Freaking high idle
Lead Driver
Joined: Oct 2016
Posts: 6,185
Likes: 633
From: Houston/Sugar Land
Here is information about the PCV and how it works which will give you better understanding about your system.
The Basics of Positive Crankcase Ventilation (PCV)
The Basics of Positive Crankcase Ventilation (PCV)
Logistics Pro
Joined: Nov 2013
Posts: 3,922
Likes: 1,192
From: Mojave, Ca
So tinkered a but last night, got ut up to temp disconnected the iac and turned out the idle adjustment screw no change. Pulled and capped/plugged lines off of the vacuum tree one at a time, the pcv line when capped did drop the idle to 750 so I will pick up new pcv valve today. Question should the pcv allow air flow to the intake, basically having a bit of a hard time wrapping my brain around how it's supposed to function. Since it's under vacuum from the intake would it not always allow air to go from valve cover area to the intake since the poppet under vacuum will unseat?
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5th Wheeling
Joined: Jan 2023
Posts: 25
Likes: 3
So I did check out the egr tonight the diaphragm is good and does gold vacuum, I had to go buy a vacuum tester the actual egr side is siezed shut tested with water needle does not move .
another question can someone explain the vacuum reservoir to me as I can not seem to get vacuum with my tester but shows no signs of leaks when I placed it under under and switched to pressure.
Also I can not get vacuum on the common solenoid line to the vacuum cannister
or the egr solenoid or the second air b solenoid key off or on
Is this normal?
another question can someone explain the vacuum reservoir to me as I can not seem to get vacuum with my tester but shows no signs of leaks when I placed it under under and switched to pressure.
Also I can not get vacuum on the common solenoid line to the vacuum cannister
or the egr solenoid or the second air b solenoid key off or on
Is this normal?
Fleet Mechanic
Joined: Aug 2015
Posts: 1,829
Likes: 362
From: Candy Mountain
The reservoir usually has a port with a check valve that closes under low vacuum. So you have to have the supply line on that port. The HVAC circuit is set up the same way, except that the check valve is not integrated into the HVAC reservoir.
The EGR control solenoid acts like a small vacuum leak when not active so that circuit will not hold much vacuum with it still in the circuit.
You should just remove the vacuum lines to the AIR solenoids if you have otherwise deleted that system. Leave the solenoids hooked up electronically.
The EGR control solenoid acts like a small vacuum leak when not active so that circuit will not hold much vacuum with it still in the circuit.
You should just remove the vacuum lines to the AIR solenoids if you have otherwise deleted that system. Leave the solenoids hooked up electronically.
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5th Wheeling
Joined: Jan 2023
Posts: 25
Likes: 3
The reservoir usually has a port with a check valve that closes under low vacuum. So you have to have the supply line on that port. The HVAC circuit is set up the same way, except that the check valve is not integrated into the HVAC reservoir.
The EGR control solenoid acts like a small vacuum leak when not active so that circuit will not hold much vacuum with it still in the circuit.
You should just remove the vacuum lines to the AIR solenoids if you have otherwise deleted that system. Leave the solenoids hooked up electronically.
The EGR control solenoid acts like a small vacuum leak when not active so that circuit will not hold much vacuum with it still in the circuit.
You should just remove the vacuum lines to the AIR solenoids if you have otherwise deleted that system. Leave the solenoids hooked up electronically.
Also forgot to mention after i got to operation temp by idleing it was about 300-400 rpm high (1000rpm) i took ut for a test run and the idle jumped to 1300-1400rpm at idle
I also reset the tps checked that the butterfly valve where not being held open and reset the idle set screw
Iac % aFter initial startup is up to 60% then settles on 16%
timing on initial start will advance to 25 then settle settle according to ob2 scanner data diplay
Hotshot
Joined: Jun 2015
Posts: 12,791
Likes: 2,426
Also forgot to mention after i got to operation temp by idleing it was about 300-400 rpm high (1000rpm) i took ut for a test run and the idle jumped to 1300-1400rpm at idle
I also reset the tps checked that the butterfly valve where not being held open and reset the idle set screw.
I also reset the tps checked that the butterfly valve where not being held open and reset the idle set screw.
Fleet Mechanic
Joined: Aug 2015
Posts: 1,829
Likes: 362
From: Candy Mountain
If you cannot adjust the idle down with the IAC disconnected then you are still fighting a vacuum leak or the throttle body is worn out.
FYI there is no magical TPS value other than keeping it less than 1V at idle. Every time you put the key in the run position the computer looks at the TPS value right then and uses that as the idle reference for that drive cycle.
FYI there is no magical TPS value other than keeping it less than 1V at idle. Every time you put the key in the run position the computer looks at the TPS value right then and uses that as the idle reference for that drive cycle.
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Tuned
Joined: Jan 2021
Posts: 377
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EDIT: Even if it is ODBII troubleshooting is pretty much the same.
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5th Wheeling
Joined: Jan 2023
Posts: 25
Likes: 3
Yes it is a 96 with the maf sensor cleaned that today, have checked the timing with spout out and it's on 10 degrees. With engine running bkocked off tb intake ports truck immediately died. Emilinated as much vacuum lines as possible. One line fro. Tree to vac side of reservoir other port on res goes to vmv valve . Rechecked everything i can think of , reset adaptive learning and will ha e to put a per.it on the truck and take it for a drive and fi gers crossed its good will update after driving for a day
Fleet Mechanic
Joined: Aug 2015
Posts: 1,829
Likes: 362
From: Candy Mountain
There should be no MAP/Baro sensor present.
I apologize for putting a rock on the train tracks.
