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GM 3 bar install... getting random check engine light, no codes
threw a GM 3 bar on today... during tuning i was getting a check engine light (never before the 3 bar)
it would light up and go away if i go into neutral and give it some gas no ECU codes. the car runs fine when the light comes on.. its weird. ECU is a PM6 OBD0 running turbo edit (setup for a 3 bar) the check engine light seems to come on when its at low throttle like going down a hill... or when slowing to go over bumps... anyone have any ideas? i was thinking cold solder joint but wouldnt that give me a map sensor ECU code? (the solder joints all look fine) http://i35.tinypic.com/2076na1.jpg |
Re: GM 3 bar install... getting random check engine light, no codes
to sum it up, you fail at life.
any more questions? |
Re: GM 3 bar install... getting random check engine light, no codes
what was the problem?
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Re: GM 3 bar install... getting random check engine light, no codes
early doses of fail mixed with chances of aids in the later hours?? thats my guess.
hopfully someone who isnt a retard will chime in and let us know. haha :y it did it to me again heading into the timmy ho's parking lot.. quick blip of throttle in neutral and light is gone... no flashing lights on the ECU or codes to read... |
Re: GM 3 bar install... getting random check engine light, no codes
have you been datalogging to see if there is anything weird happening when your CEL comes on?
i would bet that its something to do with the voltage the ecu sees...because the larger the map sensor, the less of the 0-5v range is in vacuum. so if you see a large amount of vacuum on decel, it might be below the minimum voltage of the sensor. also, did you map sensor come with a datasheet (showing voltage and absolute pressure relationships)? is so, send it to me please...i will check the formulas in TE... do you have the o2 off with a wideband hooked up to the nb02 input? because that used to give me random cels when engine braking... i doubt thats it, but just thought id ask anyways. |
Re: GM 3 bar install... getting random check engine light, no codes
the wideband goes through the stock o2 sensor wire. scaled to 3.5v max. (been running like this for MONTHS without any issues/lights... although since the tune changed the values from the o2 sensor would have changed as well)
no datasheet came with the GM 3 bar, but ill look. i havnt been datalogging but i have been watching the map trace when the light comes on, and its not doing anything weird. but ill try some datalogging to see if that is more detailed. |
Re: GM 3 bar install... getting random check engine light, no codes
found this... hope it helps.
"For GM Map sensor, go to options -> full list -> MAP kPa C =0, MAP Kpa m=300, MAP max = 4.98V, MAP min = .35V" http://hhscott.com/93tmv/images/3BARv2BAR_Map.gif |
Re: GM 3 bar install... getting random check engine light, no codes
Originally Posted by danz
the wideband goes through the stock o2 sensor wire. scaled to 3.5v max. (been running like this for MONTHS without any issues/lights... although since the tune changed the values from the o2 sensor would have changed as well)
no datasheet came with the GM 3 bar, but ill look. i havnt been datalogging but i have been watching the map trace when the light comes on, and its not doing anything weird. but ill try some datalogging to see if that is more detailed. do you have a boost/vacuum gauge? if so are the map values in ecucontrol close with the 3-bar? what kind of vacuum readings are you getting when the cel comes on? is it greater than 25 inHg (i.e. 27 inHg, or 30 inHg)? |
Re: GM 3 bar install... getting random check engine light, no codes
the manual vac gauge shows that the GM 3 bar is working fine. car drives well. the map trace is sharp and concise.
