could a crack in my intake manifold cause my car to run lean?

The other day when i was doing some pullson the highway i noticed my car was running lean, not terrible but about 12.5- 13 on my wideband, so i pulled over to check everything out, nothing really noticable was wrong under the hood but when i started looking at my honda logger i noticed my map sensor was reading about a pound or more less preasure than normal with my turboed car so i checked for boost leaks and found a pretty nasty one in the intake manifold

 

if your map sensor is reading less boost then it could make it run lean but if there is a boost leak then the engine isnt getting more boost then the map sensor is reading so if its that lean as you stated then you have a tunign issue. was it tuned on a hot day and you ran it in cooler weather or vise versa?

 

it was an average day, jeff evans tuned it, i trust his work, and i noticed is running noticably slower now im getting nervous

 

do a leak down test, i wouldnt be boosting it if the things in the 12's and 13's for a/f you need to be in the 11's. if you keep boosting it like that your goign to destyroy that motor if you havent already

 

no i havent since this happened, yeah thats my only worry i hope i havent messed anything up yet, i already ordered a new intake manifold....how do i do a leak down test?ive heard of them all the time and i have an idea of what it does just have no idea how to do one?

thanks for teh help

 

get a leak down tester and they come with instructions, or you can do a sinple compression tester, it wont tell you where the problem is but it will tell you if you have a problem

 

yeah i was going to do one first thing monday, so if nothing shows up wrong when i do a compression check im good?


but still what could be the problem with my car?

 

anyone else

 

Running leaner partial throttle? Checked battery voltage?

 

leaner at partial and open throttle, no i havent checked the voltage...
also my injecter duty is lower than it used to be

 

Check your battery voltage and post back

 

battery voltage can really effect duty cycle?

 

Examples. My own car. For one reason or another my battery voltage dropped to low 11's. My A:F went from 11.5:1 11.7:1 to 12.5:1 - 12.7:1. Recently tuning a car we lost an alternator belt. A:F went from 11.5:1 - 11.6:1 to 12.5:1. Had to add about 10% fuel to get it home

 

wow alright ill check that thanks

 

Check your fuel pressure if you have a adjustable regulaterthe tighting nut couldv came loose

 

What leak did you find in your intake manifold? Wouldn't that cause some nasty surging?

 

its a crack at the bottom of the runner near the injector