You may see some variance on a digital meter. Here's an old data capture of my car in warm-up mode.Originally Posted by Bitsyncmaster
FreqValveWarmup.jpg
Location: Lansing, MI
Posts: 1,168
My VIN: 10270
You may see some variance on a digital meter. Here's an old data capture of my car in warm-up mode.
FreqValveWarmup.jpg
Luke S :: 10270 :: 82 Grey 5-Speed :: Single Watercooled T3 .60/.48 :: Borla Exhaust :: MSD Ignition :: MS3X Fully SFI Odd-fire EFI :: DevilsOwn Methanol Injection
Posts: 743
Here the results of this mornings test.
OAT is 70F
Cold engine, just after starting 1.02 - 1.04 volts at O2 sensor
After 1 minute, .98 volts.
After 3 minutes, .97 volts
Then, at 4 minutes the engine idle started hunting, a little at first, then from 800- 1,500 rpms over and over again.
At this point the volts steadily climbed up to 1.4 where it stayed until I turned the car off. Exhaust smells obnoxiously rich through the whole test.
I don’t know if it means anything but the volts didn’t drop immediately after turning off the engine. It just slowly worked it’s way down to zero.
Posts: 743
I just thought of something. Whenever I start my car I always turn on the electricity and let the fuel pump finish priming before I start the engine (Dave's RPM relay). Doing this, I always hear a humming sound from the engine and I didn't think anything of it. Today I turned on the electricity, the pump primed, and I opened the engine covers to see what was making that noise. It was the cold start valve. I thought it was only supposed to run during cranking? Perhaps the cold start valve is running all the time?
Last edited by CFI; 04-26-2019 at 10:23 AM.
Location: Leonardtown, MD
Posts: 9,004
My VIN: 03572
The sensor should have no voltage until it warms up. This is sounding like your lambda ECU is bad. When I program my wide band I set the wideband output to 0.5 volts and to swing fast higher or lower if the AFR is not what I want. The wideband feeds the OEM lambda ECU directly into the O2 input circuit.
Last edited by Bitsyncmaster; 04-26-2019 at 10:24 AM.
Location: Northwest Florida
Posts: 324
My VIN: Midproduction
Cold start relay or cold start valve? I know the Idle motor buzzes when the key is on run. It's also right next to the cold start valve. Sure it's not that? The CSV is easy to test of course.
Location: Leonardtown, MD
Posts: 9,004
My VIN: 03572
+1
Unless you have my idle ECU the idle motor will run (buzz) when ever the key is on.
Posts: 743
Cold start valve. I touched it and felt it vibrating. I'll unplug it and see what happens.
Location: Leonardtown, MD
Posts: 9,004
My VIN: 03572
The CSV should only get power when the starter is cranking the engine. Make sure your bulkhead connectors are plugged into the correct mating connector.
Posts: 743
I unplugged the cold start valve and the noise is not coming from that, it's coming from the idle motor. Running without the cold start valve made no difference.
Posts: 743
Connectors look good but the blue one has a wire that was cut out.126738A0-889A-4323-A50B-CCBCE7FF0A45.jpg
Posting Permissions
Reply With Quote
Dave M vin 03572