty I understand but why would it be wet with gas?

09-21-08, 04:03 PM
on a semi-related note... does anyone have a vaccum diagram for a 75 8.2 liter? i put one in my '69 coupe and it runs fine but there's some lines disconnected and im wondering if thats why i'm not too impressed with the performance

DopeStar 156
09-21-08, 07:46 PM
There's prolly some shit on the 75 that requires a vacuum connection that the 69 doesn't have, like the fuel economy lights for example. I would think you'd have some left over stuff. Just try plugging them up so you don't lose the vacuum.