SharkTuner Mk 2
06-11-2010, 05:38 AM
#256
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Thread Starter
Thanks Jim !
Brian, there isn't a timer on the switch from open loop to closed loop in cat mode. The changeover is determined by engine coolant temp (temp 2 value). The switch form open loop to closed loop is around 70degC.
You could try editting the warmup enrichment mapping.
Brian, there isn't a timer on the switch from open loop to closed loop in cat mode. The changeover is determined by engine coolant temp (temp 2 value). The switch form open loop to closed loop is around 70degC.
You could try editting the warmup enrichment mapping.
06-11-2010, 11:55 AM
#257
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Thanks Jim. I never played with the adaptation and your explanation is excellent!
It was great meeting you and your lovely wife at SITM. And I might add, your wife is one hell of a driver
It was great meeting you and your lovely wife at SITM. And I might add, your wife is one hell of a driver
06-11-2010, 10:04 PM
#258
Three Wheelin'
Hi everyone thanks for the comments,
Just to make sure I'm clear, I only get a -20% adjustment at startup, and only for a minute or so. Start the car, after 15 or so seconds, the adjustment gradually moves to -20%....stays that way for a minute or so....then creeps back to 0. After that, everything is relatively fine and the LH keeps the adjustment +/-3 or 4%.
I'll try to shoot some video of it tomorrow.
Just to make sure I'm clear, I only get a -20% adjustment at startup, and only for a minute or so. Start the car, after 15 or so seconds, the adjustment gradually moves to -20%....stays that way for a minute or so....then creeps back to 0. After that, everything is relatively fine and the LH keeps the adjustment +/-3 or 4%.
I'll try to shoot some video of it tomorrow.
06-12-2010, 09:31 AM
#259
Rennlist Member
Brian,
Re-quoting part of your earlier post for clarity:
I think your analysis is correct, and I still think it is a NBO2 sensor problem. The NBO2 sensor needs to run hot in order to work, and has a built-in heater (the two white wires). The LH runs open-loop (without the NBO2 sensor) until the engine warms up, as John said. It also runs open-loop for 10-20 seconds after a warm-engine restart, I think that is to give the NBO2 sensor a chance to get back up to operating temperature.
The NBO2 sensor will eventually get to operating temperature from exhaust heat, but this will take longer-- hence the heater circuit, to speed things up.
So what I am thinking is that your NBO2 heater is not working, and on a warm restart it doesn't get back up to temp before the LH kicks into closed-loop mode. I don't know which way the error goes when the NBO2 sensor is below the proper temp, but if it reads rich then that would explain the LH (erroneously) trying to lean it out, until the NBO2 gets itself back up to temp from exhaust heat.
So check the heater wiring and voltage to the NBO2 sensor, should be 12V on one white wire and ground on the other. If it is a universal type, make sure it is a 3-wire sensor and connected properly. (Bosch 13048 is a plug-in replacement, available from Amazon for $65).
Alternately, the WBO2 has a simulated-NBO2 output, which can be connected in place of the NBO2 sensor's signal output.
Cheers,
Re-quoting part of your earlier post for clarity:
... When I run the Cat map, if I restart the car with the engine warm, after around 10 seconds I notice the o2 adjustment start to lean out and eventually bottoms out at -20%. The car naturally idles like **** during this time period, because the map has been tuned to be almost perfect at idle. After a minute or so of this, the o2 adjustment starts to work its way positive and eventually ends back up +/- 0.
It seems to me like the LH is trying to take a reading from the o2 sensor before it's been fully heated and is taking that signal and interpreting it as being rich, thus the attempt to lean out the mixture. Then, after a relatively short period, the LH starts to be fed an accurate signal of the fuelling conditions, and the o2 adjustment goes back to where it should be.
...
It seems to me like the LH is trying to take a reading from the o2 sensor before it's been fully heated and is taking that signal and interpreting it as being rich, thus the attempt to lean out the mixture. Then, after a relatively short period, the LH starts to be fed an accurate signal of the fuelling conditions, and the o2 adjustment goes back to where it should be.
...
The NBO2 sensor will eventually get to operating temperature from exhaust heat, but this will take longer-- hence the heater circuit, to speed things up.
So what I am thinking is that your NBO2 heater is not working, and on a warm restart it doesn't get back up to temp before the LH kicks into closed-loop mode. I don't know which way the error goes when the NBO2 sensor is below the proper temp, but if it reads rich then that would explain the LH (erroneously) trying to lean it out, until the NBO2 gets itself back up to temp from exhaust heat.
So check the heater wiring and voltage to the NBO2 sensor, should be 12V on one white wire and ground on the other. If it is a universal type, make sure it is a 3-wire sensor and connected properly. (Bosch 13048 is a plug-in replacement, available from Amazon for $65).
Alternately, the WBO2 has a simulated-NBO2 output, which can be connected in place of the NBO2 sensor's signal output.
Cheers,
06-12-2010, 09:38 AM
#260
Rennlist Member
06-12-2010, 01:44 PM
#261
Three Wheelin'
So check the heater wiring and voltage to the NBO2 sensor, should be 12V on one white wire and ground on the other. If it is a universal type, make sure it is a 3-wire sensor and connected properly. (Bosch 13048 is a plug-in replacement, available from Amazon for $65).
06-12-2010, 01:49 PM
#262
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Thread Starter
The O2 heater is fed from the fuel pump relay, so as soon as the engine cranks the heater is energised.
When you describe this strange behavour, what is the engine water temp imediately after start ?
