Poor Mans Repair Guide for Chevy,GMC Vortec Fuel Injector Spider or CSFI System





Introduction: Poor Mans Repair Guide for Chevy,GMC Vortec Fuel Injector Spider or CSFI System

I hope I can take some of the Dark Voodoo power away from the notorious Vortec injection spider. If your reading this then  like I did you have been searching  the web and under the hood of you GMC Jimmy, S10, Astrovan, Or Chevy Blazer trying to figure out what to do about that crazy injection system in your truck. Well you have a few choices
1. Buy a new spider set for a small fortune.
2. Buy a "MPFI" retrofit system for about $300.00
3. Try Replacing individual injectors or "poppets" 
4. Junk the p.o.s. the front end is falling apart anyway.

or you can

5. Spend about $16.00-30.00 and a few hours of your time and fix it like I do.

This guide explains how to clean/repair  leaky or stuck poppet valves/injectors. only continue if you are sure that your injectors are getting a signal from the ecu and are actuating. if your not sure, Google it, do your testing and come back.

I am not responsible for any kind of damage or injury you may cause yourself or your car.  Messing around with a fuel system is dangerous, gasoline leaks can and will cause fire and or explosion. Be Safe, Be Smart, Or be Dead.

Step 1: Take a Look at the Injector and Get You Stuff Together

At this point you have pulled the injectors from the fuel meter body, you have your injector reseal kit with all of the o-rings napa and everyone else has them .
napa's part is....

Fuel Injector O-Ring Kit
Part Number: BK 735359

Make sure the meter body has no cracks, this can be fixed in a pinch, Google plastic welding with soldering iron.

Make sure the black plastic tubing is not cracked or too brittle to be reinstalled. They need to be able to hold 60lbs of fuel pressure. If in doubt take an old piece of  tubing to the local auto parts store and get some double walled plastic gas line tubing. Ford uses quite a bit of it, as does BMW.

You will need the following in addition to your o-ring kit

1. Carb Cleaner
2.Sea Foam in a can "Deep Creep"
3. A Pot O Boil'in Water and or a Heat Gun "Heat gun is faster but water is safer"
4. A Few pairs of needle nose pliers
5. An air compressor with blow gun.
Optional but highly recommended is an ultra sonic jewelry cleaner  "got mine for $30.00 from harbor freight, for the wife......."


Step 2: Heat the Tubing and Pull the Poppet Out.

With this step be patient, you need too heat the black tubing right at the poppet to just the right temp. the safest way to do it is to dip the  last inch or two in a pot of boiling water for about a minute.  
As soon as you pull the poppet out of the water start to work it out of the tubing with two pairs of pliers.
Be very careful not to scratch the poppet or break the hose. Don't squeeze to hard on the poppet or you will crush it an then you might as well buy the MFI kit cuz the cost about $80.00 a piece.
You will only have a few second at a time to work the poppet out before it needs to go back in the pot. Be gentle and it will come out.
If you are using a heat gun it only takes a few seconds to work it out, but if you over heat the tubing it will become brittle and increase the chance of making your problem much worse.  

Step 3: You Got It Out! Time to Clean It.

Great you got that tiny little thing out!
Don't lose it!!!!
Now it is time to test/ clean it.
You might have a better way to do this but the poppet fits perfectly in hole of the rubber piece of my air compressors blow gun.
The poppet is designed to open at about 40lbs of pressure. So l like to start there.
1. Set your regulator to 45lbs.
2.Insert poppet into blow gun nozzle, or ring up some rubber tubing and clamps to hold firmly. The last thing you want is for the poppet to be shot across the garage never to be seen again.
3. Give it a 45lb shot of air. if the poppet opens then obviously it is fairly clean. most likely nothing is going to happen. 
4. Take the blowgun from its quick connect and fill it with carb cleaner.
5. Give it another shot of air, if nothing crank it up to 60lbs. and try again. 
6. When it finally gives way repeat the procedure until you are satisfied that it is clean.
7. Switch to the deep creep and repeat a few more times."the deep creep will remove varnish an keep everything from flash rusting." 

Step 4: Put It Back Together

Now all thats left is getting the poppet back on the hose.

