trying to pintpoint a problem after s/c installation

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predator_96817

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Aug 29, 2003

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May 22, 2005

#1

• May 22, 2005

• #1

ok, this bucking is getting really irratating and makes for an uncomfortable ride. it bucks at really light throttle or when i let off the gas and coast. today, when i was coming to a stop, the car died. car idles just fine. its the first time so far. ANY ideas? i changed the plugs thinking i fouled them but car still runs the same. could it be EGR? oh ya, i noticed on the plugs i pulled the center was white. maybe thats normal? i have never gone WOT yet cuz i have to get a dyno first. the car absolutely SUCKS up has now... guess ill have to get used to that

 

DBMSTNG

I fantasize about it being BIG!

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Apr 23, 2002

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not quite here

May 22, 2005

#2

• May 22, 2005

• #2

do you have a chip in the car? i think the white plugs mean it's running lean. make sure all your hose connections are tight.

 

crew_dawg16

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Apr 25, 2004

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May 22, 2005

#3

• May 22, 2005

• #3

If you haven't had the car dyno tuned yet, then that is the cause of the problem you are having. You have to get that thing on a dyno ASAP. You are going to cause damage to your engine if you drive it like that.

 

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predator_96817

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Aug 29, 2003

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May 22, 2005

#4

• May 22, 2005

• #4

hmm. this is a mongoose kit. the tune is from modularpowerhouse so im just going to get it dyno'ed then im going to email the results to them. my dyno is today so ill see how the air/fuel is.

 

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2001sleeper

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Nov 22, 2004

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May 22, 2005

#5

• May 22, 2005

• #5

be sure to tell them how you drive, it will make a difference for your driveability tune. usually a slight fix in the IAC tables will fix the funny idle when decelerating. let us know the outcome.

 

Mach428

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Dec 7, 2003

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May 22, 2005

#6

• May 22, 2005

• #6

White plugs = way to lean...Until you get a dyno tune avoid driving the car at all costs.

 

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wht99gtconv

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Dec 1, 2003

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May 22, 2005

#7

• May 22, 2005

• #7

I had the same thing happen to me when I got my supercharger put on. You need a dyno tune. I got a chip with my supercharger and it didn't cure my bucking, come to find out my mass air meter was still for stock injectors and I had 30lb injectors put on with the blower. So I found a mass air meter on ebay that was calibrated for 30lb injectors that came from another supercharged mustang same year as my car and it cured the bucking. I bet thats your problem.

 

jstreet0204

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Jun 26, 2003

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Winston Salem, NC

May 22, 2005

#8

• May 22, 2005

• #8

wht99gtconv said:

I had the same thing happen to me when I got my supercharger put on. You need a dyno tune. I got a chip with my supercharger and it didn't cure my bucking, come to find out my mass air meter was still for stock injectors and I had 30lb injectors put on with the blower. So I found a mass air meter on ebay that was calibrated for 30lb injectors that came from another supercharged mustang same year as my car and it cured the bucking. I bet thats your problem.

Click to expand...

Stock MAF doesn't need to changed. I run mine with 30's. The inector size should be taken care of on the chip.

On another note, one thing the original poster may want to check into is having the fuel_cuttoff_on_decel shut off. It made mine much smoother when I let off the gas.

 

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predator_96817

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Aug 29, 2003

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May 22, 2005

#9

• May 22, 2005

• #9

here was my dyno....kinda rich huh? we also tried running the car at part throttle and the a/f was consistantly in the 11's. maybe the whiteness on the plugs was just on the old spark plugs i changed out. i have yet to check the new ones. but he old ones were in when i had the supercharger on so it dont make sense...

 

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cobra killer

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May 22, 2005

#10

• May 22, 2005

• #10

Plugs will run white under normal driving.It has nothing to do with WOT.

A/F is to rich,the bucking is from just that,the car is to rich overall.You need to check all hose connections before the tune is adjusted.It shouldn't be rich under normal driving.If there is a leak after the maf of any kind the car will run rich.

 

Mike97gt

it doe snot

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Jan 26, 1999

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the people's republic of massachusetts

May 22, 2005

#11

• May 22, 2005

• #11

cobra killer said:

Plugs will run white under normal driving.It has nothing to do with WOT.

A/F is to rich,the bucking is from just that,the car is to rich overall.You need to check all hose connections before the tune is adjusted.It shouldn't be rich under normal driving.If there is a leak after the maf of any kind the car will run rich.

Click to expand...

suscribe. BTW the above poster is right. no input needed from me since the above poster is the guy you need to talk too.

 

jstreet0204

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Jun 26, 2003

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Winston Salem, NC

May 22, 2005

#12

• May 22, 2005

• #12

cobra killer said:

If there is a leak after the maf of any kind the car will run rich.

Click to expand...

Just curious, but why rich. I would think that unmetered air after the MAF would cause a lean condition. I realize you have seen a lot more of these situations than most of us so I am curious as to what causes it to go the other way...

 

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predator_96817

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Aug 29, 2003

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May 23, 2005

#13

• May 23, 2005

• #13

well at least my problem has been found out.. running rich. i will check for any leaks for air after the maf. i think it runs rich cuz the computer tries to compensate for the unmetered air by adding more fuel...i think.

 

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One Wicked SVT

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Nov 30, 2004

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May 23, 2005

#14

• May 23, 2005

• #14

ok had a similar problem, ended up being a tear in the boost tube after the maf.