IROC transplant into a1955 Chevrolet sedan. I had the filter coming through the radiator support, then just behind as shown. I've even removed the filter entirely! I keep getting Code 34 MAF Sensor Low regardless. Can anyone offer any advice?

Mike

Can't imagine this is causing the code. What is the history on the MAF sensor? What brand is it? I don't run a MAF car but have heard the aftermarket units are problematic I think?

New Delphi AF 10320 MAF Sensor, new harness.

Mike

Have you checked the burn off relay?

Although it is new, I just removed it from its mount on the firewall, tucked up under the dash, and checked it. Yes, it's good.

Mike

That MAF should be correct for a 1986-up system. Can you measure the analog output from the sensor with the engine running and report the values?

Is this what you are looking for?

Mike





​​​​​​COULD LOW TPS VOLTAGE AFFECT IT? I'M SEEING DESIRED .54 +/- .075. .44 ISN'T MUCH LOWER, BUT IT IS LOWER.

That filter seems too small in my opinion. Are you pulling vacuum under load?

It also happens with the filter removed.

I don't have a vacuum gauge installed... Where would you recommend checking it at?

Mike

I was more curious about the actual voltage measured at the MAF, and not the converted g/S value that the ECM thinks it is seeing.

I took a picture of every screen of the OBD1 while checking for errors, and none of them had that category. Is it something I need to physically check?

Mike

You can't read the maf voltage with a simple scan tool. It can be done with modified programming and more sophisticated scanning/tuning tools that can also be modified accordingly.

However, the MAF voltage would be between 0.00-0.090 volts (calibration dependent), which is why it is setting a Code 34. Are we sure that the maf is even being powered? Check the maf power relay and related wiring.

6 gm/sec would be about 0.00 volts (if using a 305 bin like APYS) which is less than the 0.140 volt threshold, so this value is consistent with the Code 34 failure detection settings. Sorry, I tend to forget about 305 bins.

MAF Table #1 (from APYS)

Volts Grams/sec

01.46 21.40
01.28 17.02
01.10 13.41
00.91 10.40
00.73 7.99
00.55 5.93
00.37 4.38
00.18 3.35
00.00 6.02

6 gm/sec would be about 0.090 volts (if using a 350 bin like ARAP) which is also less than the 0.140 volt threshold.

MAF Table #1 (from ABTC)

Volts Grams/sec

01.46 22.37
01.28 17.77
01.10 13.98
00.91 10.91
00.73 8.39
00.55 6.22
00.37 4.51
00.18 3.25
00.00 8.39

Have been sidetracked for a few days, and will be off and on for the coming week, but I want to wrap my head around what you are telling me. Some of this TPI stuff is beyond my scope of my experience, and that's why I am appreciating the fact you are offering assistance. What should be my next step?

Mike