Hello again everyone,

Just finished R&R the VAFM on sons '95 3.0. ECM was giving me a code 24 (Intake air temp sens). What is really weird is when first starting and driving the CEL doesn't illuminate. Only after the motor is warm does the CEL come on.

Below are old and new Ohm values for the VAFM:

Old - e2 - vs = 258.2
e2 - vc = 281
tha - e2 = open
fc - e1 = open

New - e2 - vs = 322.4
e2 - vc = 280.1
tha - e2 = open
fc - e1 = open

Would this small resistance cause a TC 24? Also, would the IATS affect the timing?

Haven't driven to see if the new VAFM took care of the TC. My guess is it's not the VAFM but something else. But dam* if I can figure it out.

Safety & blue skies,

DJ

 

Well, if you've replaced the VAFM I'd suspect wiring....possibly in the connector. The VAFM function can and does affect timing in that the ECU has to adjust according to what the IATS is telling it. The whole system communicates via resistance and voltage readings....less or more. For example....as the motor warms the resistance/voltage signal drops in the ECT sensor and the ECU adjusts the fuel ratio and spark advance (less) to compensate. The IATS works on the same principle.

So, if the ECU is detecting resistance higher or lower than spec or not getting a signal at all, then it won't work right and you'll get a code. Or should, anyway.

 

If you suspect wiring, you can chase it all the way back and measure the AFM at the ECU.. It's in the FSM, a bit of a pain, but can be done.