05-05-2017 | #71 | |
Join Date: Feb 2012
Location: Ledyard,CT
Posts: 8,259
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Re: New option for fuel pump replacement
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Fuel injected cars need steady high pressure, plus there is a return line to the fuel tank. |
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05-05-2017 | #72 | |
Join Date: Jul 2007
Location: Bartlett, IL
Posts: 7,169
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Re: New option for fuel pump replacement
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the LT5 has TWO pumps.. most find they have a bad pump because the car dies when pump #2 shuts off, Hence the Fuel Pump Jumper harness GC is selling so.. When does the 2ndary Pump Operate and when does it NOT operate. ** and not all Fuel injected cars need a return line, in fact many dead head form the pump..
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1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - Flowmaster Cats - Borla Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978 |
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05-05-2017 | #73 | |
Join Date: Feb 2012
Location: Ledyard,CT
Posts: 8,259
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Re: New option for fuel pump replacement
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05-05-2017 | #74 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,709
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Re: New option for fuel pump replacement
Well if you've eliminated the secondaries, the pump comes on right off idle aside than at first key ON.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
05-08-2017 | #75 | ||
Join Date: Jun 2013
Location: Toronto
Posts: 783
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Re: New option for fuel pump replacement
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05-08-2017 | #76 |
Join Date: Apr 2016
Location: Birmingham, Alabama
Posts: 60
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Re: New option for fuel pump replacement
I started suspecting my fuel pumps as a source of sluggish acceleration.
I pulled the pump assembly and was not pleased with the hack job someone had done on replacing the two pumps so I ordered a complete new ACDelco assembly thinking that would solve everything. I didn't do my homework as I should so I didn't replace the plastic hose clamps and, not knowing any better, I didn't check the backflow check valves in the pumps. Pressure checked good at idle but performance was not what I expected. I ruled out the pumps because they were new and looked elsewhere but eventually came back to suspecting the pumps. By then I was kicking myself for not replacing the plastic hose clamps so I pulled the assembly and found that the check valves on both pumps were bad. I bought two new Delphi pumps from Rock Auto, with good check valves, installed them along with new stainless steel hose camps and I am very pleased with the results. Last edited by mhobtr; 05-08-2017 at 07:12 PM. |
05-08-2017 | #77 | |
Join Date: Jun 2013
Location: Toronto
Posts: 783
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Re: New option for fuel pump replacement
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I'm also going to take everyone's advice on the stainless clamps and do that for sure . I will feel happy to find a broken plastic clip but not expecting it!! Here's a clip I made last year and while I have had other symptoms of my clutch being worn in this case it can be felt and my rpms aren't slipping and rising which is a common clutch -slip symptom but I can feel and hear the delay in acceleration when hitting the next gear and it has made me suspect the pumps. I have changed plugs, wires, coils, injectors, o2 sensors and the map sensor. This video was taken after it all. Leads me back to the beggining .. Around 14-15 second mark in the video. https://youtu.be/bH7F59FKPEU |
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05-08-2017 | #78 | |
Join Date: Mar 2014
Location: Warrington PA
Posts: 1,914
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Re: New option for fuel pump replacement
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I have a habit of researching and double checking parts #'s and applications. Although I might not need fuel pump replacements in the near future, I did order the LT5 Denso pumps back in April. As mentioned they are on Natioal BO, but as of late last week, my order finally got submitted. So it seems like they are in production. Will be anxious to hear your report on the pumps you just ordered. Glad my earler post helped..... Sent from my SM-G935P using ZR-1 Net Registry mobile app
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Tom 1994 ZR-1 #009 "captured test fleet car" 1974 LS4 454 Vert 1974 L-82 355 Vert. 1982 L83 CFI...now a retired "dd"....Sold WAZOO Member |
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05-08-2017 | #79 | |
Join Date: Jun 2013
Location: Toronto
Posts: 783
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Re: New option for fuel pump replacement
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05-08-2017 | #80 | |
Join Date: Apr 2016
Location: Birmingham, Alabama
Posts: 60
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Re: New option for fuel pump replacement
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As to the check valves, they shouldn't make any difference when both pumps are running but when the secondary pump turns off during normal driving, the primary pump will short cycle back through the "Y" pipe, into and out of the secondary pump, which will hurt system pressure. In my case, I believed this caused my primary pump to begin intermittent failure. I could drive for short time and "run out of gas". I could then turn the ignition off and restart immediately because the secondary pump would kick in and deliver system pressure. When I installed my primary/secondary reverse harness, the problem didn't go away because both pumps had the same issue with bad check valves. When I put the new pumps in, with the steel clamps, the intermittent failures stopped and the performance increased dramatically. |
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