MPFI spider injector swap/upgrade info and questions thread

[Andy1955]

thanks , just ordered mine from Rock Auto with confidence

 

[shamrock246]

I see threads occasionally about this. I just recently did this swap on mine and figured I would post some info I learned with my experience. Also thought this would be a good central location for people to ask questions and troubleshoot all in one inclusive thread.

For starts, some info about this system.

Originally the 96+ vortec trucks came with a central fuel handling body where the lines go in and the fuel pressure regulator is located. 8 lines branched off this central unit like spider legs and were finished with poppet style injector tips that operated similarly to a clicking pen.

They worked fine for many years but with egr and other crud in the intake these units would begin to experience failure due to debris. The plastic lines would also crack and leak and they cause all sorts of issues.

They normally are removed in condition similar to this.

You must be registered for see images attach

The solution for this was to utilize electronically fired injectors in place of the poppet style tips. The fuel metering would be handled there and is an all around better design.

Delphi was one of the main manufacturers of this updated part and to my current knowledge they are the only one left making new ones. Echlin may make them but I have no way to confirm this without purchasing one and physically inspecting it.

Which brings me to my next point. Many of the stores (AutoZone, Napa, Advanced, O'Reilly, and such) all sell house brand ones be it Duralast, echlin, etc. I have yet to find an in stock part I can physically look at to see who manufactures it. BUT, all these stores, as well as many online retailers do carry the ACDelco brand spider for $200-500 as well as the Delphi brand spider at prices ranging from $450-900. Brick and mortar locations as always tend to be pricier. eBay and online retailers can vary but you can generally get parts cheaper online with free shipping to boot.

This is where it gets fun. Delphi sells their unit to other companies to be Reboxed and sold under other names. ACDelco is one of these companies. Borg Warner is another.

If you get a chance to look at a spider injector setup in store, do so. There's a few key components that will tell you if you're getting an 800 buck Delphi unit for a zinger of a deal, or if it's a house brand you could take a swing on and miss.

One of these is the main body itself. Where the plug sits is a series of numbers. The updated Delphi unit uses the same main body but with a few modifications to accommodate for the new injectors and tips. If the body numbers match the one that's on your truck, it's likely a good sign you are holding a genuine Delphi part.

Here is the stock part 17091626 PA-86 GF33

You must be registered for see images attach

This is the Delphi spider unit

You must be registered for see images attach

The injectors themselves are the dead giveaway here. I bought an ACDelco unit and the injectors themselves say Delphi right on the grey plastics where the wires go in. Might be hard to see but it says Delphi right on the units.

You must be registered for see images attach

I got my spider off Rock Auto. Basically was a kit that included an entire gasket set and a new bracket for the spider. Came with everything I needed to do the job. Costed less than $300 for me.

Here's pics of all the parts with numbers for reference

The spider itself comes with a new o-ring

You must be registered for see images attach

ACDelco pn 217-3029 or GM pn 89060440

Also included with the rock auto setup was a new bracket

You must be registered for see images attach

same for gm and ACDelco. Pn 93442096

And a complete upper intake plenum gasket set

You must be registered for see images attach

gm and ACDelco pn 17113206

I used everything in the kit that rockauto sent. Made the job very simple and made it so I didn't have to question any of my gaskets being used twice. Install was fairly straightforward. Took about 4 hours or so. But I did plug wires and some other stuff as well. In reality it's a two hour job start to finish for a proficient person.


Common symptoms of a failed poppet spider include piss poor fuel mileage, raw fuel smell at idle, random misfires, stumbling, amongst many others. I had most of the common ones. The spider fixed most of the ones I could tell from until it decided to stop running.


I'm very pleased with it so far but I have encountered other issues that have impeded my ability to do a full review. Once I resolve those issues I will update this post.







Sent from my flagged XT1635-01

Tyler/T-Unit

Was there any difference in fuel pressure between the old spider and new spider? Mine has always run lower pressure even after replacing the entire fuel system except for the lines. It's 60-61 with pump running and 58 when it shuts off but holds 58 for hours.

 

[Sampuppy1]

Was there any difference in fuel pressure between the old spider and new spider? Mine has always run lower pressure even after replacing the entire fuel system except for the lines. It's 60-61 with pump running and 58 when it shuts off but holds 58 for hours.

Never checked my fuel pressure before or after. All I can really do is assume which is never correct.

Sent from my flagged XT1635-01

Tyler/T-Unit

 

[83GMCK2500]

Not sure. There are options for larger injectors if you need more fuel from the spider, though.

http://www.wynjammer.com/Vortec_Fuel_Injection_System.html

Also, here: https://www.fiveomotorsport.com/1996-2003-v-8-cpi-sequential-unit

 

[jasons99hoe]

Im afriad ima have to do this to my 99 burb. 3 shops including the dealership misdiagnosed my stumbling issue, saying i needed new cats. Replaced the cats and still having issues. Soo tune up and this spider conversion is next. Hope i can find a good how to video or write up on how to do it because i don't know if this is something im able to do myself.


Sent from my iPhone using Tapatalk

you can do it. if your nervous about all the electrical connections just take pictures and tape each connection and label them with numbers. the biggest mistake i see is people missing a plug and not sealing down the upper intake. its a simple job just a tedious one. give yourself ample time and walk away when your frustrated.