the vacuum readings when the light comes on vary, but its usually around -20inHg (guess). usually at a very light cruise, to the point id be slowing down without wheel breaking but the foot is still on the gas, JUST... its hard to know the exact manifold pressure as im usually looking at the road not the laptop... but i tried to bring up the RPMS to create a good vacuum and closing the TB but that doesnt make the light come on... its only when crusing. its weird. ill do some datalogging after work and see if i can get specifics. a very good idea. i havnt been able to reproduce the engine light... it just happens when it happens. im gonna recheck my solder joints after work too. the output of the GM 3 bar is linear |
Re: GM 3 bar install... getting random check engine light, no codes
Info for GM Part # 12223861 PRESSURE RANGE, OPERATING 40-304 kPa MAX. 700 kPa ACCURACY 1% to 5% OPERATING TEMPERATURE -40 to +125 C SUPPLY VOLTAGE 5.1+/- 0.36V dc SUPPLY CURRENT <10 mA V dc here is a chrome offset and scaler settings... not sure if these apply to TE at all. GM 3-bar part # 12223861 Scaler 628 Offset 0 for additional information: Tuner also said the Neetronics 3bar would probably be close to the GM 3bar. The setting for that one are as follows: Scalar: 625 mbar/volt Offset: 42 mbar The Motec 3bar settings are as follows: Scalar:609 mbar/volt Offset: 2 mbar |
Re: GM 3 bar install... getting random check engine light, no codes
thanks for the info... ill see if i can work a formula from that.
can you send me your bin file? i'll look and see if the scalars are correct... i've been real busy with work lately, so im not promising anything until the weekend... |
Re: GM 3 bar install... getting random check engine light, no codes
i sure can when i get some (4pm, about 4 hours away).
also found this. not sure if it applies to TE but does to other tuning softwares optimal settings for GM 3 Bar.... With M0=83/P0=0 and M1=190/P1=20 gradient 192 intercept 159 other sites list: (but there have been reports of this being off) Typical GM sensor calibration numbers Gradient 168 Intercept 134 a subaru member posted he received a low voltage ecu code and a sensor out of range ecu code. hope that can help. |
Re: GM 3 bar install... getting random check engine light, no codes
more info direct
http://i38.tinypic.com/2s00cpy.jpg interesting mounting diagram http://i35.tinypic.com/2cntnxf.jpg quoted from Razathorn on Clubrsx According to the specs, the GM 3 bar reads the following (pressure is absolute): .501 - .761 volts (.631 average) @ 40 kpa 4.784 - 5.044 volts (4.914 average) @ 304 kpa The range is likely tolerance for temperature changes affecting the sensor, so I've elected to split the difference for the 40kpa and 304kpa specs and use the average voltage they can output. That leaves us with the following sample to calculate the scalar and offset with. Pressure range: 2640 mbar (304 - 40 then x 10 to get mbar from kpa) Voltage range: 4.283 volts (the 4.914 average minus the .631 average) These two points tell us the scalar, which is 2640 / 4.283 =~ 616. Think of the scalar as "how much pressure each volt represents." The only thing left is the offset, which tells us "where the scalar starts at." Think of it like a linear function of P = (V * scalar) + offset where P is pressure and V is voltage. We can figure out the offset by testing a known point, such as 3040 mbar (304 kpa) at the 4.914 average volts. 3040 = (4.914 * 616) + offset 3040 = 3027.024 + offset 12.976 = offset. That makes the settings: Scalar: 616 Offset: 13 As you can see, this is very close to the neetronics 3 bar map sensor profile, which is why it works well, but you should note the following differences in map sensor readings between the two sensors as boost increases. This is probably why people's boost gauges are off from the map at higher boost levels as well. GM 616 scalar 13 offset Neetronics 625 scalar 42 offset @ 2.5 volts 1553 mbar 22.52 psi (7.82 psi boost) gm 1604 mbar 23.26 psi (8.56 psi boost) neetronics @ 4.5 volts 2785 mbar 40.39 psi (25.69 psi boost) gm 2855 mbar 41.41 psi (26.71 psi boost) neetronics So as you can see, at around 8 psi, you're almost a full pound (.75 psi) off, and at 26 psi you're a full pound off. Obviously if you're going to try these settings, note your tune will be off afterwards. Wayne |
Re: GM 3 bar install... getting random check engine light, no codes
i reworked the remap table and sent you a new map to try...dont blow anything up!
fyi, the GM 3 bar voltage/values are almost exactly the same as the motorola 3 bar... about 0.1psi difference at 13psi, the error in the sensor is more than the difference between brands. |
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