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91 MAP TPI, Prolonged start

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Old Aug 6, 2010 | 10:49 AM
  #1  
JamesLLeary's Avatar
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From: Patterson, Ca
Car: 1986 K10 Suburban
Engine: 5.7 TPI Speed Density
Transmission: 700r4
Axle/Gears: 3.42
91 MAP TPI, Prolonged start

Takes between 6 to 7 seconds to start. Just a little shakey while idling, and power seems good.
I have an AFPR, 43psi at idle. Doesn`t really bleed down after shut down.
Any ideas?
I have seen other thirdgens start instantly, usually within 2 or so revolutions.

Thanks!
Jim
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Old Aug 6, 2010 | 01:29 PM
  #2  
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From: Salina, KS
Re: 91 MAP TPI, Prolonged start

You're fuel pump relay is probably bad. By design, the fuel pump relay handles the job of priming the system. Once the engine generates oil pressure, power is routed through the oil pressure switch to the fuel pump.

Cycle the key from off to on a few times, when it's switched to on you should hear the relay click and the pump run for a few seconds. If you don't hear the click or the pump, suspect the relay.
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Old Aug 6, 2010 | 01:48 PM
  #3  
JamesLLeary's Avatar
Thread Starter
Junior Member
 
Joined: Aug 2008
Posts: 30
Likes: 0
From: Patterson, Ca
Car: 1986 K10 Suburban
Engine: 5.7 TPI Speed Density
Transmission: 700r4
Axle/Gears: 3.42
Re: 91 MAP TPI, Prolonged start

Originally Posted by Drew
You're fuel pump relay is probably bad. By design, the fuel pump relay handles the job of priming the system. Once the engine generates oil pressure, power is routed through the oil pressure switch to the fuel pump.

Cycle the key from off to on a few times, when it's switched to on you should hear the relay click and the pump run for a few seconds. If you don't hear the click or the pump, suspect the relay.
Thanks for the reply, Drew.
Check on the relay, thats the first thing I looked at, working fine.
The more I think about it, I am thinking O-rings on the fuel rails, or, it could possibly be that my oil pressure switch is the original from the 86. Its a swap into an 86 suburban, sorry I didnt mention that. Shouldn`t make a difference though

Last edited by JamesLLeary; Aug 6, 2010 at 01:52 PM.
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