Emissions test

Hi gang,
I'm having a bit of trouble with my 00 Blazer again.

I had it in the tranny shop to replace the solenoids (getting a check engine light and the code came back generic shift solenoid shift). The new solenoids fixed the problem, but when I took it in for inspection/emission test, the mechanics said it didn't pass emission because the parameters hadn't been met. We've driven it more than 200 miles since the computer was reset after the solenoids were replaced....but the mechanic said the EGF, Catalytic converter and one other parameter were not met...

Any thoughts?

Thanks.

Bob

Each monitor has a certain procedure that must be followed exactly before the monitor will run and complete its test. Some monitors only run once per drive trip, others continuously “watch” for the conditions to be met. If any test is not completed during the drive trip, the Powertrain Control Module (PCM) waits for the next drive trip, and attempts to run the test again. It will continue to attempt the test until it runs and completes. Under normal driving conditions, all monitors will eventually run. If a certain monitor takes longer to run and complete, it’s because the driver has not duplicated the exact conditions necessary to run and complete the test. If you have a monitor that is incomplete, the "drive cycle" instructions will tell you what you need to do to get it to run and complete it’s test. You can pick and choose which monitor you want to run by doing what the instructions tell you for each particular monitor. You don’t have to do the whole thing. Here is a link to the GM drive cycle instructions: http://www.obdii.com/drivecycle.html

OK, went in for a retest today. The catalyst and secondary air are still not ready to test. I see in that drive cycle writeup (and a few others) that the car needs to warm up properly. My blazer never seems to warm up. It stays under 150 degrees according to the temp gauge (not sure how accurate that is) and takes forever to blow warm air. I suspect the thermostat. Could the fact that the temp is not getting high enough keep these sensors from resetting?


Thanks again.

Bob

If it not warming up properly it will not enter closed loop which will also prevent it from doing any self diagnostic testing. Check antifreeze levels and it is quite possibly time to change the thermostat.

That's what has me a bit stumped...the EGR valve is now ready to test...it's just those two. I'll replace the thermostat tonight and see what happens. Coolant is fine (that's the first thing I checked).

If possible do a pressure test on the cooling system as well. These trucks have a bad habit of eating the cooling system up.

How do you mean "eat up?" I hit a deer last year, and it's got a new radiator, fan, shroud, etc., and I put a new water pump in 3 years ago...

Bob

The design of the intake manifold gaskets causes them to pretty much self destruct after 5 years of use and the crap design of using plastic tanks and aluminum cores on the radiator and heater core also makes them prone to failure.

GM recommends flush and refill the cooling system with Dexcool at 5 years or 100,000 miles. In reality, 3 years or 50,000 miles is more like it. If the cooling system is neglected, you WILL have problems with the cooling system, (heater core, radiator, water pump, coolant passages & gaskets, etc etc.). Don't ever install green ethylene glycol coolant in a system that was designed for Dexcool.

Yeah, not to thread hijack, but my cooling system was quite neglected by the previous owner and it has basically come undone over the last few months starting with my rad 3 months ago, the intake last month and this morning the heatercore started steaming.

When I had the waterpump replaced a couple years ago, the mechanic flushed out the orange stuff and replaced it with the green. They flushed it again last year when I hit the deer.

Last night I replaced the thermostat, and suddenly it stays around half way on the temp gage and I've got heat! Now those codes should reset!

Thanks!

Bob

Good job with the thermostat replacement! The remaining monitors should run and complete their tests when the parameters are met in the drive cycle.

Dexcool and ethylene glycol are totally different. If you use ethylene glycol in a system that was designed for Dexcool, you're asking for trouble, and you'll get it, guaranteed! It causes expensive ongoing problems that will continue to haunt you until you completely flush ALL traces of the green coolant out and replace it with Dexcool. Always use the coolant that the cooling system was designed to use. There’s a reason it’s called a “system”… all components are designed to work together. Here’s a great article that explains why NOT to use the green ethylene glycol coolant in a system that was designed to use Dexcool.

http://free-auto-repair-advice.blogspot.com/search/label/Dex-Cool

When they installed the ethylene glycol, they either don't know the consequences of substituting it, or they do know and did it to create job security. Either way, that's not someplace I would take my vehicle. It’s your vehicle and your money… take my advice or do what you want, but you’ve been warned.

Two days of driving short distances after changing the thermostat did it. The blazer passed with flying colors. Thanks for all of your help!

Bob