car running lean

[viper92086]

Hey guys i just installed a permanent wideband in my car and i noticed that when i give it gas the car will go super lean (for about a sec or two) then richen. my car is a na-t with a maft and i was having this problem in blow thru, so i switch to the normal pull thru. as for fuel my car has a warlboro, 440 injectors, gte electronics, and a gte fuel pressure reg. I am running 13psi on a stock ct-26. do you guys have any ideas what the problem could be? i've also tried doing the 12v mod to the fuel pump with the same issue.


things i am going to try tomorrow: swap out the ecu (i know its rare for one to go bad), and get a new maf sensor for my maft

 

[viper92086]

i replaced the ecu and maf with a new one i got at the junkyard today. it seems a bit better, i'm no longer hitting 17+ on wot

 

[dumbo]

Mine will also go kinda lean for a split second also, although our setups are sligtly different.

 

[sneakypete]

brian, what wideband you running? did u calibrate it when u first installed it? i dont remember, but do you have a piggyback fuel computer?
my car was doing this for a little bit with the maft pro, but i just had to mess with the tps enrichment on the maft pro

 

[viper92086]

brian, what wideband you running? did u calibrate it when u first installed it? i dont remember, but do you have a piggyback fuel computer?
my car was doing this for a little bit with the maft pro, but i just had to mess with the tps enrichment on the maft pro

its a aem uego, there is no calibration from what i understand. i have the maft setup and thats it

 

[sneakypete]

i dunno, maybe regulator or injectors

 

[viper92086]

i just found out that i have no vaccuum at all coming from the vac line connecting to the fpr. this was tested when the motor was warm; i also connected my boost guage to it while driving to see whats going on and got nothing... so i'm going to check all my lines as soon as the motor cools down. so what does this vsv do exactly? i understand it makes the car easier to start when warm but how. and will i have codes if i take it out

 

[viper92086]

i feel like an idiot.. removed the vsv and connected the fpr directly to the manifold and its working. vsv musta been clogged

 

[grimreaper]

^ the vsv allows the regulator to see atmosphere pressure on a hot startup to help reduce vapor lock. Its ecu controlled.

You will notice some low idling on a hot start and the wideband pegging lean with out this.

 

[dumbo]

Good work, I also have my VSV bypassed. Might make for a bitch on hot summer days, If I understand the system properly.

 

[viper92086]

i guess we'll see how it goes. if its bad then ill source out another vsv, but i think it will be fine. i'm just happy i found the problem

 

[sneakypete]

glad to see you got it straightened out. also explains why my car idles like crap on a hot start. i guess i have to reinstall the vsv
-pete