service engine soon light 90 beretta

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  #1  
Old 08-12-02, 11:35 AM
JJKing
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service engine soon light 90 beretta

Hi
I have a 90 beretta GT 3.1 liter engine automatic trans. The car has been running crappy. When ever I would pull up to a stop sign the car would have a very rough idle, when engine is hot. I have a digital dash and the rpms showed from 480 to 1040 just back and forth. Once in a while the car would shut off. Sometimes when the car would shut off, I would be able to start it again but as soon as I would put it in drive it would clunk out. Anyways, I did take the car into the shop to have a diagnostics done on it and they wouldnt tell me much of what was wrong with they tried to confuse me more than anything, I asked questions, and they didnt want to share their knowlege. They did give me a small summary of what was wrong. Here it is:

Right lower brake light inoperative, Check engine light on in dash, fault codes are 33, 43 & 45. Did propane sweep and no vacuum leaks were present at this time. Has coolant leak, looks like timing cover gasket. The first things to address is the MAP sensor and problem of the transmission torque converter clutch solenoid and pressure switch not dis engaging.

The brake light is fixed, I dont care about the coolant leak, the coolant stays at the same level in the reserve tank just a little low and the car never overheats.

Ok, this is what I have done.I replaced theMAPsensorand the transmission solenoid. The car doesnt have as rough of an idle anymore when the engine is warm, rpms go from 530 to 860. I can manually smooth the idle by having the left foot on the brake and very slightly rest my foot on the gas pedal.and the car will idle at about 850 rpms. Its just a pain to do this every time I have to stop and wait. By the way before the problems occured the car would idle smoothly between 730-740 rpms. Also the car doesnt "clunk" out when the car is hot anymore. I forgot to mention that before. Thats why I replaced the solenoid.

I have a chilton repair manual and for the fault code 33 it says Manifold Absolute Pressure (MAP) Sensor Circuit Signal Voltage high-low vacuum. Fault code 43 it says,Electronic Spark Control (ESC) Circuit. And code 45 says, Oxygen (O2) Sensor Circuit - rich exaust indicated.

I dont know what I am supposed to do to fix/correct any of the problems above (the codes). I dont know what they mean and there is no description in the book on how to correct them.

If anyone has any suggestions please help.

Thanks Jesse
 
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  #2  
Old 08-12-02, 12:03 PM
Joe_F
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The stalling is due to a bad converter clutch solenoid. There should be a square connector at the top of the tranny. Disconnect it and see if your problem goes away. If so, the converter solenoid is bad...common problem on GM's.

It can stay disconnected for a while, but it's not a good idea in the long haul.

Let's start there and see what we have.
 
  #3  
Old 08-12-02, 04:52 PM
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i would suggest you disconnect the battery to clear the codes out of the computer and see what code or codes return and start there.
 
  #4  
Old 08-12-02, 07:04 PM
JJKing
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I changed the solenoid, and the MAP sensor. I dont have a code scanner. Also I had the battery disconnected while I replaced them. The service light still comes on, after I run around for a while,10 mins or so, the service light goes out. I know the solenoid is working now because before I put it in, when the engine got hot and it would stall out. Thats where the car would have to set for atleast 45 mins to an hour before I could get the car moving again without it stalling when I put it in drive. Anyways, what I forgot to mention in my first post, was that when I run the car for a while and get the engine hot then I pull up to my parking spot and put the car in park and let it sit there and idle for for a couple of seconds 10-20. The idle is rough and then the car will shut off. I've also tryed everything you can with the gas, 87,89,92,and 93 octane gases. Also I put water remover in the tank one time, then the next time put in injector cleaner. I have heard a bunch of things to try, they all cost a lot of money put together and I dont want to replace something and that not be it. Anyways, some suggestions to fix the rough idle are Ignition control module, the coil, the throttle position sensor, and the crankshaft sensor.
Thanks for your replies.
 
  #5  
Old 08-12-02, 07:44 PM
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well you dont need a code reader to check codes on your car just take a jumper wire or paper clip or something metal and jumper your a and b terminals together on the aldl connector located under the dash on the driver side once jumpered just turn key on and watch the check engine light it should start with code 12 and will flash each code 3 times and then will repeat itself.
couple of things you might check is the vacum line going to the map sensor sometimes they get broken it runs partially under the intake, and check the knock sensor and knock sensor connector located on the back side of the block the side facing the firewall it will be a single wire connector.
but you really need to know which code has returned first.
 
