Trying to sort out a tune on a 5.3l swap using a modified LS1 ecm.

[kustomd]

Im trying to help a friend who just swapped a 5.3l from a 2002 chevy truck into is 240sx drift car. He's running it with a modified LS1 ecm from another car. whatever tune that was on the LS1 computer when he got it will start the car but it runs really really rich to the point it fouls the plugs out. His engine is using all the stock injectors and maf from the 2002 silverado. only things hes changed is he is using an LS1 intake manifold, headers and he put a pretty big cam in it that he got a really good deal on. Its supposed to be similar to Brian Tooley stage 4 cam unfortunately he doesnt have the cam card for me to get the specs off of. I know he changed the valve springs as well with LS7 lifters if that matters.

I was thinking I should just use the tables off of a 2002 5.3l engine and change all the LS1 stuff to match. Then start tuning up from there. I found a stock truck tune file on the repository to go by.

Does this sound like a good starting point using the truck stuff since its mostly just needing adjusted for the cam change and headers? Hes also running a t56 behind it too. with a stand alone engine harness thats independent of the chassis wiring and nothing on the transmission is hooked up to the stand alone harness either. Im including the as found LS1 tune file from where I first downloaded it off his ecm. And the truck tune file I was going to be referencing off of. I know ill need to change the engine and the cylinder stuff over to the 5.3l stuff. His engine is still stock bore as well. I told him next time to grab the stock Ecu to the engine hes buying so that it would be an easier starting point than using mismatched stuff.

ray 240sx with 00 camaro ls1 ecu as found tune.hpt
2002 silverado 5.3l auto.hpt

[rabbs88]

Stock is generally a good place to start. With just an intake manifold and headers it wouldn't have needed much work from stock but since it's cammed it will need a lot more changes.

[blindsquirrel]

...unless the MAF tubing has been changed as is common in swaps, then that could be way way off making it run like crap after seemingly minor changes to the hard parts.

[kustomd]

Yea that's what I thought.

[edcmat-l1]

1, if it's fouling the plugs it's almost certainly an injector flow rate problem. Most likely the donor PCM is setup for smaller injectors than what you have in the engine.

2, a great big cam like a stage 4 BTR, will probably barely run on a stock calibration. Starting from an original file is always best, but don't expect returning it to stock to allow it to automatically run. It will need extensive tuning to start up and idle decent.

[kustomd]

Actually it's the other way around. The donor pcm was set up for bigger injectors than what he has in the engine. The engine is running stock 5.3l truck injectors from an 02 Silverado. Where as the settings in the table for the ls1 were setup for bigger injectors. After I changed the settings to some for the stock size truck injectors it started to run a bit better.

[Matt Vardaman]

The stock injectors will not be adequate at all. They will not provide anywhere near enough fuel for a big cammed engine in a drift car. My son just bought a stock 2003 SS Silverado with the stock Lq9 with the same 25.2lb/hr injectors. It runs out of injector at 4,000rpm with Power enrichment (turned on) at 12.5 afr. The 50lb/hr later flex injectors are cheap and have stock gm injector data. I would recommend that being done first before tuning.

[horsepowerguru427]

What all injector settings did you change? Just flow rate or did you change SPA and offset as well? Have you done any VE and MAF calibrating yet? Ill try to take a look at the tune after im off work in a few hours