I'm having the craziest issue ever while trying to tune the new turbo setup. Build thread here:
https://ls1tech.com/forums/forced-in...ispreloading=1

It's a stock 4.8 with 60lb injectors and a 340 intank pump with a hot wire kit. I have the car in OLMAF tuning the transfer function, but I can't get it dialed in AT ALL. The AFR's are all over the place. I can literally hold a load to sit in a specific cell in the MAF curve and the AFR will swing from 10-18. I am using regular Siemens Deka 60lb injectors LS injectors with Multec 2 adapter harnesses and fuel rail spacers. I copied over the injector data I've used for years with no issues. This should be plug and play and be cake to tune. See the picture below. IAT/ECT/MAF sensor frequency/etc. all appear normal. Any real throttle and the AFR will bury the gauge rich, but from an idle any throttle and it'll go full leak. My thoughts are either I'm missing a table in the tune somewhere for either fueling or a "protection mode"; or there's something wonky with the fuel pressure. Anyone know if these trucks have variable fuel pressure? I attached the EFI Live tune file for those that can see it. Ignore fuel pressure in the pic as it's not wired up.

Could use input from any tuning guys like @smokeshow @NicD or others who have ideas. Any help is much appreciated as this thing should be cake to dial in.

 

Sorry but my efilive is long gone, like 8+ years long gone. I would need the tune in HP Tuners format and be able to see a log file of it happening.

 

@NicD We're in luck....while I'm tuning with EFI Live, I have HPT for another vehicle. Just did a read of what's in it at the moment. Not final by any means, just enough to be able to go scanning to dial in the MAF. It doesn't "feel" tune related, but happy to get a 2nd set of eyes. See attached.

 

I don't understand what you're doing with the OL MAF / EFI Live / analysis that focuses on fueling when you move the throttle. You'd have to give some background on the setup and probably a log file before anyone can help.

 

Perhaps I wasn't clear enough above. All I'm trying to do is dial the MAF transfer function while in open loop. Forget tuning boost, etc. no cam, etc. Stock 4.8 long block. This should be easy peazy. However, when I sit at a fixed load/throttle in a specific transfer function cell, the AFR will swing wildly. I can't tune an AFR error for a given MAF cell if we're swinging from 10-18 in the same cell, right? The picture above is just showing how far the AFR is swinging. I see it as 1 of 4 things is wrong:

A) fuel pressure is all over the place which is causing the swing in AFR.
B) fuel injectors are trash even though they're brand new.
C) fuel injector adapter harnesses are making intermittent contact.
D) I've missed something in my injector data in the tune.

I'm asking for people to check the injector data in the tune and offer any other ideas that I may have not included above. I have a fuel pressure gauge on the way to confirm Im not losing pressure or that it's way off from what I based the injector flow rate off of.

 

What MAF frequency is this happening at? Can you post up a log in HP Tuners format of the actual issue happening with a timestamp?

I finally got back to a computer to look at the file and I don't see anything that immediately stands out but the MAF table does have some higher and lower numbers out of sequence that shouldn't be in there and it should be smoother than that. You also didn't modify your transient min fuel mgs fuel table [2284] which you need to do with larger injectors.

 

Agreed the MAF is rough because it was a first pass with no wideband feedback. The 2284 min transient fuel msec is VERY interesting. It's making me wonder if that's the missing table in the tune. It looks like it's not a table only a value. What do you normally set that to for tall EV1 type 60 lb injectors? I'm wondering if that table is missing from my EFI Live tune and I need a .cax file to see it.

 

I just compared this tune with some other tunes I have with the same injectors. The table I was thinking of was a default min pulse adjustment. I don't believe EFI Live requires this table to be changed to run properly. I've got a FP gauge coming in tomorrow and will let you know the results ASAP. Unless there's a hidden table on this OS, I think my issue is probably electrical/pressure related.

 

EFI Live has a different name for that table and I believe it needs a .cax file to see it for whatever reason but again it's been like 8+ years since I've used EFI Live. It's a very important table, the larger the injector the more important it becomes as it acts as a minimum pulse width table for various fueling events even though there are two other tables with that basic name/functionality in the Gen3 computers. EFI Live vs HP Tuners has nothing to do with the setup running correctly or a table not being required editing, they are both just editors for the tables in the computer so yes it needs to be changed with both EFI Live and HP Tuners. I would start by cutting that number in half for SD60s but I'm thinking that's only part of your issue. The other part could be MAF location in relation to the blow off valve and if it's open at that particular point in time but again I would need to see a log file of the MAF airflow/frequency at the particular problem point to see further and even then that may not give the full picture.

