Does the ECU ground have to be connected to the engine?
02-19-10, 11:30 AM
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02-20-10, 10:51 AM
#4
Engine, Not Motor
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NO. The ground should go to the engine. This will help avoid ignition noise and help assure all sensors read correctly.
There are about a zillion bolts and studs on the engine that can be used for the ground.
There are about a zillion bolts and studs on the engine that can be used for the ground.
02-21-10, 09:03 AM
#7
MECP Certified Installer
The engine is grounded to the firewall about 8 inches away from where the ECU is. There is a groundstrap to the engine at the starter, which also connects to the chassis at the driver side fender.
Ground should be 0v potential. Ground loops and ignition noise are indication of other issues.
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02-21-10, 10:33 AM
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Engine, Not Motor
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I'm not sure what to explain. Several systems return to the engine for grounding (O2, ignition, etc) so the main ECU ground should go to the same place. Also, the CAS body acts as a shield and becomes continuous with the shielding on the CAS wire when the ECU grounds to the engine.
EVERY manufacturer grounds there ECU to the engine, for good reason.
There is no such thing as a zero resistance connection, so even a well grounded engine will be at a different potential then the chassis. Pop a scope on the CAS signal and look at the noise levels with the ground on the engine versus the chassis.
It's all a moot point anyway. There are about a zillion places on the engine block to pull a ground for the ECU so this should be a non-issue.
EVERY manufacturer grounds there ECU to the engine, for good reason.
Aaron Cake, you know your stuff but I have to argue this one with you.
The engine is grounded to the firewall about 8 inches away from where the ECU is. There is a groundstrap to the engine at the starter, which also connects to the chassis at the driver side fender.
Ground should be 0v potential. Ground loops and ignition noise are indication of other issues.
The engine is grounded to the firewall about 8 inches away from where the ECU is. There is a groundstrap to the engine at the starter, which also connects to the chassis at the driver side fender.
Ground should be 0v potential. Ground loops and ignition noise are indication of other issues.
It's all a moot point anyway. There are about a zillion places on the engine block to pull a ground for the ECU so this should be a non-issue.
02-21-10, 09:13 PM
#9
I'm not sure what to explain. Several systems return to the engine for grounding (O2, ignition, etc) so the main ECU ground should go to the same place. Also, the CAS body acts as a shield and becomes continuous with the shielding on the CAS wire when the ECU grounds to the engine.
EVERY manufacturer grounds there ECU to the engine, for good reason.
There is no such thing as a zero resistance connection, so even a well grounded engine will be at a different potential then the chassis. Pop a scope on the CAS signal and look at the noise levels with the ground on the engine versus the chassis.
It's all a moot point anyway. There are about a zillion places on the engine block to pull a ground for the ECU so this should be a non-issue.
EVERY manufacturer grounds there ECU to the engine, for good reason.
There is no such thing as a zero resistance connection, so even a well grounded engine will be at a different potential then the chassis. Pop a scope on the CAS signal and look at the noise levels with the ground on the engine versus the chassis.
It's all a moot point anyway. There are about a zillion places on the engine block to pull a ground for the ECU so this should be a non-issue.
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