Running like shit when cold
 

Not sure if this is in the right section, move it if need be. Fuel setup; Walbro 255 High Flow pump, DSM 450cc Injectors with resistors, stock fuel pressure regulator, and filter and lines.

I was tuned on uberdata back in September to start things off. I've always had a problem getting teh car to idle at all. Start it up, runs for a minute or two, then dies. Same thing over and over until the engine is up to it's normal operating temperature. Pretty sure it's teh IACV to blame, still need to replace it.

On another note, when it's cold, period (engine temp, or outside temp) the car runs like ----. Randomly misses, and just runs like crap in general, unless the engine can get up to operating temperature. And as of recently, it's been so cold out, that no matter how long I run teh bitch, it won't get up to it's normal operating temperature. Normal operating temperature for my shitbox seems to be a mark or two before the midway point on teh temp gauge. At which point the car runs fine, no misfires, will normally idle at a g for me, and not die.

Could my second problem also be caused by my faulty IACV? Or is it a completely seperate issue? Sorry for the stupid questions, but this area is defintely not my cup of tea.

Thanks for any help.

Re: Running like shit when cold
 

too much fuel pressure..........WAY too rich in cold start loop.........

Re: Running like shit when cold
 

sounds feasible.

but when I first turbo'd the car, same setup, different engine, I ran teh chip the guy sent me, and never had any problems. Given it was only in teh summer, but it never had a problem idling at all. And as stupid as it is, I was using his tune from his car (same setup I had) as mine.

Re: Running like shit when cold
 

different engine, different tune, different weather..........

Get a FPR to drop the base pressure at idle down to correct levels

55 psi fuel pressure in the cold is TOO MUCH fuel.

Re: Running like shit when cold
 

Ran 60psi w/ A1000 + 1000cc on a built GSR with no issues... with Neptune.

Uber / Crome currently have a nasty "bug" - the IAT and ECT correction things aren't working quite right...
I'm not doing ---- with Uberdata anymore, but Crome should see some significant updates in the coming weeks that address these issues fully. As soon as my testing is complete, I'll be making some releases. Crome's P72 support might be enough to work with Uber bins, might not. Just have to wait and see... Or learn to code and fix it yourself.

Lowering the fuel pressure drastically will probably have nasty effects on your tune at WOT.

Re: Running like shit when cold
 

Ubers current IAT and ECT.... ugh...

Re: Running like shit when cold
 

DAve, problem is he's using a stock FPR with the 255 HP pump, the regulator can't bypass enough fuel back to tank at idle/low rpms, even worse when it is cold. Once he is under way base fuel pressure will drop back to normal/stock range.

Almost like a rising rate FMU, only in reverse!

Re: Running like shit when cold
 

You're following old rules, Bone.
I've run at least two dozen cars with walbro 255 pumps and stock regs...
And guess what? With a little tuning, they idle at 14.7-15.3:1 AFRs. Perfect.

This whole cold start issue has to do with the fact that neither Crome nor Uberdata modify the ECT enrichment table used for idling! (there are about 5 or 6 ECT correction tables) In addition to the idle, there may be another table in use prior to another modifier becoming active - i.e. on startup.

Re: Running like shit when cold
 

So, it sounds like it really boils down to some problems with the Uber software.

I hadn't planned on turning the fuel pressure down without my tuner present to basically retune on the lower fuel pressure, to prevent any leaning issues at WOT.

I appreciate the input guys.

Re: Running like shit when cold
 

it sounds like it way too rich when eng. temps are cold. You should have it tuned for part throttle.

my girls car was running way too rich in part throttle and she was only getting about 160 miles per tank of gas. I took out about 15% fuel and now she gets about 240 per tank. I still have to do some more tunning in part throttle.

anyone can tune full throttle but part throttle is where the most tunning is at.