924Board.org

[Martijnus]

My LC1 is acting strange, and I don't have any reference because I haven't got it running right and stuff...

I've recalibrated the whole stuff, so that should be good.
I've programmed the LC1 to my purposes, Analog1 for analog gauge, Analog2 has the standard wideband curve, so I haven't changed anything about that.

The strange thing is, when I switch ignition on, my analog gauge tells me my AFR is 18 (I see slight movement in the needle, so it's just beneath 1 and Megatune tells me my afr is 7.40....which is odd because the engine is not running at that time.

Can anyone tell me what to do? I remember I once had another reading on MS, around 17.5, which makes more sense...but at that time I didn't had the LC1 as "wideband sensor" configured in MS iirc.

What should the reading be? So which AFR is "free air".

I also thought it could be that MS doesn't use AFR when idling and stuff, but it should at least give a reading right? Gauge is red in Megatune (guess because it isn't used at 0 rpm).

edit:
hmm ok...I found this thread:
http://www.msefi.com/viewtopic.php?f=38&t=32936

which says:

One other thing - the MS2's EGO readings do not move until it gets an RPM signal.

But then again, I remember it doing nothing when the engine ran... but that was before calibration.
I don't like to start the engine once again to check it all, too much risk during break in, no coolant etc...so that has to wait.

I do know it reacts to the stim, so I'm quite sure I don't have the same problem as the guy in the thread mentioned above.
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment

[Raceboy]

You should start the engine once it's done and wait until LC1 heats up the sensor and everything should be ok then.

You can't expect any reasonable values anywhere until the engine is not running.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

[flosho]

I had issues with the LC-1 wideband as well. It's extremely versatile and has many options, but they seem to be extremely finicky when it comes to the wiring. You HAVE to make sure all the grounds are wired securely and CORRECTLY! If not, you will have voltage offsets between MS and the LC-1.

I ditched the LC-1 for my AEM UEGO and everything is MUCH easier to wire in, and it includes a gauge so I don't have to have the laptop with to tell me my air/fuel ratio(if you don't have the xd-16 gauge to go with the lc-1).

Just my experience. Not much help, but like I said, check the grounds and read the instructions carefully on which grounds go where, and how it should be grounded with megasquirts ecu grounds(I believe that's what it says).
_________________
[This Space For Rent]

[Martijnus]

have thought about that, I sure was extremely careful while wiring it to be sure of good grounds. Both MS and LC1 are grounded directly (but through different wires) to the negative battery pole.

Still I shouldn't exclude wiring problems.

But that doesn't explain why my gauge (not XD16, that's the digital one right?) says the mixture is too lean and MS says it's way rich.

Could try to measure the voltage on both the output wires to see what it does but guess that wouldn't be accurate.

MS says it's rich, if the LC1 didn't give any output, would MS say it's rich or lean? with the standard wideband curve... I'll check that out asap, because if mine's 'stuck' at 7.40 afr, that would mean it had the correspondent voltage value supplied. Could be 0, could be 4,5V or something.. that's the difference.

I'm talking crap a bit tonight.

edit:
from the manual:

[Min]

worry about it when the car starts and idles.

Min
_________________
Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.

[RC]

It will take 30 seconds or so for the sensor to warm up and MS (MT) wont have any EGO control or autotune capability till out of warm up mode.

The earth point (ground) should be the same as MS since even a few mV differential will have a large affect on AFRs.

Now there is also a problem in MT code with LC1 presets. For best resolution set the LC1 to 0-5V, 10-20AFR and in MT set to generic WB. To get the correct curve the settings are not exactly 10 & 20 AFR. Cant recall my exact settings and my car and tuning laptop are mot with me ATM. Here are 2 threads but there are also a few additional threads on MS forum that you can search for.

http://www.msextra.com/viewtopic.php?t=27486

http://14point7.com/forum/index.php?PHPSESSID=286a6d5d8f5fc8bc43ba3e26c1c4ed40&topic=26.0

The JAW WB can be programmed to the LC1 output. That is how I came across this same problem with MT even though I`m running a JAW. So the info is relevant.

[Raceboy]

I forgot about mentioning grounds.
They have to be connected ONLY to engine (block or head) as you don't want any voltage differentials created by longer path.
Remember, sensor gets its ground from engine via exaust.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

[Martijnus]

I'm quite positive the grounds are fine. The only difference in grounding could come from an inch difference in wire.
I understand this could make the all important difference...but I don't believe it. Still I don't discard this to be the problem.

Thanks for the links RC, they're helpful!

Got me here:
http://www.diyautotune.com/faq/faq.htm#innovate_config

Guess that's what you said too and if both the LC1 and MS get the same curve, it should be fine. I guess I can only get the curve values in if I choose generic WB, instead of LC1 so I'll try it soon.

Another thing I'd like to try is program the curve in the LC1 for my analog gauge to 0V = rich and 5V = lean (or something like that...).
That way I can see if there's any voltage coming out of the LC1 whatsoever...

Raceboy, does the sensor get it's ground from it's body? I thought it had a ground wire

edit:yup, there are two wires coming out of the sensor itself which are responsible for the ground of the heater, pump and sens. So I don't think the sensor is grounded by the exhaust/engine.

Min, the car IS starting and idling, but I'm a bit afraid of running the rebuilt engine at idle too much.

Next thing to try is to see what MS does at starting rpm.
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment

[Raceboy]

You don't have to believe me, but sensor indeed gets its ground from the ENGINE.
You could try and see if it works by unplugging it from the exaust. I know the answer
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

[Martijnus]

[Raceboy]

I don't talk about LC1, I'm talking about Bosch LSU4 WBo2 sensor that LC1 uses.
_________________
'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
http://www.facebook.com/vemsporsche

[Martijnus]

me too.

Like I said, there are 2 wires for ground coming out of the sensor, going to the LC1, which has it's own 2 grounds.

Still, I don't get why bosch would ground the sensor's body, how I see it, the chances of strange readings are more plausible with such an (extra) grounding point.
Or am I wrong... is it pure the LC1 grounds which cause troubles... regardless of the sensor grounds...
_________________
"Rule: Turbo's make torque, and torque makes fun." (C. Bell)

924 "50-jahre", 1981.
MSII/extra, LPG, ITB's, 5lug.
To be turbo'ed in a while.
Killed her at the Nurburgring, Porscheless at the moment