P01 controller doesn't give me a MAF error code when I read the DTCs. I have P0101,102 and 103 set to first instance with the light turned off, EGR filter coeficient set to zero, MAF calibrations set to zero, dynamic high rpm enable set to 9000. What am I missing here?
Jim
MAF Freq Fail High set to 0Hz? Have to guess, since there's no tune file to look at to confirm everything you're saying you have done and maybe spot the one thing you missed.
You are right. File attached.
No log file? (log files have a 'Details' tab that shows any DTCs during that session)
I can tell you though, if the MAF table is all zeros and the engine still starts and runs, it's in speed density.
p.s. Get rid of the 5500 RPM PE delay!
well..this is a little embarrassing. I had what I thought was a pretty decent scanner setup and then for some reason thought it'd be a good idea to click the "Load vehicle defaults" button and it mostly quit working. So far I've not been able to get it back. I know I had it saved... Guess I'll have to rebuild it if I can remember how.
Also, it's a short log because the engine isn't starting. That's what I'm trying to get sorted out. When it does start it's been going so rich for maybe a minute that it spews raw gas out the exhaust so I've been turning off every source of enrichment I can find. Now it just cranks so I guess that's progress. Once it does run the AFR is 15:1 so not too bad on the VE I think.
Along the way I discovered it isn't throwing a MAF code. Seemed like that would have to be the first priority. Does that make sense? I'm thoroughly out of my depth by this point, but still trying.
Jim
It won't set the code until it runs. The conditions have to be met to fail the MAF, if it hasn't run since codes last cleared it won't have met the fail conditions and won't have the code stored.
Thanks, it helps to know that. I'll look for it next time I have it running.
Out of curiosity, can you think of anything in particular that would make the mixture go suddenly very rich right after the engine has fired off and run that way for maybe a minute or so before leaning out?
This is in forced open loop? Too rich in the low(er)-ECT areas of the OL multiplier table(s)? That goofy VE table? Sorry, I am not really a Gen3 guy.
OK, thanks for the help. Got my channels back by digging through old files thankfully so the scanner should work right again, try that tomorrow. Since I got it to crank without firing off I must have eliminated the over-rich scaler. I suspect the ECT and IAT initial adders. I'll go easy on those and work up from the prime pulses I guess. Maybe start by increasing the prime pulses until it'll fire off and then lower the prime pulses as I raise the ECT to see if I can get it to keep running. Not sure what else affects that sequence but I've been having trouble bridging from initial light off to rich warm-up idle. I was starting to play with prime pulse delays, maybe that's where the answer is. If I can get it to fire on a single prime pulse then maybe I can add in the other two with the delays stretched out as far as I can go without a sag and use that to cover until the ECT enrichment comes in? Or do I have this all wrong?
I would recommend at least populating the MAF table on the lower end of the scale. It helps the engine to run long enough to allow the PCM to fail the MAF.
Otherwise, each time you flash it, it has to struggled to go to SD mode for the first few seconds of run time.
Give us a little more info able your combo. I'm sure we can help you better at that point. It looks like a boosted combo, but with stock injectors.
what if the MAF is unplugged? Wouldn't that fail it immediately? I'm having a similar issue to the OP and trying a few things. I see commanded AFR's on start up at 12-13 even though the MAF is failed, EQ ratio's are all set to one. No idea why it's still commanding so rich. I have it in speed density open loop to try and address a rich ve table but it's showing crazy lean on start up and then shows rich after car is up to temp.Originally Posted by kevin87turbot
Do you have a separate IAT? If not, you also disconnected the integrated temp sensor so your PCM thinks it's really cold.
No...it's separate.
As someone mentioned you will need to populate the MAF table with some initial start-up values in order to keep the engine running while the maf is "failing"
When the battery is first connected (Every time you disc and re-connect) the ecu will "forget" that the maf is failed. So it will crank and try to run using the maf table. If you dont put enough fuel there (Or too much fuel) the engine will try to die before the maf can fail and you will be left trying to restart the engine over and over until it does.
Apparently this is normal. The symptoms go away once you put the right value in the maf table for the first "blind" startup of every new battery connection.
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Well that's certainly interesting. Is this the MAF airflow vs frequency table you are talking about? Mine is all zeros, I guess someone thought that would help fail the MAF.
I'm now working with a local tuner (Nick Skaatz) who seems to be pretty good, to at least get the startup settings closer. He dropped some values in the EQ ratio table to get rid of the over-rich condition I was having at startup which he explained to me was Open Loop and when it leans out is closed loop.
At his recommendation I'm working on doing a compare to a HP tuners library file (once I find it) for an 01 Camaro 2 bar tune. I'll try to bring the tables I've mucked with back to that as a starting point.
Currently, I get a little blip on initial crank then nothing. But this is an improvement because it's no longer got the pig rich condition. If the above steps don't get me into the range for starting and warmup, I think I should now be able to add fuel where it is needed. That business about the EQ ratio table (assuming that's what we were looking at) was apparently the critical missing piece.
I realize this is so familiar to you experienced tuners that you don't even have to think about it, but for someone who is not at all familiar with GM controllers it would be incredibly helpful to have a timeline going from Key ON through start and warmup that showed all the fuel adders and what interval of time they influence. With that tool, a new tuner could at a glance know what adder to change in order to improve his start and warmup cycles. And really, I find that to be the most challenging part of tuning a new engine that has been modified. Kinda hard to tune the VE table if you can't even get it to run.
Jim
The engine is a bit unusual for this controller, old iron. A '66 Buick 300 V8 fitted with '01 Camaro engine control system including all sensors, COP, tone ring etc. Injectors are Delphi 17114503 running a 2 bar tune with a Delco 12615136 2 bar sensor. This engine is one of a series of 3, two of which are 5.7L with 4-6psi of boost and this one which is NA and 5L. Timewise it's right in the middle. That is why the 2 bar tune is being used. The injectors were specified for up to 6L LS engines. They may prove inadequate for the other engines, if so I can worry about it then.
It appears my tune is mostly consistent with the sample tune.
Jim
That sounds like it. I think I Put 13's across the board in mine to get it fired up long enough to fail the maf.
Hah. I wish. After 4 years I Still have no clue how the cranking fuel tables work or what the @(#*@# they are doing. My engines fires up easily but that is because I played around with the settings until I got it where I want it, and the resulting numbers don't always make the most sense for cranking.I realize this is so familiar to you experienced tuners that you don't even have to think about it, but for someone who is not at all familiar with GM controllers it would be incredibly helpful to have a timeline going from Key ON through start and warmup that showed all the fuel adders and what interval of time they influence. With that tool, a new tuner could at a glance know what adder to change in order to improve his start and warmup cycles. And really, I find that to be the most challenging part of tuning a new engine that has been modified. Kinda hard to tune the VE table if you can't even get it to run.
Luckily most everything else besides cranking fuel is self explanatory and works as you would think it does.
I believe you're also meant to change "steady state" Hi/Lo RPM up to 12k
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