5.3 with sts blower help

[94heritage]

Hey guys. Im struggling with a truck of my friends. Its a 5.3 with btr stage 2 truck cam and springs with a caddy sts blower on it. Its got lsa injectors in it with a return style regulator in line. Im going to post my last log and current tune. Rolling into the throttle it seems to do pretty good following the wideband vs the command, but if you get after it heavy it doesnt come close to commanded and its super random in spots as you can see in the ve table. I haven't smoothed or blended anything off of this last log just to show how odd its acting. This is about the 4th log so far. One time I will floor it and it will pull clean the next it will be 16.0 afr and breaking up. Ive tuned several turbo setups and centri blowers but this is my first pd blower any guidance is a god send. Thanks
koester 3 bar drive 1.hpl
koester 3bar latest log.hpt

[edcmat-l1]

First of all, you can't have a VE that looks like it does. Peaks and valleys are a no-no. It's no wonder the fueling is all over the place, the VE is all over the place.

Second, you need to have a fuel pressure gauge on the car at all times, mounted where you can see it from the driver's seat. You need to leave the FP gauge on it until the vehicle is done.

Can't do any toonin if you don't know for sure what the fuel pressure is doing.

[SiriusC1024]

Which injectors are those? Offset is setup for returnless, but IFR is for return.

Pretty terrible base spark tables.

What MAP sensor?

[SiriusC1024]

Oh LSA injectors duh. There's Gen IV converted to Gen III data here:
https://forum.hptuners.com/showthrea...l=1#post766924

Reduce Fuel>Transient>MinFuelMg to 0.017.

Main problem is fuel supply, what's feeding the injectors, isn't keeping up.

LSA MAP sensor is 312.5 linear -11.25 Offset.

[94heritage]

I keep trying to edit this post it and it keeps deleting the damn thing so I have to start over. I know there are hills and valleys. Like I said in the post I purposely haven?t smoothed anything on this last log yet to show whats going on. It has a fuel pressure gauge 58 psi and raises 1 to 1 with boost. I agree the spark tables are a little rough Im just trying to get fueling in the ball park before I go any further with spark. The map sensor is an efi source 3 bar. I must have forgot to change the offset table last night when I changed everything over. Fuel pressure is hanging in and inj duty is only in the 40s at 9ish psi. Do you really think its a supply issue?

[Alvin]

This must take some sort of port adatper plate.

The LSA to cathedral port adapters are a nightmare. I won't take a car in that has them. Lots of transient issues, lean coughs when cold. The Injectors are spraying at a wall with that setup and I don't think it could ever be right.

I have no idea what a STS to cathedral adapter plate would look like.

[94heritage]

The sts to cathedral plates are made by mac daddy fab

[SiriusC1024]

Yes there is a supply issue. Look here where it leans out. Engine load isn't changing to warrant that. RPM and MAP are pretty stable, but AFR goes lean.
leaning out.png

[94heritage]

Thanks sirius I will do some digging. I may have to get a go pro and record the gauge

[edcmat-l1]

Thanks sirius I will do some digging. I may have to get a go pro and record the gauge

This is a very common mistake by DIY guys. You can't assume your fuel pressure is good while underway. You HAVE to be able to see it at all times. It can be fine sitting still, revving the engine in the driveway. While driving is a completely different story.

[blindsquirrel]

Flow Rate is referenced LSA, Offset is returnless L59 (-ish, mostly), Short Pulse Adder is mystery meat that doesn't match up with anything.

[blindsquirrel]

https://www.onallcylinders.com/wp-co...e-1024x768.jpg

Wow. LOL.

This is a really good illustration of how what works to make WOT rips on the dyno doesn't always mean that's a combo that will work for something that has to behave itself at part throttle.

[94heritage]

Ok squirrel. I updated the injector data based off your spread sheet thanks for that btw. I have another guy that I tuned this same setup in a trail buggy jeep but using a terminator x and it seems to cruise the trails great and no tip in issues. Adapter plates are never ideal but it does work pretty well

[Alvin]

Those plates don't look as bad as the ones they push on LSA-> Cathedral.

Just be conscious this might not work. And peoples definition of driveablity vary greatly. I've had people say "it drives pretty good just needs a touch up" when the engine is down a whole cylinder. Others are sure to let you know last month when the moon was full and mercury was in retrograde it had a hiccup merging on the highway. But only that one time.

Have you verified fuel pressure while driving/under load?

The VE table needs a lot of work still. It should be quite a bit smoother than that.

No 3 bar map has those scalar/offset that I know of. What sensor are you using?

[94heritage]

Efi source 3 bar truck style map

[edcmat-l1]

I have no idea how well they work but they're pretty machine work.

[Alvin]

Efi source 3 bar truck style map

I'd be careful with that. Sounds / looks like the Chinese map sensor that a popular turbo company sells. Using a GM sensor will eliminate that as a variable.


I've had 3 come by and all 3 did not work reliably.

[edcmat-l1]

Not sure why anyone would use anything BUT GM or AC Delco sensors.

[Alvin]

They weren't easy to diagnose.. Because they worked.. but they didn't read accurately. So 60kpa was really 40, 150 was actually 180.. I was like the scalar was off from what they said it should have been but also the error wasn't linear.. Just junk.


I'm sure normal people aren't aware of this.. But being a performance shop owner I'm overwhelmed with emails from china promising great injectors at $40 a set, map sensors for $10, engine harnesses for $200. etc.. It's clear when you see cheap injectors sold to the public that this is where they are getting them from. I don't trust knock off parts. And these are important parts. And you shouldn't trust them either.

[blindsquirrel]

Not sure why anyone would use anything BUT GM or AC Delco sensors.

...unless someone has an E40 and needs to read higher than 200kPa, and there's no GM 2.5 bar sensor, and the E40 can't take a Linear higher than 256 or a Offset less than 0.00...