Do I need to replace my fuel pump?
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On The Tree
Joined: Jun 2017
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Do I need to replace my fuel pump? Hey all. I am just a set of fresh fluids away from finally starting my H/C/I swap. I have a set of 30lb injectors in the rails now, and I was wondering if I should replace my fuel pump before getting the car tuned. I plan on replacing it either way, I was just hoping I could get the car on the road this week, and I don't think I'll be able to get a new pump kit in before the weekend.
It's a stock pump currently, not sure how many miles are on it. I'm going to run set of ai200's with a cam similar to a CC306, on a stock bottom end. All other bolt ons are done, and I'm *hoping* for about 430whp through a 10 bolt and an M6, though I would still be satisfied with over 410 to the tire. Is the stock fuel pump capable of feeding that? At the very least even for a few WOT runs for tuning, then I can cruise around while waiting for a new pump in the mail.
It's a stock pump currently, not sure how many miles are on it. I'm going to run set of ai200's with a cam similar to a CC306, on a stock bottom end. All other bolt ons are done, and I'm *hoping* for about 430whp through a 10 bolt and an M6, though I would still be satisfied with over 410 to the tire. Is the stock fuel pump capable of feeding that? At the very least even for a few WOT runs for tuning, then I can cruise around while waiting for a new pump in the mail.
I would secure a fuel pressure gauge so that you can see the fuel pressure from inside the car (tape it to the windshield if you have to). Then you can monitor the fuel pressure at WOT under load. Fuel pressure at idle won't truly indicate whether or not the pump is working sufficiently.
Thread Starter
On The Tree
Joined: Jun 2017
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Wouldn't a wideband also work? I figured I should probably get one for tuning anyway, so if it starts leaning out at the top end I would see it.
I am mostly interested in knowing if the stock pump is capable of flowing enough fuel for that kind of power, so I can figure out if I can get it tuned or not.
I am mostly interested in knowing if the stock pump is capable of flowing enough fuel for that kind of power, so I can figure out if I can get it tuned or not.
TECH Veteran
Joined: Apr 2008
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if you have the 30 lb injectors on the car now without being tuned for it...any scan software is going to show a pig rich condition (read don't drive around much before the tune). This can wash the cyl down with gas...no good.
For purposes of checking if your current FP is putting out enough for "sustained WOT"...you need a FP gauge you can see while doing a WOT pull.
Kinda a catch 22 in that if you are not tuned for but using 30 lb injectors it is not a good idea to run the motor much...but a quick pull with a FP gauge should be OK. You should have a FP gauge anyway. I have the Hypertech one with a hose on it so I can tape it to the windshield. Some auto part stores offer "loan-a tool" ones....which may or "may not" be accurate
If your fuel pump is 20+ years old...its certainly is closer to dyeing than not. A Walbro 255 LPH is what many go with especially with larger than stock injectors. FWIW when I did H/C, 30 lb Ford SVO's on the dyno and did have a FP gauge hooked up. At WOT nearing 5k rpm the motor started backfire and FP dropped to almost zero. Just at idle the FP showed OK. My old original stock fuel pump could not keep up. YYMV
For purposes of checking if your current FP is putting out enough for "sustained WOT"...you need a FP gauge you can see while doing a WOT pull.
Kinda a catch 22 in that if you are not tuned for but using 30 lb injectors it is not a good idea to run the motor much...but a quick pull with a FP gauge should be OK. You should have a FP gauge anyway. I have the Hypertech one with a hose on it so I can tape it to the windshield. Some auto part stores offer "loan-a tool" ones....which may or "may not" be accurate
If your fuel pump is 20+ years old...its certainly is closer to dyeing than not. A Walbro 255 LPH is what many go with especially with larger than stock injectors. FWIW when I did H/C, 30 lb Ford SVO's on the dyno and did have a FP gauge hooked up. At WOT nearing 5k rpm the motor started backfire and FP dropped to almost zero. Just at idle the FP showed OK. My old original stock fuel pump could not keep up. YYMV
Thread Starter
On The Tree
Joined: Jun 2017
Posts: 196
Likes: 1
if you have the 30 lb injectors on the car now without being tuned for it...any scan software is going to show a pig rich condition (read don't drive around much before the tune). This can wash the cyl down with gas...no good.
