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Author
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Topic: Car bucking and jumping after supercharger install
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von89stang
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Member # 7162
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posted
 
 
Just put a Paxton supercharer (6psi) on my 87 speed density mustang 5.0. Also added a 12:1 fmu and a 190lph fuel pump. After I installed everything the car still ran perfect accept when under boost it started bucking and cutting out. Wondering if anyone knows what might be the problem. Thanks
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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1fastmach1
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Member # 10137
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posted
u need 2 convert it 2 mass air
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REDLINE MOTORSPORTS CC EST 2011
1993 CHP sold
2004 mach 1 408 Windsor n20 fed
R.I.P. JORGE GUTIERREZ JR
6/13/1982- 11/05/2013
Posts: 2592 | From: clawwwitter to 7th st | Registered: Jul 2010
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von89stang
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Member # 7162
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posted
I want to keep this one speed density. And I have seen supercharged speed density ones before and they ran good. So I need suggestions for my setup not mass air setups.
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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Secnd2nun64
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Member # 1431
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posted
Maybe the fuel injectors are clogged causing it to lean out. Maybe too much timing. You need to check your air fuel ratios to figure out whats going on.
Could also have a weak spark. You should look into getting a MSD box with the BTM.
[ October 03, 2010, 09:01 PM: Message edited by: Secnd2nun64 ]
Posts: 1460 | From: CA | Registered: Jun 2002
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von89stang
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Member # 7162
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posted
Thanks for the info man. I think I found the problem. I need a one way check valve for my map sensor.
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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copcar
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Member # 10113
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posted
quote:
Originally posted by von89stang:
Just put a Paxton supercharer (6psi) on my 87 speed density mustang 5.0. Also added a 12:1 fmu and a 190lph fuel pump. After I installed everything the car still ran perfect accept when under boost it started bucking and cutting out. Wondering if anyone knows what might be the problem. Thanks
If you have a 12:1 FMU and a 190 pump, what your engine is doing is lean surging. The pump can not handle that much of a pressure spike. You are dead heading it and your fuel mass is very low. Upgrade to a 255 or, if you plan on keeping the FMU you need to add a Trex inline. Let me explain. As fuel pressure increases, flow decreases. A 12:1 FMU is delivering 12 lbs of pressure for every one pound of boost (the stock FPR is 1:1) for s total of 13:1 fuel pressure increase. At 6lbs of boost, assuming your fuel system could handle it, (it can't) you would have a spike of 118 psi of fuel pressure (40psi+(6psi x 13:1 fuel pressure, return flow restriction, due to FMU) Your pump is not rated over 65 psi. In fact the flow at 65 psi is not much more than a stock pump at 40 psi.
[ October 04, 2010, 03:05 AM: Message edited by: copcar ]
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12.37@ 109.34.NA 894DA Old Nitto 555 DR's Gt40 irons. B cam/1.7's, All emissions equipment on the car, stock air box. UPR catted X pipe.
Posts: 485 | Registered: Jun 2010
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RAP66
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Member # 3360
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posted
Adding to what copcar posted
what did you gap your plugs to??
it's possible that your blowing them out.
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91GT Kurgan Tuned:12lbs of boost 492.4 rwhp / 483.1 rwtq
http://killcarb.org/
www.fordstrokers.com
Posts: 893 | From: SF Bay Area | Registered: Oct 2003
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68dustin
CAFords OG
Member # 5388
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posted
what plugs are you running? im running my 302 with 8lbs of boost with autolights 3924 gapped at 25. When i first started i was having bad blow out problems
[ October 05, 2010, 11:30 AM: Message edited by: 68dustin ]
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"As I lay rubber down the street, I pray for traction that I can keep, and if I do begin to slide, please dear God protect me and my ride!"
Posts: 3986 | From: neverland | Registered: Feb 2005
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JohnB
Tech Moderator
Member # 969
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posted
Layman's Terms: you need a bigger fuel pump.
