#67919 - 01/09/10 11:12 AM
Compression test finally
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Registered: 03/06/09
Posts: 133
Loc: Seattle Wa
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I ran my 97 grand prix w/3800 series 2 engine for 5 - 10 min to get it to operating temperture, Did compression test 3x on each cylinder and here are the results #1: 155 -150 - 150psi #2: 150 - 150 - 150psi #3: 80 - 80 - 80psi (sh@t-f%ck) #4: 160 - 160 - 160psi #5: 170 - 170 - 170psi #6: 180 - 175 - 175psi If the compression on # 3 is that low and it was due to a ring, wouldn't there be blue smoke, cause I don't see any.
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Thanks for editing my sig Blackarrow98gp great Job! Now to get this babe back together! 1997 Grand Prix SE 3800 series 2
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#67920 - 01/09/10 11:51 AM
Re: Compression test finally
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Registered: 12/15/05
Posts: 5286
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bad valve train. gasket leaks.
If it were the rings, you would indeed see smoke. valves wouldnt produce any smoke. gaskets would make a NASTY mess outta the top/sides of your engine and of the engine bay.
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WizAire CAI w/9" K&N & HV3, 2.5" d/p w/h/f cat, Cobra CB, PowerSlot slots w/Hawk HPS, GR-2s, GMPP handling kit, NextLevel STBs, Pilot Sport A/S Plus tires. 98 L36/MM5 RaC
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#67921 - 01/09/10 12:32 PM
Re: Compression test finally
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Registered: 03/06/09
Posts: 133
Loc: Seattle Wa
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By sight I could, only see a leak between lim and head, there is a little water in oil, I think, funny thing is water never seperated from oil, and it sat for at least a month, before I checked again,thought it looked like white bubbles on oil dipstick last month, so maybe its not water in oil, just my bad eysight.. And another thing is scanner was saying p0303 twice, or whatever code for misfire is cylinder #3 is, would a hg leak in that area throw that code? Oh and I know the terminal on the coil for #3 plug was rusty collored, so I know coil was bad, just hoping that was the preset p0303 code and a loose #3 spark plug causesd the new p0303 code.
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Thanks for editing my sig Blackarrow98gp great Job! Now to get this babe back together! 1997 Grand Prix SE 3800 series 2
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#67922 - 01/09/10 01:33 PM
Re: Compression test finally
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Registered: 12/27/05
Posts: 2898
Loc: Phoenix, AZ
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Bubbles in the oil... either Blown head gasket or bad rings...
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-Mike H.
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#67924 - 01/09/10 07:06 PM
Re: Compression test finally
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Registered: 12/15/05
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Originally posted by HercMan: Pour some oil into the cylinder and re check the compression. ummm, what? please explain this because it sure sounds like a recipe for disaster to me.
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WizAire CAI w/9" K&N & HV3, 2.5" d/p w/h/f cat, Cobra CB, PowerSlot slots w/Hawk HPS, GR-2s, GMPP handling kit, NextLevel STBs, Pilot Sport A/S Plus tires. 98 L36/MM5 RaC
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#67925 - 01/09/10 08:01 PM
Re: Compression test finally
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Registered: 04/24/09
Posts: 469
Loc: Wallingford/Hartford, CT
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Originally posted by Richard Candelario: Originally posted by HercMan: [b] Pour some oil into the cylinder and re check the compression. ummm, what? please explain this because it sure sounds like a recipe for disaster to me. [/b]It's a wet-compression test. You just squirt a little oil into the cylinder, not a lot, and check it again. It will help the rings seal better, so if the psi goes up you'll know it's the rings. It won't help the valves seal better, so if the psi stays the same, it's a valve issue
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'99 Forest Green Coupe GT - Stock except for red overlays on logos and Taylor 8mm Spiro Pros
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#67926 - 01/09/10 09:15 PM
Re: Compression test finally
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Registered: 12/15/05
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AAH! man, at first it sounded like Bob wanted us to FILL the cylinder! Thanks for explaining it to me. I now feel a LOT less retarded.