1. Heat the hose like you did before. Heating only the very end will help you keep from kinking.
2. Slowly press the poppet back in, don't rush it.
3. let it fully cool and give it a few good tugs to make sure it set.

The O-ring set comes with instructions follow them.

 Make sure you don't have any leaks before you seal up the upper intake manifold!!!
Drive around for 50 or 60 thousand miles and repeat the process and save some hard earned cash.



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I had a problem with injector 8 showing as a p0308 misfire. So l replaced everything plugs, wires, distr cap, rotar, ignition coil, and the problem still remained. I took mine to a dealership because I wanted to be absolutely sure it was the injection. After a quote of 1300 bucks, I decided that I could do the job myself. From the pics below, you can see that the fuel leaked into my intake and was burned leaving a residue. I highly recommend an MFI upgrade as I've noticed an increase in the MPG and HP. I did the replacement following a youtube video and I wanted to give back to the web community. Thanks.


I have a p0300 random misfire and ive changed everything. Plugs ,wires , all vac lines. Distributor, fuel filter clean maf sensor egr valve manafold gaskets uper and lower and valve cover gaskets. Still cant get the check engine light off. Could this be my problem?

One of the problems I've faced on these units in my shop and the mileage idea is just wrong as I've got 340K miles on my 2000 Astro and so far no repairs other than one fuel pump.

One oddball problem with a code P0300 is the manifold pressure/vacuum regulator on the side of the spider. They will occasionally rupture there and even though the engine starts well cold, once warmed up and restarted, it will be flooded and pop a code like you have.

This causes all sorts of thoughts that there's a problem in the ignition system which is an easy primary voltage test. That's usually a red herring.

I can't believe that this is such a mystery. Changing batteries and starters is so 'way out in let field that I shudder at the sheer expense of not doing a thorough diagnosis of the real problem first.

Sounds like my issue so I would say yes. I mentioned all that I had done to my truck to the service guys at the Chevy house and they did their diagnostics to find out. Honestly, you get to a point where it couldn't be anything else. If your model is around the same age and mileage (160k) it's likely that the problem is the Spider injector.

So my 96 Blazer decided she wasnt going to start one day and after replacing fuel pump relays. ignition switch. battery. Spark plugs ans wires. Temp sensor. And discovering it does stay on with starting fluid sprayed but only as long as it is being sprayed.. Im assuming this is my next attempt... Cleaning the injectors? Any advice? My truck starts only once for 3 seconds if that then dies and wont fire up again.. Just continues to kil my battery from more failed attempts to start. No codes either. Although temp sensor snd o2 sensor read INC on i/m readiness check

Stop right where you are before you spend any money.

Why didn't you diagnose the system first? It's only nuts and bolts and a man can fix it if they don't just start ripping into the vehicle and their kid's college funds first.

3 second runs is usually a problem in fuel delivery. Get a FI Pressure tester and find out what the pump discharge pressure is, corrected for altitude, of course.

The only that I can tell you is follow the instruction & clean the ports where the injections & use a shop vacuum to clean out the valley.& properly torque the upper plenum the factory part has the sequence torque the bolts 1st pass is (44 lbs in) & 2nd pass is (80 lbs in) if in doubt & you have access to a Snap-on or shop grade scanner tool do a do fuel injector test! & after you're done change the oil & filter & add marvelous mystery oil to gas & oil ! & change fuel filter is cheap & by changing can save the fuel pump! a dirty fuel filter can cause the fuel pump cavitation & will burn up the pump connector & watch youtube videos without dropping the tank on the pickup only there are 2 videos

My last tip is Be Safe & take 5 seconds & think before you do something!!

Ebay sells for or $190 for a 4,3 eng & 5.7 eng $260 Brand New ! Too much work with trying to fix junk ? i just replaced on both my trucks ! Fyi ! Run marvious mistery oil all the Time!

Im getting ready to do the same. we have the extact same truck, medium beige s10 zr2

I have a 96 tahoe 5.7 vortec an So far after trouble shooting, i have changed distributor cap, fuel pump, fuel filter,oil, oil filter, spider injector an set timing, after all that its knocking can one one please help im up into the thousands an need my truck fixed or i will lose everything. Thanks lisa