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Do I really need new computer?

During cold December weather, manual transmission 2000 Civic stalled immediately after it started and I had to keep feathering the gas pedal to keep it going. Kept stalling as I drove home whenever I put in clutch and braked - check engine light was now on. I immediately took to garage where they did diagnostic test (for $94 just to tell me 4-yr-old battery was bad). Got new battery, cel went out and car drove fine. Next morning, cel came back on and it was stalling again. Same mechanic cleared the code, cel went out but he now told me I may need to replace computer (which he says is extremely rare) if the cel comes back on. After two days of driving fine, cel came back on but it was starting okay and not stalling whenever I put in clutch and braked . A week later it began stalling again (extremely cold weather now). I had to keep feathering the gas and the headlights kept dimming, also. Drove to another mechanic with a couple of incidents of car dying when I braked. He checked the code and it said “circuit problem”; he cleared code, cel went out and it started right up and drove perfectly. Two days later cel back on and stalling when starting. Do I really new (or perhaps used as mechanic suggested) computer? Since this is so rare, I find it hard to believe the whole computer system is bad after only 105,000 miles. I’m hoping this car will last to at least 200,000 miles.

You may think you have provided information in a format that makes a conclusion easy to come too, but I found your post very poorly organized, I refrain from commenting.

All this talk about a 'cel" and not one code by the numbers!

cel code reads don’t end with the customer being told they need a new battery.

Please calm down. We who reply to these posts normally are helpful. It is frustrating to not have all the codes in this situation. CEL really is not enough info to help you. There are about 70 different codes and on your car about 30 of them can cause a limp home engine mode that is similar to what you are experiencing. You have a major fault that is shutting off the computers advanced controls that causes the rough running. Post the all the codes if possible.

OP, please take a timeout and read oldschool’s comments again very carefully; and then think about your own. Oldschool’s words are not snarky, uncivil, or anything else and oldschool (who has been around here a while) is not a mean-spirited poster at all.

I agree with oldschool, you’ve posted a lot of info without providing one iota of info about any codes that exist.
The odds of the computer being at fault are near zero. Wild guessing a bit here based on what I could glean out of the symptoms I tend to think the problem could be a vacuum leak (which will show up worse on a cold engine) or an Idle Air Control valve problem (which can occur any time and may be erratic in nature)

The lights dimming may not be the sign of an electrical fault. That could be nothing more than the inability of the alterantor to keep up with all of the electrics when the engine RPMs are below what they should be at idle.

I would also add that it’s possible to have an Idle Air valve problem with no codes set.

Well it read a bit snarky to me. That said she does have a CEL issue here. It does not seem that the rough running with CEL is restricted to idle. The fact that it clears and runs ok for a bit suggests to me the limp mode. It is consistent with other manual cars I have had with limp mode set. They run terribly.

Agree; computers seldom fail these days. Especially on a Honda. The cold weather lately has baffled many persons who do not live in the Northern states. I believe a good mechanic would check to see if your car:

  1. Is getting enough fuel?

  2. Is getting the right quality gas, with no water in it? If you park in a heated apartment basement and then park at work outside, you can get considerable condenstion in your gas tank.

  3. Is your car getting a good spark from the ignition system?

  4. Is the car getting enough air; if the air filter is frozen with condensate, you could be choking the engine.

It seems your mechanics are basing all their guesses on code readings, rather than actually checking out the car itself. It’s like your doctor only going by lab readings and not checking you out personally.

Please tell us what maintenance and replacements you have done in the last few years.

I’m not convinced you need a new computer, or PCM. The computer responds and reacts to all kinds of info from lots of sensors. Since it can be reset and all is OK for a bit it seems to me to be either a sensor is bad, or a sensor is doing its job in sensing something amiss with the car.

The only way to know more is to get more specific info on the “codes” that are stored in the computer when the CEL comes on. If your mechanics can’t, or won’t, give you the specific codes for you to post here, then you can take the car with the CEL light on to an “Autozone” or similar auto parts store and they will scan the computer and give you the codes.

