check engine light ?

On pre-1995 cars you could jump between two of the pins and read the codes that were stored in the computer. 1995 and newer cars require the use of the OBDII scanner to retrieve the codes.

This guide will show you how


https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method


Please run down this guide and report back.

hi i am a mechanic, im working on this car for a friend and its runs decent but it is running way too rich on the second cylinder from the drivers side, pulled all the plugs and they were ALL golden brown but the one was wet, so i replaced all the plugs anyways,and replaced a bad vaccum line, changed the oil, changed the fuel filter, and ran injector cleaner thru it, did the ear check with a screw driver to each injector and all seem to be working just fine, took the car for a test drive and when i dropped it into first and florred it, it hit a little over 30 and sounded like it was hitting a rev limiter but it wasnt, and at the same time the coolent light and check engine light would flash back and fourth PLZ help!! its a 2.3 liter quad DOHC 16 valve

Start by scanning the PCM for codes. A malfunctioning coolant sensor will cause a rich fuel mixture.

On an OBDI system, short A and B in diagnostic link and count flashes.

my 1995 grand am 2.3l quad 4 runs great at idle but under load or quick acceleration stumbles i have changed the coils the fuel filter and checked the gap on plugs (0.060) and changed the o2 got code from snapon scan tool #55 could this be a bad ground? did notice the ground for the ecm needed to be cleaned up

1995 Pontiac Grand Am car stumbiling

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires

Hello. I have a problem with my car. The check engine light comes on and i had a scanner put on it. The scanner came up with a fault code for the O2 sensor, open circuit. So i cut the wire and spliced it and made a new connection. Then i tested the voltage into the ecm and the voltage is only fluctuating between .1 and .2 volts, and even before i spliced it, i also tested it and it was the same, when it sould be between .4 and .5 . I also bought a new 02 sensor and it still has the fault for an open 02 circuit. Please can you help me!!!

Was it code 13? the wire you cut is it still in circuit? Did you ohm out ground on ECM? Let me know

Yes the code is 13. I also tested the ground and it is good. I spliced the wire under the hood near where the harness goes into the ecm and it is still in the circuit.

I have a 1994 Pontiac grand am 4 cyclinder and engine light is on. I looked up how to test the obd but nothing is working. The connector only has 3 pins. 2 pins on top left and 1 pin bottom left.
How do i go about testing it. It does not have any other pins just the 3 on left side of connector
If need a picture i can get that
Thank s very much

On '95 and older GM products there will always be only one corner of the connector that has two wires right next to each other. Those are the two to connect to read the diagnostic fault codes.

Go to this page for the full instructions:

https://www.2carpros.com/articles/buick-cadillac-chevy-gmc-oldsmobile-pontiac-gm-1983-1995-obd1-code-definitions-and-retrieval-method

Engine Performance problem
1994 Pontiac Grand Am 6 cyl Two Wheel Drive Automatic

while driving after about an hour the check engine light comes on there are no other problems the car runs fine i have driven it several times the past owner said there were no problems with car the car starts up very well afte i turn off car the light goes off and dnt come on agian till im driving agian after about an hour later

Check engine light coming On

Have the computer scanned for code/s-you have a problem within the engine management system that caused the CEL to turn on-This is your starting point of diagnosis,finding out what's going on

1993 Pontiac Grand Am SE V6 3.3L mileage: 157,000
Hello everyone this problem has started when i bought the car it was sold as is. I just bought it one month ago at a used car lot.The problem is when im driving or the engine is cold the check oil light & the service engine light with the check gauges light come on & blink.The oil gauge is at 120psi when its cold but it goes down when it starts to get warm. I have given the car a tune up myself. I took it to a mechanic he couldn't figure out what the problem was. I then took it to one of my brothers who knows alot about cars to. We removed the oil sending unit and the oil level sensor that goes to the oil pan.Replaced them with new ones. That stopped the light for a few days but it keeps on coming on now. I know the car is at level with the oil & its not heating up im just so frustrated with this i have no idea who to ask anymore. :? I would really appreciate some help with this im totally clueless.

Update

Their were two problems

1st Problem: Bad Cluster
Check Oil Light + Check Gauges Light

2nd Problem: Engine Vacume Leak
Service Engine Light

Check engine soon light

Check engine light on

Have the computer scanned for code/s-you have a problem within the engine management system that caused the CEL to turn on-This is your starting point of diagnosis,finding out what's going on

Hi, my grand am, when i start the car "normally" the check engine light comes on and the engie idles really slowly and heavily, ie the car rumbles and can shake for a minute, after idling for a minute the engine speed will level off and sound more normal however when i go to press on the gas pedal and drive off the engine hesetates and drives like a tank, there is clearly no power and the engine will heat up very quickly but won't overheat. Now i had the engine tuned up at my local midas, "level 2 service" according to the bill which they said should fix it. It worked for a week. They said whent hey scanned the computer they were getting a "long cranking code error" now whe i took it back tehy rescanned and said it was the same error and it was most likely becasue the car was old. This was about 1 year ago, Now i recently learned that if i crank the engine for a minute but don't allow it to start, then wait for the lights and stuff to shut off and then recrank the engine it starts very quickly with no check engine light. Also if i am driving and the check engine light came on at startup that if i get to 60km/h i can pull a fuse, top eft i think it's labelled ECM, wait 5 seconds while costing the engine sounds like it stalls the speedometer drops to zero and the check engine light flickers, once i plug it back in the engine starts running and everyhting comes back on and the engine runs wonderfully. Now i was wondering what is causing this, it's a new starter, new spark plugs(not sure about the spark plug wires) but what i can't figure out is why it does this, is it the computer? i bought a a reader, i turn the car to on but don't start it and the check engine light blinks out the codes that are stored, i get code 42 all the time and once and a while code 33, right now that one isn't there jsut 42. Thanks for any help!

