225 bucking and surging in gear while stopped....

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73SlantSwinger

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73 225 swinger runs great except when at a stop when its warm.....in gear at a traffic light, stop sign, etc it will buck and miss, rpms drop, vehicle shakes. Could the idle just need to be bumped up a little? timing issue? 106K on the odometer, pretty much stock.....just does this under a load, when you rev up no miss or hesitation......thanks
 
I would look at a basic tuneup, Including checking the timing and idle speed. Check all vacumm lines, and do a valve adjustment.
 
Vacuum lines ive looked at, recently replaced distributor cap, rotor, plugs, plug wires.....maybe i will try and adjust idle speed when in gear???
 
Get a vacuum gauge and check your vacuum. You should be between 17 to 20 inches of vacuum. I put a super six setup on mine and had low vac and replaced this then that to only find out that my valves were out of adjustment. I went from 12 to 19 inches of vac and now the 6 is running great.
 
My 69 Dart 225 ran like that for decades until I got a good Holley 1920 carb and it purred like a kitten. All the others idled too lean. I had pursued vacuum leak theories, changed manifolds, head jobs, ... After a new long block and same problem I thought must be the carb. I had only tried 3 before that. Look for a rich/lean indicator on ebay. I have bought them for $25 w/ O2 sensor. Otherwise, you are always flying blind.
 
I had my grandfather look at it, he's rebuilt so many carb's over the years its crazy, and with all the chrysler's he's owned over the year's, i wanted to get his opinion. He said there were a few things out of adjustment, also said it was running really rich loading up dumping way too much fuel....i'm gonna let him re-build it and we'll go from there....keep u guys posted....as dirty as it looks, i'm sure it could of used a good tear down anyway.....
 
You didn't tell us which carb you have. If the Holley 1920 (side bowl), there is an internal metering block that you can't easily rebuild. I think those get clogged and is why there are so many bad rebuilt ones out there. When pristine, they run great. Your symptoms sure sound like too lean, especially slowing way down in D and bucking. When too rich, an engine usually "dies quietly", pouring out black smoke before that.
 
It could also be a torque converter issue, trying to lock up. If all else fails, try looking at that.

Mike
 
Update: grandfather rebuilt it, looks great. Said it was extremely dirty, missing c clips, gaskets were toast, and when taking off, two of the bolts holding to manifold were hand tight.....we fired up, ran rough at first, played with the settings a little, took on drive, still has those symptoms we started off with.....maybe try timing??
 
Are the valves clacking away? May be time for a valve adjustment. Is your EGR valve stuck open? I'm thinking, I'm thinking...

Mike
 
valvetrain is quiet, previous owner bent the vacuum fitting on the egr valve, it doesnt have a cap on it....could the points be off causing this? im gonna check the vacuum tomorrow....this has me stumped.
 
Is it an automatic trans? There are sections in the service manual that discuss bucking and surging, but I don't remember what in the trans caused it.
 
DustyRoads said:
Is it an automatic trans? There are sections in the service manual that discuss bucking and surging, but I don't remember what in the trans caused it.
Click to expand...

I am very interested in this if you could track some of that info down. Or what book/manual the info is in.
 
Update: sprayed some brake cleaner around the intake manifold bolts and sure enough that's the problem....i think at least 4 out of the 6 runners were leaking, time to replace the manifold gasket.....is this a difficult job? doesnt look that bad besides the rusty freakin bolts im scared will break off...
 
Most suggest removing the intake and exhaust as a unit and keeping them tightly together. However, yours might not be aligned properly (why it leaks) so you might need to separate them. The bad part is that the 3 thin bolts that attach them are the most likely ones to snap. Spray the bolts w/ WD-40 and let sit overnight. When you loosen, try working both in and out to help free the rust. It will help a lot if you have a real long 3/8" socket drive extender to get at the lower, inner nuts. There is an excellent post on slantsix.org showing how to orient the triangle washers. Someone linked to it here recently. If you don't get them correct, the exhaust manifold can later crack, and they go opposite what most people would think.
 
Better yet, use PBlaster or Kroil if you can find it. They are formulated for creeping into rust and breaking it loose. The "WD" in WD-40 is "water displacing. Made for general lubricatio.
 
Be careful these intake/manifold bolts are only tightened to 15 Inch pound NOT foot pound!!! PB blaster soaking at least 5 hours and going out there an shoot them a couple times and wire brush what thread you can get to slowly remove these!! In out in out till they remove easily to prevent braking one and use a 1/4 in ratchet... I recommend not useing the fel-pro gasket... use the good one . no leaks in 3 yrears and 9.000.00 miles of daily driving.

One of my big problems was the flange bolts so PB plast it also :coffee2:
 

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A good gasket is worth the money thats for sure. When I was going through the trials of trying to find my vac. leak one of the things I did was replace the intake/exhaust gasket and this one was suggested to me http://catalog.remflex.com/MOPAR_Header_Exhaust_Manifold_Gasket_p/6008.htm It's a little pricey but well worth it. The price includes both gaskets which is good to have. It's a nice thick gasket that crush molds to the intake/exhaust manifolds so if they are not perfectly flat the gasket will fill in where needed as long as it's not a big gap. Good luck, go easy on the bolts and I hope this solves the problem.
 
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