Guest Posted March 10, 2003 Share Posted March 10, 2003 I have a 73 Delta 88 with a 455 and a TH400. It is my daily driver and usually has no problems. Sometimes, however, when I shift into a drive gear (forward or reverse) the engine almost dies. I have to pump the accelerator pedal and start moving to keep the engine running. Then, when I start driving, the engine feels bogged down. This happened several years ago and some grit in the needle and seat in the carburetor was the culprit, but there is no sign of flooding this time. I would appreciate any advice that I can get. Link to comment Share on other sites More sharing options...
another old car Posted March 10, 2003 Share Posted March 10, 2003 bdchave you tryed replacing fuel filter might be fuel pumpsounds like engine running out of gasjust a few ideasaoc Link to comment Share on other sites More sharing options...
Guest Posted March 11, 2003 Share Posted March 11, 2003 Thanks. Actually, the fuel pump and filter are only about 4 months old. I have not tested the pressure/flow rate yet, but since they are so new, I would not expect them to be the problem (Knock on wood). Link to comment Share on other sites More sharing options...
DoubleSnorkel Posted March 11, 2003 Share Posted March 11, 2003 Had the same problem with my 66!!! the base gasket between the carb and intake manifold was bad! To check this and be careful, start the car up and let it run until it is warm!, Spray some starting fluid at the base of the carb and intake manifold, if the RPM's increase, that is a sure sign that you are sucking air through there!!! Go to your local NAPA, or what ever and replace the gasket. <img src="http://www.aaca.org/ubbthreads/images/graemlins/cool.gif" alt="" /> Link to comment Share on other sites More sharing options...
Guest Posted March 11, 2003 Share Posted March 11, 2003 Could be a vacum leak , but also check and see if your choke plate is closing on it , this will cause a stumble and a bog....Chris Link to comment Share on other sites More sharing options...
Guest Posted March 12, 2003 Share Posted March 12, 2003 First thing I would do, is get a vacuum gauge and check your vacuum at idle when warm. If you have less that typically 16.5 to 20" of vacuum, you have a leak somewhere below the throttle plate. Your description sounds like a classic lean condition vacuum leak. You have enough fuel passing the idle jets, but once the transition takes place from idle to accelleration, and your throttle plates are open, you have parasitic air entering somewhere, causing a lean condition that makes you lose enough power to kill the engine. Check the condition of any vacuum lines below the throttle plate. Tighten the bolts that mount the carb to the manifold. When you check the hoses, look especially for any that are gummy, partially collapsed, or loose on the fittings. On something that age, it's good housekeeping to just replace them all. Also check your pcv valve for suction, and make sure the ball is rattling in there when you transition between idle and acceleration ie: vacuum, /no vacuum. after you have checked everything , and your poor power is still eveident and the vacuum is good, you might consider checking the power piston on your carburetor, if so equipped. That device is the enrichening valve that noves vertically, lifting the primary needles out of their seats to supply the proper fuel/air ratio at varions loads and speeds. Over time, the bore may have become worn, and is leaking the vacuum for the proper operation. The only seal there is metal-to-metal, with machined ferrules in the pistion to create a nominal air seal, and the carb body bore , which is pot metal, and very suceptible to wear. Try removing the top of the carb and inspect the power piston assembly. Determine how freely it moves, and inspect the bore and piston for burrs, grit, excessive wear patterns, and anything else that may impede it's movement. One last item to check, would be your distributor advance movement. Remove the cap, and rotate the rotor back and forth, opening and closing the weights and springs. Look for a broken spring, or a seized advance mechanism. In the order of occurance , try the advance mechanism first, vacuum second, and the carb last. Hope that gives you some pointers. One note on the vacuum gauge, the numbers i gave are approximate, and you may see some fluctuations on the needle. The proper use of a vacuum gauge for diagnostics can tell you many things about your overall engine condition, but right now, you are just looking for excessively low vacuum, so we'll leave it at that for now . Hope that helps, and happy Big Bock motoring! <img src="http://www.aaca.org/ubbthreads/images/graemlins/smirk.gif" alt="" /> Link to comment Share on other sites More sharing options...
DoubleSnorkel Posted March 12, 2003 Share Posted March 12, 2003 When was the last time you went through your carb? you might have a weak accelerator pump!!! Link to comment Share on other sites More sharing options...
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