For purposes of checking if your current FP is putting out enough for "sustained WOT"...you need a FP gauge you can see while doing a WOT pull.
Kinda a catch 22 in that if you are not tuned for but using 30 lb injectors it is not a good idea to run the motor much...but a quick pull with a FP gauge should be OK. You should have a FP gauge anyway. I have the Hypertech one with a hose on it so I can tape it to the windshield. Some auto part stores offer "loan-a tool" ones....which may or "may not" be accurate
If your fuel pump is 20+ years old...its certainly is closer to dyeing than not. A Walbro 255 LPH is what many go with especially with larger than stock injectors. FWIW when I did H/C, 30 lb Ford SVO's on the dyno and did have a FP gauge hooked up. At WOT nearing 5k rpm the motor started backfire and FP dropped to almost zero. Just at idle the FP showed OK. My old original stock fuel pump could not keep up. YYMV
For purposes of checking if your current FP is putting out enough for "sustained WOT"...you need a FP gauge you can see while doing a WOT pull.
Kinda a catch 22 in that if you are not tuned for but using 30 lb injectors it is not a good idea to run the motor much...but a quick pull with a FP gauge should be OK. You should have a FP gauge anyway. I have the Hypertech one with a hose on it so I can tape it to the windshield. Some auto part stores offer "loan-a tool" ones....which may or "may not" be accurate
If your fuel pump is 20+ years old...its certainly is closer to dyeing than not. A Walbro 255 LPH is what many go with especially with larger than stock injectors. FWIW when I did H/C, 30 lb Ford SVO's on the dyno and did have a FP gauge hooked up. At WOT nearing 5k rpm the motor started backfire and FP dropped to almost zero. Just at idle the FP showed OK. My old original stock fuel pump could not keep up. YYMV
After speaking to my tuner, he's a bit backed up so that has me set back a few weeks minimum by the sound of it. So I suppose I'll have plenty of time to order that kit and get the new pump and wiring in before I hook up to a laptop. All things considered, that's probably my best bet.
TECH Veteran
Joined: Apr 2008
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a good operating "stock" fuel pump will work fine.....but you need to confirm your stock pump is in fact up to the task. Thus the FPG and WOT test to see if FP holds steady and does not fade...
Nothing wrong with upgrading to the RT kit....IIRC you need to join their forum to get install instructions "after" you buy their product unless you can find a donor copy or "description" online
You can also just buy a Walbro 255 from another vendor (just confirm its a "real" walbro and install it in your stock enclosure. Just confirm your wiring and connections are good to the fuel pump assembly
Nothing wrong with upgrading to the RT kit....IIRC you need to join their forum to get install instructions "after" you buy their product unless you can find a donor copy or "description" online
You can also just buy a Walbro 255 from another vendor (just confirm its a "real" walbro and install it in your stock enclosure. Just confirm your wiring and connections are good to the fuel pump assembly
Thread Starter
On The Tree
Joined: Jun 2017
Posts: 196
Likes: 1
a good operating "stock" fuel pump will work fine.....but you need to confirm your stock pump is in fact up to the task. Thus the FPG and WOT test to see if FP holds steady and does not fade...
Nothing wrong with upgrading to the RT kit....IIRC you need to join their forum to get install instructions "after" you buy their product unless you can find a donor copy or "description" online
You can also just buy a Walbro 255 from another vendor (just confirm its a "real" walbro and install it in your stock enclosure. Just confirm your wiring and connections are good to the fuel pump assembly
Nothing wrong with upgrading to the RT kit....IIRC you need to join their forum to get install instructions "after" you buy their product unless you can find a donor copy or "description" online
You can also just buy a Walbro 255 from another vendor (just confirm its a "real" walbro and install it in your stock enclosure. Just confirm your wiring and connections are good to the fuel pump assembly
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^^^ The secret to long fuel pump life is to use the fuel pump bucket. If it isn't used it will continuously overheat after the fuel level goes below the pump and cause it to fail.