This is for 4.6's typically with an lack of flow code for the EGR system. (p1401, p0401, etc)
These engines use a Differential Pressure Feedback system. What that means is that the DPFE sensor measures the pressures of the egr system to determine flow. On some of these vehicles the MIL can become illuminated with a DPFE flow code. This can be due to clogged EGR Ports in the intake manifold under the throttle body. The clogged EGR ports are more likely to get clogged on 99 and newer vehicles because of the design of the EGR flow.
This first section is on cleaning the Ports for the 99 and new vehicles, as it is a quicker writeup:
Tools needed:
3/8" hand ratchet (or air ratchet if you have)
6-10" 3/8" extension
8mm 3/8drive socket
1/4" hand ratchet + extension (for removal of engine cover)
flat head screw driver
small pick
shop towel
Parts needed:
Throttle body gasket
Throttle body cleaner
Operation instructions:
1. Remove engine cover
2. Remove air inlet tube from throttle body
3. Remove cruise control cable and throttle cable from throttle body
4. Disconnect Throttle Position sensor
5. Disconnect throttle return spring
6. remove the 4 bolts for the throttle body
7. shove shop rag in big hole under throttle body
8. with the pick, clean out the carbon buildup from the ports around the big hole under the throttle body (in the intake manifold)
9. VERY IMPORTANT STEP, REMOVE THE SHOP RAG!!
10. installation is reverse of removal. install new tb gasket (not mandetory, but recommended)
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EGR valve removal, 92-95
Removal
1. Remove air cleaner outlet tube
2. Raise vehicle on hoist
3. CAUTION: Use care not to damage EGR valve tube to manifold connector (9F485) .
NOTE: Hold EGR valve tube to manifold connector with a wrench while disconnecting EGR valve to exhaust manifold tube (9D477) .
Disconnect EGR valve to exhaust manifold tube from EGR valve (EGR valve) (9D475) and EGR valve tube to manifold connector .
4. Lower vehicle.
5. Disconnect EGR pressure sensor hoses from EGR valve to exhaust manifold tube .
6. Disconnect vacuum hose from EGR valve .
7. Remove two EGR valve retaining bolts.
8. Remove EGR valve , EGR valve gasket (9D476) and EGR valve to exhaust manifold tube from vehicle.
Installation
1. Clean intake manifold sealing surface with a plastic-tipped scraper to remove any residual EGR valve gasket material.
NOTE: Do not tighten EGR valve to exhaust manifold tube nut on EGR valve at this time.
2. Position EGR valve to exhaust manifold tube into EGR valve and loosely connect EGR valve to exhaust manifold tube nut to EGR valve .
3. Position EGR valve gasket , EGR valve and EGR valve to exhaust manifold tube into vehicle.
4. Install two bolts retaining EGR valve to intake manifold . Tighten bolts to 20-30 Nm (15-22 lb-ft).
5. Connect vacuum hose to EGR valve .
6. Connect EGR pressure valve sensor hoses to EGR valve to exhaust manifold tube .
7. Raise vehicle.
NOTE: Hold EGR valve tube to manifold connector with a wrench while tightening EGR valve to exhaust manifold tube nut.
8. Connect EGR valve to exhaust manifold tube to EGR valve tube to manifold connector . Tighten EGR valve to exhaust manifold tube nuts to 35-45 Nm (26-33 lb-ft).
9. Lower vehicle.
10. Install air cleaner outlet tube as outlined in Section 03-12.
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These engines use a Differential Pressure Feedback system. What that means is that the DPFE sensor measures the pressures of the egr system to determine flow. On some of these vehicles the MIL can become illuminated with a DPFE flow code. This can be due to clogged EGR Ports in the intake manifold under the throttle body. The clogged EGR ports are more likely to get clogged on 99 and newer vehicles because of the design of the EGR flow.
This first section is on cleaning the Ports for the 99 and new vehicles, as it is a quicker writeup:
Tools needed:
3/8" hand ratchet (or air ratchet if you have)
6-10" 3/8" extension
8mm 3/8drive socket
1/4" hand ratchet + extension (for removal of engine cover)
flat head screw driver
small pick
shop towel
Parts needed:
Throttle body gasket
Throttle body cleaner
Operation instructions:
1. Remove engine cover
2. Remove air inlet tube from throttle body
3. Remove cruise control cable and throttle cable from throttle body
4. Disconnect Throttle Position sensor
5. Disconnect throttle return spring
6. remove the 4 bolts for the throttle body
7. shove shop rag in big hole under throttle body
8. with the pick, clean out the carbon buildup from the ports around the big hole under the throttle body (in the intake manifold)
9. VERY IMPORTANT STEP, REMOVE THE SHOP RAG!!
10. installation is reverse of removal. install new tb gasket (not mandetory, but recommended)
----------------------------------------------------------
EGR valve removal, 92-95
Removal
1. Remove air cleaner outlet tube
2. Raise vehicle on hoist
3. CAUTION: Use care not to damage EGR valve tube to manifold connector (9F485) .
NOTE: Hold EGR valve tube to manifold connector with a wrench while disconnecting EGR valve to exhaust manifold tube (9D477) .
Disconnect EGR valve to exhaust manifold tube from EGR valve (EGR valve) (9D475) and EGR valve tube to manifold connector .
4. Lower vehicle.
5. Disconnect EGR pressure sensor hoses from EGR valve to exhaust manifold tube .
6. Disconnect vacuum hose from EGR valve .
7. Remove two EGR valve retaining bolts.
8. Remove EGR valve , EGR valve gasket (9D476) and EGR valve to exhaust manifold tube from vehicle.
Installation
1. Clean intake manifold sealing surface with a plastic-tipped scraper to remove any residual EGR valve gasket material.
NOTE: Do not tighten EGR valve to exhaust manifold tube nut on EGR valve at this time.
2. Position EGR valve to exhaust manifold tube into EGR valve and loosely connect EGR valve to exhaust manifold tube nut to EGR valve .
3. Position EGR valve gasket , EGR valve and EGR valve to exhaust manifold tube into vehicle.
4. Install two bolts retaining EGR valve to intake manifold . Tighten bolts to 20-30 Nm (15-22 lb-ft).
5. Connect vacuum hose to EGR valve .
6. Connect EGR pressure valve sensor hoses to EGR valve to exhaust manifold tube .
7. Raise vehicle.
NOTE: Hold EGR valve tube to manifold connector with a wrench while tightening EGR valve to exhaust manifold tube nut.
8. Connect EGR valve to exhaust manifold tube to EGR valve tube to manifold connector . Tighten EGR valve to exhaust manifold tube nuts to 35-45 Nm (26-33 lb-ft).
9. Lower vehicle.
10. Install air cleaner outlet tube as outlined in Section 03-12.
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