Fuel Pump Replacement Problem - Busted line!

somejarhead · 10-16-2008, 10:46 PM

So I replaced my fuel pump this afternoon (second time, but I got about 3 years and 40,000 miles out of the last one). Unfortunately, I did two things wrong.

First, I didn't carefully note which fuel supply lines plugged into which of the three outlets on the pump.

Second, I busted one of the lines. I was able to manufacture a replacement with the help of the local auto parts shop, but that line has a kink in it.

Current status: Vehicle runs well at speed, idles poorly (possibly a spark issue, probably involves the kink). Pump is loud.

So, 2 questions:

1. Does anyone know which line goes where (or will the vehicle not run if I connect them wrong)? One of them is a different size, so that's easy, but are the other two interchangable?

2. Does anyone know the part numbers for those small lines (about 5 inches long) or where I can find them? They have the snap connectors on both ends and join the pump to the lines mounted to the frame. PartsDirect was no help...

Thanks.

***Wicked Mayhem*** · 10-16-2008, 10:52 PM

the lines can not be connected wrong.

one line is bigger than the other 2(top line in pic)

then the other 2 have different style clips so its idiot proof

somejarhead · 10-16-2008, 11:01 PM

Well, this is for the bravada, and one is definately bigger. As for the clips, the other two have the same clips because they both broke during disassembly, so they were replaced from the same package of 6...

But, best I've been able to find out is that it's supply, return, and vapor recovery. So, if supply was connected to return, would the vehicle run?

And, more importantly, any thoughts on the part number? My manufactured replacement won't work long term.

Kaznlilgreenmen · 10-17-2008, 12:06 PM

Quote: Originally Posted by somejarhead

Well, this is for the bravada, and one is definately bigger. As for the clips, the other two have the same clips because they both broke during disassembly, so they were replaced from the same package of 6...

But, best I've been able to find out is that it's supply, return, and vapor recovery. So, if supply was connected to return, would the vehicle run?

And, more importantly, any thoughts on the part number? My manufactured replacement won't work long term.

No it wouldn't..Don't mind my illustration

As for the part number I can't pull anything up directly..sorry you should be able to just pull both ends off from the pump and the fuel line and take it to car quest or a gm dealer..remember to put a few drops of clean engine oil on your plastic connectors to..it will prevent the o-ring from leaking when it swells

Yogi · 10-17-2008, 12:43 PM

Quote: Originally Posted by somejarhead

Well, this is for the bravada, and one is definately bigger. As for the clips, the other two have the same clips because they both broke during disassembly, so they were replaced from the same package of 6...

But, best I've been able to find out is that it's supply, return, and vapor recovery. So, if supply was connected to return, would the vehicle run?

And, more importantly, any thoughts on the part number? My manufactured replacement won't work long term.

Supply is the big line, so no way it will connect to the return.

somejarhead · 10-18-2008, 08:47 PM

OK-

First, this is for a 2000 Bravada.

Looking forward from the rear of the vehicle, three hoses exit the fuel pump. The left hose (closest to the frame) is the return line. The middle is the vapor return line. The right (furthest from the frame) is the feed.

The feed and return lines are about 9" long with double quick-connect ends (the vapor line is fixed at the frame end). The feed line is GM part number 15109091 and retails at the dealer for $122.94. The return line (the one I damaged) is GM part number 15109085 and retails for $70.88.

No, those prices are not typos. I spoke to folks at three dealerships. They all expressed surprise at the prices.

However, there is a silver lining. The first long trip (100 miles) with the new pump showed 26mpg. By the time I did another 60, including dropping the tak again and making a mess, and filled-up, I averaged 20mpg. This from a vehicle that never gave me better than 18, and usually ran at about 15mpg.

I assume the increased efficiency is due to the higher pressure of the pump causing better vaproization at the injectors. Wish I'd known about it 3 years ago...

Yogi · 10-19-2008, 08:33 AM

Congrats on the mileage, Jarhead!

somejarhead · 10-19-2008, 08:52 PM

Well, I replaced the broken return line with a repair kit from Autozone (includes a quick-connect fitting), two 5/16 barbed fittings, a 12 inch piece of flexible high pressure fuel injector hose, and 4 hose clamps. Total cost: about $40, and it's flexible!

Unfortunately, there's a down side. My incredible fuel mileage of 25mpg or better is gone. I'm back to the usual ~17mpg.

Here's what I know:

1. When the return line was restricted (by my poor first repair attempt that had crimps in the line), the running pressure at the injector test port was around 75psi. This set an "Engine too rich" code on bank 1 and 2.

2. Once I fixed the return line, the static pressure was 60psi, but the running pressure is now 54psi. This is too low. My book says 60 static is in spec, but running should be higher.

3. The next step is to remove the plenum and look at the upper manifold where the injectors and regulator sit. If I see washing (a clean area that has been washed by leaking fuel), I'll know I have a problem. However, I'm going to replace the regulator anyway...

