No Spark

[Guest danny_samb]

Hi all I have a sierra dohc running efi. I currently have no spark. Ive change the rotor arm and dizzy cap no change. Tried a spare coil still no spark. Any suggestions guys I'm stumped now

[tractor]

crank sensor or have you got power at ecu

[theduck]

Has the engine been running? Has it been flooded?

[Guest danny_samb]

Iv put new fuel lines in, went to start it turned over a few times nothing. Pulled a plug lead off no spark. Took the plug lead off the dizzy from the coil no spark.how do I test power to the ecu

Edited September 23, 2015 by danny_samb

[tractor]

obviously you have a dizzy so no ecu

Edited September 23, 2015 by tractor

[Guest danny_samb]

I'll get the multi meter on the connectors that go on the ecu then. What would I need to check on the ignition side of things

[tractor]

Not had much to do with 8v dohc engine go for basics first is all wiring connected is there power at Coil

Edited September 23, 2015 by tractor

[Guest danny_samb]

I know I have 12v at the positive side of the coil when the ignition Is on

[tractor]

well if you have 12v at coil its not getting to dizzy so is dizzy connected correctly

12v live to dizzy and I think it needs an earth as well

[Guest 2b cruising]

Crank sensor is at the bottom end of engine near to the oil filter.

Don't know how to check this though.

These are known for bad earth problems.

Everywhere you can see a cable attached to the chassis remove it and clean all thr parts with emery before replacing.

I'm told it is something to do with the stainless chassis.

Mine also has a couple of loose fuses behind dash. Look at every fuse you can find.

Ecu is exhaust side under a removable panel on the bulkhead.

Ignition circuit I believe has two seperate relays in main fuse box. I found what was for what by searching Sierra forum sites and asking direct questions.

Somehow ford didn't number on top lid for relays as the fuses do.

They did letter them but have to trace on wiering diagrams as no direct simple list.

[Guest danny_samb]

Still no spark. Changed dizzy, rotor arm, coil, plug leads. Tested the crank sensor and getting resistance on the ohms meter. Not got a clue what to look at next

[stevedohc2b]

You need to check the continuity back to the ecu

from all sensors

 

there are 2 large conectors that may be old and not connecting back to the ecu

 

Have you got a haynes man

i have a pdf if you dont

i could send you on e mail

 

 

 

Stephen

[stevedohc2b]

from haynes

 

2.0 litre DOHC fuel injection models
A development of the EEC IV system is
used to control both the ignition and fuel
injection systems. The module receives
information from a crankshaft speed/position
sensor (similar to that described for the ESC
Hybrid system), except that the sensor is
activated by a toothed disc on the rear of the
crankshaft, inside the cylinder block), a
throttle position sensor, an engine coolant
temperature sensor, a fuel temperature
sensor, an air charge temperature sensor, a
manifold absolute pressure (MAP) sensor, and
a vehicle speed sensor (mounted on the
gearbox). Additionally, on models with a
catalytic converter, an additional input is
supplied to the EEC IV module from an
exhaust gas oxygen (HEGO) sensor. On
models with automatic transmission,
additional sensors are fitted to the
transmission, to inform the EEC IV module
when the transmission is in neutral, and when
the kickdown is being operated.
The module provides outputs to control the
fuel pump, fuel injectors, idle speed, ignition
system and automatic transmission.
Additionally, on models with air conditioning,
the EEC IV module disengages the air
conditioning compressor clutch when starting
the engine, and when the engine is suddenly
accelerated. On models fitted with a catalytic
converter, the EEC IV module also controls
the carbon canister-purge solenoid valve.
Using the inputs from the various sensors,
the EEC IV module computes the optimum
ignition advance, and fuel injector pulse
duration to suit the prevailing engine
conditions. A “limited operation strategy” (LOS)
means that the vehicle is still driveable, albeit at
reduced power and efficiency, in the event of a
failure in the module or one of its sensors.
1.6 litre and 1.8 litre (R6A type) CVH models
A development of the EEC IV system is
used to control both the ignition and fuel
injection systems. A fully electronic
Distributorless Ignition System (DIS) is fitted,
replacing the mechanical distribution of high
tension voltage (by a rotating distributor) with
“static” solid-state electronic components.
The system selects the most appropriate
ignition advance setting for the prevailing
engine operating conditions from a threedimensional
map of values stored in the EEC
IV control module memory. The module
selects the appropriate advance value
according to information supplied on engine
load, speed, and operating temperature from
various sensors.
The EEC IV module receives information
from a crankshaft speed/position sensor
(similar to that described for the ESC Hybrid
system), except that on 1.6 litre engines, the
sensor is activated by a toothed disc on the
flywheel), a throttle position sensor, an engine
coolant temperature sensor, an air charge
temperature sensor, a manifold absolute
pressure (MAP) sensor, a vehicle speed
sensor (mounted on the gearbox), and an
exhaust gas oxygen sensor.
The module provides outputs to control the
fuel pump, fuel injector, throttle valve control
motor, pulse-air control solenoid, carbon
canister purge solenoid (where applicable),
and the ignition system.
Using the inputs from the various sensors,
the EEC IV module computes the optimum
ignition advance and fuel injector pulse duration
to suit the prevailing engine conditions. A
“limited operation strategy” (LOS) means that
the vehicle will still be driveable, albeit at
reduced power and efficiency, in the event of
a failure in the module or one of its sensors.
Precautions
General
It is necessary to take extra care when
working on the electrical system to avoid
damage to semi-conductor devices (diodes
and transistors), and to avoid the risk of
personal injury. In addition to the precautions
given in the “Safety first!” Section at the
beginning of this manual, take note of the
following points when working on the system.
Always remove rings, watches, etc before
working on the electrical system. Even with
the battery disconnected, capacitive
discharge could occur if a component live
terminal is earthed through a metal object.
This could cause a shock or nasty burn.
Do not reverse the battery connections.
Components such as the alternator or any
other having semi-conductor circuitry could
be irreparably damaged.
If the engine is being started using jump
leads and a slave battery, connect the
batteries positive to positive and negative to
negative. This also applies when connecting a
battery charger.
5•4 Engine electrical systems

 

stephen

[Guest 2b cruising]

Are you getting impulses voltage to the neg side of coil.

If yes, simple. You need a coil.

If no, most common fault crank sensor.

[Guest danny_samb]

Iv replaced the coil. How do I test for impulse voltage. The at was fine when parked up come.to use it a few days later and nothing