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97 blazer fuel leak


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aviers
User

Dec 7, 2006, 6:49 PM

Post #1 of 6 (3401 views)
97 blazer fuel leak Sign In

there is a fuel leak coming from the fuel injector wiring harness on top of the plenum. this a 4.3. when i first took the cover off of the harness there was a rubber gasket/seal sticking out from around the base of the plug. is this where the problem is or is there something bigger and more indepth to look for. I don't have the name in front of me(for the fuel system type) but from what I can remember the fuel system had like a five letter acronym like "pesfc" in my terms that is "programmed electric sequential fuel control" Again that is the best that I can recall of the name there was another type but it has only three letters. I am trying to find this gasket but before I order it I want to know if it is the real problem.


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Anonymous Poster

Dec 9, 2006, 2:05 PM

Post #2 of 6 (3395 views)
Re: 97 blazer fuel leak Sign In

any one???


steve01832
Veteran
steve01832 profile image

Dec 10, 2006, 3:07 AM

Post #3 of 6 (3390 views)
Re: 97 blazer fuel leak Sign In

Carefully inspect the fuel pipes going into the assembly. They use internal o-rings. Also, look around the fuel pressure regulator for signs of fuel. That too mounts up with an 0-ring. The best way to check is to turn the key on engine off while checking for the leaks. Do not open the system while it is pressurized! These run at 55-60 psi. If you find a leak, you should loosen the gas cap and wrap a shop towel around the unit prior to disassembly. Do not let fuel come in contact with ignition wires or wiring harnesses. If no visible leaks are found, you may have to run the engine while checking. Be very careful and let us know what you find.

Steve


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Anonymous Poster

Dec 10, 2006, 8:02 PM

Post #4 of 6 (3383 views)
Re: 97 blazer fuel leak Sign In

when I unplugged the main wiring harness it was full of gas. I soaked it all up and let it dry up then put it all back together and when I turned the key nothing happened so I started the engine and within about 30 seconds it started to over flow from the harness again.


steve01832
Veteran
steve01832 profile image

Dec 11, 2006, 4:04 AM

Post #5 of 6 (3381 views)
Re: 97 blazer fuel leak Sign In

If the leak is coming internally from the connector sounds like the main body is leaking. Without seeing the vehicle, my best guess is that you are going to have to pull the upper intake plenum to investigate the leak. If you find a puddle of fuel inside the plenum you will have to replace the fuel injector assembly. I have done quite a few of these. They are not that bad, but they are expensive. Make sure you replace the upper intake gasket with a NEW one even if the old one looks O.K. Also, it is crucial that you get a torque sequence diagram and a torque wrench for the upper intake plenum because they do crack quite easily if you tighten them down the wrong way.
Good luck, let us know what you find.
P.S. If you decide to do this hit back with your e-mail address and I can send you the upper intake torque info. I haven't been able to post diagrams on this website for some reason. Also, if you have a digital camera, feel free to take a picture and e-mail it to me. That may help aid in finding the problem. My e-mail address is posted under my user name in my profile. steve01832@yahoo.com

Steve


(This post was edited by steve01832 on Dec 11, 2006, 4:09 AM)


DanD
Veteran / Moderator
DanD profile image

Dec 11, 2006, 6:10 AM

Post #6 of 6 (3376 views)
Re: 97 blazer fuel leak Sign In

If I read your post properly and the fuel leak is originating from under the harness connector; then I agree with Steve; you’re going to have to replace the CSI (central sequential injection) unit.
If this is your course of repair, check with the dealer there is an updated unit that turns this into a MFI (multi-port flexible injection) system. Doing away with the poppet valves and replaces them with six injectors much less troublesome then the poppets; which were famous for sticking. It’s not a hard conversion to do the replacement unit more or less plugs in where the old unit was.
Here’s a list of the part numbers available for the conversion.
Dan.





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