hooked up a real time scanner to my truck and it looks as though im getting distributor advance that bounces from 13 to 17 at idle. also changed injectors again but still get misfires codes 300 and then 301 303 305 on 1 3 5 . mostly 3 an 1 . I can drive for about 20 mins before the randoms show up they don't usually turn on the mil light. also the o2 takes a long time, over an hour before the tests get finish if they finish at all. mostly the heater on the o2. just driving down the freeway 65 mph. any ideas?
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1996 Dodge Dakota Question: distributor advance bouncing
Answer #1cardocIII from Gillespie's Auto Service, November 17, 2013, 20:18Master
The ignition timing changing is part of the PCM's strategy to keep the idle speed as close to the desired level as possible. Some IAC systems can overshoot and you end up with surging as the computer keeps changing the IAC counts. By using the ignition timing, small changes can be made on almost a cylinder by cylinder rate.
If the system is detecting misfires, it might suspend the O2 sensor testing. You have to look at the code description and code set criteria to know for certain. Chrysler tests the O2 sensor at a very light throttle and iirc about 25 to 30mph. With a DRBIII scan tool you can command the monitor to run, and a screen is displayed that has minimum and maximum values that the driver has to stay in-between and the test will run in a few seconds, so long as there are no suspending or blocking conditions in play.
Replyjjddii77, November 17, 2013, 21:33Rookie
thank you. I drove for almost an hour until the misfires came up as codes and I was going 65 mph on the freeway. now I am getting misfires on all but cyl 6. this triggers the ck eng light. also noticed the alternator bouncing voltage. new battery only holds a 12.7 charge. alternator is putting out 14.75 when checked. maybe the alt is going too , its the original one. I did see the volt meter in cab bouncing at night while driving. awwwwh. what next!!
Greg's Orange Auto (13269 Answers) , Orange, CA - (714) 361-9386globalhelper November 18, 2013, 06:05Master
poss loose timing chain?
Replyjjddii77, November 28, 2013, 18:28Rookie
replaced timing chain and gears still have misfires.
ReplycardocIII, November 28, 2013, 19:07Master
Can you feel the misfires, or does the check engine light just flash or come on reporting some?
Replyjjddii77, November 29, 2013, 08:51Rookie
the pending code usually comes up on the scanner with 300 first and then 301 303 305. I don't really feel them I notice that it usually happens when the road is rough leading to think loose pcm connections. the only time it sets off the check light is after there are more then 4 cyls. this is while I drive with the scanner attached to the system.