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TBi problems galore (long post) 87 350 TBI FYI

Discussion in 'The Garage' started by my87Half-ton k5, Jan 13, 2006.

  1. my87Half-ton k5

    my87Half-ton k5 Registered Member

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    ok heres the update on my (stuck?) injector problem...so today i find my old firebird in the junkyard and grab its injectors and the retaining cap held on by i believe 8 torx head screws, 5 short ones, and 3 long ones. take the plastic injector electrical plugs and cut the red blue white and green wires at the point where they join the rest of the wires near my intake manifold-mounted MAP sensor....my original ones were looking a lil melted but they work(ed) so i said '**** it ill use some butt connectors and splice the new plugs in' cuz theyre mint. so i spliced them in to my harness on my k5 and that was fine.next i pulled off my injector retaining cover and found the gasket to be intact so i pulled the 350 injectors out and put the 305 injectors in(note i am only using these for test purposes cuz i know that they were good last i knew). i noticed off the bat that the original 350 injectors only had a rubber o ring to seal the injectors while the 305 ones had come with a rubber o ring as well as a metal gasket that sits underneath the rubber o ring. so i put the metal gasket and the o ring in the 350 throttle body, it seemed to fit perfectly...put my original retaining cover back on with the gasket untouched...fire it up...it starts but its obvious theres a problem cuz gas is leaking from the retaining cover and the passenger side injector is dripping at idle..the driver side one seems a bit drippy too but when i unplugged the passenger side one the truck ran better...so i
    unplugged both of them and the truck started dying....then i plugged the drivers side one in and it caught again and ran fine....so WTF is goin on here..
    since that i have put in the 305 injector retaining cover and applied indian head gasket shellac to the mating surface of the retaining cover and the injector seat and i let it dry for approximately 6 hours(granted it was like 40 -45 out) and i came home and it stil wasnt dry and i tried it and it sprayed gas everywhere...What the hell? i was told i cant buy this gasket anywhere and it looks too precise to make out of gasket material....also my buddy seems to think that its not electrical cuz its getting too much fuel and it seems to be only on one side however i havent tried swapping the injector pulse plugs over to the opposite sides. i had no idea that theyre constant flow so i didnt know that this would work....i need serious help here people...
    now on a good note someone gave me a very grease covered whole throttle body setup w/ injectors and everything else for free out of a 92 350 tbi van....problem is the vans 1992 TPS setup is different and definately not compatible with my current 1987 TPS and plug setup...my truck is an 87.i need the right plug and to know which wires go where (both are 3 wire setups thank God)..my other though is to just swap out the whole injector tower (fuel inlet and outlet holes and all )and leaving my current throttle body on as i dont think that has anything to do with the problem..problem with that is im pretty sure i cant buy a new gasket for that either...is that an area i can make a gasket out of so ame gasket material and if so what kind should i use(cork, rubber etc) ? any help you guys could give is appreciated more than you even know( although i betcha you all know very well)i NEED my baby bertha back...due to a free (sympathy) tow, the local town towing guy said i owe the his company a free pull out of the local mud pit that everyone goes to on easter day, cuz im the only guy in town that has a rig big enough. or so he says. thanks alot
     
  2. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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  3. my87Half-ton k5

    my87Half-ton k5 Registered Member

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    would any shops carry that? i assume thats AC delco?
     
  4. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Yes, anyone who carries AC delco either has it or can order it.
     
  5. my87Half-ton k5

    my87Half-ton k5 Registered Member

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    you seem to know ur stuff have you ever had anything similar...truck wont idle long gets WAY too much gas..but till now hasent tripped a check engine light until it gets real bad and flooded (i assume an o2 sensor readin is teling it to trip the light)if i hold the throttle open itll run cuz it uses the fuel
     
  6. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I would have bet an injector with a piece of crap stuck in it. I think you said you installed some 305 injectors but it did the same thing so that would rule that out. It may be your ECM is bad.
     
  7. randy88k5

    randy88k5 1/2 ton status

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    That is the correct number for the gasket git. The only thing it does not come with is the base gasket and the small injector filter screens IIRC.

    And those metal gaskets should be there. They might just be seated tightly in your TB so you think its part of the housing itself.

