QuestionHi, I have a '96 Chrysler T&C LXI with 3.8l V-6, It wont stay running when its cold usually in the morning< but once its warm it will start fine n run but will b sluggish at take off and slow stops. the pcv valve hose was worn so i replaced it and the valve since it looked old, but i want to get this figured out, lol. I did the check engine flash code thing and got these codes 12,43,43. I know the 12 is the disconnected battery within the last 50-100 key turns, but 3 different websites had different problems for the 43, please help, Thank you.
AnswerHi Jose,
The 43 code suggests that there is an issue with the wiring to the spark coil pack or with the primary winding of one or more of the three sections of that pack. You could check the wires for shorting to ground or the primary windings for being out of spec. The coil pack plug has 4 pins, one for the 12v common supply to the + end of all three coils and that one you can find by measuring for 12v to show up on one of the four pins in the plug itself when you turn the key to run and should last for about 1 second before disappearing. The other three are then the 'driver' pins that drive the spark production by grounding the other ends of each coil, in turn. The resistance between the common 12V pin of the coil pack and each of the other three pins should be 0.45 to 0.65 ohms. The wires on the plug are dark green/orange which carries the 12v from the autoshutdown relay, and that is on pin 3, while pin 2 gray/red is connected to pin 11 at the pcm plug, pin 1 red/yellow is connected to pin 2 at the pcm, and pin 4 dark blue/tan is connected to pin 3 of the pcm. Check those out for resistance being near 0 ohms and shake the harness to be sure each wire isn't shorted to ground. Those measurement should be made with the pcm plug removed.
The cold running problem is likely not related to the 43 code, however. That might produce misses at any time. Rather I would suggest that you check out the egr valve to see it its stem might be sticking slightly ajar when it is cold which will lean out the mixture and make for hard starts/poor idle. The valve is located near the throttle body air intake at the end of the engine, mounted in pipe that recirculates exhaust gas from the rear cylider bank exhaust pipe back around to the intake manifold. The exhaust gases have some fumes that can plate out a crud on the valve stem and thus keep it from closing tight when you are at idle. That makes for a too lean mixture so the engine stalls. The valve proper is mounted horizontally with the stem visible in a space between the body of the valve mounted on the pipe and the round top of the valve which is flanged and so if you look carefully you will see a metal rod (stem of the valve) with a slot around its circumference. You can take the tip of flat blade screwdriver and insert it in the slot and then lever the valve back and forth to check if it is moving freely (against spring action in one direction) or not. If it doesn't seem to close easily with the help of the built-in spring, then I would spray the base of the stem with solvent from a pressure can (such as WD-40 or carb cleaner) while moving the stem back and forth. Then see if that solves the issue.
Roland
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