Throttle Body Fule Injection - pressure regulator - 1991 Caprice 305

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  #1  
Old 03-24-14, 10:01 AM
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Throttle Body Fule Injection - pressure regulator - 1991 Caprice 305

If the car is left to set for a day or two , it must be cranked , not a lot , but more than the other FI vehicles I have had experience with .

I suspect the Throttle Body Fule pressure regulator ?

If you kill it and re-start it latter that day , starts quickly , as expected .

I have never worked on TBFI . How about you all ?


Thanks , :-)
Wyr
God bless
 
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Old 03-24-14, 11:00 AM
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Most likely the fuel pump check valve is not holding.
I get around this problem by turning key on - off - on - off a few times to allow pump to re-pressure and then crank. Computer turns on pump for 5 seconds to build pressure each time key switch is turned on.

Try that.

RR
 
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Old 03-24-14, 03:54 PM
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It has a relatively new fuel pump and filter . No idea if it has a check valve or where it would be ?

I crank it , stop , crank it , stop , crank it , stop . While pumping the accelerator ( do not know if that really helps on TBFI ? ) .

God bless
Wyr
 
  #4  
Old 03-24-14, 03:56 PM
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Pumping does nothing on a fuel-injected engine.
 
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Old 03-24-14, 04:54 PM
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I kind of expected that . :-(

But it gives an old duffer like me a nostalgic sense of satisfaction . :-)

God bless
Wyr
 
  #6  
Old 03-24-14, 05:01 PM
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Rest pressure usually only holds for a few hours but your problem is slow starting after a few days. It may be your injector is slowly leaking and draining the hose that feeds it. Priming the pump will not help that problem. Some injected engines have a cold start valve that helps that problem but not sure what your engine has.
 
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Old 03-24-14, 07:39 PM
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Hope you have better luck than I have had with mine.Have checked fuel press, changed filt, inst off car kit in throttle body, changed oil press sender. Turning the switch off and on as no effect. If you gas in throttle body it will fire right up, or if you crank it over a couple times,turn the switch off then try it again it will fire right off. It only cranks about 4-5 seconds but it seems like a minutes.
 
  #8  
Old 03-25-14, 07:21 AM
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Once I start it and drive it , it starts pretty well ( multiple trips ) the rest of the day . That has lead me to the leaking down theory . Which I guessed was the pressure regulator . Second guess is injectors .

I need to pull a plug on each " bank " of the engine & see if it is black / sooty from running rich ?

I do not have a problem with replacing all the plugs , while I am at it , but I doubt they need it . The car has 43 thousand original miles on it .

If it is not running rich , I may just let the issue ride . Not a big problem . Does not take any longer to start , cold , than most of the cars with carburetors , that I drove in years past . I guess I am just spoiled by the almost instant start of FI cars ? :-(

God bless
Wyr
 
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