no o2 signal to MS

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tapedshoes
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Joined: Sat Feb 25, 2006 4:21 pm
Location: Seattle

no o2 signal to MS

Post by tapedshoes »

Howdy friendly onlookers.

I just got back from a 3 month stay in Washington DC. Before I left I was fiddling around with idle valves, tip122's, wasted spark, and a whole bunch of stuff. In the process I ended up removing and adding alot of parts. For the record im using a v3.0 board with MS1-extra, and an AEM wideband.

The car starts up and runs fine, however Megasquirt will not read anything from the O2 gauge. It is locked at the lowest value and is not altered at all by any change in RPM or MAP or nothing. Im thinking I might have fried one of my components or accidently removed one in my megasquirt frenzy before I left, but I cant remember.

What parts on the board relate to the O2 signal? Any thoughts? Thanks
knutte
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Re: no o2 signal to MS

Post by knutte »

Have it worked before?

Do you have the preheater to the widebandsensor connected?

In my LC-1 the green cable from controller is the 02 cable. Maybe in your case too?
MS1 extra, ver 3.0, code 0.29y4
shameem
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Re: no o2 signal to MS

Post by shameem »

EDIT: It seems megamanual site is blocking image requests

Goto - http://www.megamanual.com/ms2/pcb.htm and scroll down - you will see the components for EGO - its just R10,R11 and C10
Last edited by shameem on Wed Jul 16, 2008 10:52 am, edited 2 times in total.
tapedshoes
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Location: Seattle

Re: no o2 signal to MS

Post by tapedshoes »

It has worked before.

The wideband in question is the AEM UEGO. It comes with a gauge. The gauge functions fine, and changes numbers according to engine dynamics, so the sensor is being heated fine.

I can't see the picture you posted shameem.

I will test the 02 signal from the controller to see if it is outputting a 5v signal.
lucasjoel
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Joined: Sun Jul 03, 2016 8:22 pm

Re: no o2 signal to MS

Post by lucasjoel »

im having THE SAME problem. after a modification (adding a second coil driver) the wideband stops working just as tapedshoes said.

what do you do to fix the problem?
billr
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Location: Walnut Creek, Calif. USA

Re: no o2 signal to MS

Post by billr »

You really have the same problem, an MS1 on V3.0 that you have "done a whole bunch of stuff to", "removing and adding a lot of parts"?

I suggest you start a new thread, and detail what those mods are.

The O2 input is very simple and robust; just R10, R11, and C10. I doubt any of those components got damaged. Do you have any voltage at pin 23 of the main DB37?
lucasjoel
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Re: no o2 signal to MS

Post by lucasjoel »

you are very right, is not the "same" but it is quite similar.

i have a ms2 with v3 board.
The megasquirt has put a vr circuit (max 9926);
Has boost controller for mac valve;
has output for lauch shift;

A few days ago was added a driver (bip373) to control another coil, to have wasted spark.
And a toothed wheel 36-1 was also added to the car. the rpm are read perfectly.
but in the tunner studio i have always 10.5afr

Already check the calibration of the sensor in the configuration of the tunnerstudio
Also measured on the corresponding pin that is arriving the sensor signal, ruling out a problem in the wiring.

I have no idea what else to check the wideband is also aem uego
lucas turbo.msq
billr
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Re: no o2 signal to MS

Post by billr »

You have no O2 sensor specified in the calibrations shown in that MSQ, most likely that is a problem. Do you get any voltage at the DB37 pin 23, does it vary as the engine runs?
lucasjoel
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Posts: 13
Joined: Sun Jul 03, 2016 8:22 pm

Re: no o2 signal to MS

Post by lucasjoel »

yes i have. and its vary depending of the engine status.. with a multimeter i check the circuit, and a found that i have continuity with every point of the wideband circuit with ground c10 r10 r11 all of those have ground bridge.

I removed all the components c10 r11 r10 and the line in the board contues bridge to ground.. i removed the processor board and everithing go to normal.. nothing grounded, i checked with multimeter and the pin of wideband in the proccesor board was bridged.. i dont know where but it goes to ground. may be thats is the problem
billr
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Re: no o2 signal to MS

Post by billr »

Are you saying that when R10 and R11 are removed, the DB37 pin 23 is shorted to ground? And, that pin 23 is no longer shorted when the MS2 is removed? That's making no sense to me, as the MS2 should have no possible influence if R10 is removed. I'm thinking there must be some soldering issues here, perhaps you should post pictures of the PCB. By "shorted" you mean < 1 ohm, not just a beeper tone?
lucasjoel
MS/Extra Newbie
Posts: 13
Joined: Sun Jul 03, 2016 8:22 pm

Re: no o2 signal to MS

Post by lucasjoel »

I must have expressed badly, my English is very poor.

With r11 and r10 outside, the line going from there to the ms2 is to ground, not pin 23. pin 23 is not going anywhere with r11 and r10 out.

And with ms2 outside the entire circuit line of the wideband is ok

Then the problem has to be somewhere on ms2
lucasjoel
MS/Extra Newbie
Posts: 13
Joined: Sun Jul 03, 2016 8:22 pm

Re: no o2 signal to MS

Post by lucasjoel »

Solved!
The problem was in the ms2 daughterboard, as everything else was okay I assumed that the daughteboard does not read for some reason the signal from the wideband, then i replace it with a new one and now everything works perfectly :)

I have to thank you. I just could not have found the problem, thank you very much!
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