Noise on/from the flex fuel signal.

S.Bretz · Post by **S.Bretz** » Wed May 26, 2010 9:10 am

WTF>...where the heck was that wiring diagram?

I'll give that a shot and see how it does. Thanks a bunch.

racingmini_mtl · Post by **racingmini_mtl** » Wed May 26, 2010 9:46 am

S.Bretz wrote:WTF>...where the heck was that wiring diagram?

James just made it.

Jean

S.Bretz · Post by **S.Bretz** » Wed May 26, 2010 10:44 am

Oh, well that explains why I have never seen it before.

How/ why is the original circuit dangerous? Does it allow too much current and/or potential to the provcessor?

I'll try with a .001uf like racing mini stated was in Una's build....I have 3 of that size as spares. If it helps but doesn't work, I'll get some .01uf's.

Post by **jsmcortina** » Wed May 26, 2010 11:08 am

It is dangerous because you are directly taking a connection from a CPU out into the wilds of the car. A voltage spike or a short to power would like likely destroy the CPU instantly.
Use the capacitor that Jean suggested. The value I put on that diagram was a guess. I'll update it soon.

James

S.Bretz · Post by **S.Bretz** » Thu May 27, 2010 4:46 am

I did the update to the circuit last night.

It works beautifully...flawless.

I used the .001uf cap with a 1/4w 10K resistor with a 5% tolerance...incase any one wanted to know.

Post by **jsmcortina** » Thu May 27, 2010 5:32 am

Thanks for the feedback.

James

S.Bretz · Post by **S.Bretz** » Thu May 27, 2010 8:07 am

Thanks for the help.

...now the only things left I have are to play with the intake cam timing and to get the IAC workig correctly.
It worked great on the B&G code (2.8x), but only goes to wide open with the extra code. I can put the BG code in and it works after the re-wire, but not with the extra code. I have tried it as always on, moving only, open loop, closed loop, and even in test mode, it just goes wide open. Luckily I have a OTC IAC tester for gm and chrysler IAC's so I can just close it again. I probably won't be messing with it for another week or two. At that time I'll start a new thread.

Rick Finsta · Post by **Rick Finsta** » Sat Sep 13, 2014 7:19 am

James, I noticed that the current diagram for this on an MS2 does not show the capacitor to ground. It is found on the top of page 27 in the .pdf hardware manual. Is this something I should add?

87quest-TSI · Post by **87quest-TSI** » Wed Sep 17, 2014 10:09 pm

Rick Finsta wrote:James, I noticed that the current diagram for this on an MS2 does not show the capacitor to ground. It is found on the top of page 27 in the .pdf hardware manual. Is this something I should add?

I was going to ask the same thing. Page 27 in the 3.57 manual.
I'm getting ready to do this so should I be adding the capacitor to ground?

Thanks

Rick Finsta · Post by **Rick Finsta** » Tue Oct 21, 2014 7:06 pm

Back to the top. Sorry to harp on this, but my sensor is in and wired according to the current manual and it is not working. It gives seemingly random spikes from 1% to 87% when the actual ethanol content is 84.3%. I am bringing the signal in through SPR4 and then splitting the line to JS11 and 5V Proto, with 10K resistors to each. I have no capacitor to ground; is this something I should try adding?

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Noise on/from the flex fuel signal.

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