2001 Chevy Blazer LS 4.3L CA emissions chase
#21
Senior Member
Join Date: Oct 2019
Location: West-Central Florida
Posts: 520

American, born and raised.......Valve job done, no vacuum line leaks, new (head) gaskets after 3 smoke tests no hint of smoke leaks anywhere. As before, engine runs very smooth, no hint of misses from idle through just before redline. This is my first California car and whole emissions thing, here, new to me. Layout of your engine bay different than mine. From above pictures, what did you circle in blue? Thanks again!
You mentioned a valve job, was any performance modifications done? either higher valve lift, ported heads/intake, or anything at all that would make it run differently, the PCM knows how a stock 4.3 should run and what it should see from its sensors, and if anything is done to make it run differently from stock, the PCM will pick it up and throw any number of codes, including the mystical P0300.
#22
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Join Date: Nov 2020
Posts: 24

No modifications, but I bought the car "as is" with a chromed air intake, not stock. Cannot find a stock air intake anywhere, so far. I suspect that the previous owner may have tried to tune it at some time, just a hunch, though. I may go ahead with both the check valves, popped the P0440 code again today.
#23
Senior Member
Join Date: Oct 2019
Location: West-Central Florida
Posts: 520

No modifications, but I bought the car "as is" with a chromed air intake, not stock. Cannot find a stock air intake anywhere, so far. I suspect that the previous owner may have tried to tune it at some time, just a hunch, though. I may go ahead with both the check valves, popped the P0440 code again today.
#24
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Join Date: Nov 2020
Posts: 24

2001 Chevy Blazer LS 4.3L engine bay
2001 Chevy Blazer LS 4.3L engine bay
#25
Senior Member
Join Date: Oct 2019
Location: West-Central Florida
Posts: 520

. it has a 411 PCM??
thought those were a model year 2003 and forward thing.
You mentioned the previous owner may have tried to tune it, have any way of verifying it?
and lots of exposed wiring...
thought those were a model year 2003 and forward thing.
You mentioned the previous owner may have tried to tune it, have any way of verifying it?
and lots of exposed wiring...
#26
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Join Date: Nov 2020
Posts: 24

#27
Senior Member
Join Date: Oct 2019
Location: West-Central Florida
Posts: 520

man model year changeovers are weird, dont make much sense either since GM didnt switch S10s to the new Serial bus until 2003+
#28
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Join Date: Nov 2020
Posts: 24

I exposed the wiring because "rats" had eaten, a lot. This was painstaking, but, I had to find the shorts, exposed copper, etc. The ecu has been a question in my head, since I bought the car. I even ordered a new (refurbished) one, by a supposed reputable company, that ended up screwing me over. Anyway, stayed with the old one! Blazer starts just like it should, runs great and all. All finish work will be done when I get it through, smog!
#29
Senior Member
Join Date: Oct 2019
Location: West-Central Florida
Posts: 520

I exposed the wiring because "rats" had eaten, a lot. This was painstaking, but, I had to find the shorts, exposed copper, etc. The ecu has been a question in my head, since I bought the car. I even ordered a new (refurbished) one, by a supposed reputable company, that ended up screwing me over. Anyway, stayed with the old one! Blazer starts just like it should, runs great and all. All finish work will be done when I get it through, smog!
this includes - Knock sensor, Cam sensor, and the crank sensor
#30
Beginning Member
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Join Date: Nov 2020
Posts: 24

Wiring still going over. I feel there may be a spot I didn't see or detect. This has been ongoing. It seems I've performed every detection procedure, My main focus has been wiring, from first seeing those eaten wires.