 

[slowburb]

I had bad joojoo with an MPFI unit from AutoZone. It was branded "Sorenson". The Delphi set me straight.

Some history. The MPFI's were around when these trucks were new. Under warranty TSB for idle quality and fueling issues called for pressurized fuel system purge/flush, and if that didn't work after a couple tries, the pressure actuated poppet spiders were replaced with an MPFI setup.

 

[Andy1955]

I see threads occasionally about this. I just recently did this swap on mine and figured I would post some info I learned with my experience. Also thought this would be a good central location for people to ask questions and troubleshoot all in one inclusive thread.

For starts, some info about this system.

Originally the 96+ vortec trucks came with a central fuel handling body where the lines go in and the fuel pressure regulator is located. 8 lines branched off this central unit like spider legs and were finished with poppet style injector tips that operated similarly to a clicking pen.

They worked fine for many years but with egr and other crud in the intake these units would begin to experience failure due to debris. The plastic lines would also crack and leak and they cause all sorts of issues.

They normally are removed in condition similar to this.

You must be registered for see images attach

The solution for this was to utilize electronically fired injectors in place of the poppet style tips. The fuel metering would be handled there and is an all around better design.

Delphi was one of the main manufacturers of this updated part and to my current knowledge they are the only one left making new ones. Echlin may make them but I have no way to confirm this without purchasing one and physically inspecting it.

Which brings me to my next point. Many of the stores (AutoZone, Napa, Advanced, O'Reilly, and such) all sell house brand ones be it Duralast, echlin, etc. I have yet to find an in stock part I can physically look at to see who manufactures it. BUT, all these stores, as well as many online retailers do carry the ACDelco brand spider for $200-500 as well as the Delphi brand spider at prices ranging from $450-900. Brick and mortar locations as always tend to be pricier. eBay and online retailers can vary but you can generally get parts cheaper online with free shipping to boot.

This is where it gets fun. Delphi sells their unit to other companies to be Reboxed and sold under other names. ACDelco is one of these companies. Borg Warner is another.

If you get a chance to look at a spider injector setup in store, do so. There's a few key components that will tell you if you're getting an 800 buck Delphi unit for a zinger of a deal, or if it's a house brand you could take a swing on and miss.

One of these is the main body itself. Where the plug sits is a series of numbers. The updated Delphi unit uses the same main body but with a few modifications to accommodate for the new injectors and tips. If the body numbers match the one that's on your truck, it's likely a good sign you are holding a genuine Delphi part.

Here is the stock part 17091626 PA-86 GF33

You must be registered for see images attach

This is the Delphi spider unit

You must be registered for see images attach

The injectors themselves are the dead giveaway here. I bought an ACDelco unit and the injectors themselves say Delphi right on the grey plastics where the wires go in. Might be hard to see but it says Delphi right on the units.

You must be registered for see images attach

I got my spider off Rock Auto. Basically was a kit that included an entire gasket set and a new bracket for the spider. Came with everything I needed to do the job. Costed less than $300 for me.

Here's pics of all the parts with numbers for reference

The spider itself comes with a new o-ring

You must be registered for see images attach

ACDelco pn 217-3029 or GM pn 89060440

Also included with the rock auto setup was a new bracket

You must be registered for see images attach

same for gm and ACDelco. Pn 93442096

And a complete upper intake plenum gasket set

You must be registered for see images attach

gm and ACDelco pn 17113206

I used everything in the kit that rockauto sent. Made the job very simple and made it so I didn't have to question any of my gaskets being used twice. Install was fairly straightforward. Took about 4 hours or so. But I did plug wires and some other stuff as well. In reality it's a two hour job start to finish for a proficient person.


Common symptoms of a failed poppet spider include piss poor fuel mileage, raw fuel smell at idle, random misfires, stumbling, amongst many others. I had most of the common ones. The spider fixed most of the ones I could tell from until it decided to stop running.


I'm very pleased with it so far but I have encountered other issues that have impeded my ability to do a full review. Once I resolve those issues I will update this post.







Sent from my flagged XT1635-01

Tyler/T-Unit

thanks , just ordered mine from Rock Auto with confidence

thanks , just ordered mine from Rock Auto with confidence

thanks , just ordered mine from Rock Auto with confidence

 

[Andy1955]

i replaced my old injectors with AC Delco part number 89060440 - 2173029 , it now puts a smile on my face when i stomp the gas , but before i replaced it the engine acted like it was flooded at start up , i figured it was because of a bad pressure regulator or a leaky injector , after replacement there was no change , am i missing a possible alternative cause ? or do i have terrible Luck ? i did the fuel pressure leak down test and i found i loose about 4 lbs of pressure every 10 min. if i start it before the first 10 min. it starts up just fine.

 

[big_mike]

I just bought the same MPFI unit with bracket and seals included off Amazon for $249 with free shipping. Also grabbed a new ACdelco pump MU1777 which came complete with float, seal and harness for $130 with free shipping.

Pump is in, now waiting on good weather for the spider.

 

[The_Family_Tahoe]

Excellent write up. Are these EV1 style injectors?