Hi jared575,

Thank you for the donation.

Is this a 2.3 L or 2.5 L engine?

There are various different specifications and the correct one is needed for accurate diagnosis.

Code 33 is the MAP sensor circuit.

Code 42 is for EST (Electronic spark Timing) circuit.

The VIN would help in determining the system used.

the vin, which i'm assuming is the vehicle identification number is 1g2ne54u3mc510398 it's a 2.5L LE model 91 pontiac grand am.

Yes VIN is Vehicle Identification Number. You are able to provide the details so here are the description and diagnostic procedure. CODE 42, EST CIRCUIT OPEN OR GROUNDED Code 42 indicates the ECM has seen an open or short to ground in HEI EST or by-pass circuit. NOTE: Test numbers refer to test numbers on diagnostic chart. 1. This test confirms Code 42 and determines if fault is a hard failure or intermittent condition. 2. This test checks for a normal EST ground path through the ignition module. If EST circuit is shorted to ground, reading will be less than 500 ohms. 3. As test light voltage touches by-pass circuit, the module should switch. This will cause the ohmmeter to switch from hundreds of ohms to thousands of ohms. This test assures that the module "switched". 4. If module did not switch, this step will test for a short in circuit No. 423, an open in circuit No. 424, and a faulty ignition module connection or module. 5. This step confirms that Code 42 is a faulty ECM and not an intermittent problem in circuits

About 6 months ago my car stopped working, the car would just stall dead, no notice, turned out to be a "spark plug relay" or something like that where the car was not sending spark signals to the engine. After i had that fixed the check engine light would come on, at first it would come on every 2-3 times the car would turn on and would remain on until the car was cold, it eventually turned into an all the time thing, had the car scanned and came up with "long cranking code" they reset the computer and it went away for sever weeks then started all over again. They then recommended a level 2 service, the cleaned the fuel system, chenged the oil and did whatever else they did for nearly 300 bucks, the light still came on. but only one the car had be on and warm and only every 6th-7th time the car was turned on. since then i've replaced the battery, starter, exsaust pipe and muffler and for a short while the car ran fine. Then it would only come on after the car was turned off and back on from driving it for at least an hour. Now it's back on continuously. When the car has this check engine light on the car hesitates horribly, loses speed going uphill guzzles gas and idles really roughly. The engine also heats up quite quickly compared to when the check engine light is not on it runs perfectly... well as quickly and well as a 3 speed auto can... what's wrong with my car? the mechanics said tune up did that, still does it, they said it's old, it's got like no miles on it and when the check engine light isn't on it runs perfectly. Thanks!

https://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm Go here and checkout our video. It could be the fuel pressure regulator. If not recheck the codes like this, then post your findings.

Cross these two terminals as shown, then turn the key on. Count the flashes, a 22 will flash as 2 flashes then a short pause, then 2 flashes, if more than one code is stored, the pause will be longer. The codes will display three times and end with 12. Write them down and post here. This connector is right under the middle of the dash...

I used a paperclip to short that wire on teh diagnositc accroding to the directions. It reported 3 times code 12, then 3 times it did code 42(four blinks pause 2 blinks) according to the sheet
42- Electronic Spark Timing (EST) bypass circuit, or EST
circuit open or grounded.

whatever that means... thanks any help would be great!

Check the module and pickup inside your distributor...

My son has a 1991 Grand Am that runs fine, once it’s started. It has been experiencing problems starting for the last six months. Details of the problem:

1. The engine starts hard, cranks multiple times for maybe 15 – 20 seconds.
2. The fuel pump and filter were replaced last year. Don’t know how to check fuel pressure.
3. At 100K miles the injectors were replaced with rebuilt units.
4. The check engine light is not on.
5. The plugs look OK, all tan in color.
6. Good compression on all cylinders, does not use oil.
7. Seems to start better if throttle is held slightly open while starting.

Would appreciate any help.

Find the fuel pressure regulator on the fuel rail, it has a vacuum line to the intake manifold. Remove vacuum line after shutting engine down and see if there is fuel present, if so the reg is blown, replace it

my grand am check engine light comes on if the car is in park or at an idle and runs rough. if i turn the the ignition off it resets or drive it for a while. i've tried jumping the ab terminal and can't get a code to pop up. can anybody tell me what wrong?

[quote:2a19770445="kenaibeast"]my grand am check engine light comes on if the car is in park or at an idle and runs rough. if i turn the the ignition off it resets or drive it for a while. i've tried jumping the ab terminal and can't get a code to pop up. can anybody tell me what wrong?[/quote:2a19770445]

Hey ken,
So when you jump the a/b you cant get the CEL to flash? Hmmm ..... i would have to recommend you get it scanned for codes, then we can get ya in the right direction.

Chris