06-12-2010, 03:49 PM
#263
Three Wheelin'
Hi John,
It's definitely during a warm start. When the car is cold, I don't believe this phenomenon occurs. Once energized, does the heater remain energized as long as the fuel pump is running?
It's definitely during a warm start. When the car is cold, I don't believe this phenomenon occurs. Once energized, does the heater remain energized as long as the fuel pump is running?
06-13-2010, 11:22 AM
#265
Race Car
I actually have similar problems like Brian in my car:
- When I start the car cold, it runs fine
- When fully warmed up, if I shut it down and start it in 1 minute, it runs fine
- If I wait 20 minutes, it will start quite lean for 10 or so seconds and then run fine
- If I wait 1 - 2 hours and start, it will start and oscillate idle like crazy and almost die for 10 or so seconds and then run fine, unless I feather the throttle to even it out. It is running super rich at start
For me the only scenario I have a real issue with is the last one. I have been modifying my acceleration enrichment map, but there is a good deal of guess work involved with that. But I think I have it set pretty good because logging acceleration runs shows no overly lean spots right at the onset of pressing the accelerator (an easy way to see the effects of accelerator enrichment is to set it to like 150 and press the accelerator: car dies of overenrichment
). At first I thought it was because I was using the nbO2 emulation from my wbO2 to feed the LH, so I bought a brand new nbO2 (the original 928 one, so no splicing), but it did not help at all. Interestingly, on the last scenario above I can see in ST2 that the injectors are in Normal mode instead of Enhanced for those 10 seconds. With the hood open I can also hear that they are, as they fire twice the number of times per second. I haven't been able to figure out as of yet why LH is trying to put in so much more fuel than is required, since my warmup map is 0 for that startup temperature, same as fully warm, and there is no other configurable parameter for idle setting other than the base map itself, which seems to be properly set because it works fine in open loop mode and also works fine after those "magic" 10 seconds. There is also the cranking map, but I have configured that pretty well because if I drop the values any, the car cranks longer to start.
Dan
'91 928GT S/C
475hp/460lb.ft
- When I start the car cold, it runs fine
- When fully warmed up, if I shut it down and start it in 1 minute, it runs fine
- If I wait 20 minutes, it will start quite lean for 10 or so seconds and then run fine
- If I wait 1 - 2 hours and start, it will start and oscillate idle like crazy and almost die for 10 or so seconds and then run fine, unless I feather the throttle to even it out. It is running super rich at start
For me the only scenario I have a real issue with is the last one. I have been modifying my acceleration enrichment map, but there is a good deal of guess work involved with that. But I think I have it set pretty good because logging acceleration runs shows no overly lean spots right at the onset of pressing the accelerator (an easy way to see the effects of accelerator enrichment is to set it to like 150 and press the accelerator: car dies of overenrichment
). At first I thought it was because I was using the nbO2 emulation from my wbO2 to feed the LH, so I bought a brand new nbO2 (the original 928 one, so no splicing), but it did not help at all. Interestingly, on the last scenario above I can see in ST2 that the injectors are in Normal mode instead of Enhanced for those 10 seconds. With the hood open I can also hear that they are, as they fire twice the number of times per second. I haven't been able to figure out as of yet why LH is trying to put in so much more fuel than is required, since my warmup map is 0 for that startup temperature, same as fully warm, and there is no other configurable parameter for idle setting other than the base map itself, which seems to be properly set because it works fine in open loop mode and also works fine after those "magic" 10 seconds. There is also the cranking map, but I have configured that pretty well because if I drop the values any, the car cranks longer to start.Dan
'91 928GT S/C
475hp/460lb.ft
06-13-2010, 11:31 AM
#266
Rennlist Member
Thread Starter
When you leave for 1-2 hours, what is temp 2 showing on startup ?
I can't think of a good reason why the LH will go into normal mode on the injectors (what size are you running?).
It should only switch from enhanced to normal when the injector on time (normal) is above 2mS IIRC
I can't think of a good reason why the LH will go into normal mode on the injectors (what size are you running?).
It should only switch from enhanced to normal when the injector on time (normal) is above 2mS IIRC
06-13-2010, 11:51 AM
#267
Race Car
When you leave for 1-2 hours, what is temp 2 showing on startup ?
I can't think of a good reason why the LH will go into normal mode on the injectors (what size are you running?).
It should only switch from enhanced to normal when the injector on time (normal) is above 2mS IIRC
I can't think of a good reason why the LH will go into normal mode on the injectors (what size are you running?).
It should only switch from enhanced to normal when the injector on time (normal) is above 2mS IIRC
, but I believe the temp shows around 70-73 deg C or so in Fuel and Ignition parameters pages. I am running 42lb injectors.Dan
'91 928GT S/C
475hp/460lb.ft
06-13-2010, 01:51 PM
#268
Three Wheelin'
I get the same problem with the oscillation at startup. It's when the engine is really heat soaked. I'm sure all the temperature variables are high. I haven't logged many variables at that point but I didn't think over-richness was the cause, because when I increase the fuel at low RPM, high load, the oscillation seems to moderate. The car almost dies a couple times as RPMs drop and then surge, but after 2 or 3 of those cycles, it all evens out. This is true on the non-cat map...
06-14-2010, 02:04 PM
#269
Rennlist Member
Thread Starter
If it still "sticks" try switching to the EPROM screen and then back to the LKH fuel map.
06-14-2010, 03:52 PM
#270
Supercharged
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But i'll give it a shot next weekend.