Fuel Injector/spider How To

[JoshBarber]

This is being done on my 98 Blazer LT 4x4

After realizing that the dealer wanted to charge me 3-4 hours labor ($89/hr) JUST to remove the upper intake.....not including any work within, I decided it was a definite DIYS!
After removing it once....it takes no more than 15-20minutes at most.

The most important thing to remember is you need to immediately block your intake ports firmly with shop rags. If not, you may learn the hard way...as I did....that you can easily lose a part or tool inside and find yourself removing the lower intake as well....with much aggrevation, and time wasted.
I can't say it enough! It takes 5 seconds to be safe.

As soon as you remove the upper intake cover:
BLOCK YOUR INTAKE PORTS IMMEDIATELY BEFORE ANYTHING ELSE!

Disconnect your battery, and relieve the fuel pressure from the system at the fuel rail (either with a vent on a fuel pressure gauge, or pressing in the valve pin holding a shop rag over it to catch any excess)


Remove your air intake as a whole. (4 screws on filter, and twist screw on top of throttle body)


Disconnect the fuel supply and return lines at the firewall (16mm)


Remove the 12mm bolt securing the lines to the bracket.


Remove the two 8mm nuts securing the fuel lines to the fuel meter body. (This is what I dropped into the intake, and they're NOT magnetic!)


Remove the four 10mm bolts securing the throttle cable brackets.




Remove the throttle cable and cruise control cable. The cruise cable will pop off backwards, but you'll need to relieve the tension and take the throttle cable bullet off to disconnect it.



Disconnect all electrical connections (including the main fuel spider connection), and using a DEEPWELL 10mm socket, remove all 10 bolts securing the upper intake cover. Gently guide the fuel meter body back out of the cover, and remove the cover.


You now have access to the fuel spider. Using a flat screwdriver, gently pry the tabs of the fuel meter from the bracket securing it. Pinch the injector tabs and remove the poppets from their holes.


Inspect the fuel spider thoroughly for leaks. If it appears as though the injectors are leaking from underneath the fuel meter body, you can remove them individually.


Remove the two 8mm bolts securing the metal bracket underneath the fuel meter body and set aside.
Using a small screwdriver and needle nose pliers, gently pry the plastic cap from the fuel meter body that secures the injector. Again VERY GENTLY, taking care not to damage the plastic injector line, pull the injector from the body using the the needlenose pliers. You may need to use a small dull screwdriver from the inside to help push the injector out.


With the injector free, you can inspect the two orings on each.


Here you see the Oring kit for the fuel spider which includes all o-rings on the spider, as well as the metal bracket and nuts that brace the injectors into the body. This seal kit is: GM # 17113205
Remove the Plastic retaining caps, and Orings. Be sure to use a slight coat of Oring grease when reinstalling them. Replace all Orings on the fuel meter body in the same manner. Now would be the time to replace the regulator if necessary. It's approx. $90 from GM.


Before reinstalling the spider, carefully inspect the two Orings on the fuel supply and return lines...replace if needed. You may also choose to replace the upper intake cover gasket at this time. It comes in a set with the Upper Intake Gasket, Throttle Body Gasket, and Fuel Meter Body Oring (seen in orange). This Gasket kit runs around $30, and is GM#17113215.

Installation is reverse of removal.

If you choose to replace the whole assembly, there is an updated fuel spider. Below are the part numbers and PDF GM Bulletin for the changeover. It's supposed to correct the problem of sticking injectors, and is half the price if you believe you may have more than one bad injector. It also includes the regulator, which alone is $90. NOTE: The blocked intake ports, and cleaned intake!

If you choose this route, as I eventually did, you'll need:

Here's the part numbers:
12568332 - MFI Assembly
88894355 - Bracket
17113215 - Seal kit

Here his the GM Bulletin for install (thanks to Blazee!):
http://www.savefile.com/files.php?fid=1709708

[drdd]

nice write-up

[blazee]

Good Job. Added to the FAQ.

[muzzy1maniac]

Damn! That's a sweet write-up! Thanks!

[srbianats]

Good job. Happy to see things turned out the way you wanted.

[JoshBarber]

Originally Posted by blazee

Good Job. Added to the FAQ.

FUEL MILEAGE APPEARS TO HAVE DOUBLED SINCE THE REPLACEMENT OF THE SPIDER!!!!!!! Will reply with actual mileage change

[sebryce]

Excellent post!!! You are right, a picture is worth a 1,000 words... Looks like they have done away with the poppets... If your mileage has improved that will definately offset the cost. Is this this updated assembly very expensive?

[blazee]

Originally Posted by sebryce

Excellent post!!! You are right, a picture is worth a 1,000 words... Looks like they have done away with the poppets... If your mileage has improved that will definately offset the cost. Is this this updated assembly very expensive?

$300 - $400 from the GM dealer.

Less than $200 from www.GMPartsDirect.com

[sebryce]

Thanks Blazee, I will look into replacing mine, sounds like gmpartsdirect.com is the way to go...

[sebryce]

Did installation of the MFI assembly require any special instructions?

[JoshBarber]

Originally Posted by sebryce

Did installation of the MFI assembly require any special instructions?

It's pretty straight forward. That GM Bulletin that (Blazee) and I provided the link for, gives the specific directions on the install. It's pretty much just replacing the bracket (it sits in a specific direction front to back), and making sure the fuel injector lines are in a specific routing. I believe one has to run under another etc. And then its just making sure the electrical connectors at the tip of each injector are facing the center of the intake to allow clearance when reinstalling the cover. It also notes that once the injector has snapped into its hole, it should not be removed or it may damage the tip.

[BlazerBoyLT98]

Great write up

[sebryce]

Thanks guys! This website rocks big time!!!! Replaced the spider assembly this evening and I am still in shock at how responsive and quick my '98 suv is now running! Hope my gas mileage will improve as well... Checking for lower manifold leaks and so far so good as well (after replacing the gaskets the 2nd time and torquing to correct specs). Saved serious $,$$$ over the dealer as I replace both oil cooler lines, spark plugs & wires, rotor & cap, lower & upper manifold gaskets and replaced the fuel injector spider assembly. I seriously could not have done most of these jobs without your help!

Thanks again.

[JoshBarber]

Originally Posted by sebryce

Thanks guys! This website rocks big time!!!! Replaced the spider assembly this evening and I am still in shock at how responsive and quick my '98 suv is now running! Hope my gas mileage will improve as well... Checking for lower manifold leaks and so far so good as well (after replacing the gaskets the 2nd time and torquing to correct specs). Saved serious $,$$$ over the dealer as I replace both oil cooler lines, spark plugs & wires, rotor & cap, lower & upper manifold gaskets and replaced the fuel injector spider assembly. I seriously could not have done most of these jobs without your help!

Thanks again.

Glad to help bro. Judging by the fact that yours is a lot more "responsive and quick" now, (if the spider made a difference I'd say the injectors may have been stuck partially closed...where mine were stuck open. That was the problem with the old spider assemblys. Don't ask me why GM never recalled them when so many different models used them....also,
I'd say the new plugs, wires, cap & rotor are likely causes of the quickness as well.

[98 headache 4.3]

great write up. done like a pro. I wanted to know if after making the swap to MFI does it always start first crank?