Engine cranks but does not start and there is no check engine light

CURTIS ZINK

MEMBER
1991 LEXUS LS 400
4.0L
V8
2WD
AUTOMATIC
150,000 MILES

Cranks but won't start. Has no spark from the coil, no injector pulse and no check engine light.

Thursday, March 4th, 2021 AT 10:28 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,758 POSTS

Hi,

If you aren't getting spark or an RPM signal, it sounds like the crankshaft position sensor has failed.

Take a look through this link:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

This is where I would start. Here are directions for replacement. The pics below correlate with the directions.

________________________

1991 Lexus LS 400 V8-4.0L (1UZ-FE)
Procedures
Vehicle Powertrain Management Sensors and Switches - Powertrain Management Sensors and Switches - Computers and Control Systems Crankshaft Position Sensor Service and Repair Procedures
PROCEDURES
PROCEDURE

Removal

1. Disconnect negative terminal cable from battery.

CAUTION: Work must be started after 90 seconds from the time the ignition switch is turned to the LOCK position and the negative (-) terminal cable is disconnected from the battery.

2. Remove engine under cover.
3. Disconnect crankshaft position sensor connector.

pic 1

4. Remove the bolt and crankshaft position sensor.

Installation

pic 2

1. Install the crankshaft position sensor with the bolt.

Torque: 6.4 N.m (56 in.lb.)

2. Connect crankshaft position sensor connector.
3. Install engine under cover.
4. Connect negative terminal cable to battery.

____________________________________

Let me know if this helps or if you have other questions.

Take care and God Bless,

Joe

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