Dead Vacuum advance

[06Daytona]

I have a feeling that my vacuum advance is dead. The car runs and idles nicely until I put it in gear and try to take it for a spin. Then it starts feeling like I'm towing a D8 CAT. I popped the distributor off and sucked on the advance hose and nothing happens now. I checked it a few weeks ago and it seemed to be working, but not now. How difficult is it to replace one on my distributor? I've done it on Chev stuff before and it wasn't too difficult. I'll be replacing the rotor at the same time since it looks like it got hot at some point.

[Supercuda]

Not quite GM-easy, but still not too bad. If you have decent mechanical skills, it's easily enough accomplished.

[Chryco Psycho]

if you just reset the timing at around 12-16* at idle & 35-38 above 3000 rpm the car should run great without the vacumm advance connected

[06Daytona]

I'll try that. I ordered a new vacuum advance module today, but it won't be here for 3 to 5 days so I'll reset the timing until it gets here.

[BB73Challenger]

I tune to Chryco's specs. and now have no vacuum advance on the Chally or Cuda.
They both start great, idle nice and pull/drive fine.

My vacuum adventures started when replacing old distributor with new Mopar model and it WAY over advanced. (In Challenger - Cuda still has original distributor)

Now no problems.

[Aussie Challenger]

Vac advance is really only an economy devise and should have no effect on the performance of the motor. If you do a lot of cruising then it will help with the MPG a bit.

[moper]

Actually it depends on how you define performance. If you mean wide open throttle acceleration, then yes, it's not really important because it doesnt function during that. If you mean perforamnce bt the way of throttle response, power, and economy when driving on the street at any throttle position besides idle or wide open, it's a very good thing to have. The fact that it's so misunderstood is what makes it useless to many. There is a point that they will cause more issue than deliver benefit, but that's when the camshafts get much larger or whn a combo is mismatched.

[06Daytona]

Apparently I'm a little braindead at the moment. I replaced the coil, wires, rotor and I have the vacuum advance sitting at the store waiting to be picked up. I didn't bother to replace the cap because it looked good. I picked up a cheap timing light so I could play with the timing a little and the clamp wasn't getting enough juice to flash the light. I tried it on the Charger and it worked fine, so I know it's not the light, and I even tried it on my neighbors Toyota since he has 7mm wires on his car too. I thought the clamp might have too much play so it wasn't picking up anything but apparently that wasn't the case. I guess I'll be picking up a new cap when I pick up the vacuum advance tomorrow. I dunno why I didn't just replace cap, rotor, coil and wires all in one shot.

[Aussie Challenger]

Spare parts stores love people who just buy and replace everything, I have seen my fair share of cars over the years where people have done that and still not fixed the problem so bring it to my shop, sometimes it can be quite simple.   

[Bullitt-]

Strange that you don't get a signal for the timing light...try putting the pickup on other plug wires on the Cuda, you can't use to time but this might help determine where the problem lies. 

[Aussie Challenger]

I meant to mention in my previous post that I have used a timing light pick-up to test leads when a scope wasn't available because it can find a dead lead.   

[06Daytona]

I forgot to mention that I tried it on number 3 wire and I got an intermittent signal there. I've replaced the vacuum advance, the coil, plug wires, rotor and cap now. It still won't start without a hassle. I noticed that the piece that goes beside reluctor looked a little worn, and it didn't seem to be set to any particular gap but it was adjustable. I can't remember the name of the bit at the moment. I was planning on replacing all those parts at some point, so changing them now doesn't bother me too much. Somebody was nice enough to paint everything under the hood with runny, nasty flat black paint so having a few shiny bits isn't too bad either. I had the same problem with my Pontiac last summer and it turned out that the points just needed re-gapping. I can put the insurance on next week, so I'd like to have it running well enough that I can at least get it to a shop if I really need to. I'm not really familiar with Mopar ignition systems yet, so I don't know what to look for or replace yet.

[Moparal]

Well, it was running before you changed the vacuum advance and started moving around the pieces inside of the distributor. The magnetic pick up and reluctor must be out of adjustment now.  When you installed the advance, you moved the plate out of adjustment some how. It will start and run once you get that stuff dialed back in. A rebuilt electronic distributor is 35 bucks or so,for the whole distributor, this would get you going faster if you do not understand the internal parts............

[06Daytona]

It was running, but it wasn't running well, and it wasn't starting all that easily. I thought about just picking up a new distributor, but I want to learn all the little things about Mopar stuff that I can. When I've got the car starting and running well I'll move on to the alternator and rebuild it just to see how it goes together and to clean it up a little.

[06Daytona]

Pulled the distributor back out again. Took the whole thing apart to the point of removing the reluctor and the bits below it. I didn't touch the springs or anything at the bottom to the distributor though. I wire brushed the outside to get off the coat of nasty flat black, and gave a good cleaning to all the pieces before I put them back in. There was overspray on everything under the cap, so I figured it couldn't hurt. I set the reluctor gap to .008 since I read than in an article that I found online. Put the distributor back in the car and hooked everything up and turned the key. The car finally started like it just came off the assembly line. I'll need to set the timing now, but it hasn't started that well cold since I picked it up. I guess the next step is to see if the tranny or rear end need any love.