Higher than normal Idle, and occasional stumble

[XfireZ51]

Originally Posted by Billy Mild

I haven't yet. It sounds like I need to get a hold of a tech1 and check that stuff.

Dynomite I have replaced that check valve BTW. It seems that when its warm outside and my engine is warmed up the vacuum pump doesn't run all the time. So it is intermittent.

Would it be a bad idea to replace all vacuum lines with silicone hoses?

The hard plastic lines are there to avoid collapse during high vacuum operation.

[Dynomite]

Originally Posted by XfireZ51

The hard plastic lines are there to avoid collapse during high vacuum operation.

Concur

I have found in addition to that check valve failing, that the usual vacuum leaks are caused by the rubber connectors getting hard and shrink with age on the ends of the hard plastic lines. If you cannot remove the rubber connectors they probably do not need to be removed. It is the loose rubber connectors that have shrunk and leak. Or.....have disconnected themselves from the hard plastic lines.

Be careful that you do not kink the hard plastic lines by excessive bending.

Originally Posted by Billy Mild

It seems that when its warm outside and my engine is warmed up the vacuum pump doesn't run all the time. So it is intermittent.

That fits right in with the connectors getting a bit tighter as they warm up.

[secondchance]

Originally Posted by Billy Mild

I haven't yet. It sounds like I need to get a hold of a tech1 and check that stuff.

Dynomite I have replaced that check valve BTW. It seems that when its warm outside and my engine is warmed up the vacuum pump doesn't run all the time. So it is intermittent.

Would it be a bad idea to replace all vacuum lines with silicone hoses?

You don't need Tech 1 to check. I believethere are three wires coming out of TPS. Use paper clip inserted on top and bottom where wires are connected (I belive the middle is reference voltage). Turn the key to run position (don't start the motor) and read voltage between the top and bottom wire. At idele it should be around .55 volts. Have someone dpress the gas pedal and see if the voltage increases gradually. If you see voltage fluctuating, you got a bad TPS.
Typically (perhaps not always), vacuum leak from the secondary vacuum system does not cause high idle nor stumbling based on my experience.

[Billy Mild]

Can you get those rubber pieces new?

[secondchance]

Originally Posted by Billy Mild

Can you get those rubber pieces new?

You can't get OEM rubber pieces only. However, Advance Autoparts has an aisle with assortment of plastic vacuum lines, fittings and rubber hose ends.

[RussMcB]

Originally Posted by Dynomite

Be careful that you do not kink the hard plastic lines by excessive bending.

Concur. I surprised myself when one broke in two easily when I was trying to move it off to the side while working. Luckily I was removing secondaries, so it wasn't a big deal. I guess they can get pretty brittle in that environment after a few decades.

[XfireZ51]

Originally Posted by Dynomite

Concur

I have found in addition to that check valve failing, that the usual vacuum leaks are caused by the rubber connectors getting hard and shrink with age on the ends of the hard plastic lines. If you cannot remove the rubber connectors they probably do not need to be removed. It is the loose rubber connectors that have shrunk and leak. Or.....have disconnected themselves from the hard plastic lines.

Be careful that you do not kink the hard plastic lines by excessive bending.



That fits right in with the connectors getting a bit tighter as they warm up.

I spread a bit of silicone gasket sealer around the joint of the hard line and the rubber connector.
Will also use tie wraps around that area.