Is this just the nature of the vane style AFM?

[caliGreen]

You probably still have intake leaks. A number of the places where an intake leak can occure won't respond to a spray of carb cleaner. Either because you can't saturate the area or because it is too far from the intake ports. Only a smoke test will find leaks at any of the possible locations.

Well, that or you can replace every hose, gasket, and seal that could result in an intake leak. The complete list of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hose and valve
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

good info.. my thoughts were the same as the thread starter.. good power but when i tap the gas makes a boging? just dont go Vroommm but tap to half throttle makes the vroom..

[nando]

yea, that's just an AFM for ya

no, it's not. it's a result of something wrong with the engine, and partially from no acceleration enrichment. the movement of the flapper door is probably 2% of the total equation.

half a second is not normal. it should be maybe a 1/10th or so off idle.

[Sagaris]

It is about a half second hesitation. I can blip the throttle, take my foot off the pedal, it cuts out and then it responds.

I have replaced the plugs, wires, cap, rotor, timing belt, O2 sensor (OEM) coolant temp sensor (OEM) , air filter (K&N panel filter) cleaned the ground wires, and done a visual inspection for vac leaks.

Again, it runs perfectly besides this minor response issue off-idle.

Im going to attempt to make my own smoke test apparatus this week and see if I can find anything.

[jlevie]

You probably still have intake leaks. A number of the places where an intake leak can occure won't respond to a spray of carb cleaner. Either because you can't saturate the area or because it is too far from the intake ports. Only a smoke test will find leaks at any of the possible locations.

Well, that or you can replace every hose, gasket, and seal that could result in an intake leak. The complete list of possible causes of an intake leak is:

Intake boot
Throttle body gasket
ICV hoses & connections
Brake booster, hoses, and connections
Crank case breather hose
Evaporative control hose and valve
Fuel pressure regulator & hose
Injector seals
Valve cover gaskets & bungs
Oil filler cap
Dip stick o-rings
Oil return tube o-rings

[AnimalE30]

My car has the exact same problem. Never did a smoke test, did spray carb cleaner in every nook and cranny to find any leaks. Found a couple, fixed them, but the car still doesn't respond to blips too well.

[jlevie]

That can be the result of an intake leak. Both my Spec E30 and my 87 325is, that I know to be in good condition with no intake leaks, respond as expected to throttle blips. So I submit that this car has some problem with the engine management system. A smoke test of the intake would be the first action to take.

[SpecM]

yea, that's just an AFM for ya

[Sagaris]

My car runs excellent. I get between 26-29 mpg, It accelerates well and sounds teriffic but when I am idling and blip the throttle, it doesnt seem to respond well at all. It revs just fine when I give it more throttle , but when its just a quick blip, not even to 1000rpm then it bogs and cuts out a bit. I am thinking that this is just the downfall of having a vane style AFM and that the flap inside the AFM cant respond accurately when it has something so sudden happening.

Again, car runs fine but I wonder if this is typical or not

Any thoughts?