  #6  
Old 08-12-02, 10:45 PM
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First check your vacuum lines like bejay said.
Also, a bad O2 sensor could cause the idle problems you're descibing. If the engine has over 75,000 miles I would go ahead and change that. (O2 sensor should be included in tune ups)
(Just FYI a lot of fuel additives will wreck an O2 sensor.)
A bad knock sensor should cause a code 42. A 43 would be caused by a ESC circuit as you stated. Has anyone tried to set the timing lately? This engine timing is supposed to be set with the ESC wire unplugged. If was not done that way, the timing will be far enough off where the ESC can't control the spark advance properly.
You say that the code light is going out after 10 or so minutes. Are you having to dump on the gas to make it go out or is it just with normal driving?
How's the engines power at highway speeds? If any difference, is it better with the light on or off?
 
  #7  
Old 08-12-02, 11:51 PM
JJKing
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reply to dirtydan

For the codes, there is a code for a degrading oxygen sensor, that code didnt come up. But code 45 came up and that says oxygen sensor indicated rich exaust. Do you still think I should replace it, I did run a lot of additives though the gas. The service light goes out with the cruise set at a highway speed without getting on the gas at all. It also goes out just driving around town without getting on the gas real hard. The car has full power with or with out the service light on, at any speed.
 
  #8  
Old 08-13-02, 05:49 AM
Joe_F
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You should start checking your ignition components with the information in autolibrary.org below.

With that said, an O2 sensor is a maintenance, not failure item, so you should definitely change it.
 
  #9  
Old 08-13-02, 05:55 PM
JJKing
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Reply to bejay

I checked the codes and only 43 came up besides 12. Also, I checked the vacuum hose from the map sensor, and it was fine. In my book it says 43 is the electronic spark control circuit. It doesnt say whats on the circuit tough. So if you or anyone knows let me know. Thanks
 
  #10  
Old 08-13-02, 07:18 PM
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basicly code 43 is set when the ecm detects an inncorrect voltage reading from the knock sensor, the possible causes can be a bad knock sensor, bad wire or connection, bad ecm or even a bad memcal which is the removable chip inside the ecm, the memcal in the ecm rarely ever goes bad so its doubtful that it would be the problem.
have you checked the connector at the knock sensor they usually break easily and a replacement pigtail can be purchased at any parts store, i would start there, if the connector is in good condition and you have access to a digital volt ohmeter you can test the voltage to the knock sensor by disconnecting the knock sensor turning the key on hooking the positive lead to the knock sensor connector and the negative lead to battery ground or a good ground on engine the voltmeter should read between 4-6 volts, if it reads lower than 4 or higher than 6 the problem will be either wiring or ecm related.
if the voltage is correct you can use an ohmeter to test the knock sensor by placing one of the ohm meter leads into the knocksensor and the other to good ground or engine block and if i remember right the ohmeter should read between 3300 and 4500 ohms if it is out of that range the sensor is bad.
you can buy a manual that is specific to engine performance that goes into greater detail but most of the flow chart for code 43 consist of what i have written above, you can also try alldata or auto library or your local library to get a copy of the flow chart for code 43 which will help you to track down wich component is bad.
but i would start with these first few steps and see if you cant locate the problem before looking for a flow chart.
 
  #11  
Old 08-16-02, 02:33 AM
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Location: Louisiana
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Normally, on these old GM's, if you get a code 43 the computer thinks it doesn't have control of the ignition timing. Consequently, it will normally let go of the timing which puts you at your base timing. You should get a noticable loss of power at hghway speeds when this happens.
 
  #12  
Old 10-12-02, 11:37 PM
JJKing
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Fixed!!!

Sorry I didnt get in touch sooner. I ended up taking my car to a GM garage. Of course they had to run another diagnostics check...oh well. Anyways what they had to do is a "Idle Relearn" at no extra cost. Im not sure if its just with 90 berettas or other cars, but they told me that every time the battery is disconnected the position is lost/forgotten. Now my car runs like new. So I hope this info was helpful to all of you.
 
  #13  
Old 10-13-02, 08:46 AM
Joe_F
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Thumbs up

Absolutely correct. This is quite important.
 
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