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Old 04-21-2013, 10:20 AM
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Default SCFI to MPFI Conversion

I have a 1997 Chev Blazer 4.3L V6 that would not start. The problem turned out to be either a leaky SCFI line or the fuel pressure regulator, not sure which was the exact problem since once I removed the upper manifold, I decided to convert to a MPFI. For around $180 on Amazon, you can get an OEM unit (Delphi FJ10565 Fuel Injector). I am posting pictures in case you would like to do the same. I am sorry the picture of the poppet valve is not very sharp, but I can tell you it was full of sludge and all were like this. Probably why I had to use injector cleaner in the fuel tank every 12K miles or so to stop engine ping. I have included a photo of the old SCFI assembly and the finished MPFI assembly installed.

Here are a few notes. Make sure when you remove the upper manifold assembly, you plug the ports with some kind of shop cloth or rag to prevent dropping foreign objects, nuts, bolts and the like into the manifold. Although I used paper towels to clean the intake, I recommend using shop cloths. Paper towels tend to fall apart and leave bits of paper in the manifold. Use choke and carb cleaner but be careful to wear gloves and also don't spray into sensors like the MAP sensor.

You have to adjust the injector tubing as indicated on the drawing. The unit comes with a set of replacement instructions. Ensure the injector tube #3 is routed behind #5 and #1. I have attached a photo of the unit prior to installation.

Install #3 injector first, followed by #5 and #1, with #6, #4, #2 to follow on the right bank. You have to apply a little pressure to orient the electrical connectors inward, but you can do this after the injector is inserted. Be very careful to insert the correct injector into its associated port. Once you insert and seat the injector, I am not sure how to remove it. I labeled each injector with a pen to ensure it was clear when I inserted and seated them.

Overall I am very pleased with the outcome and results. The vehicle runs like new. Once I have it out on the road and can get some MPG checks, I will post results.
Attached Thumbnails
SCFI to MPFI Conversion-acfi-spider-assy.jpg   SCFI to MPFI Conversion-intake-clean.jpg   SCFI to MPFI Conversion-mpfi-tube-location.jpg   SCFI to MPFI Conversion-upper-intake.jpg   SCFI to MPFI Conversion-mpfi-assembled.jpg  

SCFI to MPFI Conversion-poppet.jpg  

Last edited by glcblazer; 04-21-2013 at 10:23 AM.
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Old 07-19-2013, 11:05 PM
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2001 Chevrolet Blazer
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any improvement?
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Old 04-11-2014, 04:08 PM
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I just did this upgrade myself however the new spider seems to squeal during pre starting pressure build up. And it's not the fuel pump buzzing, it's the actual spider buzzing, and loudly. However when the fuel bleeds back into tank it will not buzz but, if I start it up again soon after a drive, it humms.. My mechanic says he needs to reset my fuel trims. Anyone have any input on this?
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Old 04-11-2014, 04:49 PM
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1989 GMC S-15
Join Date: Apr 2008
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I did this upgrade about 6 months ago and have been very happy with the results.
1989 S15 Jimmy (DD) with 450K Miles, GM Factory Rebuilt Engine/Trans. New Paint, Headliner, New Suspension Bushings, Eddlebrock Waterpump/Shocks, Adj. Fuel Pressure Regulator and in line Fuel Gage, Injector Spacer, K&N Air Filter, Stock Exhaust, Michalin X-Radial Tires (215/70) Stock Rally Rims, Pioneer Head Unit, IPOD Adapter, Pioneer 4X6 Plates in the front, Pioneer 6X9 5 way sp Rear, 8" Clarion enclosed amp & supwoofer, 10 Disk CD Player. ABS Headliner, Original Owner.
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