lean at idle and now wont idle

[DSMridehigh]

Car was idling but was reading lean on my wideband. Then i put a new alternater on it ### it was bad. Now when i try to have the car idle it dies? When the car is running and driving normal my afr reads 14-15 and when boosting 11-12 witch is running good but like i said when i try to let idle or stop at a light/sign it dies. lost since it runs fine just wont idle

 

[Maverick4g63]

Are you using a fuel management system or stock ecu?

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[XiKeiyaZI]

Sounds like you have a pretty decent vacuum leak. Time to whip out the boost leak tester and start searching.

 

[Maverick4g63]

X2 cant believe I missed that. Still waking up. The leak tester is a must have item.

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[DSMridehigh]

fuel management, dont have the maf senor. everything run off my ecu. it runs a 4bar map, one o2sensor that is apart of wideband. 1g cam angle senor. what is the best to use to find boost leaks? and ### is the best way to do this? Thanks for the help guys!!!

 

[keviebaby]

Get a piece of radiator house from your local auto parts store that will fit on the compressor side of your turbo (intake side). One the other end put a pvc end cap from home depot. drill into the end cap and put a valve stem. Make sure the entire apparatus doesn't leak itself. Install on the turbo and pump air into to pressurize the system. You want to boost leak up to whatever pressure you want to have your boost set to. Theres a link somewhere on here on how to make one. If i find it I will post it here.

IC Pipe Tester
How to make a boost leak tester.

What I wrote above is the same thing, this link has pictures though. You want to make sure you use a good compressor to do this. I was using a cheap-o little cigarette lighter powered one and couldn't get above 5psi, even though I had no boost leaks. Used a better compressor and was able to pressurize to 16psi quickly. Just pump air into the tester and have someone keep an eye on your boost gauge to know when you've reached the pressure you are looking for. Then listen for the air escaping. Be ready to get really frustrated. Sometimes these leaks are a real PITA to find.

 

[DSMridehigh]

Have'nt done the leak test yet going to get the parts, but car is idling now but still runs lean at idle. want to see if you guys still say its a boost leak, my boost gauge gain vaccum when giving alittle gas but the starts to go to no vacuum once you give it more gas. any clue?