SD Tune Help... Can't get it to start
 

I've got a 5.3 with 76mm turbo in a 54 Chevy Pickup.

I have been trying my hand at tuning, I've gotten the truck to run and drive (not that great, but it runs) with a MAF tune. I applied the Speed Density Code Modification in HPTuners, put the tune on the truck, and now it will start and run for a second or so, then dies...

I've attached the tune and a log. Any help is greatly appreciated.

Cool project man. Got any pics? I have a 53 Chevy truck mothballed for another project down the road.

I'm not on a computer at the moment so I can't see your tune..
Did you fix your VE table after applying the speed density operating system? When I applied mine it made the entire VE table one number....

VE table looks fine to me.

Here are a few pictures of the truck. I still need to route wires/wrap exhaust/misc little things.

I don't have any from the current state, after I hooked up all the charge piping.

So, I reverted to a tune before I did the SD OS Modification. Everything is exactly the same except for the code modification and the MAF isn't failed.

It started up just fine. Then I unplugged the MAF and it also started just fine...

The big issue with this is that the IAT is a part of the MAF...

Any suggestions?

when you set the maf HZ to zero to fail it, you do a write entire?

then when you fire it'll try and die , usually two pumps of the pedal and it'll idle.

if that's nothing doing perhaps look at your base idle airflow. DBW set ups are outside my wheelhouse so i dont know if the idle throttle area needs work after a maf delete or not.

oh yeah you gotta have an IAT sensor or it'll just read stone cold like -38*F

you could use the tried n true ac delco 25036751 or just leave the pins for the IAT in your maf plugged in (and the maf installed)

Truckdoug,

I have done write entire after the MAF fail, didn't help.

Any idea which wires to de-pin on a truck MAF to only keep the IAT??

Sick truck man.

Might be easiest to just get the individual IAT sensor like Doug mentioned and mount it in the charge pipe. That's what I did.

I'm assuming this has rising rate reg and return style fuel system and 76lb/hr inj?

unless I'm missing something here this is E38 and 2 bar OS with 3 bar MAP sensor....

E38 numbers are much much much bigger than LS1 numbers in VE table. like 20-30x bigger.

try setting cranking VE to one solid value also

see attached files

you'll also want to max your enable values for P101,P106,P121 and P0068 codes under engine diag> airflow.

there's quite a bit that could use cleaning up in your file.

feel free to email

luke@dieseltech.com.au

Iat wires will be one black and tan wire on the end of the maf. If u plug the connector into the maf housing u will be able to tell which 2 they are. Just look inside the maf for the iat sensor and follow it up.

Luke,

I don't have a boost referenced regulator at this point. I have Siemens Deka 80lb/hr @ 43psi running at 40psi so it comes ut to 76lb/hr with return line to tank.

The only code modification that was an option in HPTuners was a 2 bar OS mod. I applied it then updated the MAP values to the 3 bar MAP sensor that I had.

As for the VE numbers, I got them from a 2000 6.0 tune, so that makes sense... thanks for the info. Cranking VE was initially all one value and I updated it I'l change it back.

Thanks for the files, I took a look at them and updated mine accordingly. Next question, what is the best way to richen it up? I increased the VE tables in the idle range by 25% above this file and it still showed very lean.

Brandon,

Thanks, I'll take a look at the sensor.

if you have a fixed fuel pressure and no rising rate reg then your IFR data should slope. easiest way is put stock IFR numbers in, highlight the entire table and multiply by 1.02 until you see 76lb/hr at the 128KPA end.

best way to richen it up is by populating the three VE tables with numbers that will command a pulsewidth.

disregard any of the stuff i posted about the actual tune. e38 computers and I don't get along

So, it runs and drives (sort of..)

The attached tune & Log are from my latest test drive I tried reducing spark numbers to remove the KR and increasing the VE numbers based on STFT and it still looks like it is running lean and as soon as it goes into boost , even 1psi it stumbles and fals on its face.

Any suggestions?

Get rid of that stainless braid flex connector. Its going to come apart and choke the crap out of the exhaust and then end up inside your turbo housing and wheel. Ask me how I know. 1 was completely gutted already and pieces were in my housing. https://cimg4.ibsrv.net/gimg/ls1tech...5bf115cb2d.jpg
https://cimg5.ibsrv.net/gimg/ls1tech...f00ab274f5.jpg
https://cimg6.ibsrv.net/gimg/ls1tech...0c9e75735a.jpg
https://cimg7.ibsrv.net/gimg/ls1tech...9e3cbd7046.jpg

Yup!!! ^^^

Exactly why I didn't use one. If you support the turbo like you should and don't let it hang off of the pipework you really shouldn't need one of those flexy things anyways.

I just ordered a borescope, so I'll take a look through the O2 sensor port for now to make sure its not coming apart I will put a flanged connection in its place later on.

Regarding the tune, I am having issues where the spark goes do zero momentarily during acceleration. Any suggestions on how to fix this? I tried going back to the stock trans config to see if it made a difference and it didn't.