fuel pump prime / cold start

[97Formula]

On my 1997 Formula, the fuel pump prime seems to be high pitched for a split second before it sounds normal. I then have to hold the key in the start position for a full second before it fires up (used to be a half second cranking). Any ideas before I start guessing again? Already had the fuel pump replaced 5 years ago....could it be the fuel pressure regulator? I guess I should probably hook a fuel pressure gauge to it (or worst case, take it to a shop only to be told nothing is wrong even though I am sure something is wrong as it has not done this before).

Today I tried priming 3 times before starting. Only the first prime sounded abnormal with the high pitch. 2nd and 3rd primes sounded normal but the cold start still took a good second of cranking before it fires up. Once running, no sputtering or anything, car runs smooth at idle and strong when moderate to WOT, never runs rough or stalls. No SES light either.

I was thinking maybe there is a leak somewhere but I don't smell any gas in my garage where my car stays when not in use.

I may just take it to the dealer and see if they can thoroughly check the fuel system (maybe there is a leak I am unaware of). Or does anyone know a good shop in Central NJ that knows these cars / LT1's?

Car has 38000 miles, and other than the weird initial pump noise, the car runs awesome...

[LTb1ow]

I would just put a fuel pressure gauge on it. Verify either its not building pressure, or bleeding off too fast.

Can you pull the vacuum line off the fuel reg and smell for fuel?

Do you know what the shop replaced the fuel pump with brand wise?

[The_Bishop]

Sounds like the fuel line pressure is bleeding off when the car's off. The high pitched sound is the pump running against zero pressure initially.

It's not supposed to bleed off that much, though.

[97Formula]

I would just put a fuel pressure gauge on it. Verify either its not building pressure, or bleeding off too fast.

Can you pull the vacuum line off the fuel reg and smell for fuel?

Do you know what the shop replaced the fuel pump with brand wise?

Since it was done at the dealer, I hope it was an AC Delco!

And they did not cut a hole in the back.....I made sure they actually drop the tank instead. :)

[ThoR294]

https://i.imgur.com/cYsKXeH.jpg

[97Formula]

So it's with the dealer, and of course they check the fuel pressure and it all checks out (the issues don't happen on a warm engine, only on a "left-overnight" cold engine so they are keeping it overnight and will try to replicate the issue first thing tomorrow).

[97Formula]

Just got a call.....they say it's the fuel pump.

What causes these pumps to prematurely go bad?

[ThoR294]

Just got a call.....they say it's the fuel pump.

What causes these pumps to prematurely go bad?

bad fuel pump :bertstare:

[LTb1ow]

Just got a call.....they say it's the fuel pump.

What causes these pumps to prematurely go bad?

Was it a infant mortality thing? Sounds like it was done a while ago, which IMO just adds to the argument that ACdelco is no longer the quality name it used to be. China is really good at copying and pasting so a knock off could have been used as well.

[97Formula]

Pump was replaced 5 years ago and only got 7000 miles out of this one.

[LTb1ow]

IMO, drive it more. Or at least cycle the pump every once in awhile.

[97Formula]

New pump installed by dealer, failed during road test. :(

[ThoR294]

New pump installed by dealer, failed during road test. :(

did they test all the wiring/relays?

[97Formula]

I'm pretty sure they did. I'm also pretty sure these pumps are total garbage as this is actually my 4th pump (lifetime warranty on just the pump, but not the labor).

Is there a better brand or part number I should request?

[The_Bishop]

When I changed my pump out I did the racetronix kit; hot wire and pump setup, a 255 lph pump.

It's pretty hard/impossible to get a quality stock pump for these cars any longer.

Edit: Assuming you're running an LT1 setup, this would be your monkey:

http://www.racetronix.biz/itemdesc.asp?ic=FPA-003A&eq=&Tp=

This kit will make sure the pump sees full alternator voltage, and only uses the stock wiring to actuate a relay:

http://www.racetronix.biz/itemdesc.asp?ic=FPWH-003&eq=&Tp=

[97Formula]

Darn it!

I wish I still had the original pump with the fuel gauge sending unit, as the gauge has been reading between 3/4 and F when in fact it is full (ever since the first pump replacement).

The original sending unit was more accurate and told me it was full when it was actually full.

So now I am basically screwed......the lifetime guarantee is a guaranteed piece of......

