Noise Concern

For discussing how to choose sensors and create a wiring harness for all Bowling and Grippo versions of the MegaSquirt® EFI controller.
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nismoryco
MegaSquirt Newbie
Posts: 22
Joined: Tue May 04, 2004 10:15 am
Location: Coeur d'Alene, ID

Noise Concern

Post by nismoryco »

Hi,

I'm getting ready to install a MS-II on my 1986 Nissan Stanza Wagon (aka Prairie/Multi) with the CA20E engine. This 4-cylinder engine has 8 spark plugs and 4 of them are on each side of the engine. From the factory, the spark plug wires nearly touch the fuel injector wires. Is this going to be a concern with Megasquirt? I'm worried about feeding noise back into the ECM. Does anyone else have experience with a setup like this? If so, what did you do to better isolate the two components? Thanks.
1986 Nissan Stanza Wagon 4WD, CA18DET, GT2860RS, 850cc Injectors, Microsquirt, Shuttle XS35GT Carputer
loren
Helpful Squirter
Posts: 52
Joined: Mon Nov 19, 2007 8:27 pm
Location: Safety Harbor, FL
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Re: Noise Concern

Post by loren »

The noise induced from the plug wires to the injector wires would likely be on the millivolt level at its worst. The injector opening signal being 12v, I can't imagine it would be a problem. If it were a problem, better plug wires, and/or shielded injector wires would solve it.

I'm still a relative newb here, but I've never heard of such a problem. I wouldn't worry about it.

Where noise is a factor is with sensitive low-voltage sensors, like VR sensors. In general, I'd say that if an OE application isn't using shielding for it, it's going to be fine.
LBC + Technology = ???
Matt Cramer
Super Squirter
Posts: 2951
Joined: Sat Jul 03, 2004 11:35 am

Re: Noise Concern

Post by Matt Cramer »

I have seen problems caused by spark plug wires touching wires leading to the Megasquirt - sometimes you can get a lot more than millivolt level noise. However, the injector wires are the least vulnerable to this sort of problem.
nismoryco
MegaSquirt Newbie
Posts: 22
Joined: Tue May 04, 2004 10:15 am
Location: Coeur d'Alene, ID

Re: Noise Concern

Post by nismoryco »

Thank you guys for your feedback. I will proceed as planned.
1986 Nissan Stanza Wagon 4WD, CA18DET, GT2860RS, 850cc Injectors, Microsquirt, Shuttle XS35GT Carputer
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