1998 Disco no spark issues
#24
Find the "Main" relay. Take the cover off and check the contacts. If it has failed call the bone yard you snagged the ECM and 10AS ask them if they have a "Main" relay. Must be a 98 or later since you have AEL.
Main relay
The main relay supplies the power feed to the ECM
with a tap off to feed the fuel injectors (8 amps) and
air flow sensor (4 amps). This relay is controlled by
the engine management ECM. This enables the ECM
to remain powered up after ignition is switched off.
During this ’ECM power down routine’ the ECM
records all temperature readings and powers the
stepper motor to the fully open position. Failure of this
relay will result in the engine management ECM not
being switched on resulting in engine not starting due
to absence of fuel and ignition.
Main relay
The main relay supplies the power feed to the ECM
with a tap off to feed the fuel injectors (8 amps) and
air flow sensor (4 amps). This relay is controlled by
the engine management ECM. This enables the ECM
to remain powered up after ignition is switched off.
During this ’ECM power down routine’ the ECM
records all temperature readings and powers the
stepper motor to the fully open position. Failure of this
relay will result in the engine management ECM not
being switched on resulting in engine not starting due
to absence of fuel and ignition.
#25
#28
Yes, just in front of the ECU. It's a split relay box, one side is the fuel pump and the other side is the "main" relay.
I'm running out of ideas. The only other device that would effect spark is the crank sensor.
Have you checked every fuse on this truck? All the engine bay fuses, all the fuses under the steering wheel? I mean other than these there would have to be a wire loom problem at a splice or like the knock sensor - have wires fused together.
I'm running out of ideas. The only other device that would effect spark is the crank sensor.
Have you checked every fuse on this truck? All the engine bay fuses, all the fuses under the steering wheel? I mean other than these there would have to be a wire loom problem at a splice or like the knock sensor - have wires fused together.
#29
I have checked every fuse at least 10times, I even cleaned the connections. The Knock sensor did have wires fused together. I spliced it at the plug and ran new wires. I will ohm it out to the ECM today and make sure they are not fused somewhere else. I will also ohm out the crank sensor wires. Don't give up on me ihscouts you are the only one in here that is helping. A guy on another forum suggested running the motor and measure the readings off the Crank sensor. Do you have any input on how to do this? i was going to try that as well.
#30
Is there any chance that the ECM & alarm module that they sent are not a matched pair? I'm still too new to these but I have a running 98 LE and if you have certain electrical readings you want let me know and one evening after work we can do a call and work through a few things if you want.
John
John