[ThoR294]

If my pump goes again, I am definitely doing the racetronix like bishop posted.

i have never had an accurate fuel gauge in an fbody lol. my 94 formula I ran out of gas at a 1/4 tank...

[97Formula]

This is going to be quite the challenge asking my GM dealer to use a non-GM part and telling them why (because the replacement AC Delco pumps are junk)....

I asked them yesterday to look into alternate fuel pumps that are more reliable. This lifetime guarantee is a lifetime disappointment, as it does not cover labor (which is very expensive).

[sweetbmxrider]

:facepalm:

[The_Bishop]

I run away from dealers like I'm covered in gasoline and they're a giant match unless I absolutely need to deal with them for warranty work. Then I watch them with a microscope.

Also: Lifetime warranty doesn't mean jack if it needs $300 in labor to replace a $150 part that keeps failing, and the labor isn't covered.

[97Formula]

I had no idea this GM part has such a high failure rate. I figured "how can you go wrong? it's a GM part for my GM car."

Is there a GM customer service number I can call to voice my concern / dissapointment?

[sweetbmxrider]

I had no idea this GM part has such a high failure rate. I figured "how can you go wrong? it's a GM part for my GM car."

Is there a GM customer service number I can call to voice my concern / dissapointment?

It is an Ac Delco part.

[BonzoHansen]

This is going to be quite the challenge asking my GM dealer to use a non-GM part and telling them why (because the replacement AC Delco pumps are junk)....

I asked them yesterday to look into alternate fuel pumps that are more reliable. This lifetime guarantee is a lifetime disappointment, as it does not cover labor (which is very expensive).

The only reason they might agree is because they are tired of your car and want it gone for good. Because you will have zero warranty after that. Your part, your problem, bye bye

[ThoR294]

The only reason they might agree is because they are tired of your car and want it gone for good. Because you will have zero warranty after that. Your part, your problem, bye bye

I'm sure they have some liability somewhere. They could fudge the install

[BonzoHansen]

I'm sure they have some liability somewhere. They could fudge the install

lol. maybe a 30 day labor warranty.

[LS1ow]

Slim chance you get the dealer to install after market parts. We wont even install off brand wheels for a customer.


how handy are you yourself?

[ThoR294]

Trap door time!

[PolarBear]

Trap door time!

Oh god, NO!

[ThoR294]

Oh god, NO!

Look instead of having to drop the rear 4 times in this case he could have just popped the cover off!

[97Formula]

I see that Delphi has a part number as well FHP10036. Are they any better than AC Delco?

Asking because another problem I had with the "new" fuel pumps are that the gas gauge reads between 3/4 and F when the tank is full.

[ThoR294]

That's the fuel sender not the fuel pump that is causing that

[The_Bishop]

Pretty sure all the replacements come with the whole assembly.

[PolarBear]

Look instead of having to drop the rear 4 times in this case he could have just popped the cover off!

NO! Bad ThoR294!!

[LTb1ow]

Yea, don't hack up your car to save some time now.

You sound like you have a very nicely kept OEM car, so don't ruin that.

[97Formula]

I'm aware the sender is why I have fuel gauge issues. The problem is.....it comes with the whole assembly so when the dealer replaces the pump, the sender unit goes with it too.

Hopefully I have better luck with the next pump they install...

[ThoR294]

I'm aware the sender is why I have fuel gauge issues. The problem is.....it comes with the whole assembly so when the dealer replaces the pump, the sender unit goes with it too.

Hopefully I have better luck with the next pump they install...




Pretty sure all the replacements come with the whole assembly.

Back in the day it was extra

[ar0ck]

+1 for Trap Door

[FlyingDutchman]

I swapped a Delphi unit in last fall, I haven't had a problem. Got it off rockauto. I was having long crank times, thought it was from the airtex that was installed, but after resealing the manifold it seems to have solved that issue.

[97Formula]

Finally got the car back.....WOW!!!

I immediately noticed crisper throttle response! Seems to have resolved the issues i took it in for. Still got an inaccurate gas gauge even with the new pump assembly (full tank reading between 3/4 and F, sometimes just below 3/4 with heavier braking, sometimes reads F when accelerating...probably fuel sloshing around). I questioned the dealer they say its normal (not sure if I agree since it hasn't happened with the original pump, just the replacements).

Hopefully the pump will last longer than the previous.