More to come.

Yogi · 10-19-2008, 09:19 PM

54 psi running is normal. Mine runs 52 psi at idle. If you can get better gas mileage with higher pressure, more power to ya!

somejarhead · 10-19-2008, 09:41 PM

Quote: Originally Posted by Yogi

54 psi running is normal. Mine runs 52 psi at idle. If you can get better gas mileage with higher pressure, more power to ya!

All I know is that when the pressure was higher, my mileage was higher. Significantly.

So, we'll see what happens. The regulator is only $60 and about an hour's worth of work.

Yogi · 10-20-2008, 11:08 AM

I'm afraid that a new regulator is going to disappoint you. The pressures will be the same. You might have better luck trying to modify your existing regulator to give higher pressure. Of course, you could always get a custom PCM tune that richens up your mixture.

somejarhead · 10-20-2008, 12:44 PM

Well, ok, but what explains the increased economy when the pressure was higher from the kinked return line?

And before you say I'm dreaming, it wasn't just the computer saying my economy was up - I topped off the tank before my 100-mile trip (as full as I could get it, expecting my usual crummy mileage) and filled it again when I returned to verify what the computer was saying.

So, something must be going on...

Yogi · 10-20-2008, 01:07 PM

All that I can figure is that your engine is running too lean for your driving conditions. Making the mixture richer makes it more efficient and your mileage goes up. Ppl that have tuned their motors with a wide band O2 sensor say that the 4.3 runs too lean. A custom tune from Wait4MePerformance.com can set it as rich as you want it to be. Cost: $75 on your PCM, $159 to buy a tuned PCM outright.

10-16-2008, 10:46 PM	#1
somejarhead Registered User Join Date: Oct 2008 Posts: 6 Location: User is: OffLine	Fuel Pump Replacement Problem - Busted line! So I replaced my fuel pump this afternoon (second time, but I got about 3 years and 40,000 miles out of the last one). Unfortunately, I did two things wrong. First, I didn't carefully note which fuel supply lines plugged into which of the three outlets on the pump. Second, I busted one of the lines. I was able to manufacture a replacement with the help of the local auto parts shop, but that line has a kink in it. Current status: Vehicle runs well at speed, idles poorly (possibly a spark issue, probably involves the kink). Pump is loud. So, 2 questions: 1. Does anyone know which line goes where (or will the vehicle not run if I connect them wrong)? One of them is a different size, so that's easy, but are the other two interchangable? 2. Does anyone know the part numbers for those small lines (about 5 inches long) or where I can find them? They have the snap connectors on both ends and join the pump to the lines mounted to the frame. PartsDirect was no help... Thanks.
	[Reply w/Quote]

10-16-2008, 10:52 PM	#2
*Wicked Mayhem* Moderator Join Date: Nov 2002 Posts: 16,352 Location: :noitacoL User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! the lines can not be connected wrong. one line is bigger than the other 2(top line in pic) then the other 2 have different style clips so its idiot proof
	[Reply w/Quote]

10-16-2008, 11:01 PM	#3
somejarhead Registered User Join Date: Oct 2008 Posts: 6 Location: User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! Well, this is for the bravada, and one is definately bigger. As for the clips, the other two have the same clips because they both broke during disassembly, so they were replaced from the same package of 6... But, best I've been able to find out is that it's supply, return, and vapor recovery. So, if supply was connected to return, would the vehicle run? And, more importantly, any thoughts on the part number? My manufactured replacement won't work long term.
	[Reply w/Quote]

10-17-2008, 12:06 PM	#4
Kaznlilgreenmen I piss excellence Age: 25 Join Date: Oct 2004 Posts: 850 Location: Springville Ny User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! Quote: Originally Posted by somejarhead Well, this is for the bravada, and one is definately bigger. As for the clips, the other two have the same clips because they both broke during disassembly, so they were replaced from the same package of 6... But, best I've been able to find out is that it's supply, return, and vapor recovery. So, if supply was connected to return, would the vehicle run? And, more importantly, any thoughts on the part number? My manufactured replacement won't work long term. No it wouldn't..Don't mind my illustration As for the part number I can't pull anything up directly..sorry you should be able to just pull both ends off from the pump and the fuel line and take it to car quest or a gm dealer..remember to put a few drops of clean engine oil on your plastic connectors to..it will prevent the o-ring from leaking when it swells Last edited by Kaznlilgreenmen : 10-17-2008 at 12:14 PM.
	[Reply w/Quote]

10-17-2008, 12:43 PM	#5
Yogi Registered (Ab) User Join Date: Feb 2008 Posts: 4,093 Location: League City, TX (Houston) User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! Quote: Originally Posted by somejarhead Well, this is for the bravada, and one is definately bigger. As for the clips, the other two have the same clips because they both broke during disassembly, so they were replaced from the same package of 6... But, best I've been able to find out is that it's supply, return, and vapor recovery. So, if supply was connected to return, would the vehicle run? And, more importantly, any thoughts on the part number? My manufactured replacement won't work long term. Supply is the big line, so no way it will connect to the return.
	[Reply w/Quote]

