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95 z71 extended Cab 350


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Cotybstone
User

Mar 12, 2012, 1:02 PM

Post #1 of 24 (3352 views)
95 z71 extended Cab 350 Sign In

My truck will not start. The fuel pump is working, I have fire, but no gas coming out of the injectors, but have pressure at the injectors even tried replacing the injectors but to no avail, I can put gas in the throttle body and will run for a second, please help....


(This post was edited by Cotybstone on Mar 12, 2012, 1:04 PM)


Hammer Time
Ultimate Carjunky / Moderator
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Mar 12, 2012, 1:09 PM

Post #2 of 24 (3341 views)
Re: 95 z71 extended Cab 350 Sign In

 All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.



Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on. This one is OK


2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on.


3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.


Once you have determined which of these functions has dropped out,
you will know which system is having the problem.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 12, 2012, 1:15 PM

Post #3 of 24 (3333 views)
Re: 95 z71 extended Cab 350 Sign In

Got fire.
don't have that light
What is the fuel pressure supposed to be?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 12, 2012, 1:17 PM

Post #4 of 24 (3330 views)
Re: 95 z71 extended Cab 350 Sign In

You'll have to get the light. It's a TBI so the fuel spec is 9-13PSI



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 12, 2012, 1:21 PM

Post #5 of 24 (3325 views)
Re: 95 z71 extended Cab 350 Sign In

Ok. Thanks I'll get it in the next couple of hours.


Cotybstone
User

Mar 12, 2012, 1:47 PM

Post #6 of 24 (3307 views)
Re: 95 z71 extended Cab 350 Sign In

Ok, fuel pressure good, light shows no gas coming out, but have power on one side...


Hammer Time
Ultimate Carjunky / Moderator
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Mar 12, 2012, 2:45 PM

Post #7 of 24 (3278 views)
Re: 95 z71 extended Cab 350 Sign In

You haven't tested with a noid light yet.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 12, 2012, 2:46 PM

Post #8 of 24 (3272 views)
Re: 95 z71 extended Cab 350 Sign In

Is that like A uv light?


Hammer Time
Ultimate Carjunky / Moderator
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Mar 12, 2012, 2:50 PM

Post #9 of 24 (3268 views)
Re: 95 z71 extended Cab 350 Sign In

No, it's a little bulb that you plug into the injector plug to test for the operating signal. They cost under $10.










~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 12, 2012, 3:10 PM

Post #10 of 24 (3261 views)
Re: 95 z71 extended Cab 350 Sign In

Wow I feel, slow...lol. But I hooked it up and it flashed and then stayed on as I tried to start it, but once I hooked it back up the injectors starred working again and ran... So now I'm really scared to drive it for fear of breaking down.


Hammer Time
Ultimate Carjunky / Moderator
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Mar 12, 2012, 3:11 PM

Post #11 of 24 (3259 views)
Re: 95 z71 extended Cab 350 Sign In

Do you mean it remained solid while you were cranking or it continued to flash?



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 12, 2012, 3:14 PM

Post #12 of 24 (3253 views)
Re: 95 z71 extended Cab 350 Sign In

Looked as if it was solid, but it its not an led and the guy says those are not as reliable.


Hammer Time
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Mar 12, 2012, 3:16 PM

Post #13 of 24 (3248 views)
Re: 95 z71 extended Cab 350 Sign In

I don't know what you're trying to use here but if you're using anything but a noid light to do this you could end up with a fried computer if you haven't already.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 12, 2012, 5:35 PM

Post #14 of 24 (3232 views)
Re: 95 z71 extended Cab 350 Sign In

Got truck running again, shut off on me again did the noid light again no light...


Cotybstone
User

Mar 12, 2012, 5:37 PM

Post #15 of 24 (3228 views)
Re: 95 z71 extended Cab 350 Sign In

And I still have power to one side, but when it was running the injectors was making a clicking sound...


Hammer Time
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Mar 12, 2012, 5:40 PM

Post #16 of 24 (3225 views)
Re: 95 z71 extended Cab 350 Sign In

You're losing injector pulses. If you are not losing spark at the same time, then it's looking like a bad computer or something related to it. Be sure to check all the grounds for the computer.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 12, 2012, 5:55 PM

Post #17 of 24 (3220 views)
Re: 95 z71 extended Cab 350 Sign In

Thank you so much I will check and keep you posted. I learned alot today, you even taught my local advanced auto parts what a noid light was...lol ps, dont buy one from there $38, but it worked,


Hammer Time
Ultimate Carjunky / Moderator
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Mar 12, 2012, 5:58 PM

Post #18 of 24 (3214 views)
Re: 95 z71 extended Cab 350 Sign In

Wow, here's a whole set of them for $18

http://www.bing.com/shopping/astro-pneumatic-7898-deluxe-noid-lite-and-gm-ac-signal-test-lights-set/p/863EA14F7F1A8EA45006?q=Injector+test+light&lpq=Injector%20test%20light&FORM=HURE



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



(This post was edited by Hammer Time on Mar 12, 2012, 5:59 PM)


Cotybstone
User

Mar 13, 2012, 4:17 PM

Post #19 of 24 (3172 views)
Re: 95 z71 extended Cab 350 Sign In

Ok this is what is going on, I pulled the fuel pump now when testing the fuel pump is it suppose to stay on when pumping gas from the tank to A bucket?


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 13, 2012, 4:22 PM

Post #20 of 24 (3169 views)
Re: 95 z71 extended Cab 350 Sign In

That depends on what you are powering it with. The car will only power it for 2 seconds.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 13, 2012, 4:25 PM

Post #21 of 24 (3163 views)
Re: 95 z71 extended Cab 350 Sign In

Well how do I know if it its bad cause if I beat on the tank then the truck will start, but then shuts off again then I can twist the process with same results


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 13, 2012, 4:29 PM

Post #22 of 24 (3158 views)
Re: 95 z71 extended Cab 350 Sign In

If pounding on the tank makes it start, then you likely have a bad fuel pump but if you have followed my instructions in the first place instead of lieing to me about the fuel pressure, you would have known that a long time ago and wouldn't have wasted everybody's time.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Cotybstone
User

Mar 13, 2012, 4:37 PM

Post #23 of 24 (3153 views)
Re: 95 z71 extended Cab 350 Sign In

Well when the fuel pump does run it has good psi... Out just works when it wants to like it has a bad connection, and out makes my fuel pump relay get extremely hot which is what led me to my fuel pump today, was not lying, sorry for wasting your time....


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Mar 13, 2012, 4:39 PM

Post #24 of 24 (3149 views)
Re: 95 z71 extended Cab 350 Sign In

If you were monitoring the fuel pressure during the failure as you were advised to, it would have been very obvious. I know you never used a fuel pressure gauge.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







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