AFM test results - can I be sure my AFM is defective?

[PreCat Griffith]

Sorry to bombard this site, but I'm testing my AFM as per:

"Turn on the ignition, but do not start the engine. The meter should immediately indicate a reading of approximately 0.3-0.34 Volts. Most defective airflow meters will overshoot to 0.5 Volts or higher, and take at least 2 seconds to come down to the correct voltage."

My meter does indeed shoot to 0.5 (1.6 in the very first instance!) and then falls down to 0.35 over a few seconds. So can I be confident my AFM needs replacing?

I have a video of the meter reading if it's possible to upload here?

[PreCat Griffith]

I do actually have Rovergauge. I had it up and running fine, but after removal and refit of dash it now no longer connects. I'm going to give it another go today on a different laptop. Fingers crossed.

[PreCat Griffith]

Belle427 said:

Here is the thread, never overlook the basics!
https://www.pistonheads.com/gassing/topic.asp?h=0&...

Ah, thank you so much! I'll have a thorough read. While I've got you here, just to pick your brains further, my coolant and fuel temp sensors (tested in situ) are BOTH giving resistance of approximately 1500 ohms when cold (11C). Going by the Steve Heath bible, these are way off (should be more like 4000?), but seems coincidental that they both read roughly the same.

"The Coolant Temperature Sensor should change resistance with heat, per the following specs.
-10C (14°F) 9100-9300 Ohms
0C (32°F) 5700-5900 Ohms
20C (68°F) 2400-2600 Ohms
40C (104°F) 1100-1300 Ohms
60C (140°F) 500-700 Ohms
80C (176°F) 300-400 Ohms
100C (212°F) 150-200 Ohms"

[PreCat Griffith]

I tried a new laptop and RG is working! I'm so pleased.

Ok, great thanks for your assistance. What would you have me do? Take it for a drive while logging? Need half an hour to get the car all back together first. Be right back.

[PreCat Griffith]

Frank (and RoverGauge) has been so helpful!

We're making steady progress; I could never have done this on my own.

Vacuum advance diaphragm needs replacing, and we've also established that clamping this hose (with annotated yellow stripe) from/to the plenum will cause the revs to drop until stalling, so perhaps our vacuum leak.

Edited by PreCat Griffith on Monday 1st January 20:56

[PreCat Griffith]