G2: DIY: Miscellaneous: EGR Cleaning
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Work-In-Progress!
This guide explains how to remove and disassemble the intake manifold to clean out all of the EGR (Exhaust Gas Recirculation) passages. The EGR system recirculates exhaust gases back into the intake manifold under certain conditions, to reduce emissions of NOx (oxides of nitrogen, primarily nitric acid and nitrogen dioxide) by lowering combustion chamber temperatures. The EGR system on Legends is known to become clogged with carbon deposits formed by the mixture of exhaust gases from the EGR and oil from the PCV system. When the EGR becomes clogged, is it not enough to simply remove the EGR pipe and clean it, the entire intake manifold must also be removed to clear out the passages inside. Note: Cleaning the EGR system will not clear CEL code 12. Code 12 is set when the ECU detects there's a problem with the EGR valve opening and closing. (see G2: FAQ: Error Codes: CEL 12)
1. Removing The Intake Manifold
A. Drain Coolant
Raise the car and put it up on jackstands. Remove the splash shield from underneath the radiator, this shield is held on by more than 10 bolts (M6x1.0). Remove the radiator cap. Loosen the drain plug on the bottom drivers side of the radiator with a drain pan underneath it. Once the coolant stops flowing from the drain, tighten the drain plug (loosely, just until snug, it's only made of plastic). The coolant does not need to be emptied completely for this procedure, so don't worry about getting out every last drop. Remove the upper radiator hose. Remove the coolant hoses from the IACV (Idle Air Control Valve) and FIV (Fast Idle Valve), two hoses each. Alternatively you may unbolt the IAC and FIV from the intake manifold and leave the coolant hoses attached (this will not leak any coolant), don't forget to replace the o-rings (two on the FIV, one on the IACV) if you use this method.
B. Strut Bar
Remove the strut bar (five M8x1.25 bolts and one M8x1.25 nut).
C. Fuel Rail Covers
Remove the fuel rail covers (two M6x1.0 acorn nuts for each cover).
D. Fuel Line
Wrap a rag or towel around the fuel filter. Loosen the "service bolt" on the fuel filter slowly until fuel starts leaking out. Allow the fuel to leak out and absorb it with the towel. Continue to loosen the service bolt until the fuel stops leaking and the pressure has been relieved. Do not loosen the service bolt too quickly or fuel will spray out.
Remove the main fuel feed hose from the fuel filter and passenger side fuel rail.
E. Throttle Body
The throttle body does not need to come off with the manifold, so we'll be leaving in place for this procedure. This way you don't have to disconnect the throttle and cruise control cables. Loosen the clamp around the air intake tube and slide the tube off of the throttle body. Remove the two bolts and two nuts that hold the throttle body to the manifold. Push the air intake tube out of the way and slide the throttle body off the studs, then set it aside but make sure not to bend or kink the throttle cables.
F. Electrical Connectors
Disconnect all the electrical connectors from the IAC, Coolant Temperature Sensor, Coolant Temperature Sending Unit, Intake Air Temperature Sensor, and all six fuel injectors. Try not to twist the fuel injectors as you remove the electrical connectors, that could damage or tear the o-rings and cause a fuel leakage. Unbolt the ground from the passenger side fuel rail.
G. Vacuum Lines
Disconnect (and label!) all the vacuum lines from the Fuel Pressure Regulator, PAIR valve (Type I engines only), and both IAB diaphragms (aka VIS). Also disconnect the three vacuum lines from the upper rear passenger side corner of the intake manifold. These three can be installed on any of the three ports there, so don't worry about labeling them individually. Disconnect the PCV hose from the intake manifold, behind the throttle body opening. Unbolt the FIV air pipe "elbow" from the back of the intake manifold, also disconnect the hose from the metal pipe that runs along the top of the passenger side valve cover. Disconnect the brake booster vacuum hose from the rear of the intake manifold.
H. PAIR and EGR Pipes
Unbolt the PAIR pipe between the PAIR valve and drivers side exhaust manifold (Type I engines only). It's not necessary to completely remove the PAIR pipe, you can just unbolt it from the intake manifold and leave it connected to the exhaust manifold. Remove the EGR pipe from between the intake manifold and the passenger side cylinder head. Don't forget this step! If you try to yank the intake manifold off without this pipe disconnected, it could very easily break.
I. Manifold
Unbolt the water passage from the block. There are two bolts on each end (10mm M6x1.0). This water passage will come out as a unit with the intake manifold, so don't try to pry it out after removing its 4 bolts.
Unbolt the intake manifold from the cylinder heads. There are 4 bolts and 4 nuts (12mm M8x1.25). Lift the manifold up slowly, always checking for any remaining hoses or electrical connectors that are still connected. There is one pipe underneath the manifold that may appear to still be connected, but it is only pressed in with an o-ring. Simply pull up to break it free.
2. Disassembling And Cleaning The Intake Manifold
Now that the intake manifold has been removed from the engine, it can be disassembled to reach the internal EGR passages.
A. Disassembly
Turn the manifold upside-down. Unbolt the two nuts and nine bolts. Many of these bolts are different lengths, so make sure you label which one came from where. Removing these bolts will also free the throttle body neck and water passage, just set those aside. After all the nuts and bolts have been removed, pull apart the manifold lower section, leaving the two upper sections in place. If the lower section is still stuck, you may gently pry with a screwdriver between the bolt holes (not between any gasket seating area).
B. Cleaning
Notes
C. Reassembly
Notes
3. Reinstallation
Installation is the reverse of removal. Remember to replace all o-rings and gaskets.
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