1985 Volvo 240 Hesitation at Hard Acceleration

Hey All,

Been trying to diagnose a stutter and hesitation when I accelerate hard. I’ve literally went through everything, intake and exhaust tight, new spark plugs, distributor cap and rotor, all intake and vacuum lines are tight, new crankshaft pulley, etc. Hell idk why it’s hiccuping when I throttle quick. It idles fine and ive done fuel work recently so it can’t be a fuel thing. AMM is working and in full operating order.

I don’t see any exhaust leaks in the system. It’s like it’s losing air when I throttle quick but catches itself and then does fine. Any ideas would help greatly, I’m trying to get this thing sold!

Thanks!

Smoke test it.

Where are you in NC?

Wilmy

What’s up people I believe it has something to do with my IAC. It’s really old and I could tell when I tightened clamps and cleaned with carb cleaner it made a difference. I was wondering if I have the IAC backwards.

I have the arrow facing down, with input coming from the flame trap hose and the output side to the air box hose nipple. Is this correct? Is it suppose to flow from flame trap to air box hose, or air box hose to flame trap hose?

Lemme Know!!!

Thanks

Not sure if the 85 is different, but that doesn't sound right to me.

It should be running from effectively one side of the throttle body to the other. It's job is to function as an air bypass to allow metered air to go around the throttle plate so the car doesn't stall.

So which direction should it run? Input from air box hose and output to flame trap hose?

That would be the opposite to how I have it ran now. So as of now it’s running in the flow of input from flametrap hose to output of airbox hose nipple.

Air should go from the air intake side TO the intake manifold motor side.

But you should DEFINITELY wait for someone with experience with the 85's to chime in.

I noticed the IAC in the 2.2 has two ports only. LH 2.4 has 3 ports on the IAC.

But yes I agree. I think flow should run from air box hose to flamtrap/intake. I guess I will reverse the IAC and see what happens.

2.4 also only has 2 ports. It's just a 90 degree turn vs. a straight through design.