10-18-2008, 08:47 PM	#6
somejarhead Registered User Join Date: Oct 2008 Posts: 6 Location: User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! OK- First, this is for a 2000 Bravada. Looking forward from the rear of the vehicle, three hoses exit the fuel pump. The left hose (closest to the frame) is the return line. The middle is the vapor return line. The right (furthest from the frame) is the feed. The feed and return lines are about 9" long with double quick-connect ends (the vapor line is fixed at the frame end). The feed line is GM part number 15109091 and retails at the dealer for $122.94. The return line (the one I damaged) is GM part number 15109085 and retails for $70.88. No, those prices are not typos. I spoke to folks at three dealerships. They all expressed surprise at the prices. However, there is a silver lining. The first long trip (100 miles) with the new pump showed 26mpg. By the time I did another 60, including dropping the tak again and making a mess, and filled-up, I averaged 20mpg. This from a vehicle that never gave me better than 18, and usually ran at about 15mpg. I assume the increased efficiency is due to the higher pressure of the pump causing better vaproization at the injectors. Wish I'd known about it 3 years ago...
	[Reply w/Quote]

10-19-2008, 08:33 AM	#7
Yogi Registered (Ab) User Join Date: Feb 2008 Posts: 4,093 Location: League City, TX (Houston) User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! Congrats on the mileage, Jarhead!
	[Reply w/Quote]

10-19-2008, 08:52 PM	#8
somejarhead Registered User Join Date: Oct 2008 Posts: 6 Location: User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! Well, I replaced the broken return line with a repair kit from Autozone (includes a quick-connect fitting), two 5/16 barbed fittings, a 12 inch piece of flexible high pressure fuel injector hose, and 4 hose clamps. Total cost: about $40, and it's flexible! Unfortunately, there's a down side. My incredible fuel mileage of 25mpg or better is gone. I'm back to the usual ~17mpg. Here's what I know: 1. When the return line was restricted (by my poor first repair attempt that had crimps in the line), the running pressure at the injector test port was around 75psi. This set an "Engine too rich" code on bank 1 and 2. 2. Once I fixed the return line, the static pressure was 60psi, but the running pressure is now 54psi. This is too low. My book says 60 static is in spec, but running should be higher. 3. The next step is to remove the plenum and look at the upper manifold where the injectors and regulator sit. If I see washing (a clean area that has been washed by leaking fuel), I'll know I have a problem. However, I'm going to replace the regulator anyway... More to come.
	[Reply w/Quote]

10-19-2008, 09:19 PM	#9
Yogi Registered (Ab) User Join Date: Feb 2008 Posts: 4,093 Location: League City, TX (Houston) User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! 54 psi running is normal. Mine runs 52 psi at idle. If you can get better gas mileage with higher pressure, more power to ya!
	[Reply w/Quote]

10-19-2008, 09:41 PM	#10
somejarhead Registered User Join Date: Oct 2008 Posts: 6 Location: User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! Quote: Originally Posted by Yogi 54 psi running is normal. Mine runs 52 psi at idle. If you can get better gas mileage with higher pressure, more power to ya! All I know is that when the pressure was higher, my mileage was higher. Significantly. So, we'll see what happens. The regulator is only $60 and about an hour's worth of work.
	[Reply w/Quote]

10-20-2008, 11:08 AM	#11
Yogi Registered (Ab) User Join Date: Feb 2008 Posts: 4,093 Location: League City, TX (Houston) User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! I'm afraid that a new regulator is going to disappoint you. The pressures will be the same. You might have better luck trying to modify your existing regulator to give higher pressure. Of course, you could always get a custom PCM tune that richens up your mixture.
	[Reply w/Quote]

10-20-2008, 12:44 PM	#12
somejarhead Registered User Join Date: Oct 2008 Posts: 6 Location: User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! Well, ok, but what explains the increased economy when the pressure was higher from the kinked return line? And before you say I'm dreaming, it wasn't just the computer saying my economy was up - I topped off the tank before my 100-mile trip (as full as I could get it, expecting my usual crummy mileage) and filled it again when I returned to verify what the computer was saying. So, something must be going on...
	[Reply w/Quote]

10-20-2008, 01:07 PM	#13
Yogi Registered (Ab) User Join Date: Feb 2008 Posts: 4,093 Location: League City, TX (Houston) User is: OffLine	Re: Fuel Pump Replacement Problem - Busted line! All that I can figure is that your engine is running too lean for your driving conditions. Making the mixture richer makes it more efficient and your mileage goes up. Ppl that have tuned their motors with a wide band O2 sensor say that the 4.3 runs too lean. A custom tune from Wait4MePerformance.com can set it as rich as you want it to be. Cost: $75 on your PCM, $159 to buy a tuned PCM outright.
	[Reply w/Quote]