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 Post subject: Suddenly Running Lean
PostPosted: May 30, 2014, 7:31 pm 
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Well, I've got an interesting problem. The car has been running great until this afternoon. It suddenly lost power and while it continued to run, it ran very roughly. reloaded them, which had no effect.

I did find that the inlet fitting to the fuel rail is leaking, the fuel pressure was a bit over 30 psi, instead of the 45 it should be. When I removed the fitting, the o-ring kind of disintegrated. At least that would explain the leak.

I've ordered parts to replace the fitting, but was wondering if this is likely the source of the problem, or something unrelated.

Thanks for any thoughts.

Bill


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PostPosted: May 30, 2014, 11:28 pm 
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Whatever attacked the Oring may have attacked the regulator?

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PostPosted: May 31, 2014, 1:43 pm 
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I got the leak stopped, at least for now. The regulated fuel pressure is within speck, now that ai actually looked it up, and quit relying on my memory. With the engine running, the fuel pressure should be 30-40 psi and it seems to settle around 35 so all is good on that score.

Unfortunately, the engine is still very lean, with AFR still 19 or more. anyone got any thoughts?


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PostPosted: June 1, 2014, 7:09 pm 
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Bill, did you make any firmware upgrades or TunerStudio upgrades recently? The O2 sensor calibration must be set for your brand of wideband controller. Won't hurt to check. it may have hicupped and lost that setting. Highly doubtful. If you have no readout on your wideband itself, you have no way of knowing for sure.

I am currently in my own MS Hell. I've been communicating with the software writer. His test system performance is not matching my system. I'm pulling for you. We've only got a few days left to straighten this out!

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PostPosted: June 1, 2014, 7:59 pm 
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Chuck, I have not changed the firmware since I started. It's version 2.905, IIRC.

The O2 sensor is a Bosch unit that does not require calibration if used with their controller. At least that's what the documentation says.

I'm using version 2.6.1of Tuner Studio. I haven't seen an obvious problem with the software. What sort of problems are you seeing?

I agree time is short, but I am glad if it had to happen, I'm glad it happened at home, rather than on the road somewhere.

Bill


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PostPosted: June 1, 2014, 8:28 pm 
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Pretty Old version of firmware most will recommend upgrading, that may cause other issues though, you could reload that version (if you don't have time for a retune).

O2 gets configured in Tuner Studio in the tools dropdown menu "calibrate AFR".

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PostPosted: June 1, 2014, 9:40 pm 
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My current problem is nothing like yours. My trailing ignition is cutting out below 1000-1050 RPM. It is specific to rotary operation and my ignition coils. James "something" who is the firmware writer, has it working on the bench without fault. I, unfortunately, cannot match his lab results. And the experiments go on.......

My suggestion to you is do not upgrade the firmware. You could easily loose any tuning that you currently have worked for. upgrading firmware is what got me in my current mess. I am now running MSExtra 3.3.2 firmware in a MS2 ECU.

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PostPosted: June 3, 2014, 1:09 pm 
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Chuck, I don't plan to upgrade the firmware. Last time I checked, there was a more recent version, but it seemed to enhance functions I wasn't using. Since things were working, I just let well enough alone. I'm running the straight B&G code.

I have replaced the O2 sensor, just on principle, with no effect. I'm wondering now of the O2 controller itself has a problem. The only information I get is the flashes of a couple of lights. One indicates a possible fault, but when I called tech support yesterday, the person thought that might be normal. I'll try calling again and see if I get a different answer. I've also tried to run Open loop by disabling the O2 sensor, but that had no effect either. I'm not really sure that the MS unit got the hint to ignore the O2 sensor.

Bill


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PostPosted: June 3, 2014, 3:27 pm 
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Bill, Have you checked that the temp sensor, intake air sensor and the MS internal voltage meter (as displayed in TS) are acting properly? Higher than normal readings than expected in any of these would cause the MS to run lean and be low on power.

Re: not being sure if the MS got the message about ignoring the O2 sensor, Diff firmwares show up differently in TS. I am not familiar with your firmware.In my firmware version it is called EGO control it can be turned "off", set for "wide band" or set for "narrow band". You should find it somewhere near the fuel settings dropdown menu. Here, the VE tables are the tuning table rather than the AFR table.

I really want to see you there with your car.

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PostPosted: June 3, 2014, 8:28 pm 
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if the 02 sensor is not being seen by the ms, maybe there is a fault with the wire.

is this a wide band or narrow band sensor?

if wide band, is there voltage to the sensor and a ground and does it actually heat up and generate voltage?

if a narrow band, is it generating voltage?

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PostPosted: June 4, 2014, 7:21 am 
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The O2sensor is a wideband unit from AEM Electronics. I've spent the last couple of days checking it out and have come to the conclusion that it is probably OK. The wiring from the controller has been checked and shows no breaks up to the plug on the MS unit itself. The probe does get warm when it is powered up. The signal line (to the MS) shows 4.9 volts with the power on, but the engine not running. From what I can get from tech support this is normal.

Other sensors , coolant temp, intake air temp seem to give normal readings with the TS software. I'm not sure how to test them beyond that at this point. I'll have to research that further.

As to disabling the O2 sensor, TS has a menu item to disable the sensor. I also changed the item that told the computer to use wideband O2 sensor data in the fuel calculations. These changes had no effect on the operation of the engine. This also suggests that the O2 sensor is not the problem.

I've even checked for some mechanical problems on the car, like a collapsed muffler, or the timing chain jumping a tooth. So far, these haven't helped the situation either.

Bill


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PostPosted: June 4, 2014, 7:34 am 
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Does your WUE end at less than 100%?

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PostPosted: June 4, 2014, 8:50 am 
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post your tune and a data log...either here or over at MSextra forum. If you have an old pre-problem data log that would be useful too.
MS is going to rely on constant fuel pressure when calculating injector pulse width. 35 PSI will work if that is where you created your tune and nothing changed. If you created your tune at the more standard 3 Bar or 43 PSI and its 35 PSI now it is going to be really lean. MS does not have a fuel pressure sensor so it can not compensate. Disabling O2 feedback probably made the problem worse if this is your issue.

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PostPosted: June 4, 2014, 9:03 am 
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Quote:
MS is going to rely on constant fuel pressure when calculating injector pulse width. 35 PSI will work if that is where you created your tune and nothing changed. If you created your tune at the more standard 3 Bar or 43 PSI and its 35 PSI now it is going to be really lean. MS does not have a fuel pressure sensor so it can not compensate. Disabling O2 feedback probably made the problem worse if this is your issue.


JPS, Not related to Bill's problem directly, I'd like to understand this statement a little better. My understanding is that a regulator referenced to manifold pressure is preferred, as it keeps a constant pressure differential across the injector. As the manifold pressure goes down, so does the actual fuel pressure (relative to atmosphere) and the injector "sees" the same pressure differential regardless of (steady state) load. So that should be OK. But using a fixed pressure regulator and a MAP sensor. Under speed/density, we tune the VE table. MS should should still be able to compensate pulse widths for the varying pressure diffeentials at the injector. No? Further, if we run loosed loop with a wideband and tune the AFR table, the MS should be able to compensate no? That is assuming the AFR table is correct. Paramount in this arguement is that the injector(s) all follow the same volume vs pressure differential flow rate. At least that is how I think it should be.

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PostPosted: June 4, 2014, 9:16 am 
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That is correct. I misread his previous post.
mea culpa. :oops:
Tune and logs would still be useful though.

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