QuestionHi Roland,
I have a 1996 Dodge Grand Caravan with a 3.3 liter engine. While in drive at a stop light, the engine began to run rough and cut out completely when I pressed the accelerator. The next few times I tried to start it, it idled rough, but cut out once placed in gear. I took it to a mechanic, who diagnosed it as a bad ignition coil (he said possibly plugs and wires as well). I replaced plugs, wires and ignition coil. The engine will crank, but won't turn over. Another mechanic said to replace the crankshaft position sensor, which I did, but no luck. I read an answer that you gave another guy on a similar problem, so I checked the fuses and ASD relay. All check ok. I should mention that when I turn the key to the "run" position, I can hear the fuel pump go on. I also did the "key dance," and I'm getting check engine codes 12, 42, 55. I know that 42 is the one I'm after. In the Power Distribution Center, I switched the ASD relay with the Transmission Control relay (same part number). When I do this, the engine will crank, turn over two or three times, then cut out. I think I've told you everything, and any suggestions you have would be appreciated. Thank you.
AnswerHi Chris,
We could look further into the asd relay circuit situation, but because you have improved things by switching out the asd I would like to suggest that you take a look at a device that affects the mixture such as to make for hard starting/poor ruuning at idle and which is not well-monitored by the engine self-diagnostics: the exhaust gas recirculation (egr) valve.
The egr valve is mounted on the rear of the intake manifold. If you look at the rear (fire wall side) exhaust manifold, just to the rear of the oxygen sensor, you will see a small diameter pipe running toward the back of the engine where it meets the egr. The egr has a round vacuum operated top piece, the body of the valve which attaches to the pipe, and between those two parts is a flange inside of which you will see a rod, horizontal, with a slot which is the valve stem. There is also a vacuum hose attached to the top of the valve that comes from an electrically operated transducer mounted slightly above and forward of the valve, which controls the vacuum applied to the valve through a hose between them.
Check to make sure that the egr valve stem is not gummed up such that it is either not opening or not closing tightly. Use the tip of a screwdriver in the slot of the valve stem to move that back and forth, against spring-action in one direction that attempts to close it. If it is sticky or doesn't close to a dead stop by the spring-action then spray some WD-40 on the stem where it enters the valve body and work the stem some more to free up the action. See if that solves the the no start/quick die/rough idle situation.
Roland
