blue40sx

I have searched for a few days and haven't gotten the answer I am looking for, so if this issue has been addressed I apologize.

I bought a 411 PCM under the assumption it was bone stock and untouched. Well after hooking it up to HPT I realized it was not in fact "stock" I am unaware of what all has been changed, things I do know are it has a 3bar OS and 80lb injectors. I am sure much more has been changed but I am not sure to what extent.

My setup is a stock L33 with 862 heads, 120lb Holley injectors, Speed Inc 1 turbo cam, BTR valve springs, 3bar SD, 91 octane, 4l80e, stock LS1 intake & TB and a 76mm On3 turbo. All this has been put into a 240sx.

I can get the car to start and idle after what feels like forever cranking (15-20sec), will idle around 950-1000 just fine, but any throttle will kill it. Now before we all start yelling at me saying it needs to be tuned i realize this. My issue is I dont want to mess with anything not knowing if I am forcing the PCM to makeup for the previous tune. I am wanting to get a stock untouched tune and just copy and paste all the fields into my PCM. Is this the best route for me? Or is there a better way to get me going in the right direction. Also is there any info on the Holley 120lb injectors for the HPT? I new to HPT so forgive any ignorance I may have.

Thanks!

JoeNova

If you have an HPT account, log into their tune repository and download a stock tune for wherever you want to start as a base.

Then load the tune from the ECU, and open the stock downloaded tune as a compare file. I think its CTRL+1. You can open whatever table you want and switch back and forth between the 2 tunes. You can copy entire tables over from the stock tunes and paste it onto your current tune.

Any table or setting that has been changed will show in green as you browse through the interface in HPT, so you'll know where to look.

blue40sx

Hi Joe,
Thanks for the response, I have done that my concern is whether or not its truly an untouched file. I have yet to copy over the values and load them into the PCM but have thought of it. I am prob over thinking this whole situation, I just dont want to make more work for myself. I guess I could always try a "test" tune with one off their site and if it doesn't help I can switch back to my Frankenstein tune.

After loading a stock tune IYO, whats the best route for getting the car started with similar mods to mine?

JoeNova

Finding a good base tune. TBH, it sounds like you already have one that isn't too far off. Update the injector data before you make any decisions.

blue40sx

I am trying to find info on the Holley 120lb injectors but I haven't had any luck besides the dead time, might call Holley and see if they can help. Do you know if the options like the motor size and type have an effect on the performance of the tune? I.E. if it states F-body and or 5.7L should I change those to suite my setup or just leave it as is?

blue40sx

Made some progress last night, not sure what to enter for my injector data so if anyone can help with these holly 120lbers that would be great. I was reading up on adjusting throttle tup-in, is it as complex as it seems? Or is there a simpler way to adjust this? I appreciate any and all help!

Boosted53F

save whatever you have in the tune already..... then open new.... and use your new file to copy all stock 5.3ls values from the repository tune over using COMPARE FILES. then start working on your timing tables, running airflow for your cam size, and injector data. I dont see why it wouldnt start and run fine with this.... unless you have issues elsewhere

You are using a gen3 pcm with gen3 hardware? you said l33 aluminum?

120lb holley - you need to figure what pressure they are rated 120lb/hr at....remember gm is 58 base.... then use a flow chart to convert for manifold pressures across the board. look at injector flow rate chart for your SD OS

rpturbo

iTrader: (47)

Give Holley a call and ask them if you can't find the data. Most of their guys in tech are great. IMO, injector data is critical for the tune to idle, and run correctly. Other than that, make small changes and 1 change at a time, and always save as. Keep file after file, it really helps in the progression.

gametech

iTrader: (1)

I'm a bit confused. Are these 120lb high impedance injectors, or low impedance? The stock computer won't properly drive low impedance, and high impedance 120's would be a nightmare for idle tuning. That would only make sense for E85, and still might be overkill for a 76mm turbo, depending on whether they are rated at 45psi or 58. Also, as has been stated, the compare feature of HPT is of great help in finding random changes in an unknown tune.

blue40sx

Thanks for all the help guys. I have done everything under the sun with no luck. I'm leaning towards pcm as I found in another forum with similar issues. I'm going to toss some borrowed stock injectors in and see if the problem stays or goes away. I'm planning on e85 with a bigger turbo come next year, I wanted to avoid swapping injectors and all the HPT data but at this point I need it running asap so I can get it tuned.

I will update with my results.

MY_2K_Z

iTrader: (1)

Gametech has a point are the high impedance or low impedance injectors. From a quick search it looks like Holley only makes 120 low impedance injectors which would be your problem. Stock ecu requires high imp.