Thanks for the help, your posts are excellent, I do have a question, my engine light, 96 4.3 2W Blazer, is on, and the scanner mentions that the mixture is too rich, and refers to the rear sensor, do you think cleaning the EGR Valve and the Maf Sensor might be an option to try and resolve the problem before changing sensors? Thanks a lot for your help!!!

 

*Moved to a new thread* - The DIY article discussion threads are for the discussion of the article content and not for tech help.

What is the specific code that you are receiving?

 

Thanks for establishing this new thread, I do not have the scanner right now with me, it is a problem I have had for quite a bit, the Engine Light turns on and off, and the scanner tells me that the mixture is too rich, and apparently the rear sensor has a lot of carbon in it, I have read that changing the sensor when the mixture is too rich is not the solution, should I rescan the car or do you have any simple tests or parts I can clean to see if the error diappears? Thanks for your help, I really appreciate it.

 

The code will lead you to a diagnostic sheet that has the checks that need to be done to find the root of the problem.

 

Thanks, I will rescan the car and see...

I think I made an important observation today: I drove about 50 miles for an hour at 60 miles per hour, but as soon as I left my starting point, I switched off the cruise control in the car, and a few miles down, the engine light went off, I had already noticed this, but had failed to see the relationship between the cruise control and the engine light turning on, do you think it could be a computer errror? Thanks for your help!!!

 

Really comes down to what the code is. Need that to diagnose further.

 

Dear swartlkk:

I really do appreciate your help, I had not come back because the scanner I had access to was unavailable to me. I bought my own scanner and have the error codes that my blazer 1996 4.3 2w gives me: (engine light comes on and off ocassionally). I do love my blazer, and would like to keep it for a long while longer, it has 104000km. Error codes:

P0134
P0172
P0175

As far as I can read from these codes from the software included with the scanner, (I put the options GM truck S series Engine X=4.3L Auto transm, I hope they are correct), they represent:

P0134 O2 Sensor CKT No Activity (Bank 1 Sensor 1)
P0172 System Too Rich (Bank 1)
P0175 System Too Rich (Bank 2)
The monitors given are:
Misfire
Fuel system
Comprehensive Components Monitor
EGR

Any guidance you can give me would be truly appreciated.

Best regards,
Agustin

 

P0134 - HO2S Circuit Insufficient Activity Bank 1 Sensor 1
P0172 - Fuel Trim System Rich Bank 1
P0175 - Fuel Trim System Rich Bank 2

These diagnostic pages and many more are in the OBD2 Code Index.

How is your fuel pressure? Specifically pressure bleed down after the pump shuts off?

 

My truck runs fine, I actually take it out on the highway every week, sometimes when on standby the rpm's lower a bit, but nothing too significant. I replaced the fuel filter a couple of months ago, and basically just want to fix the error codes. Have been looking through the OBDII codes, and it mentions several actions to take in correcting the problem, by evaluating the sensor's activities and its electrical counterparts, should I replace it?

Another question, what do the "monitors" refer to?

Thanks for all your help.

 

Dear Blazer Forum experts:

I have tried as many things as I have been able to find in the search for the answer to my mixture rich problem, I keep receiving messages p0172 and 175 after attempting several different things (truck runs fine):

Cleaning the MAF sensor and the entire air system up to the motorhead, changed new air filter.

Two powerful injector cleaners.

Replaced oxygen sensor in bank 1 sector 1 (got another error in the last few months, I think it was P0139 which recommended changing that sensor).

All cables seem fine and all of the muffler and catalytic converter system seem fine, still sometimes I get these messages.

Hope you can help, all my best, Arlekin