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1965 Shelby Cobra
1993 Cobra
2012 F150 Raptor
2020 GT500
Posts: 6523 | From: Orlando FL/Redding CA | Registered: Mar 2002
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Duncan Motors
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Member # 7045
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posted
all the basic superchargers at a stock 6 pounds in bolt on kits dont include a higher fuel pump. i know it should have a bigger one, but there doesnt seem to be a wide problem in that area till much higher boost levels.
Posts: 6310 | From: Vallejo | Registered: Sep 2006
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von89stang
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Member # 7162
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posted
so i should throw a 255lph in it?
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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von89stang
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Member # 7162
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posted
autolite 24 i beleive and there at like 40 gap
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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Blind
2.3L
CAFords OG
Member # 3052
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posted
quote:
Originally posted by von89stang:
so i should throw a 255lph in it?
I would first try a boost a pump.
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89 LX Notchback ex 4cyl, 14psi
02 Harley F150, 15psi
Posts: 8521 | From: Fairfield | Registered: Jul 2003
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von89stang
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Member # 7162
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posted
what is a boost a pump?
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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von89stang
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Member # 7162
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posted
i just saw what a boost a pump is and it is like double the price of a 255lph fuel pump.
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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von89stang
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Member # 7162
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posted
i just saw what a boost a pump is and it is like double the price of a 255lph fuel pump.
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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Blind
2.3L
CAFords OG
Member # 3052
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posted
quote:
Originally posted by von89stang:
i just saw what a boost a pump is and it is like double the price of a 255lph fuel pump.
they're used to take the load off the intank pump, and they operate at a much higher pressure rating, this one from my buddy's shop for example is rated 300lph at 72.5psi
http://highflowfuel.com/i-4791020-bosch-044-300lph-inline-pump.html
[ October 06, 2010, 08:47 PM: Message edited by: Blind ]
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89 LX Notchback ex 4cyl, 14psi
02 Harley F150, 15psi
Posts: 8521 | From: Fairfield | Registered: Jul 2003
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copcar
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Member # 10113
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posted
That is not a "Boost-A-Pump." That is an inline pusher pump, like the T-rex I suggested in my earlier post. The "Boost-A-Pump" is a product marketed by Kenne Bell For the returnless setups which ramps up the voltage to the intank pump to meet the demands of a supercharged setup.
http://www.kennebell.net/accessories/boostapump/boostapump.htm
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12.37@ 109.34.NA 894DA Old Nitto 555 DR's Gt40 irons. B cam/1.7's, All emissions equipment on the car, stock air box. UPR catted X pipe.
Posts: 485 | Registered: Jun 2010
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copcar
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Member # 10113
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posted
Just to add to that, most setups run a .035 gap on the plugs but in a low boost situation .040 is about as wide as I would recommend. Your Spark plugs seem to be the least of your issues at this point however they are worth regapping.
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12.37@ 109.34.NA 894DA Old Nitto 555 DR's Gt40 irons. B cam/1.7's, All emissions equipment on the car, stock air box. UPR catted X pipe.
Posts: 485 | Registered: Jun 2010
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RRRCobraSC281
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Member # 7086
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posted
98 Cobra running .040 gap with T-rex 6# blower had issues with blowing out spark.
T-rex or get the larger fuel pump and shorten the gap.
Since it's the weekend, I guess all you can do is shorten the gap. See if it helps.
Robert
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Project 93GT500 has started
90 Coyote Coupe (sold)
88 Mach 1 Coupe MM&FF 6/14 (sold)
65 FFR Cobra (sold)
Posts: 1746 | From: Fremont, CA | Registered: Sep 2006
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BOOSTED92GT
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Member # 8650
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posted
i having a similiar problem. anyone know where i can buy the fittings that clip into the fuel filter and go to a barb? i have a fuel pump already, but i dont want to cut lines up..
Posts: 446 | From: east bay | Registered: Sep 2008
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von89stang
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Member # 7162
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posted
What gap should I go with?
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65 mustang
13 f150 ecoboost
Posts: 334 | From: 707 | Registered: Oct 2006
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