I just got my car tuned yesterday and it is driving horribly. I just had someone install a cam, p&p heads, throttle body and some other miscellanous stuff. The car just seems slugish and doesn't seem like it is making the 380rwhp that the dyno sheet showed. Also the guy who did the work said the stock 24lb/hr injectors were fine, where I have read they should be upgrade for this level of hp. He used an adj. fuel regulator to get it to 50psi and that took care of it. Should I upgrade injectors? It looks like my O2 sensors are acting up from the two diag logs from AutoTap that I linked below. In the second one it flatlines near 900, and the car just through a code of 02 sensor bank 1 insufficent switching. Can somebody look at the scan_1 especially because at this point I had no error. Scan_2 has the O2 sensor bank 1 problems. Is it just the O2 or does the tune need tweaking?

Thanks
http://home.comcast.net/~RAnderson16/Scan_2.atl
http://home.comcast.net/~RAnderson16/Scan_1.atl

 

Raising the fuel pressure to 50psi increased the stock 24# injectors (24.9# in the program) to the equivalent of 26.7#/HR injectors. Assuming a 13% drivetrain loss on your M6, that would put you at 437 flywheel HP, and assuming a very good tune, a 94% duty cycle on the injectors. Generally, its not a good idea to run over 90% DC, so you're still marginal on the injectors. But for a brief dyno pull, or a short WOT pull, the problems might not show up.

When I tried to look at your files, I got a message that the requested page does not exist. If you post the files in ".csv" format, anyone can look at them with Excel. They don't need to have the same scan software you have.

 

Sorry about that. Everything should work now. I also added some csv files of the same scan below.

I spent some time today trying to figure out the problem. I removed both front 02 sensors and they were black on the tip which confirms the rich condition. So I decided to look at some of the spark plugs and they didn't look too bad. When I attempted to put the car on some ramps it didn't want to idle. It sounds horrible, so I hooked the computer back up and was getting a misfire in cylinder #8, I checked that plug it was black and had raw gas on it, I dried it off and put it back in the car. But since I have the delteq system I decided to check the #5 plug as well, come to find out it is really loose. It took me a number of turns to get it tight. When I was checking the drivers side earlier I skipped that plug because it is harder for me to get at. All of the other plugs on that side seemd okay. With a loose plug what kind of problems does that raise? Loss of compression? So I tightened it up and the car is showing a misfire on #8. Is it possible that loose plug damaged my coil pack? The car has new 02 sensors in it now, and the service engine light went away but the car still barely idles.

http://home.comcast.net/~RAnderson16/Scan_1.csv
http://home.comcast.net/~RAnderson16/Scan_2.csv

 

You're recording way too much data. As a result you are getting 1.7 seconds between frames. Delete some of that stuff. You don't need the system ready indicators, no tranny info if you're looking for engine problems, don't need dual and triple units of measurement on sensors, etc. By getting such a huge lag between frames, you're masking the data. You were at 100% throttle position for 7 seconds, but you only captured 4 frames of data. In one of those frames, load, rpm and MAF drop, even though you appear to have held it at WOT.... but its hard to tell what's happening because of the huge gap between frames.

The PCM shows it running rich. Its pulling out up to 15.6% fuel on the drivers side and 14.1% on the passenger side. As a result, when you go WOT the PCM defaults to 0% fuel correction. The stock narrow-band sensors are indicating its pretty rich on the drivers side, not so bad on the passenger side at WOT.

So far I only looked at the first log... it takes a lot of manipulation to peel away the unneeded data columns, time stamps, etc.

 

If I get the car to run without misfiring I'll re-record the log and post that without all of the data that there is now. I didn't know the extra data slowed the sample rate. Thanks for the help.

 

Well I got the car running and brought it back to the tuner to have them lower the fuel pressure to 47psi. Everytime I bring up needing new injectors they keep telling me that the stockers are fine. I'm starting to second guess the horsepower numbers, because I wasn't there when it was dyno'd.

I created a new data log, I cut some data out of it, so hopefully it has a better sample rate. I noticed that I keep showing a misfire. I looked up the cylinder and it is only #8, with a count of the limit autotap lists of 200. It keeps saying 221 or something. The car seems to run good but is there a way to tell from the logs if the injectors are maxed out?

Here is the file http://home.comcast.net/~RAnderson16/scan_5.csv