I've been looking at picking up a 1990 GXL for $300 and the person I spoke to about it said its not idling well
finally spoke to the owner in person and he told me that his intake manifold is clogged up.
I need to find an S5 intake manifold. (not sure if I need upper or lower)
any help would be appreciated in finding one.

 

Hey man, ive got a 91' and im getting rid of my engine pretty soon, so if you want we can work something out and I can sell you my intake manifold if your interested.

 

The intake manifold won't clog unless the air filter was left off & some critters got in there.

The main idle control is the BAC (Bypass Air Control)
It's a duty (vibrating) solenoid.
It's mounted on the upper intake manifold.
It can stick or fail or have bad connections.

 

the user says the BAC valve is clean, he tells me there is something wrong with the auxiliary intake port.

 

the intake manifold is a chunk of metal. the aux ports are activated outside the intake manifold, but the aux port sleeves themselves are in the engine block. they seem to be good about locking up.
in short, the intake manifold should not be your problem.

 

so, what would cause the auxiliary ports to lock up?
I know the aux ports are in the actual engine itself, but he says they are clogged in the intake...

 

I'm suspicious of this seller’s guessing.

Aux intake ports, VDI & secondary throttles all affect performance, but not idle.

Things that can screw up idle:
A worn out/low compression engine.
A vacuum leak.
The short range TPS.
AWS - the electronic accelerated warmup system.
TB thermowax - the mechanical cold start fast idle cam & its controls.
More vacuum leaks.

 

Wait a minute a '90 for $300?

Bad idle is peanuts.

Does this car have a title?
Does it run at all?
Does it look OK - smell funny?

Grab it & fix it.

 

Id say it looks ok




planning on using it for my track car.

 

You might even make a few bucks selling the back seat..

 

yeah.
its gonna be a 2+2-2
I could use a couch

 

ill buy your backseat and your old s5 intake, upper and lower

 

rear seat litte as hell. im putting one in mine so i feel sorry for the poor bastards that sit back there

 

for 300 bucks, you should probably check compression. I bet the motor isn't right. Is it hard to start? Is it low on power?

 

He says its recently rebuilt
I hear it just idles poorly.

 

an s5 for $300? that's a steal, buy it.

 

I'd have to say though if you think the intake is clogged you may as well have a look at both the muffler belts and make sure they're somewhat tight but not too much :-).

 

:P
I've had an oil clogged intake before... and I'm pretty sure that with the overlap the pre-renesis rotary engines have, you could force unburnt hydrocarbons back into the intake.
Its possible, but not probable.