So about two weeks ago I noticed my blazer was starting a little rough. As time went on it has been getting worst. Sometimes only 2-3 seconds of cranking, other times 7-8 seconds of cranking. Once it starts it runs fine. So from what I found searching it is either a leaky injector or the whole spider assembly. Now since I have a 1996 Blazer with 140k miles I would assume the whole assembly is bad. So its seem that when this happens it is best to upgrade to aCPI system. The part numbers I found were 12568332 - MFI Assembly
88894355 - Bracket. Since I have a 1996 I need the bracket correct? I will be making a 1000mile round trip in about 2-3weeks so I would like to have my blazer running in top shape. Does this info correct? Any other suggestions? Any help would be great. Thanks

 

It is difficult to say that you need a new spider... I would first start by running two large bottles of Chevron Techron Fuel System Treatment Plus (20gal treatments) in one tank of gas and see how that affects the problem.

If that doesn't have any affect on the hard start, I would then pull the cap and check the condition of the rotor and the terminals inside the cap. If you find carbon trails on the terminals, then it may be time to change the cap/rotor. After that, I would inspect the plugs.

If all of that checks out and you do not have the tools/equipment to do an individual injector pressure drop test (openning an injector for a specific amount of time and monitoring the drop in fuel pressure with a gauge), then the next step may be to remove the upper plenum. You can then pull each injector individually and point it into a glass jar with the system pressurized (you'll have to reinstall the fuel lines after pulling the plenum off). If you find any of them leaking, then replace the spider.

If you don't have the time to do this, then I'm sure that the MFI spider won't hurt anything but your wallet. It's up to you, but the above steps are what I ran through with my Bravada before I replaced it. And yes, you should get the bracket as well.

 

Ok, I hooked a fuel presure gauge up yesterday. I'm at 54-55psi at idel. Then when I shut it off it takes less than 10seconds to drop to zero. So I assume this means its leaking. So I'm probably going to order MFI next week. But do I forsure need the new bracket or will mine work? Or can I even modify mine a little to work?

Edit: Also am I better off buying the kit. www.gmpartsdirect.com (PN-PK12568332) $223.60?

 

You could get away with just the FPR. Won't know until you are in there. The FPR is much cheaper than that.

If you do go the MFI route, I would get the kit. You really don't need the seals, but the bracket is mostlikely necessary. I think that it wasn't until '98 that the bracket is the same as that used in '02, but I do not know the specific changes.

 

So my fuel pressure regulator is most likley what is leaking? What about the injectors, do they have 0-rings? If so would they be the only other option for leaking? I would much rather spend $50 for a FPR or a couple bucks for o-rings than $300 for the new assembly.