Isuzu NHR 4J Series, Workshop Manual

Page: 385 / 406

6E – 4 EXHAUST GAS RECIRCULATION (EGR) SYSTEM
Exhaust Gas Recirculation (EGR) System Check
Step Action Value (s) Yes No
1
Check the EGR valve for looseness.
Is the EGR valve loose?
- Go to Step 2 Go to Step 3
2
Tighten the EGR valve.
Is the action complete?
- Verify repair -
3
1. Engine "OFF."
2. Ignition "ON."
3. Using test light to ground, check the EGR harness
between the EGR valve and ignition feed.
Does the test light illuminate?
- Go to Step 5 Go to Step 4
4
Repair the EGR harness ignition feed.
Was the problem corrected?
- Verify repair Go to Step 5
5
1. Remove the EGR valve.
2. Visually and physically inspect the EGR valve pintle,
valve passages and adapter for excessive deposits,
obstructions or any restrictions.
Does the EGR valve have excessive deposits,
obstructions or any restrictions?
- Go to Step 6 Go to Step 7
6
Clean or replace EGR system components as necessary.
Was the problem corrected?
-
Verify repair Go to Step 7
7
1. Remove the EGR inlet and outlet pipes from the intake
and exhaust manifolds.
2. Visually and physically inspect manifold EGR ports and
EGR inlet and outlet pipes for blockage or restriction
caused by excessive deposits or other damage.
Do the manifold EGR ports or inlet and outlet pipes have
excessive deposits, obstructions, or any restrictions?
- Go to Step 8
EGR system
working
properly.
No problem
found.
8
Clean or replace EGR system components as necessary.
Is the action complete?
- Verify repair -