Hot Engine

Disconnect No. 16 vacuum hose from EGR valve and connect vacuum gauge to hose. Back probe voltmeter positive probe into terminal at control box No. 1 connector (Yellow/White on 1300, Brown/Black on 1500 HF and Gray on 1500 except HF models). Connect negative probe to ground.

On 1300 and 1500 HF models, jack up front of vehicle. Support with safety stands, block rear wheels, and set hand brake. Start and warm-up engine (cooling fan must come on). On all models, vacuum and voltage should be as shown in EGR SYSTEM TEST table.

EGR SYSTEM TEST

Engine Condition & No.

EGR Valve Vacuum

Specified Voltage

1 Idle

2 4500 RPM

⁽¹⁾ 1-3 in. Hg

⁽²⁾ No

3 Hard Acceleration ⁽³⁾

2-6 in. Hg

⁽²⁾ Yes

⁽¹⁾	No on 1500 model with man. trans. except HF.

⁽²⁾	Yes on 1500 model except HF.

⁽³⁾	Disconnect and plug No. 12 vacuum hose at control box No. 1 (except Federal 1500 HF). On 1300 and 1500 HF models, vehicle must be in 2nd gear and at more than 10 MPH.

If vacuum is available for condition 1, check vacuum hose routing. If no problem found, replace EGR control valves A and B.
If there is no vacuum available for condition 2 (1500 auto. trans. and 1500 HF) and condition 3 (1500 man. trans. except HF), connect voltmeter to EGR control solenoid A (Blue on 1300 and 1500 except HF models, and Yellow/White on 1500 HF models).
There should be no voltage. If there is voltage, check the following: On all 1500 HF models except High Alt., check control switch and thermosensor B. Check for voltage at control unit connector (Yellow/Black wire) with ignition on. There should be voltage. If no voltage, check fuse and wiring.
Check Black wire for continuity between control unit and ground. There should be continuity. All other models, check thermosensor B. If okay, replace control switch and retest.
If there is no voltage, disconnect vacuum hose No. 15 from EGR control solenoid valve A. Check for vacuum at 4500 RPM at EGR control solenoid valve A. If no vacuum is available, check vacuum hose routing and carburetor port. If vacuum is available, replace EGR control solenoid valve A and retest.
If there is no vacuum, check vacuum line routing and carburetor port. Clean and retest. On 1500 man. trans. except HF models, with vacuum available for condition 2, if there is voltage at Gray terminal, replace EGR control solenoid valve A and retest.
On 1300 and 1500 HF models, if there is no voltage available for condition 2, but vacuum is greater than 3 in. Hg, replace EGR control solenoid valve B. On 1500 auto. trans. models, if there is voltage available for condition 2, but vacuum is greater than 3 in. Hg, replace EGR control solenoid valve C.
On 1300 and 1500 HF models, if voltage is available for condition 1 and 2, or no voltage is available for condition 3, check vacuum switch B and speed sensor. On 1500 except HF models, if voltage is available for condition 1 or 3, or no voltage for condition 2, check for voltage at control unit connector (Blue wire) with ignition on. There should be voltage.
If no voltage, check Blue wire between ignition coil and control unit. Check vacuum switch B. Check for voltage at control unit connector (Black/Yellow wire) with ignition on. There should be voltage. If no voltage, check wiring. Ensure Brown/Black wire between control unit and ground has continuity.
On Federal 1500 HF models, check vacuum with the condition in which the primary air cut-off solenoid valves are on. Vacuum should be 1-2 in. Hg, if not, replace EGR control solenoid valve C and retest.
To test EGR valve, start engine and let it idle. Disconnect EGR valve upper hose. Connect vacuum pump to EGR valve. Apply 5.9 in. Hg vacuum. If vacuum remains steady and engine dies, EGR valve is working properly. If vacuum does not remain steady and engine does not die, replace EGR valve and retest.
If vacuum remains steady but engine does not die, remove EGR valve. Check EGR valve and manifold for blockage. Clean or replace as necessary and retest.