QuestionQUESTION: I have a 95 plymouth neon automatic 2.0> I am experiencing stalling upon starting and loss of power while dreiving, running codes by counting check engine light flashes gives me code 55. Should I disconnect battery and run test again? could it be pcm or the mfs or oxygen sensor?
ANSWER: Hi Mel,
I wouldn't disconnect the battery as you alread have no codes to erase. I wouldn't guess at bad parts as that is a waste of money.
My thought is that your exhaust gas recirculation valve is sticking slightly ajar due to gum on the stem. It is mounted on the rear of the cylinder head and it has a round actuator which is connected to a vacuum line and the valve body proper is connected to the cylinder head and has a small tube coming to it from the exhaust manifold. In between the actuator and the valve body there is a flange that separates the two parts, and hidden hehind the flange is a rod with slot, which is the valve stem. Put the tip of a screwdriver in the slot and use it to move the stem back and forth and notice spring-action which tries to close the valve. If the valve stem doesn't come to a dead stop via the spring action then that causes a too lean mixture (loss of power/hard starting) because the ajar condition allows exhaust gas to enter the manifold when it shouldn't.
Spray some WD-40 on the stem where it enter the valve body proper and work the stem back and forth to free up the action. Then check to to see if that resolves your problem. It may be necessary to remove the valve and clean up its interior, but this is a good way to start to see if it can be corrected without removing it.
Roland
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QUESTION: Thank you for the answer I will try that tomorrow, since i first wrote i am now pulling the code 12 21 55, which i am lead to believe is the oxygen sensor the car has 140,000 miles so its probably time also someone showed me a code book that said code 55 could be the idle control sensor, have you heard of this listing? I wouldnt say my problem is a rough idle. When i do experience loss of power or stalling i can give it throttle and i will either snap back into having power in acceleration, or holding the throttle for a moment when i cant get it to stay started will clear it up and keep it started. I will try cleaning the valve and let you know when i return for the follow up answer, thank you so much for a straight up no money eating answer.
ANSWER: Hi Mel,
The 12 code means the battery was disconnected recently, the last 50-100 key on-off cycles. The 21 code means the oxygen sensor signal is not changing which could be that it is no longer functioning, but check its wires which are fragile as well which would be the same as no longer working if they are broken. The 55 code always means 'end of readout' to corroborate that a readout has been accomplished.
So see what the egr check-out nets you, and probably you'll want to replace the oxygen sensor which is mounted on the exhaust manifold. Soak it around the thread area overnight with penetrating oil before trying to remove it and then run the engine enough to warm up the manifold which also will ease the removal process. Torque the new one in like a spark plug, and use the anti-lock grease on its threads. That sensor only comes into play after the engine is warmed up, so it wouldn't be involved in the hard starting.
Roland
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QUESTION: thank u i am replacing the oxygen sensors also i have a pontiac bonneville 1995 that gets hardly any registration on the temp gauge but when sitting at idle it gets close to 200 when i put the heat on it drops it down quick also my ac compressor is cycling on and off every 10 seconds it also just got a new engine put in does that mean there could be air in system and how would i get that out? thanks
AnswerHi Mel,
Air in the cooling system is a possibiity, but I am not familiar as to whether your engine would have an air bleed valve. If so it would be high on the engine probably near the thermostat housing. Are the radiator fans coming on? If not, that might also explain the cycling of the AC compressor. Of course the refrigerant level in the AC syxtem could be marginal which would also cause that sort of behavior.
Roland