The most specific info you can provide will get you the best answers.

UncleTurbo,Thank you for the most helpful of all the responses. As far as I’m concerned, you and Docnick are the only ones with whom I care to communicate. I will definitely go to AutoZone to get the codes which you said would be helpful, go back to the Honda mechanic, then perhaps to another Honda mechanic I’ve used in the past. All I was I hoping to get from this blog was a little help. I appreciate that others have more expertise than I in mechanical issues. However, we all have our areas of expertise in this life and it would be nice if one could feel free to ask a question and get positive input instead of condescension. Too bad some people are so insecure that they latch onto perhaps the one thing they know something about and batter others over the head with their unhelpful so-called advice. Some of the responses (especially from Oldschool and Euryale1) were not at all what I expected. Thank you again, UncleTurbo and Docnick.

Has anyone bothered to check the CHARGING SYSTEM?? An alternator with a bad diode can make the computer go crazy (A/C ripple) and throw all kinds of codes…

Check Caddyman’s comment below for a good area to look at.

OK4450. I have found oldschools posts condensending as well. I was posting on another thread and he came into the middle of it with a very condensending attitude toward me. Just my take on it though.

Let’s start with the basics. When were air filter gas filter and plugs last changed?

Sorry you feel that way. I do not think you should call anyone names. I feel I tried to help as much as possible given the info you had given. Sorry You dont appreciate it. It is interesting that your response to oldschool that I replied to was pulled out. Likely the content of your message was reflected in my initial response to your question. I merely thought to ask you to calm down since I saw your comment to oldschool and if you read my response it is reflected in the posts by others.

There might be two different problems on your car. The headlights dimming is the first. This could be caused by poor connections on the battery. The battery cables need to be disconnected, and the terminals, and battery terminals, cleaned with a round wire brush. Where the ground cables attach to the car body, engine, and alternator positive cable, need to be undone, and re-tightened to get improved electrical connections.
You can, somewhat, control the stalling by manipulating the throttle? This indicates that the air flow through the intake tube / throttle plate/bore isn’t the proper amount; OR, the part which controls idle air flow is having problems doing so, OR, the sensor which measures the air flow (MAF Sensor) is in error.
To treat the shortage of air flow, your mechanic needs to use a throttle body cleaner to clean the air intake passages. To, hopefully, improve the accuracy of the MAF Sensor’s output to the engine computer, the MAF sensor needs to be cleaned with MAF Cleaner. The MAF Sensor output voltage signals need to be checked. {These are simple things for a mechanic to perform.]
The engine coolant temperature sensor sends signals to the engine computer. It uses that information to make adjustments to the fuel injector and to the idle air control valve. When the engine is cold, the engine computer commands more fuel from the fuel injectors. The mechanic can use a test meter to check the electrical resistance and the voltage signal output of the coolant temperature sensor.
These are ideas your mechanic needs to be versed in. Please, don’t assume that they are so versed. Ask for proof.

Oil filter and plugs done last July when I had the timing belt/water pump replaced at 100,500 miles. From my records, it looks like gas filter was changed in May of 2007 at 90,600 miles.

That makes three of us.

Thanks for this thorough reply. I am going to my original mechanic with all these suggestions next week. They all seem to make more sense to me than to simply install a new computer for a lot of $$ and not check some basics first.

It is a possibility fuel injectors are fouling, try a dose of sea foam.

willey, someone had to correct your “jumping the gun” by saying “its your PCM”. You just got your feelings hurt when I had to explain proper diagnostic techniques. You resorted to name calling and harassment, this does not say much about your credibility.

This OP also got her/his feelings hurt when I explained that her/his post was not in a format that made diagnosis possible.

My first thought was also the idle control valve, but when mine has had that problem, the CEL did not come on, so either not Idle control or two problems,I am betting not idle control.