darren1031

What is acceptable for manifold pressure?

Still trying to track down my crappy idle. Off-idle, the car has great power and runs great. But my idle sucks.
Sometimes real bad, sometimes fairly smooth. At red lights, the idle will surge up to 1200rpm and then drop
and the engine almost dies. I don't know what else to check/replace. I'm baffled.

I measure vacuum at the line that connects to the fuel damper
and it was 13-14". Revving the engine, it goes up to 20". Am I measuring at the correct place?

Things I have replaced to correct my crappy idle:

All vacuum lines
ISV and the two hoses on both sides (venturi delete)
Coil
ICM
Air filter
spark plugs
Dist cap/rotor
TPS
O2 Sensor
DME temp sensor
AFM
FPR

KuHL 951

Are you sure the AFM wiper arm doesn't have a dead spot? Has it ever been re-tracked? Is the TPS adjusted correctly to signal throttle closed? Oh, and what year, model is the car? Your manifold vacuum looks OK unless it is pulsing, a bit low but not really an issue.

darren1031

Oops! Hit submit before I signed my msg.

I have a rebuilt AFM (Paragon).

I have a new TPS and it's adjusted properly.
It clicks just off idle and again when the throttle
is closed.

Darren
'87 944S

theedge

If youre close to sea level, it should be between 18 and 21" when fully warmed up. Is that when you tested it, operating temp?

darren1031

Close to sea level (167 ft).

Engine at operating temperature. 13" and increased to 14" after a few minutes. It seemed too low, that's why I was wondering if I was measuring at the proper place. My VW bus is higher than 13" at idle.

I must have a major vacuum leak somewhere, but I dont know where.

Darren
'87 944S