running lean problem after 550cc install

[robbo185]

Im pretty sure i know the answer to my own question but id like a little reasurrence before i go on a scavenger in my engine bay. Last night i installed 550cc injectors in my car. Car runs great under normal driving. However, at a stop sign/light when i start to move again the car goes above 20 a/f ratio on the wideband and the car bogs for about 200 rpm then quickly returns to a 14.5 a/f ratio for normal cruising. Also when im cruising and try to give it more gas, it does the same thing. When i go to wot.....it does it but i will get a 11.5 a/f ratio when boosting. Boost was at 13 psi....it made it all the way there.


So im assuming this is a boost leak due to unmetered air getting in when you give it more throttle but i just wanted to be sure. All Ic pipes are tight but i will double check. It may be the 3000 pipe/ throttle body coupler.

*EDIT***** There is a small crack in the rubber hose in the pCV and in the throttle body coupler.
Im assuming this is now my problem. Do I have to go to toyota for these parts or can i just get a vacuum hose and then a 4ply coupler for the tb?

Maft is set for 550cc injectors. Idle set at -15% which makes idle around 14.5-15 a/f ratio.

Any input would be great

 

[WeDgE]

Usually if you have a boost leak you'll run rich due to metered air escaping...I don't think I've ever heard of a car running lean due to boost leak, though.


Do you have a TPS function on the Maft? Because it sounds like you need a bit more fuel on "tip in".

 

[robbo185]

its wierd cause it runs lean for like a second or two only.....not for a lengthy period of time. Then the car stutters a bit then you can really feel the fuel enter the engine.

 

[WeDgE]

Yup, that's what "tip-in" is for...dumps a bit more fuel than usual to keep smooth transitions from low-hi throttle.

 

[hottscennessey]

maybe try re-setting the ECU.. I had a problem like this after fixing a boost leak. I guess the ECU "learned" the leak? I dunno..