QuestionI metered the temp sensor and got about 4000 ohms. I did the code thing the way you said and got, 12, 54, 22 and 55.
Thanks,
Steve
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The text above is a follow-up to ...
-----Question-----
I have a 95 Concord that won't idle. I have to give it some gas to get it to start and keep it idling. If I take my food off the gas it dies. It was a little cold this morning also.
Thanks,
Steve
-----Answer-----
Hi Steve,
One possibility is that the temp sensor is not accurate and similarly with the manifold absolute pressure sensor, but you would need a voltmeter to access whether either of those could be true. So let us sit on those until we 'exhaust' the other possibility and you let me know if you have access to a volt-ohm meter.
I have another idea, one of my favorites when bad idle rears its ugly head. I would take a look at the exhaust gas recirculation valve which is located behind the engine near the air intake throttle valve. It is mounted in a pipe that runs between passenger side exhaust manifold and the air intake manifold. The valve is mounted horizontally and has a valve stem between its round vacuum actuator top and the body of the valve attached to the pipe, inside the flange that connects the two parts. The stem has a slot into which you can insert the tip of a flat-bladed screwdriver so as to lever the stem back and forth against spring action which should move freely and close tightly. If the stem seems to be sticky so that stem doesn't close all the way by spring action, then you can try spraying some penetrating solvent like WD-40 on the valve stem to freeup its motion.
If the valve is sticking slightly ajar it will make for a rough idle and poor acceleration such as you describe because the mixture is too dilute. It is one of the most common causes of this symptom. So see if you can find the valve and check/lubricate the stem. To check it in motion you can rev the engine from idle to 2500 rpm and back to idle and watch to see if the valve stem moves freely in both directions to the extreme open and closed positions. It may be that the interior of the valve is cruddy so that might require that it be unbolted from the pipe where it it attached and cleaned. But chances are good it will only be a sticky stem.
The final thing to try is to readout the fault codes stored in the engine controller memory, using your ignition key:"on-off-on-off-on and leave on" doing this in 5 seconds elapsed time or less. Then watch the check engine light which will remain "on" to begin to flash, pause, flash, etc. Count the nubmer of flashes before each pause. Then repeat to verify the count. Then combine the numbers in pairs in the order they read out. The last such number will always be 55 which is the code for end of readout. Then either write back, or go to www.allpar.com/fix/codes.html for a code listing. Then write me with the codes other than 55 for direction.
In any case feel free to write back with the results and other questions you might have.
Roland
AnswerHi Steve,
We have an answer. If the engine was cold (70F or less) the 4,000 ohms is too low a value, and the 22 code says that the controller thinks there is something wrong too with that sensor. That would cause a too lean mixture when you try to start the car cold. So if it isn't at least 7,000 ohm at 70F you would do well to replace the coolant temp sensor.
The 54 code says that the cam sensor signal is not reliably reaching the controller. That would mainly impact the sync of the fuel injectors with the pistons. See how it is running after the coolant sensor is replaced. If it seems ok then I would erase the codes and check again in a week or so to see if the 54 returns.
The 12 is often seen because whenever the battery is disconnected it will set a 12 code (that the power to the engine controller was disconnected recently). Generally this is not a relevant code. But in order to erase the other codes you have to disconnect the battery for about 6 minutes. So after you do that the next readout will always show 12, 55. So try it, verify that, then try again later to see if the 54 has come back or not.
Roland