    I had a similar problem it took me a while to diagnose. It was running real rich. Turns out one of my orings (lower injector oring) was missing/fell apart, so when the injector cavity filed with fuel, it would leak past it. That is why you see the fuel dripping out. That is wrong. It should be sprayed in a nice conical pattern. You can verify that with a timing light.

    I would not use any sealant on any of those gaskets. Just get a rebuild kit, replace all necissary items (it is recommeded that you not remove the fuel pressure regulator from its housing. I believe it is a square unit held in my hex screws under the upper plate) I paid $22.41 for my rebuild kit from a local ACDelco distributor. The 17113116 is a GM number. Cant find the ACDelco number offhand, but its around here somewhere. They should be able to cross it anyway. I think you can cross it on ACDelco's website also.
     
  8. midnitewarya

    midnitewarya Sounds like a problem for future me. Premium Member

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    I rebuilt a TBI (305) on a '90 Camaro and had the same problems. I thought the poor idle had to do with the fact it was spraying gas everywhere. I pulled the TBI off and took it apart, and put it together by tightening the littl allen screws from the inside out. Whe I put it back on, no leaks and everythings worked fine. This was back in 2001, and I last drove the car (it's my bro's) over Christmas, still goin strong.

    Also, I got the seals at the local Chevy dealership.

    Al
     
  9. my87Half-ton k5

    my87Half-ton k5 Registered Member

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    wouldnt a bad ecu trip a check engine light?
     
  10. my87Half-ton k5

    my87Half-ton k5 Registered Member

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    btw all the o rings are intace.it was the first thing i checked..and also wouldnt an ecu problem make both injectors not work? it seems ( and i havent run a test lite on the injector plug wires to verify this yet) that one has the correct pattern while the other is all messed up..this really is the strangest thing ever
     
  11. fortcollinsram

    fortcollinsram 1/2 ton status

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    go to napa and get a TBI rebuild kit. it is like $23. Part #2-1752. it comes with the injector pod gasket, fuel line o-rings, injector o-rings, injector filters, FPR diaphragm, etc. Just assemble the injector pod DRY with the new gaskets and no more leaks...just make sure you seat the injectors correctly...push down on them hard until you feel them "click" THEN put the top of the injector pod back on.


    Chris
     
  12. sandawgk5

    sandawgk5 3/4 ton status

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    The ECU has a ground for each injector that it completes to tell each injector to fire. It is possible to determine if it is an ecu problem by buying a $7 noid that you plug into the injector connector and crank over. It has a light that will flash each time the injector is told to fire. You said you checked the orings and they were all intact. No cracks is just one part of the dynamics with rubber seals. These things are 20 years old and in a hot very caustic environment (fuel). The rubber gets hard and loses its original shape there fore it does not have the proper crush to seal properly. Now that you have taken it apart you really need to save yourself some hassle down the road and replace all of the gaskets in the injector area and try it again. Also make sure that you do not have 2 of the metal seals underneath the injector:D .

    Ira
     
  13. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    the boys are more than likely right on taking the injector assembly apart and redoing it... it will leak if the metal ones aren't in right..

    one other too... i had a bad IAC do this too, where it would dump a ton of fuel at idle like that...
     
  14. my87Half-ton k5

    my87Half-ton k5 Registered Member

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    any surefire way to diagnose the IAC? cuz i mean it just started doing this one day....and how would the IAC send extra fuel...if its something you can explain
     
  15. my87Half-ton k5

    my87Half-ton k5 Registered Member

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    btw where is the fuel pump fuse or relay so i can disable it so i can plug the test light into the injector plugs without dumping ass loads of gas into the motor
     
  16. sandawgk5

    sandawgk5 3/4 ton status

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    Just unplug both injectors then no way for fuel to get in motor.
     
  17. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

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    most of the noid light kits come with an iac tester.. pretty cheap usually, 6 piece kit or whatever is about 30, $35 usually... iirc its testing voltage at the iac coils... on mine the iac plunger got stuck all the way out.. closing off that additional air...

    the fuel pump relay is a little black box hanging off a bracket, usually on the upper passenger side firewall.. above the valve cover... (definitely something i keep a spare of in the truck :wink1: )
     
  18. my87Half-ton k5

    my87Half-ton k5 Registered Member

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    went to napa got the rebuild kit...23 bucks like you said. thanks a million..
     

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