Ok so according to some pictures I took I have "wash" inside my throttle body, I do not want to go crazy taking it apart and fixing one thing at a time to figure out what the problem is, I rather spend the few hundred in parts and just do what I can.

So I want to replace my spider and FPR.
Is there any brands I should be looking at? (From reading these trucks seem to be picky on parts)
Is there a write up anywhere on this forum for doing these two things? I searched the DIY section and unless I am blind I didn't see one.
Rigged something up so I can test fuel pressure at the filter outlet so tomorrow I will check the pump also.

Any help you guys can offer would be great, brand new to the fuel injection scene and I love the truck but it lacks power and 12mpg mostly highway isn't going to cut it for me, lol.

Thanks all,
-Steve-

 

There's a really good write up about changing the spider/fpr. Also, replace the two lines going to and coming from the spider inside the upper manifold. I've heard them called the "nut kit" or "nun kit." Not sure of the actual names.

 

Stick with delco or delphi. I wil post the GM book method for upgrading to the MfI setup when I get home tonight. You might as well. What year is your truck?

 

What system do you have? CMFI uses a "nut kit" and can not be upgraded. CSFI does not use the "nut kit" and the injector assembly can be upgraded. Does a fuel pressure leakdown test indicate excessive leakdown in the plenum?

 

I have a 2000 zr2. The leak down test did yes I started with 56 psi and dropped to 40. I am not sure on what system I have, brand new to these trucks how can I tell?

What is the mfi upgrade for? Right now I just want to try and fix my MPG and periodic rough starts and I think about lack of power compared to other 4.3 I've driven


Everyone keeps saying about a great write up on changing the spider and fpr but I just can't find it
I just want to see what I'm getting myself involved in before I start pulling things apart.

 

I bougt mine from here, good price

 

Newguy That is an upgrade to mfi?
What are the pros of going to mfi? Was something wrong with whatever my original set up is? (Sorry not sure what my 2000 zr2 system is)

50lb_cat Id appreciate you posting anything that will help me get an idea of what I'm doing before I dive in, can't afford to have the truck down for a few days while I figure it out lol.



So if I have CMFI I have a "nut kit" and can't upgrade to MFI but if I have CSFI I do not have the kit and I will be able to upgrade to the MFI? How do I tell which type I have initially?

 

SO from a little reading it seems since I have a MAF sensor I assume I have CSFI and thus am a candidate to switch over to MFI?

 

Your fuel pressure at 56psi is too low, and leakdown to 40psi is excessive. Those results do not tell you where the problem is, it only indicates that a problem exists. Further diagnosis is necessary to determine what/where the problem is. You'll need to check fuel pressure by disconnecting the fuel line from the fuel filter and modifying the fuel pressure tester so it will connect directly to the line from the fuel pump. All fuel pressure and flow must end at the tester. This will check fuel pump maximum output pressure and determine if the pump can hold presure. When the pump is running, pressure must be 73psi to 108psi and must remain above 55psi for at least 10 minutes after the pump shuts off. Results of this test will determine if the problem is in the tank or in the plenum.

1996 and newer "W" VIN code engines were equipped with CSFI, (Central Sequential Fuel Injection). It uses 6 injectors in a centrally located housing. There is a nylon line that runs from each injector to its respective intake port. In the end of each line, there is a spring loaded, (closed) poppet valve and a nozzle. When an injector is activated, fuel pressure from the injector is what opens the poppet valve so it can squirt fuel. The poppets require ~43psi of fuel pressure to open and squirt fuel. The problem with the CSFI system is the poppets get varnished up and either won't open, won't close, or stay partially open and leak. Your 2000 originally had CSFI and is a candidate for the upgrade using the injector assembly in post #6. The upgrade relocates the injectors to the intake ports and eliminates the poppet valves. The upgrade is "plug & play", no relearns, no retrofitting, just install it and enjoy the benefits. This upgrade essentially upgrades your "W" engine code to an "X" engine code.

EDIT: Here's a link to the GM TSB that explains the cleaning & replacement procedure: http://ww2.justanswer.com/uploads/Bl...conversion.pdf

 

Well if you said you can see the gold wash color from pictures you took, then you dont need to test from the fuel filter.

If we could see those pictures that would be nice as well so we can make sure