RF interference freezes logs but move ecu 6-8 inches... ok

s300 and SManager software questions & answers
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twkdcd595
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Joined: Fri May 20, 2005 6:02 pm

RF interference freezes logs but move ecu 6-8 inches... ok

Post by twkdcd595 »

Ok so I am on an S300 with a p28 in an Accord. The ecu sits on the pass side floor in the factory position. Car has a pro10 ignition with T1 harness, pro10 box/ coil are up in front of the strut tower, running resistor plugs... etc. Have good grounds on the engine in multiple places, battery is in trunk and grounded both front and back of the car.

I noticed something strange when logging recently.

If the ecu is in the factory position it will freeze the logs over a certain rpm (internal or external logging). Normally when logging though I pull the ecu out and put it on the floor (moving it 6-8" basically)... it is 100% fine, will not freeze the logs or have any issues at all.

(I am using a Hondata cable with a ferrite bead and also an additional ferrite bead is on the cable with the cable looped through it again.)

Anyone see anything like this? Anyone experimented with shielding material or a simple faraday cage around their ecu?

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Hondata
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Re: RF interference freezes logs but move ecu 6-8 inches...

Post by Hondata »

First make sure that you use resistor spark plugs. This is the most likely cause of the problem.

Second you need to look at the wiring and make sure the grounds are correct. Too many grounds are bad - they create ground loops and current can pass through ECU wiring. If you exactly match the factory wiring with a single ground point on the thermostat housing and two engine to body straps it should be ok.
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twkdcd595
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Joined: Fri May 20, 2005 6:02 pm

Re: RF interference freezes logs but move ecu 6-8 inches...

Post by twkdcd595 »

Running NGK bkr9eix.

This is in an accord platform so it does not use the thermostat housing ground. On this platform that ground runs to the plenum. It is unmodified and connected. I have the battery relocated to the trunk. I run a ground directly from battery to the chassis in the trunk. Also a ground directly from the battery all the way to the front which terminates at the engine and then a leg to the chassis as well from that point. Have an valve cover to engine mount bracket ground strap like stock configuration, also have a ground strap from the head to the motor mount bracket on the opposing side.

So with the exception of the battery relocation grounds, I am using 2 engine to chassis ground straps plus the main harness ground to the intake manifold. No wire tuck/ harness modifications have been done.

If I physically move the ecu out 6-8" it will log.

I was thinking about putting the ecu in an rf shielding pouch, do you think this is worth trying? Does the ecu make enough heat I need to worry about heat buildup?

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Hondata
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Re: RF interference freezes logs but move ecu 6-8 inches...

Post by Hondata »

Remove the unnecessary ground straps. The battery should be grounded only to one place (BTW battery relocations often are problematic). The engine should have a thick ground strap from the chassis to the transmission near the starter motor, and another ground strap from the manifold ground point to the chassis. A small valve cover to chassis strap may be ok as well, but there should not be any other grounds. Remove and clean all ground points so there is bare metal to metal contact.
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twkdcd595
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Joined: Fri May 20, 2005 6:02 pm

Re: RF interference freezes logs but move ecu 6-8 inches...

Post by twkdcd595 »

10-4. Will make the changes and report back.

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