S10 blazer Problem

[PR0T0TyPE670]

I have a 1990 S10 Blazer Fuel injected 4.3 liter. The engine has been running progressively rough and the check engine lite just came on and it has overheated once. Do you have any Ideas what the problem could be ?

Thanks for the help

[89s10]

do you have to ad antfreze ? You may have a leaking head gasket . Welcome to the form good luck.Be sure and check the codes .

[danny]

first off pull the codes from the computer.

[PR0T0TyPE670]

Its not the head gasket because I changed the thermostat gasket. The temp gauge reads close to the read mark. I think it is running hot because it is running rough. And as for the computer numbers I dont have a diognostic computer to get any numbers from. All I know that its a chevy s10 4.3 fuel injected.

[KA9MOT]

Here is the procedure for 1995 and older GM's as copied from Chilons website:





Remember that a code only points to the faulty circuit NOT necessarily to a faulty component. Loose, damaged or corroded connections may contribute to a fault code on a circuit when the sensor or component is operating properly. Be sure that the components are faulty before replacing them, especially the expensive ones.

The Assembly Line Diagnostic Link (ALDL) connector or Data Link Connector (DLC) may be located under the dash and sometimes covered with a plastic cover labeled DIAGNOSTIC CONNECTOR.

The diagnostic trouble codes can be read by grounding test terminal B. The terminal is most easily grounded by connecting it to terminal A (internal ECM ground). This is the terminal to the right of terminal B on the top row of the ALDL connector.
Once the terminals have been connected, the ignition switch must be moved to the ON position with the engine not running.
The Service Engine Soon or Check Engine light should be flashing. If it isn't, turn the ignition OFF and remove the jumper wire. Turn the ignition ON and confirm that light is now on. If it is not, replace the bulb and try again. If the bulb still will not light, or if it does not flash with the test terminal grounded, the system should be diagnosed by an experienced driveability technician. If the light is OK, proceed as follows.
The code(s) stored in memory may be read through counting the flashes of the dashboard warning lamp. The dash warning lamp should begin to flash Code 12. The code will display as one flash, a pause and two flashes. Code 12 is not a fault code. It is used as a system acknowledgment or handshake code; its presence indicates that the PCM can communicate as requested. Code 12 is used to begin every diagnostic sequence. Some vehicles also use Code 12 after all diagnostic codes have been sent.
After Code 12 has been transmitted 3 times, the fault codes, if any, will each be transmitted 3 times. The codes are stored and transmitted in numeric order from lowest to highest.
The order of codes in the memory does not indicate the order of occurrence.

If there are no codes stored, but a driveability or emissions problem is evident, the system should be diagnosed by an experienced driveability technician.
If one or more codes are stored, record them. Refer to the applicable Diagnostic Code chart in this section.
Switch the ignition OFF when finished with code retrieval or scan tool readings.
After making repairs, clear the trouble codes and operate the vehicle to see if it will reset, indicating further problems.

I modified the picture some time ago to make things a little easier.

[PR0T0TyPE670]

Its 70$ just for a diognostic to be done soo i wanna see if I can figure out it is and try and fix it before having to do that.

[KA9MOT]

Moderators, Maybe we can sticky this so it is not so hard to find in the future.

[danny]

the engine doesn't have to run hot for the head gasket to be bad, if it's using water or running rough then it still could be bad. you can take it to an autozone or other local parts store for the test-they sell parts and will usually be happy to assist you in retrieving the codes. thanks beefy you posted while i was typing so i may have repeated

[KA9MOT]

Originally posted by PR0T0TyPE670
Its 70$ just for a diognostic to be done soo i wanna see if I can figure out it is and try and fix it before having to do that.

Ummm.......Look up. I just gave you directions.

[PR0T0TyPE670]

Ther isnt anything wrong with the wires Bronco. Dan could be right about the head gasket. At stop lights the car stall some times and runs extremely rough. But if it was a gasket that wouldent triggger the check engine lite that is on. Im thinking its a bad sensor or somthing.

[KA9MOT]

I just told you how to run the codes. This will tell you what is triggering the light. It has nothing to do with the wires.

[PR0T0TyPE670]

Yea I know what your saying but I dont have the 700$ machine that tells you the codes.

[danny]

the sensors tell the computer what is happening, the head gasket wouldn't necessarily trigger a sensor unless the knock sensor or temp sensor picks up something.

[KA9MOT]

Never mind. That's 2 in a row. LOL

[danny]

did you read beefy's post about how to retrieve your codes?