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WizAire CAI w/9" K&N & HV3, 2.5" d/p w/h/f cat, Cobra CB, PowerSlot slots w/Hawk HPS, GR-2s, GMPP handling kit, NextLevel STBs, Pilot Sport A/S Plus tires. 98 L36/MM5 RaC
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#67927 - 01/09/10 09:44 PM
Re: Compression test finally
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Registered: 04/24/09
Posts: 469
Loc: Wallingford/Hartford, CT
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LMAO. Trying to compress oil in the cylinder would have indeed been bad. I wonder what would break first...
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'99 Forest Green Coupe GT - Stock except for red overlays on logos and Taylor 8mm Spiro Pros
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#67928 - 01/10/10 02:23 PM
Re: Compression test finally
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Registered: 04/18/05
Posts: 8901
Loc: Bradenton, FL
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Originally posted by nyjets91: LMAO. Trying to compress oil in the cylinder would have indeed been bad. I wonder what would break first... Our bottom ends are pretty strong, but I would guess the rod.
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Corey Smith
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#67929 - 01/10/10 06:18 PM
Re: Compression test finally
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Registered: 11/08/08
Posts: 2689
Loc: Eagan,MN
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Originally posted by nyjets91: LMAO. Trying to compress oil in the cylinder would have indeed been bad. I wonder what would break first... You'd hydro lock the engine and rape a connecting rod
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#67930 - 01/10/10 10:01 PM
Re: Compression test finally
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Registered: 02/20/08
Posts: 2647
Loc: Wall Lake Iowa
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Originally posted by jorgs_7: Originally posted by nyjets91: [b] LMAO. Trying to compress oil in the cylinder would have indeed been bad. I wonder what would break first... You'd hydro lock the engine and rape a connecting rod [/b]nicely put
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why im here: 00 Grand Prix GT; Wrecked. PARTS FOR SALE ; PM ME
-98 GTP DAYTONA 752/1500 -Intake -CCG grills -HID -Tint -1 12" Pioneer Premier soon to come: projectors,exhaust work, 3.4 setup.
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#67931 - 01/12/10 01:54 PM
Re: Compression test finally
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Registered: 03/07/09
Posts: 355
Loc: Topeka, KS
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So what's an ideal psi reading?
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sig by R.S. CAI, GM 85 MM MAF, HV3, MSD ignition packs, PLOG, 3" SS Catless DP, ZZP PCM, ported TB, ZZP PCM, KYB GR2 Struts, SSC springs, black 18's with mirror machined lip and spoke face, 03 Limited Edition spoiler. coming next: stattma turbo, ST4 cam, aluminum heads...
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#67933 - 01/12/10 07:56 PM
Re: Compression test finally
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Registered: 03/06/09
Posts: 133
Loc: Seattle Wa
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Originally posted by HercMan: iirc over 150.
But you'd prefer a balance across all the cylinders. If all were 180 and one was 150 you'd want to get that taken care of.
The book will have the accurate limits and variation limits Originally posted by grandprix38: I ran my 97 grand prix w/3800 series 2 engine for 5 - 10 min to get it to operating temperture, Did compression test 3x on each cylinder and here are the results #1: 155 -150 - 150psi #2: 150 - 150 - 150psi #3: 80 - 80 - 80psi (sh@t-f%ck) #4: 160 - 160 - 160psi #5: 170 - 170 - 170psi #6: 180 - 175 - 175psi If the compression on # 3 is that low and it was due to a ring, wouldn't there be blue smoke, cause I don't see any. So what about these readings, hope and pray it is just the valves, the car did overheat and shut down on the freeway and been down for a few months now, are the rest of the readings other then #3 ok, or probobly something to do with valves also. And I would have to remove head anyway to fix wouldn't I?
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Thanks for editing my sig Blackarrow98gp great Job! Now to get this babe back together! 1997 Grand Prix SE 3800 series 2
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