 

I literally just came across the B9021 (minimum transient pulsewidth) cax file in EFI Live. I just loaded up the cax and reopened the tune and can see that cell now. It's currently set to .88 but I foudn someone who posted they cut it to .4 and saw a huge improvement in startup and idle. I'm going to try that and let you know. I'll check the BOV, but it should be closed and get a log and post up. Appreciate the support on this.

 

The addition of B9021 via the .cax file was a no go. No change. Fuel gauge comes tomorrow along with the AN to NPT. Then we'll see what's what.

 

Ive got adequate fuel pressure. The gauge fitting I installed had a leak (of course it would be defective) and was still showing a stable pressure above 50 psi so unless fixing the leak sends my pressure sky high I'm barking up the wrong tree with fuel pressure. It's making me wonder if my brand new injectors are bad. I've ruled out pretty much everything else.

 

Where did you get the injectors? Are they flow matched?

 

I can't post the link due to non-sponsorship, but they're a typical parts distributor that sells everything from AFR heads to fuel systems, engines, etc. They offered "their" branded 60lb injectors or genuine Siemens Deka tall EV1 style injectors. I bought the genuine SD set to avoid any issues. I also went through the various websites online for how people tell real from fake Siemens 60lbers and all the markings, colors, tip design, etc. all confirmed them as real. Every car I've tuned with these injectors has been cake, so I assumed a stock 4.8 that hasn't gotten into boost yet would also be cake lol. I'm going to confirm a few thigs on the truck, fix the FP gauge leak, and give the MAF another try and see if just sitting at idle moves the AFR where it needs to go. If that doesn't work, Im pulling the injectors off and putting the old tune back in and see if it solves the AFR/drivability issue. That SHOULD confirm if its injector/tune related or something else.

 

Good that you confirmed fuel pressure. If you suspect it's the injectors, you can swap the stock ones (along with cal values) back in to see if you have control at idle and cruise. You only need the big injectors for boost, but let's see if you have anything else going on before trying that, right?

*edit* I looked at your file. You have OLD SD60 data, rougher interpolations vs some of my newer measurements that are more precise. It's close enough that the injector characterization shouldn't be the reason for toggling AFR measurement though.

Move your stoich point before you get too far into this too. 14.68 fuel doesn't exist anymore with e10 pump fuel. Use something like 14.1ish and get a few percent closer on everything.

It was said before, but WTF is going on with that MAF curve up top? You know that's not plausible, why leave it like that even for testing? Also, you'll probably hit the 512g/s limit with a turbo and a combo that needs deka 60's, time to scale EVERYTHING before you get too far into the project.

 

Exactly my plan. If I swap back to stock injectors and the old tune and it idles and drives fine with good AFR, then it has to be either the injectors or something in the tune file. If it's still wonky, then Ive got something else going on.

 

if you are able to share your updated data I would certainly use it. I only have your old excels. Data up top was totally giant chops, I never even got into boost.....also I don't know if I've been so happy and pissed at the same time....with everything bolted up you couldn't yell it was split until it finally split all the way. Going straight to an LS7 MAF setup. With that setup it's 50/50 if I max out the little 4.8 on a stock cam with some boost. If I do I'll rescale everything then. Hoping for a good weekend when parts arrive!!!

 

LOL, you didn't see that in the MAF frequency data? That had to be unstable as all hell! So another 85mm MAF bites the dust, can't even count how many of those I've seen split over the years from Procharger kits but not normally on turbo setups. Definitely change it out to a card style setup, or better yet ditch the MAF. LOL

 

Call it forest for the trees, but the swing in MAF frequency was so slow that it didn't trigger a thought to me that there was a MAF issue. I never saw a sudden spike or shift in frequency at low load. See pic below. To be fair, I haven't confirmed this fixed it yet, I'm waiting on the LS7 MAF to arrive to confirm I actually have control, but it seems highly probable. I think it started with a small separation and slowly worked its way around the seal which made it drive worse and worse until it finally fully separated and revealed itself.

 

Here's a more recent run of the short 60's that I did for FIC (Georgia).

Moving to the LS7 card style MAF is great for range and reversion suppression. With the older ECU, you will still hit the 512g/s airflow limit, just at a lower raw MAF Hz. You'll need to scale for that.