Starting tune on a car but have DTC code issue after starting MAF ve tune.

[2000Phoenix]

Hello,

I am new to the Tuning scene and always wanted to tune my car myself as I have read it is not that hard if you have the proper tools at your disposal. I am mechanic and computer savvy. I have purchased all of the Hptuners books and as well as the latest tuner. I am running into an issue and can't get past the updating my LTFT in the maf ve tuning book. My trim level are in 1000 plus range compared to the pick in the book are between 3-30. I know its dumping a lot of fuel in the system and the issue also is when ever I take the numbers and copy them to the VE tables and write the file the car want start. I also am getting codes p0103,p0327,p0332,p1637 on top of Evaporative System, Secondary Air pump, Oxygen sensor, and oxygen heater sensor all reading incomplete even they I just put in new knock sensors with harness and two new oxygen sensors. Any help pointing me in the right direction would be great after I correct these error codes. I have gm knock sensors with harness and bosch corvette rear o2 sensors I am going to replace and hope this fixes the problem so that I can start tuning this thing properly.

My car specs:
2000 WS6
maf has been de screened
TB slightly ported
PCv system deleted
catch can
Egr and air pump deleted
moser 9in with 3.90 gears
t/56 with z06 clutch
rear cats deleted
headers
stock injectors
oil catch can
pcv and air pump system removed
msd coil, ac delco plugs and msd wires
Racetronics fuel pump
cam specs:ADV DUR: 273 277 DUR@ /050: 220 224 LOBE SEP:112.0 VALVE LIFT:.530 .534 with matching springs.

[5FDP]

Code P0103 is typical if the MAF is not plugged in or it was failed in the tune for VE tuning. That code needs to be present for VE tuning.

If the fuel trim channels are not reading right you can try removing the channels from the main channels list, re-poll for supported parameters under the vehicle tab while connected to the car, then add the channels back in and start logging to see if they report regular values.

[2000Phoenix]

I will try unplugging plugging and replugging the maf. As for the channels. You are saying the book has you set up the ve table I need to remove it and re add it back while connected? Also I am new to some of the terms so forgive me. When you say repoll do you me set the ltft parameters? Sorry if it’s a dum question I just want to make sure I understand completely.

[5FDP]

I honestly have no idea what the books say for anything, never read them.


I'm just saying that when tuning the VE tables the MAF sensor has to be failed within the tune so it goes into speed density and only uses the VE table for fueling. If that is what someone was doing they would have set the MAF fail high hz from whatever value like 13,500hz down to 0hz and would have set the 3 MAF dtc code to MIL on first error.

If the tune was setup up that way, that could have been a reason for you seeing the MAF code. Without you posting the tune I couldn't see if that is the reason why the code is showing up or you have another issue with the MAF sensor.


As for the fuel trim readings in the scanner. If the bank 1 and bank 2 LTFT are reading some crazy number like 1000 or whatever, then something might be wrong screwy with the channel pid for some reason. To attempt to fix the problem you would do what I said. In the scanner you would remove the LTFT channels, then re-poll for supported parameters under the vehicle tab at the top of the window, once re-polled you would add the two LTFT channels back into the scanners channel list.

Again you didn't post a log so I can't see what you see and can only offer a suggestion based upon what you tried to type out.

[2000Phoenix]

What you described is exactly what I did per the book and saved the original settings as I will need to put them back. The mil was set as well so it has to be the channel I will post this up tomorrow as I am on my iPad an my laptop is downstairs so you can get a better idea of what’s going on. I really appreciate you you taking the time to explain this to me. Thank you.

[2000Phoenix]

Here are the files. On the second file after I copied and pasted the scanner results to the ve tables and write the calibration the car want hold idle like its not getting enough fuel. Let me know what you think is wrong.

[5FDP]

The log isn't very helpful because nothing is really working. It's in open loop with no fuel trims and the o2 sensors look to be unplugged.

The 2nd tune won't run right because you have values of 519% in the VE table in some cells, obviously that won't work.

You need a wideband to tune something like this, trying to use fuel trims just won't cut it when you have no much to correct.

[2000Phoenix]

The second tune is what the book said the values would come down by half from the ve table. Do I need to switch it to closed loop as i did not see that in book? also the numbers before I pasted them over the ve table are what they were in the scanner I up loaded. Are they suppose to be that high? As stated earlier I have new gm knock sensors and bosce corvette rear oxygen sensors hoping this will fix my problem. I deleted the graph and remade it. I will see if the numbers change as well.

[5FDP]

Fuel trims only work in closed loop. So you must have functioning upstream o2 sensors to do anything with the short term fuel trims and long term fuel trims.

Open loop does not use fuel trims and if you had a wideband sensor you'd be tuning in open loop.

[2000Phoenix]

The book only has using with the ltft so far and because the Oxygen sensors are reading incomplete I am in closed loop?

[5FDP]

No, you are in open loop if the o2 sensors are not working.

Your log even says that the fuel system status is OL - not ready. Meaning that it's in open loop. Closed loop must have working o2 sensors.

[2000Phoenix]

I’m planning to get a wide band soon. Just started doing research on which one as I was told I didn’t not need it to start but I did not expect these issues with the incomplete oxygen, knock sensors, and Evaporative system to arise.

[2000Phoenix]

So when the 02 sensor starts working right I am guessing my numbers will look lower on the ltft table like the example in the book states I need to be + or - 3?

[5FDP]

So when the 02 sensor starts working right I am guessing my numbers will look lower on the ltft table like the example in the book states I need to be + or - 3?

Doubtful they will be anything close to +/- 3% right now. With all the mods you did and how far off the airflow model is they will probably be 10-20% off at least.

Fuel trim tuning isn't that accurate when you have a camshaft, headers and custom exhaust. And fuel trim tuning can only be done for idle and part throttle. Anything that is medium to full throttle will take it out of closed loop and into open loop/power enrichment where the fuel trims are not active and the wideband is required to figure out the air fuel ratio. This is why I suggest a wideband straight away, the entire MAF and VE can be tuned straight away with no time wasted on fuel trim tuning. I do all my fuel trim corrections if needed once I'm done with the wideband.

[2000Phoenix]

So for now what can I do until I get a wideband and which one is good but. It crazy expensive. I was looking at the afr500 v2

[5FDP]

If you get your upstream o2 sensors working, do what you can with the trims while you wait for a wideband. No wide open throttle pulls or anything like that, just idle and normal driving.

I run AEM widebands. They make several different ones that range from $170-250 dollars or so. If you have the PRO interface it will make logging the wideband quick and simple but if you have the normal interface you can log it a different way. Either through serial or it can be wired in through a 5v reference circuit on the computer. The EGR circuit is probably the most popular and works great. Lots of information and youtube video's on using the EGR setup.

[2000Phoenix]

I am not sure which one I have. I have been doing everything from the ecu connected to my laptop. Any idea why new 02 sensors and knock sensors would be throwing a code?

[5FDP]

If your MPVI 1 has a green plug in on the side, it's a PRO version. I forget what the PRO MPVI 2 looks like.

GM has a spec for the knock sensors I believe, you can ohm out the new sensors to see if they within spec first.

Check your fuses for the upstream o2 sensors, make sure the harness has power. Make sure the part numbers you bought are the correct upstream sensors for a 2000 Firebird.

[2000Phoenix]

I will check fuses and I have a mpvi 2 it saids. I order gm knock sensor and will install the corvette bosch oxygen sensor if the other ones don’t work after checking fuses

[2000Phoenix]

Are the oxygen sensor fuses inside or under the hood?