PAUL T Posted October 27, 2004 Report Share Posted October 27, 2004 Could a bad alternator cause the engine miss at light acceleration. I was checking and overriding the injectors to pinpoint a surging and a message came up saying something like "Alternator not charging" then it went away and no codes came up. The battery stays charged up and I do not have any noise from the alternator. To recap, I have changed the plugs, plug wires, fuel filter, air filter, (all with OEM parts), cleaned the phenolic plates, and inspected the EGR valve, all to no avail to cure my surging at light acceleration. No codes are ever on the display. I am also noticing a vibration after I hold the brake and put it in gear, like it is trying to take off. I am really getting frustrated and really do not want to just throw parts at it. Any other suggestions? Link to comment Share on other sites More sharing options...
adallak Posted October 27, 2004 Report Share Posted October 27, 2004 serpentine belt/tensioner/pulleys? alternator might not rotate fast enough at light acceleration for the reason/reasons mentioned by me . just a guess. The saddest thing in life is wasted talent Link to comment Share on other sites More sharing options...
navion Posted October 28, 2004 Report Share Posted October 28, 2004 Paul, The first thing that I would check are the battery cables for tightness. I find that I need to snug mine up about every time that I change oil. If one of the cables slightly loose, it can cause the "alternator not charging" message to be displayed momemtarily and no code will be set. This can also be a cause of surging. If the battery connections are tight, then I would selelct "battery voltage" on the DIC and watch to see if the voltage falls below 13.2 or so while diving. If it does, I would have the battery and the alternator checked. I would suspect the loose battery cable. It was probably getting more vibration while you were checking the injectors. If so, it is an easy fix. Let us know what you find. Good Luck, Britt Britt Link to comment Share on other sites More sharing options...
PAUL T Posted October 28, 2004 Author Report Share Posted October 28, 2004 I finally got a code this morning. P071 - intermittent MAP sensor - I checked the PCM data PD02 with engine at idle and the sensor reading was 34-36 which in the service manual calls for a MAP sensor replacement. Would this cause the stumbling? Link to comment Share on other sites More sharing options...
PAUL T Posted October 28, 2004 Author Report Share Posted October 28, 2004 On second thought, the PCM parameter values chart shows the MAP value at cold idle should be between 30-50 so I guess the MAP is o.k.. The MAP could have been set off by me when I was playing with the PCM overrides. Oh well, I guess my next thing is to clear the codes and check the battery voltage while driving, if I can get my wife to leave it at home long enough to check it out. Link to comment Share on other sites More sharing options...
Scotty Posted October 28, 2004 Report Share Posted October 28, 2004 I had an Bonneville with a bad MAF that surged intermittantly, dont over look that code, it may be an intermittant problem that clears up when it gets warm. Link to comment Share on other sites More sharing options...
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