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Thread: Texas speed 228r cam help needed, LS1 4th gen

  1. #1
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    Texas speed 228r cam help needed, LS1 4th gen

    Alright so a bit of back story the engine and trans has just shy over 80k on the clock, I got the PCM with a mail order tune from Texas Speed for LS6 heads, LS6 intake, 228r cam, LTs, and 42lb injectors. When starting the car for the first time of the day it'll fire off and then immediately high idle around 1800 then drop to 1000 and then its target idle, I have already check for vacuum leaks and have found none of the sorts.

    Whats a normal reading for the o2 sensors on a startup, i understand that they would vary from going open loop to closed though when looking at my o2 readings there about a 100-150 mV difference between the two. is it possible that my o2 are bad? i've had a case where my o2 were bad and the car ran light ass until i went WOT and it ran like it normally would. though in the case with this new tune when blipping the throttle the rpms will hang up for a bit and will take a fair amount of time until returning to target idle.

    I also came across the reading of the map sensor that it was reading a positive pressure in psi though since i don't have forced induction shouldn't it read a negative value for vacuum? could it be a bad map sensor?

    The only DTCs that popped up were Fan 1 and 2 circuit fault, and a pending injector P0200. I'm not worried about the fan code as i pulled the relays to test out others so i understand why those were on.

    After the car has had its first startup the only way for me to start again is crank over and hold the pedal wide open and when it does fire off it'll run extremely rough for a few seconds and then have a back fire.

    Any help would be much appreciated, I haven't been able to drive my car in roughly 6 years and i've been aching to get back to it. I have attached log files to see if anyone can stop irregularities the ones labeled 228r are a startup and idle while the other two are short trips totaling in maybe 2 miles.

    228r cam log.hpl
    228r cam log v2.hpl
    trip to apartment.hpl
    Oriellys trip.hpl.

  2. #2
    Tuner evolmotorsprt's Avatar
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    Quote Originally Posted by z28dave View Post
    Alright so a bit of back story the engine and trans has just shy over 80k on the clock, I got the PCM with a mail order tune from Texas Speed for LS6 heads, LS6 intake, 228r cam, LTs, and 42lb injectors. When starting the car for the first time of the day it'll fire off and then immediately high idle around 1800 then drop to 1000 and then its target idle, I have already check for vacuum leaks and have found none of the sorts. This could be something they tuned in, start up flare, or some other routine running in the background.

    Whats a normal reading for the o2 sensors on a startup, i understand that they would vary from going open loop to closed though when looking at my o2 readings there about a 100-150 mV difference between the two. is it possible that my o2 are bad? i've had a case where my o2 were bad and the car ran light ass until i went WOT and it ran like it normally would. though in the case with this new tune when blipping the throttle the rpms will hang up for a bit and will take a fair amount of time until returning to target idle. I ignore the O2s at startup, and so does the car because they need to get hot to function correctly. If you have long tubes you might have to ignore the O2s at idle as well. I was able to get mine to switch with the 228r and longtubes, but it took a good amount of time getting fueling right, setting the integrator correctly, and getting proportional idle right.

    I also came across the reading of the map sensor that it was reading a positive pressure in psi though since i don't have forced induction shouldn't it read a negative value for vacuum? could it be a bad map sensor? Outside the engine is ambient pressure. Inside the engine is less than ambient, but not less than zero. If you idle at say 40kPa and are at sea level the ambient is ~100kPa. That means you have 60Kpa of vacuum, but we are thinking in absolute pressure not relative.

    The only DTCs that popped up were Fan 1 and 2 circuit fault, and a pending injector P0200. I'm not worried about the fan code as i pulled the relays to test out others so i understand why those were on.

    After the car has had its first startup the only way for me to start again is crank over and hold the pedal wide open and when it does fire off it'll run extremely rough for a few seconds and then have a back fire. Sounds lean?

    Any help would be much appreciated, I haven't been able to drive my car in roughly 6 years and i've been aching to get back to it. I have attached log files to see if anyone can stop irregularities the ones labeled 228r are a startup and idle while the other two are short trips totaling in maybe 2 miles.
    I'm sorry if that isn't much help, but no one is going to be able to help you without posting your tune.

  3. #3
    I looked over your log files and there seems to be something wrong with either your map sensor or a vacuum leak somewhere. the map sensor shouldn't jump around that drastically. the scaling might be off in your tune for the map sensor or a bad map sensor if there is no vacuum leak. just by watching the O2 milivolts its rich just idling. idle tuning will help out here is a guide with good info https://forum.hptuners.com/showthrea...e-(w-pictures). you should run the Russ K idle config as well to dial in your Base Running Airflow. do a search on here to find the tutorial and download file for the scanner. After that is done you should go speed density to dial in the VE table. Lastly you can tune your Maf table. you should log your long and short fuel trims as well so you can see how much fuel is being added or subtracted by the ecm. Injector pulsewidth is a good channel to log as well. If you can't find a problem with the map sensor you can always throw an old school vacuum gauge on one of the fittings on the intake if it isn't holding steady vacuum readings on the gauge its a mechanical problem, if it is holding steady the it is a bad map sensor or the scaling for the map sensor is wrong in the tune file. if you post your tune it would help everyone narrow it down

  4. #4
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    My apologies everyone I was under the impression that the tune file was uploaded when I attached the log files, I have now attached the tune file below. I have only narrowed down for it not to be a vacuum leak by using a flammable aerosol spray to see if the idle should change, though i will go ahead and check again just in-case I may have overlooked something.


    Again I do appreciate the time you have taken to look over the log files.

    1999 Hugger Z28 M6 LS1 TSP 228r Cam.hpt

  5. #5
    Senior Tuner
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    You've got a bad MAP Sensor. Look at the O'Reilly's Trip datalog. The sensor was stuck at 10 kPa during the entire trip.
    Replace it and you'll be good to go.