Search the Community
Showing results for tags 'smog'.
Found 5 results
-
hello gm-trucks commuinty i’m having issues with a smog readiness monitor not completing. any information on this issue would be greatly appreciated. my truck is a 2001 Chevy Silverado LS 1500 with a 5.3L v8 and it’s 4x2. all the readiness monitors complete except the secondary air system causing the truck to fail smog in california. i’ve heard the air pump turn on at cold starts and even replaced the passenger side check valve. also replaced the solenoid that sends vacuum. everything in the secondary air system seems to be operating properly but the monitor won’t complete. i’ve driven 100s of miles and done countless cold starts but no luck. even the smog referee said the system is working properly and i should just drive the truck more. anyone else experience this issue and what did you have to do to complete the monitor? there are no codes stored currently and the truck runs fine. thank you to anyone that helps -
My truck won't pass emissions. It shows "not ready" for the Evap system, catalyst, and an o2 sensor. I drove it for about 500 miles between tests. I got looking at the vehicles history and it looks like the "not ready" issue has been ongoing for this truck? Any ideas?
-
Guys, I need some help with my 2001 5.3l Silverado. I need to smog test my truck but in Caliornia all monitors must be ready to pass. The only monitor that has not completed is the secondary air injection. The truck is not throwing any codes and there are no drivability issues. I've complete every drive cycle I can find numerous times, including the generic GM drive cycle, none have enabled the secondary air injection monitor. I've driven the truck for at least 2 months and put on 1000+ miles since changing the battery which caused my monitors to reset. Each morning I complete a cold start idle for 2.5 minutes hoping the secondary air will run. Below is a list of items I've inspected or changed in an effort to fix my problem. Secondary air pump-I tested its operation at startup. The pump enables at startup and pumps air at an acceptable volume. There are no signs of wear or issues with the pump. Secondary air valve- I tested operation at startup The valve opens and allows air to flow from the pump to the exhaust. There are no signs of wear and all vacuum line were inspected for leaks. Secondary air check valves- Both valves were inspected and replaced due to carbon buildup. Neither were clogged but I still replaced. O2 sensors- I replaced both pre cat O2 sensors because both had 100,000+ miles. The O2 sensors have been monitored using a scan tool and no signs of issue have been noted. I've monitored both pre cat O2 sensors during startup and I can see when the secondary air pump is enabled. Both sensors go lean until the pump is deactivated and closed loop is achieved. I've monitored engine coolant temp, intake air temp and ambient air temp with my scan tool to ensure all sensors are allowing for a cold start. Again the truck runs great and has no pending or stored codes. It just will not run the secondary air injection test. I'm no slouch when it comes to wrenching on cars but this one has me stumped! What would be my next option? Does anyone know what sensors are monitored to enable the secondary air injection monitor? Thanks for the Help. -
Hey everyone My 4.8 finally blew out after 360k miles, since imma need to replace the motor, I thought I might as well switch to a 5.3 since they're cheap and readily available at my local junk yard. I'm planning on getting one from the same year truck (99-02) along with the computer from whichever truck I pull it from to avoid having to flash my current pcm. Will i have any problems passing smog if I go this route? I know that as of July this year they've started checking your ecu for tunes. Im hoping if I swap my 4.8 computer with the factory 5.3 it shouldn't be a problem since it'll be the original one that came with the engine.
-
Hey guys, I'm new to this forum and new to owning my first chevy truck (with a small problem - hopefully!) and I wanted to post this here for some help/advice/guidance. I have done some research on this problem and only found one other post on the internet with this problem so it seems like a rare one! Unfortunately, the post I found died once the OP stopped responding. So here is the story and the problem:. As of yesterday, I am the new owner of my first Chevy truck! It's a: 1989 GMC Sierra 2500 with a TBI 350 It's completely stock and runs great! (while the EST Bypass wire is connected) No check engine light Got it for $500 There is a problem... The truck does not pass CA smog testing Smog Visual: Passed Smog Emissions/sniffer: Passed Smog Functional test: Failed The reason it failed (as printed on the smog failure report) is: Ignition timing is not readable. Also vehicle will not run when single wire tan/black connector is disconnected which is procedure for checking timing. This was my first attempt at resolving the problem: Started the engine and warmed it up Disconnected the tan/black EST bypass connector WHILE the engine was running and the engine went from idling smoothly to a idling rough. Using a timing light: I set the timing to 0 degrees. The engine then began to run smoothly! I reconnected the EST bypass connector. (This was done while the engine was still running - The engine continued to run smoothly.) I shut the engine off I started the engine and it ran perfectly fine. (I thought I had resolved the issue!) Just to double check: I shut the engine off then I disconnected the EST bypass connector again. I tried to start the engine Results: Engine cranks over but does not start After realizing the engine was not going to start: I reconnected the EST bypass connector. The engine took quite a bit of cranking before it started. Once started, it ran fine. Basically I am able to replicate the exact same same problem that the smog shop came across. Based on my research, the correct procedure to check the timing is: Warm up engine Shut off engine Disconnect EST bypass wire Start engine (Cannot get past this step...) Set timing to 0 Shut off engine Reconnect EST bypass wire I'm guessing this is the procedure the smog shop is trying to follow so seems I need to get this to work for them so the smog test passes. I hope this is enough details for everyone. Please let me know if you have any ideas guys. Thanks for the help in advance!
