3.1 running rich why? - 3000GT/Stealth International Message Center

machV · 09-11-2008, 02:14 PM

First off.

I am not sure what size the pistons actually are. This motor was built by a guy off this board that sold several for a while. He was in Penn state or some where up in the North East.

Anywas, it runs rich. The basics, everything is stock down to the fuel system.
9bs
360's
FMIC
I don't even think there is a hot wire on it(this is not MY car or else I would know for sure, sorry for the mistake if it does but there is only one hot wire runing to his subs in back.)

Could boost leaks really cause this much of a rich problem? I mean it runs so rich you can smell the gases.

I am doing a engine swap for him, and he has given me his 3.1 for my rebuilt stocker. I am just at a loss of what could have been this possible easy fix in the first place.

I talked to someone else as well with a 3.15L that is having this same issue. Any comments would be great.

I appolize for my poor typing skills. If I could elaborate better please speak up, I am use to people bashing my english written skills.

-jimmy

drcustom · 09-11-2008, 02:30 PM

Boost leaks can definitely cause the car to run rich, so can leaks between the MAF and the turbo. When air after the MAF is escaping the ECU still adds fuel to account for all of the metered air.

You might also check out the MAF itself to see if anyone has removed the lower honeycomb.

donniekak · 09-11-2008, 02:35 PM

Removing the honeycomb and leaks before the turbo cause a lean condition. Leaks after the turbo cause it to run rich under boost. If you smell gas just sitting there idling, it's probably a leak of some sort.

silky · 09-11-2008, 02:40 PM

I was losing a significant amount of fuel through a boost leak.

machV · 09-13-2008, 09:33 AM

thanks for the quick replies.

drcustom · 09-13-2008, 09:37 AM

Quote:

Originally Posted by donniekak

Removing the honeycomb and leaks before the turbo cause a lean condition. Leaks after the turbo cause it to run rich under boost. If you smell gas just sitting there idling, it's probably a leak of some sort.

Touche, I don't know what I was thinking.

I would also wonder if you're smelling fuel generally, or from the exhaust. If not from the exhaust I'd second a fuel leak.

09-11-2008, 02:14 PM	#1 (permalink)
machV having it my way Join Date: Jan 2007 Location: kansas Drives: FL70 frightliner Trader Rating: (16)	3.1 running rich why? First off. I am not sure what size the pistons actually are. This motor was built by a guy off this board that sold several for a while. He was in Penn state or some where up in the North East. Anywas, it runs rich. The basics, everything is stock down to the fuel system. 9bs 360's FMIC I don't even think there is a hot wire on it(this is not MY car or else I would know for sure, sorry for the mistake if it does but there is only one hot wire runing to his subs in back.) Could boost leaks really cause this much of a rich problem? I mean it runs so rich you can smell the gases. I am doing a engine swap for him, and he has given me his 3.1 for my rebuilt stocker. I am just at a loss of what could have been this possible easy fix in the first place. I talked to someone else as well with a 3.15L that is having this same issue. Any comments would be great. I appolize for my poor typing skills. If I could elaborate better please speak up, I am use to people bashing my english written skills. -jimmy __________________ been screwed around with to long *-Jimmy*

09-11-2008, 02:30 PM	#2 (permalink)
drcustom Forum Member Join Date: May 2007 Trader Rating: (8)	Re: 3.1 running rich why? Boost leaks can definitely cause the car to run rich, so can leaks between the MAF and the turbo. When air after the MAF is escaping the ECU still adds fuel to account for all of the metered air. You might also check out the MAF itself to see if anyone has removed the lower honeycomb.

09-11-2008, 02:35 PM	#3 (permalink)
donniekak Forum user Join Date: Feb 2008 Location: wintersville oh Drives: 92rt/tt Trader Rating: (5)	Re: 3.1 running rich why? Removing the honeycomb and leaks before the turbo cause a lean condition. Leaks after the turbo cause it to run rich under boost. If you smell gas just sitting there idling, it's probably a leak of some sort.

09-11-2008, 02:40 PM	#4 (permalink)
silky mc.noob Join Date: Sep 2006 Location: Toronto Drives: consistently slow Trader Rating: (8)	Re: 3.1 running rich why? I was losing a significant amount of fuel through a boost leak.

09-13-2008, 09:33 AM	#5 (permalink)
machV having it my way Join Date: Jan 2007 Location: kansas Drives: FL70 frightliner Trader Rating: (16)	Re: 3.1 running rich why? thanks for the quick replies.

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