Starts fine and idles when cold. Then runs a little rough.

[tfitzgerald]

Hi guys,

1981 FI 2000.

The car starts fine, and then as it warms up the idle drops very low to almost a stall (sometimes it does stall). After it has warmed up, it runs a LITTLE rough with some "puff" noises coming from the exhaust.

The car recently had a tune-up which included plugs/wire/cap/filter/fuel pump.

Any and all help would be greatly appreciated.

Regards,
Todd

[rlux4]

When you did the tune up were you able to set the idle according to the manuals?
It doesn't sound like a problem that can be pinpointed to any particular component, so a couple of things you may want to check; is the AAR (auxilliary air regulator) closing when it warms up? Check for any obvious breaks or wear spots on the resistance track in the AFM. Sometimes cleaning it with rubbing alcohol will help it make better connectivity. When it's warmed up and running rough unplug the cold start valve, could be it's stuck in the open position. As always, make sure you have no air leaks in the intake components (boot, AAR branch plumbing, intake plenum.)
Good luck, let us know how you're doing with it.
Ron

[tfitzgerald]

Hi Ron,

Could you explain to me exactly what the Air Flow Meter does (besides the obvious) ? Does it have any other functions?

Regards,
Todd

[divace73]

Hi Ron,

Could you explain to me exactly what the Air Flow Meter does (besides the obvious) ? Does it have any other functions?

Regards,
Todd

In the AFM housing, the unit is responsible for 3 things
1. Measuring Air flow via a tensioned flap which swipes a track with different resistance levels
2. Turning on the Fuel pump when there is movement on the flap (caused buy the suction from the engine)
3. Air temp sensor to measure the Air temp for the system.