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01-15-2009, 02:53 PM
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#1
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Join Date: Feb 2005
Location: west orange nj
Posts: 2,415
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need help fixing a truck
my uncle just bought a 98 chevy 1500 4x4 the motor runs like crap the number 5 and 7 cylinders are dead we did a compression check all 8 cyl are good now when you start the truck it smells like gass and pops alot i just ran 2 bottles of seafoam in it to try to clear it it still pops and dies out and still no power what do you think the prob is
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01-15-2009, 03:00 PM
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#2
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Join Date: Aug 2008
Location: Sewell,NJ Washington Township
Posts: 2,416
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5 and 7 dead as in not fireing? no spark?
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1995 Pontiac Firebird - V6 few mods
1988 Mustang - supercharged, heads/cam etc...
2012 Mustang - 5.0 6spd / 437rwhp 420trq
Quote:
Originally Posted by LTs1ow
Verts are gay and stalkers ride in them.
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01-15-2009, 03:34 PM
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#3
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Join Date: Apr 2006
Location: Landing, NJ
Posts: 1,042
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hes there is spark and fuel, the timeing and fireing order are rite, and the cap, rotor, plugs and wires are all new too.
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87 Trans Am 5.7, Auto, posi disc rear, flowmaster muffler, all org car.
88 Iroc-Z TPI, Cammed 350, Vortex Heads, Magnaflow, T5, 4 Wheel Disc, 3.27 9 Bolt PBR.
91 Trans Am VertTPI 350. 700r4, K&N Air Cone, Ryven Muffler.
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01-15-2009, 03:39 PM
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#4
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Join Date: Feb 2005
Location: west orange nj
Posts: 2,415
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everything is new the timeing is right
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01-15-2009, 03:59 PM
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#5
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Join Date: Mar 2008
Location: Shreveport Louisianna Barksdale AFB
Posts: 1,415
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Sound oddly familiar to my motor that had two blown pistons...compression checked out but it ran piss poor. Pop them heads off one more gan' maybe check the cam too(wiped lobes)?
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USAF Jet Propulsion Specialist
 1985 383 Camaro-nothing special I promise 
2000 NBM z28-also nothing special
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01-15-2009, 04:23 PM
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#6
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Join Date: Feb 2005
Location: west orange nj
Posts: 2,415
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i had the valve covers off the everything works
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01-15-2009, 04:33 PM
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#7
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Join Date: Aug 2008
Location: Sewell,NJ Washington Township
Posts: 2,416
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is it getting fuel
__________________
1995 Pontiac Firebird - V6 few mods
1988 Mustang - supercharged, heads/cam etc...
2012 Mustang - 5.0 6spd / 437rwhp 420trq
Quote:
Originally Posted by LTs1ow
Verts are gay and stalkers ride in them.
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01-15-2009, 04:35 PM
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#8
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Join Date: Aug 2006
Location: Browns Mills
Posts: 177
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how did you check for fuel? maybe you can move injectors around and see if the misfire moves with injectors
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Ogres are like onions.... they have layers!!!
'86 Camaro
'16 Ram 1500
'14 Charger
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01-15-2009, 07:56 PM
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#9
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Join Date: Dec 2008
Location: Garwood NJ
Posts: 221
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98, should be just a regular vortec. A few common failures on that. The injector assembly(poppets go bad or regulator leaks). Intake gasket failure causing a vacuum leak into the lifter valley. Pull off the oil cap while it's running and see if it changes RPM, if it does there is most likely a lower intake gasket leak. The simplest one is a bad distributor cap/rotor, they tend to crossfire badly on a vortec when they fail.
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Artie
73 Camaro 25.3 build TT LS in progress
67 Camaro
99 T/A
Other crap not worth mentioning
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01-15-2009, 09:55 PM
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#10
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Join Date: Feb 2005
Location: west orange nj
Posts: 2,415
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Quote:
Originally Posted by BigRocsFirebird
is it getting fuel
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its getting fuel
Quote:
Originally Posted by crazyblazer87
how did you check for fuel? maybe you can move injectors around and see if the misfire moves with injectors
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i checked for fuel on the fuel rail with a fuel pressure gauge
Quote:
Originally Posted by SRGN
98, should be just a regular vortec. A few common failures on that. The injector assembly(poppets go bad or regulator leaks). Intake gasket failure causing a vacuum leak into the lifter valley. Pull off the oil cap while it's running and see if it changes RPM, if it does there is most likely a lower intake gasket leak. The simplest one is a bad distributor cap/rotor, they tend to crossfire badly on a vortec when they fail.
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im going to check that tomorrow thanks alot
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01-15-2009, 10:38 PM
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#11
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Join Date: Aug 2004
Location: Hillsborough, NJ
Posts: 2,630
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fuel pressure gauge won't tell you if a poppet has gone bad. What do the plugs look like from those two cylinders? That may be your best indication. Also as stated an internal vac leak will cause it to misfire or run bad.
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--==RPM Resto & Custom==--
1989 IROC-Z Media Coverage:
Chevy High Performance - Readers Rides 4/03
GM High Tech Performance - Tech Article 3/06
Chevy Rumble - Tech & Feature Articles November 2006
Auto Restorer Magazine - Feature Article 5/11
SkinAndSteel.com
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01-17-2009, 06:31 PM
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#12
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Co-Founder / Site Admin
Join Date: Jul 2004
Location: Ewing, NJ
Posts: 22,476
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Yea, just because it's got fuel pressure at the rail doesn't mean that the two cylinders you mentioned are getting fuel.
- Justin
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1999 Camry - Beigemobile DD
2002 Suburban - Wife's DD
2004 Grand Cherokee - Not running / Project / Selling?
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01-17-2009, 10:53 PM
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#13
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Join Date: Jul 2008
Location: NJ
Posts: 819
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what do the plugs look like in the dead cylinders? if theyre wet after running, spark problem. If theyre dry after running, fuel problem.
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01-18-2009, 01:08 AM
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#14
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11 Second Club
Join Date: Feb 2008
Location: Edison, NJ
Posts: 4,620
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Quote:
Originally Posted by SRGN
98, should be just a regular vortec. A few common failures on that. The injector assembly(poppets go bad or regulator leaks). Intake gasket failure causing a vacuum leak into the lifter valley. Pull off the oil cap while it's running and see if it changes RPM, if it does there is most likely a lower intake gasket leak. The simplest one is a bad distributor cap/rotor, they tend to crossfire badly on a vortec when they fail.
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Yup. Happened on both out 98 and 96... Got a whole new "spider" injector assy.
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1999 Z28 Convertible. 6 speed swap, wide cowl hood, full hockey stripes, and a whining 10 bolt.
2008 Sierra Vortec Max. 6.2 swapped, headers, Magnaflow catback, GMPP CAI, NHT optioned tow package.
2006 GTO, 11.48 @ 118.3
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