Fuel - Rough, Erratic or No Idle Condition
88nissan05Classification Section: Engine Fuel &
EF&EC88-012 Emission Control
Reference:
TECHNICAL BULLETIN TS88-077
Models: 1987-1988 Van, 1986.5-1988 Truck, 1987-1988 Pathfinder
Date:
June 6, 1988
VG30i AND Z24i ENGINE DRIVEABILITY, ENGINE THROTTLE BODY INJECTORS
APPLIED MODELS: 1986.5-1988 Trucks 1987-1988 Pathfinder 1987-1988 Van
SERVICE INFORMATION
Some of the applied vehicles may exhibit the following symptoms:
A. A lack of power during acceleration.
B. Rough, erratic, or no idle conditions that may require throttle application to keep the engine running.
This condition may be caused by a mechanical malfunction of one or two throttle body injector(s). Since this particular malfunction is mechanical, and not electrical, the E.C.C.S. Self-Diagnostic system will not detect this incident.
NOTE:
These symptoms are similar, but different, than the symptoms of a faulty Throttle Valve Switch (TVS) as described in Technical Bulletin EF&EC87-012 TS87-135. TVS incidents:
A. Produce a severe "miss" or "buck" just as the throttle position is changed (tip-in or tip-off).
B. Have little or no effect on engine idle quality.
SERVICE PROCEDURE
Test drive the vehicle to determine the exact characteristics of the incident. If an injector incident is suspected, use the following service procedure.
1. Perform the Mode III Self-Diagnostics procedure shown in the appropriate model Service Manual.
a. If no Trouble Codes (Code 44 or, for 1988 models, Code 55) are found, proceed to Step 2 on the following page.
b. If a Trouble Code is found, correct the condition as described in the appropriate model Service Manual. If the original incident still exists, return to the beginning of Step 1.
2. Test the injectors for proper operation by performing an "Injector Balance Test" as follows. NOTE:
The throttle body harness connector numbers for the applied vehicles are listed below:
MODEL CONNECTOR #
Truck/Pathfinder (Z24i) 64M
Truck/Pathfinder (VG30i) 70M
Van (Z24i) 19F
a. Check the operation of injector "A" by disconnecting the red wire from the throttle body harness connector (at the location shown below) to disable injector "B".
b. Start the engine and allow to idle. With injector "B" disabled, the engine should run at idle on injector "A" in the FAIL-SAFE MODE. If idle is satisfactory, injector "A" is good. Turn off the engine, reconnect the red wire disconnected in Step 2a and proceed to Step 2c. If the engine will not idle, or idles poorly, injector "A" is faulty and should be replaced.
c. Check the operation of injector "B" by disconnecting the green wire from the throttle body harness connector (at the location shown above) to disable injector "A".
d. Start the engine and allow to idle. With injector "A" disabled, the engine should run at idle on injector "B" in the FAIL-SAFE MODE. If idle is satisfactory, injector "B" is good. Turn off the engine, reconnect the green wire disconnected in Step 2c and proceed to Step
3. If the engine will not idle, or idles poorly, injector "B" is faulty and should be replaced.
3. If injectors "A" and "B" are both determined to be operating satisfactorily, and the incident still exists, contact the FIXS Hotline for additional assistance.
PARTS INFORMATION
APPLIED MODEL INJECTOR PART NUMBER
1986.5 TRUCK(Z24i) 16021-03G15
1987 TRUCK/ 16021-41G00
PATHFINDER (Z24i)
1986.5-1987 TRUCK 16021-12G00
1987 PATHFINDER (VG30i)
1988 TRUCK PATHFINDER 16021-41G00
(Z24i & VG30I) 16021-41G00
1987-1988 VAN 16021-17C00