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Is fuel pump on the way out....***UPDATE AS OF 2/3/12***


oz37k

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Last Friday when I got off work I attempted to start my car and it acted as if it was flooded when I initally turned the key, I let it sit for a few seconds and attempted to start and it did but white smoke came out of my tailpipe once it started and surged a bit til it stabilized and only does it when it acts as if it was flooded, no other times.

Car starts perfectly in the mornings, no hesitation or anything but when I drive it to work and let it sit thru my 8 hr shift and go home it seems to get this problem. I already changed the fuel filter and thru the 7 yrs that I have owned my 1995 Monte Z34 I have never changed my fuel pump, could it be this? Also my gas gauge needle started bouncing around as well and never did this before.

I have searched and read other post and most of them state symptoms that I already know would happen if the pump was out but nothing like I am experiencing.

Car runs very strong and accelerates with no problems. I have not noticed any decrease in performance.

Any help would be appreciated.

Edited by oz37k
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fuel pressure test time! If you have no test gauge, either rent a good one (Autozone has em) or buy one and check it out.

 

I recommend the Bosch pump, which can be bought cheap from advance auto parts online using a discount code(try code word VISA), and has a lifetime warranty as long as you buy the filer and strainer at the same time...

Edited by Crazy K
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I was thinking the same. I got one 2 christmases ago from Harbor Freight and now that I need it I cannot find it. I will look for it if not I will rent one at Autozone and check it out. I know that when it acts funny I return the key to off and then on again and it starts. Must be building pressure during this on and off time.

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also consider that you could have a leaky injector. watch for pressure dropping off after the fuel pump is fully primed.
this

 

also, is it hard to start after every long break? if so, could be the evap purge valve is stuck open.

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***FIXED***

It was the fuel pump. Took it to the Big O tire shop around the corner from my job to see if they would test the pressure for free since my company get discounts from them. They checked and showed me the results and it was no where near the 41-47 psi stated in the service manual. Got it replaced with new pump and strainer and now fires up at first try everytime with no hesitation and car does feel more alive.

The guy at the shop told me that it was a matter of time til the car left me stranded cause the pressure was very low from their test results.

Thanks to all who pitched in and helped.

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So I thought I fixed my problem with the new fuel pump but it started actiing funny, so I checked the plugs and luckily none were fouled but were worn so I replaced them. I also decided to give all the vacuum lines a once over and found that when I pulled the fuel pressure regulator vac line to the upper manifold fuel squirted out. Finally after all the money put in to find the problem it was what I should have originally checked. Luckily I was able to pick one up at my local auto parts store and will be putting in, hope problem goes away. I also checked vacuum leaks using the brake cleaner method and found none, didn't think so cause in December I replaced my manifold gaskets and all vacuum lines and hoses for precaution.

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I also checked vacuum leaks using the brake cleaner method and found none

Brake cleaner is often non-flammable. Therefore worthless for testing vacuum leaks.

 

I use aerosol carb cleaner. Highly flammable--at least the brands I buy are.

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Brake cleaner is often non-flammable. Therefore worthless for testing vacuum leaks.

 

I use aerosol carb cleaner. Highly flammable--at least the brands I buy are.

 

 

It would still displace the air/fuel mixture if there was a vac leak

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You shouldn't need that quick disconnect tool unless this is on a L67, or something other than a W-body. Also, the ability for brake cleaner to be flammable or not depends on if it's chlorinated or non-chlorinated.

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You shouldn't need that quick disconnect tool unless this is on a L67, or something other than a W-body. Also, the ability for brake cleaner to be flammable or not depends on if it's chlorinated or non-chlorinated.

 

So all I have to do is uncrew and pull the regulator off the fuel line and pop in the new one in the fuel rail and fuel line. Seems to easy. My car is an LQ1 (3.4 DOHC).

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42384652

[TABLE=width: 100%]

[TR]

[TD=align: center][TABLE=width: 90%]

[TR]

[TD]REMOVE OR DISCONNECT

 

  1. Disconnect negative battery cable.
  2. Relieve fuel system pressure.


    • Refer to Fuel System / Service and Repair.

  1. Upper manifold assembly.

DISASSEMBLE

 

  1. Fuel pressure regulator bracket attaching screw.
  2. Regulator assembly and O-rings. Discard O-rings.

INSPECT

If fuel pressure regulator is to be reinstalled, inspect filter screen (if equipped) for contamination. If contaminated, remove and discard filter screen.

 

ASSEMBLE

 

  1. Lubricate new O-rings with clean engine oil and install.
  2. Regulator and attaching screw.

Tighten

Pressure regulator screw to 9.5 Nm (84 lb. in.).

 

INSTALL OR CONNECT

 

  1. Upper manifold assembly.
  2. Negative battery cable.

[/TD]

[/TR]

[/TABLE]

[/TD]

[/TR]

[/TABLE]

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Thanks AL. My FSM shows the above but there is a cover retaining the fuel lines going into the fuel rail and regulator and I could not make out if the tool was needed for disconnecting the line from the regulator.

Again. Thanks.

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not trying to hijack, but how much of a pain is it to disconnect the line from the bottom of the FPR?

 

Just did the FPR change today and it is not hard to pull the lines off the FPR. Just take off plate that hold them in place and pull and wiggle and out they come but make sure you have a bunch of rag to catch the fuel that will come out. The hard part is trying to get the star socket and ratchet to fit and unscrew. I had to take off the fuel rail to be able to remove the old FPR and replace it with the new one.

Edited by oz37k
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Today I did the FPR install. Time consuming task, had to remove the fuel rail in order to get the star socket and ratchet extension to fit cause the line is somehow curved around the FPR and cannot fit in the socket and ratchet by themselves. I replaced the vac line from the FPR to the intake and add new connectors for precaution. I also sprayed the intake with TB cleaner until it loosened everything and let it drain on a rag. I also took the time to clean the MAF with maf cleaner and I can say it seems my Z is back on the road running smoother. I took it for a long ride and not issues. Let it sit for 2 hours and started it up again and it lit up without any extra cranking. Knock on wood, hope nothing else goes wrong. This car is truly a love and hate type of thing. I love to drive but hate to work on it.

Thanks to all that helped along the way.

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