it recorded fuel trim error based on the O2 input signal until it hit the max trim value then reset the trims and ignored the O2 because the signal was shit.
it recorded fuel trim error based on the O2 input signal until it hit the max trim value then reset the trims and ignored the O2 because the signal was shit.
2000 Ford Mustang - Top Sportsman
Thanks. I assume you are referring to the reset of fuel trims at the 1'48 point. What I don't understand is for the preceding 15s where the engine was stable around 1600rpm, the fuel trims were not changing. Which value hit a max? Are you saying that if I adjust the maf calibration as suggested (richen) then it will solve that issue by avoiding the achievement of high trims?
Do you have any idea what is going on at the 24s mark when I lose O2? Did I kill the sensor somehow?
In my log file I see O2(v) and O2 voltage b1s1(mv). The O2 channel is showing exactly half the voltage of b1s1 (up to 24s when they both go to zero). Why?
Thanks again guys, I know my questions are elementary. Does anyone know a good tuner in socal that I could either take the car to or come take a look?
Daniel
the EQ ratio you see is target from ecu.
a faulty o2 sensor of course, could pull down its signal too, what is causing the trims to freak out.
blowthrough maf is shit for the following reasons, the measurement with these MAFs is based on a flow velocity mesurement on barometric pressure, the output is highly dependent on pressure, temperature and tube diameterand of course velocity.
the induction usually is around 3" what's your carge pipe usually on an e39 equipped car 2"? so take the cross section area of both and you will have a rough estimation how much your MAF signal is already off only by housing size.
then take into account presssure ratio, on the induction side the MAF has to handle baro to vacuum so less than 15psi and now imagine putting it to an engine with 30psi boost, the range it has to deal with now is 3x as high, but your physical frequency output stays the same.
same with temperature intake air temp is pretty stable in most cases, charge air tamp varies alot depending on operating conditions...
all the mafs are applicated to their stock housing diameter, and if they max out you're close to a range where laminar flow around the measuring cell gets unstable... the only correct way than is to increase housing size and recalibrate the maf anything else is BS.
Astra config_ext.Channels.xmlE39_Astra.Layout.xml
I just attached my layout and channels for E39, i am doing just everything with it...100% proven
For what it's worth, I have a 2.75" charge pipe as this matched the throttle body and was a better fit with the intercooler (water to air). I'm hoping the intercooler is acting like a reasonably good flow straightener. Anyway, thanks for your input.
It sounds like I need to figure out this O2 signal and add some fuel.
Daniel
Any progress?
There is a fellow on the Fiero forum with a turbo 2.4 ecotec that he got from Alphfab as well. He is from Winnepeg Manitoba and they did not bother to tune his ECM for starting in cold weather. They did make it right eventually.
I haven't had a chance to work on it. Hopefully this weekend I'll add fuel and give it another go.
Well, I wish I had something positive to report, but I couldn't get it to fire. I scaled everything up in the MAF calibration by 30%. After substantial cranking I could smell fuel and I got a few ignitions out the exhaust, but it didn't start. Here is what I noticed:
- Mass Airflow Sensor State: showing MAF FAIL or MAF FAIL TRNS during cranking (no fail before cranking)
- I see no indication of engine speed while cranking. This is odd as I've seen ~200rpm show during cranking in the past. It's also odd to me that fuel would be injected if there was no crank signal
So, what now? Should I go test the crank sensor to see if it has failed? Should I back off on the MAF calibration to see if leaning it out a bit will get it to start (maybe i've gone too far too quickly?)?
What a PITA. Why is this so hard? I miss the days of stupid ECU's that just did you asked without a million hidden algorithms.
Daniel
Last edited by TurboWood; 03-12-2018 at 08:32 AM.
I looked through the history of starts/cranks over the last few months. Sometimes I get an engine speed signal and other times I don't. What could cause that? I'm tempted to just replace the sensor in order to eliminate that possibility.
Daniel
broken sensor, improper sensor gap, bent reluctor wheels, poor harness connections, or damaged harness
2000 Ford Mustang - Top Sportsman
That makes me think it's a harness problem. Everything else is factory GM (crank/wheel, sensor, block). I ordered another sensor as they are cheep. We'll see what happens.
Daniel
It's usually one of the easier repairs. The others are rare
Replaced the crank position sensor. Upon first cranking I did get engine speed again, but it wouldn't start. I noticed that voltage was dropping a lot during cranking so I turned on my maintenance charger (3A I think) and let it charge for a few minutes. It's a small battery so it needs every bit of charge available.
When I tried cranking again engine speed was gone and the MAF Fail or MAF Fail Trns came back. This leads me to believe that there is something else going on. I've attached the first and last log files from today. The first has engine speed / MAF. The second does not.
So, what now? The active DTC's are 1682, 2122, and 2227. These have been there since the start so I don't think they are the root cause. Is my MAF toast?
Aside from this starting issue, I was giving some more thought to what might cause the ECM to struggle with controlling my engine. As I have removed the PCV, purge valve for charcoal canister, and the brake booster, there is no path for air to bypass the throttle. Could this mean that the engine is opening the throttle more than it normally would for idle which causes it to have poor control of the system?
Daniel
On a side note, I'm thinking about using this (http://www.dakotadigital.com/index.c...rod/prd825.htm) for my tach signal. Does anyone have experience with it?
Daniel
one of my customers was using it on a chevy panel Van/ CTS-V conversion...worked well.
but i think for you it's the wrong choice, because it only reads trans/ ecu tach OUTput from OBD2
what you need is vice versa to generate a speed signal for your ECM
Sorry, I mixed topics. The OBDII reader is purely to get a signal from my ECM to my tach. I currently do not have such a connection. AFI included an Autometer Tach Adapter (9117), but they failed to wire this in from the beginning. This box works by interrupting the power signal to the coils. Unfortunately these wires are buried in the harness which makes it difficult to get to. This box from Dakota Digital is much easier other than I have to find a way through my firewall (ECM/OBDII are in the engine bay).
None of this fixes the issue of the ECM seeing engine speed which is clearly the bigger problem.
Daniel
Last edited by TurboWood; 03-19-2018 at 07:35 PM.
Ok, it starts again. I think the tiny little Caterham battery doesn't have the cranking capability to consistently keep the ECM happy. I jumped it with my truck w/o the truck running. It fired right up. I had also added 30% fuel to the MAF and I think it helped the engine reach stability more quickly. Unfortunately the same thing ultimately happened: unstable --> STFT ramps to max --> engine starts to stabilize --> LTFT ramps to max --> both fuel trims zero out --> engine becomes unstable again.
The fundamental problem I think I'm having is a lack of O2 signal. I now have two DTC's related to the O2 sensor: P0053 and P0131. I'm either using the wrong O2 sensor or something is up with the harness/ECM.
It seems to me that if I figure out the O2 and get the MAF calibration correct then it should work.
The latest log is attached. Comments welcome.
Daniel
I just noticed that "Fuel System #1 Status" is going into "OL Fault" at the same time the fuel trims are zeroing out. For me this points more and more towards the O2.
Daniel
Looking at the last two logs where the engine ran, I see that I have O2 voltage for the first 20-22seconds (22 on previous one, 20 on latest) and then it zeros out (0.003V).
Could I be overheating the sensor from the cat light-off procedure? Is there a way to turn that off? The exhaust is getting very hot very quickly which makes me believe it is still active. Spark timing is also -6 to -18 degress while the engine is surging which further supports a late ignition.
Daniel
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