Yup, sorry. I've read through everything I can find in search and haven't found an answer yet.
The subject: '97 LC, 248k, stock gears, 285 Duratracs.
Before 1st test was done I did:
- Oil change, 5w30 Mobil 1 & Toyota filter
- New plugs (Denso), wires (NGK), cap (Denso), rotor (Denso)
- New air filter, Toyota washable.
- Recent EGR work including: clean passage in intake, clean throttle body, replaced all vacuum hoses for EGR and under intake, replaced EGR modulator (new blue top). This fixed my P0402 CEL.
Results #1: 1/9/17
HC: 0.8266 Limit: 1.2 Pass
CO: 28.3386 Limit: 15 FAIL
CO2: 709.1657
NOx: 1.7091 Limit: 3.0 Pass
Changed engine temp sensor (this helped last time), checked timing, & decided to try the "easy" way out and added 2 bottles of Guaranteed to Pass to the fuel. Due to dealing with some driveshaft issues I didn't get back to test the truck with the next tank of fuel after I ran out the additive like the product recommends. 4 weeks and 5 tanks later I went back.
Results #2 2/10/17
HC: 0.4346 Pass
CO: 18.3501 Limit 15 FAIL
CO2: 680.4616
NOx: 1.6221 Pass
Replaced all other vacuum lines I could find, tested TPS, and cleaned MAF sensor.
Results #3: 2/14/17
HC: 0.5068 Pass
CO: 20.2299 Limit: 15 FAIL
CO2: 707.0228
NOx: 1.9111 Pass
I started to suspect the downstream O2 sensor after seeing some high voltage readings on my ScanGauge. Tonight I checked both O2 sensors per the FSM and both are within spec (upstream is 14.4 ohms, downstream is 14.0 ohms, FSM range 11-16 ohms). Is it possible for them to still be bad and causing the rich condition? I have two new Denso sensors sitting here just in case but I'd rather not throw $ at somthing that tests OK and may not fix the problem. What else am I missing that could cause high CO?
I did replace the charcoal canister with the vatozone one recommended here, due to pressure at the fuel cap at fill ups. Could that have anything to do with it? Could it be pulling more fuel vapor from the canister than intended?
I can post the graphs from the tests if that would be helpful.
TIA!
The subject: '97 LC, 248k, stock gears, 285 Duratracs.
Before 1st test was done I did:
- Oil change, 5w30 Mobil 1 & Toyota filter
- New plugs (Denso), wires (NGK), cap (Denso), rotor (Denso)
- New air filter, Toyota washable.
- Recent EGR work including: clean passage in intake, clean throttle body, replaced all vacuum hoses for EGR and under intake, replaced EGR modulator (new blue top). This fixed my P0402 CEL.
Results #1: 1/9/17
HC: 0.8266 Limit: 1.2 Pass
CO: 28.3386 Limit: 15 FAIL
CO2: 709.1657
NOx: 1.7091 Limit: 3.0 Pass
Changed engine temp sensor (this helped last time), checked timing, & decided to try the "easy" way out and added 2 bottles of Guaranteed to Pass to the fuel. Due to dealing with some driveshaft issues I didn't get back to test the truck with the next tank of fuel after I ran out the additive like the product recommends. 4 weeks and 5 tanks later I went back.
Results #2 2/10/17
HC: 0.4346 Pass
CO: 18.3501 Limit 15 FAIL
CO2: 680.4616
NOx: 1.6221 Pass
Replaced all other vacuum lines I could find, tested TPS, and cleaned MAF sensor.
Results #3: 2/14/17
HC: 0.5068 Pass
CO: 20.2299 Limit: 15 FAIL
CO2: 707.0228
NOx: 1.9111 Pass
I started to suspect the downstream O2 sensor after seeing some high voltage readings on my ScanGauge. Tonight I checked both O2 sensors per the FSM and both are within spec (upstream is 14.4 ohms, downstream is 14.0 ohms, FSM range 11-16 ohms). Is it possible for them to still be bad and causing the rich condition? I have two new Denso sensors sitting here just in case but I'd rather not throw $ at somthing that tests OK and may not fix the problem. What else am I missing that could cause high CO?
I did replace the charcoal canister with the vatozone one recommended here, due to pressure at the fuel cap at fill ups. Could that have anything to do with it? Could it be pulling more fuel vapor from the canister than intended?
I can post the graphs from the tests if that would be helpful.
TIA!
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