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Misfire cylinder 3 tear down pictures MPFI Already?

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  #1  
Old 07-14-2011, 12:30 PM
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Default Misfire cylinder 3 tear down pictures MPFI Already?

After being fed up with 7 mpg, I decided to go ahead and replace my what thought to be SCFI but appears to be the MPFI? Below are some pics. You can see in the second picture there's a clean area... would this be where the unit could have been leaking?

Now question should I replace whole unit or just the one injector/line?

this is the updated version correct?

CIMG0221.jpg picture by Chad_Bierniat - Photobucket




Signs of gas leak here?



http://i1210.photobucket.com/albums/...CIMG0222-1.jpg
 
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Old 07-14-2011, 04:21 PM
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That doesn't look like a fuel leak. Besides, the intake ports in the lower intake near that cleaner area are for cylinder 4 (port just ahead of the 3 in the LIM) and cylinder 6 (the port just behind the 5 in the LIM).

It could have been a bad injector for cylinder #3, ignition component problem, a valve issue, or other problem affecting the compression on that cylinder.
 
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Old 07-15-2011, 03:39 PM
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Well I replaced the whole unit and it seemed to fix the misfire problem. No more CEL or rough idle.
 
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Old 07-15-2011, 03:40 PM
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Must have been a bad injector on #3. Glad you were able to fix it!
 
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Old 07-15-2011, 03:55 PM
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how much did that cost you? Did you get a new system or one from a junk yard?
Figure since I changed my gaskets may as well get those changed now to. Completely rebuild the top end you know.
 
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Old 07-16-2011, 01:32 PM
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I replaced whole unit and cost $230 from Autozone. The brand name is GP Sorensen. 200 miles and so far so good. Don't forget to plug your intake manifold ports with towels to prevent anything from being dropped into it as soon as you remove the upper plenum. If you have a the right tools I would advise you to remove the gas lines at the firewall. It would give you a lot more room to play... I didn't so it's doable just more difficult. I believe its a 5/8


Gp Sorensen/Fuel Injector (800-1512N) | 2000 Oldsmobile Bravada AWD 6 Cylinders W 4.3L SFI | AutoZone.com
 
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Old 07-18-2011, 11:34 AM
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I'm glad to hear that worked out for you. I tried to change my SFI to a MPFI unit and it caused random misfires. So I put the old one back in. Either I had a bad part, or screwed up the install. In either case, i didn't feel like getting back in there, so I'll leave the old one for awhile.
 
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