TraviZ

iTrader: (2)

in my friends camaro with a 350tpi speed density, after he shifts gears (5speed) his car bogs real bad. not sure what it is. is the TPS on speed density systems the same as maf? and the only problem i can think of, is he is running 10AN fuel lines in replacement of the stock rubber lines in the engine bay. would these be too big?

8Mike9

Too big can't hurt.

TPS is not adjustable on an SD...ECM sees/uses it differently than on MAF.


May want to post up your buddies engine specs.

TraviZ

iTrader: (2)

its just a stock TPI out of a 91 vette. but for some reason he has an adjustable TPS just like on my throttle body? his is SD and mine is maf. how is this?

8Mike9

He may have put a TPS from MAF on it. The MF TPS is slotted in the holes, but bthe SD's (least the one's I've seen) are not...there is enough lop in the holes to make some adjustment, but it's not really needed. When the key is turned on, SD setups look at the closed throttle voltage to scale. So if it's .6 or .7 vols, SD uses that for reference. MAF looks for the .54 +/- .06 volts for throttle closed.

TraviZ

iTrader: (2)

so at idle he should be reading .6 or .7 volts? and what about WOT? 4.6volts+ ?

91Z28-350

approximately, yes. What's being said is that the SD setup is auto-zeroing. The key-on voltage is what is set to 0% TPS and everything is relative to that for the %. 4.6+V sounds about right for WOT.

What do the data logs show? What bin is he using? Bog on a shift, under what conditions? WOT, or part throttle? Light load or under AE?

TraviZ

iTrader: (2)

stock ecm as well, the only mod he has is long tube headers dual exhaust.. no emmissions on it. he is currently swapping his -10AN fuel lines to -6AN hoping that may do something.. its always their whether he is driving normal or under load, of coarse under load, its alot worse. he says he really only noticed it after he swapped the auto for the 5speed.

91Z28-350

Wait, he's using the auto memcal (from a 350 TPI) with the 5-speed?

That'll do it...

Edit: He's going to need a new/custom prom.

TraviZ

iTrader: (2)

thanks! do you know what exactly needs to be changed so i can tell him?

91Z28-350

Quite a bit of stuff, there's a manual transmission flag to set, throttle follower stuff, all the TCC stuff needs to be disabled. Does he have aluminum heads? If so, it's easiest to start with a Vette bin (axcn for example), and tweak from there. If he has iron heads, he could use the 305 T-5 bin and copy over his aujp tables or use the axcn bin and tweak from there. I've got iron heads, and a t-56. I modified my aujp bin to work, and it did fine for a year. I'm going over to the axcn bin now, but I've got a bit more knock than with the aujp bin. That's still a work in progress.