Carlarena1

Hey guys, Just picked up a 99 Suburban 2500. I bought it from a friend who has owned his shop for 45 years. He told me it needs a new spider injector set up. I've got no problems at all doing the work, I am just curious about the 2 things.

1. They sell an "upgrade" to MFI placing the injectors right at the port. Is this set up really any better then the factory popet valve design?

2. There are almost literally an unending amount of different companies that sell these injectors, both CPFI (central port fuel injection) and MFI (multi port fuel injection). Is there really a difference between the brands? I've seen knock off versions listed at multiple sellers that are between $90 and $150 which isn't bad. But the GM original is close to $400! Is this one of those situations where the knock off version is just junk and i need the GM original?

Thanks as always!

Olds64

I'd buy the injectors from the parts store. Standard Motor Products FJ224 has a lifetime warranty at O'Reilly's.

https://www.oreillyauto.com/detail/c...new/std0/fj224

No need to buy NOS AC Delcos, but I'd avoid Chinesium ones off of Amazon.

jmcghee

Standard Motor Products is the manufacturer of many OEM parts. I prefer Standard brand over others. Less money than AC Fomoco or Mopar. Usually better warranty. Im my experience, quality is as good or better .

65Delta

I did this job on my old '98 K1500 Suburban with the Vortec 5.7. There's a huge difference between the original CSFI setup and the replacement MPFI spider. I used the Delphi MPFI spider and it worked well with no issues.

If you're pulling the upper intake to access the fuel injection spider it's well worth the extra time to pull the lower intake and replace the lower intake gaskets. Use the Fel Pro problem solver gaskets to replace the OE thermoplastic intake gaskets. They're a known problem on many GM vehicles of that era.

BillK

A friend of mine just did them on his 99 Suburban. Ill ask him which kit he used. My 99 Tahoe has 287k miles on it and has never had a problem with the CSFI setup. Still gets the same 20-21 mpg highway as it did when it was new. I think if I was going to do it and change it over to the new style I would use the GM / Delphi kit.

Hammerdrop

Buy the GM kit and save yourself from disappointments. Just my 2¢. I watched a Pine Hollow Auto Diagnostics You Tube video on this.

Carlarena1

Hey guys, thanks for all the replies so quickly. So ill get one of the better kits instead of a Chinese made one. Also ill be replacing the Lower gaskets as well as they show signs of leakage in the front (probably the back too) Ill be really getting to work on this thing Tuesday, so ill know the extent then. Anything other "while i'm in here" stuff i should do while its apart? Thanks again!

gs72

The spider set up is crap, they were failing in 1999. I doubt they are any better now. If there is an upgrade to a multipoint efi do it. I had a co worker that had a 1996 V6 Vortec (in1996) and by 2001 the spider failed, just outside of warranty. It is a terrible design.

olds 307 and 403

I really don't understand why GM used a bunch of goofy efi systems on their trucks. They had the perfect EFI in 1985, the Tuned Port Injection. They made the same HP and TQ with crappier heads years before. Do the upgrade to MPFI.

Carlarena1

Thanks for the info guys, I am going with the MPFI upgrade. And i agree, what a stupid set up. I will never understand the need to overcomplicate things... especially when the design you have already works fine.

Carlarena1

Hey all, Just to wrap this 1 up. Finally got around to changing out the spider injector. 2 of the poppets were gone completely (melted off at the end) and the pressure regulator looked like a fountain. Changed it out for a Delphi MPFI unit, and it runs like a new truck! Thanks everyone for your info and suggestions.