12-14-2018 | #11 | |
Join Date: Apr 2016
Location: Birmingham, Alabama
Posts: 60
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Re: 90 Z cranks but will not start
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If he replaces either or both pumps, tell him to make sure the back flow prevent valves are working. I have had two new Delphi pumps that I had to exchange because those valves were not working. Also tell him to remove all of the plastic hose clamps and replace them with stainless steel clamps, properly tightened to prevent leaks. |
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12-14-2018 | #12 | |
Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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Re: 90 Z cranks but will not start
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Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry |
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12-14-2018 | #13 |
Join Date: Feb 2018
Location: Austin, TX
Posts: 104
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Re: 90 Z cranks but will not start
I learned the importance of properly sized and tightened clamps the hard way: http://www.zr1.net/forum/showthread.php?t=29943
-Stephen 1990 #2288
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-Stephen 1990 #2288 |
12-14-2018 | #14 |
Join Date: Oct 2017
Location: TX
Posts: 2,042
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Re: 90 Z cranks but will not start
While you are in the fuel tank I would suggest changing the plastic "Y" out with one of Carter's machined fittings. (Carter200)
25 year + plastic has a tendency to get brittle. Mine had a crack in it.
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Kenny 1990 #442 |
12-25-2018 | #15 |
Join Date: Feb 2017
Location: waxhaw, nc
Posts: 93
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Re: 90 Z cranks but will not start
I don't think this is relevant to the situation described, but posting this for others that may be searching in the future.
After removing the plenum and changing the coils, I had the same problem. Car would crank and crank but not start. After an embarrassingly long time troubleshooting, I noticed that the connecter plug to the Coil assembly had come unplugged during the plenum re-install. A long screwdriver to push the plug back in later, It fired right up. Something worth the 10 sec it takes to check and potentially fix, just in case... Curt |
12-26-2018 | #16 |
Join Date: Nov 2007
Location: Squires (near Ava MO in the Mark Twain N'tl Forest) - Missouri
Posts: 6,493
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Re: 90 Z cranks but will not start
Any updates? Hope you got it going. But, if not, anything those of us "standing around your car", drinkin a brew can suggest further?
.
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Good carz, good food, good friendz = the best of timez! 90 #1202 "FBI" top end ported & relieved Cam timing by "Pete the Greek" Sans secondaries Chip & dyno tuning by Haibeck Automotive SW headers, X-pipe, MF muffs Former Secretary, ZR-1 Net Registry |
12-26-2018 | #17 | |
Join Date: Aug 2009
Location: South Dakota/California
Posts: 3,799
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Re: 90 Z cranks but will not start
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I have to put that in Solutions
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Left Clickable links -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 12-26-2018 at 04:17 PM. |
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01-02-2019 | #18 |
Join Date: May 2015
Location: Loveland, Ohio
Posts: 18
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Re: 90 Z cranks but will not start
I do have an update. I went ahead and ordered fuel pumps from a link on the site, got the car and the pumps to my mechanic. He found that the hose and come off but the pumps themselves were fine. Hope that makes sense, I did not get any more details when I picked it up. He did replace the plastic clamps, as was suggested here. Great that there was decent weather here on Sunday and I got to get out and let the beast breathe. Thanks again everyone for the feedback! Great family to be in.
Sent from my iPhone using ZR-1 Net Registry
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KWood 1st Time Owner 1990 ZR-1[SIGPIC][/SIGPIC] |
01-02-2019 | #19 | |
Join Date: Aug 2012
Location: Ellicott City, MD
Posts: 1,714
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Re: 90 Z cranks but will not start
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Charlie __________ Dredgeguy WAZOO Member 1992 Bright Red/Black ZR1 #246 Dana 4:10 gears Polished LT5 by Haibeck Polished Fikse FM5's with Michelin Pilot Sport 2 Stainless Works headers and cats with Corsa |
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01-02-2019 | #20 |
Join Date: Apr 2016
Location: Birmingham, Alabama
Posts: 60
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Re: 90 Z cranks but will not start
That's great news.
The ZR1 dual pump setup is precarious. When both pumps are running, and all in-tank hoses are tight, it works great. If a hose clamp comes loose, part of the pumped fuel will leak back into the tank resulting in lower fuel pressure at the injector manifold. In a worse scenario such as yours, where the hose comes off, all of the pumped fuel just blows back into the tank resulting in little to no fuel pressure at the manifold. The most aggravating to me was a bad check valve in the secondary pump. When the engine started, both pumps ran and everything seemed fine but when the secondary pump timed out and stopped pumping, the fuel from the primary pump had a path back into the tank, backwards through the secondary pump, resulting in very low pressure at the manifold. (Took me over an extra hour to get home because I kept "running out of gas". Had to coast to the shoulder, restart and then drive until the secondary pump timed out and I "ran out of gas" again. This created some very undesirable lean conditions). A bad check valve in the primary pump will result in loss of fuel pressure at the manifold after the engine shuts down and slower starting because the system has to re-pressurize. But other than that, I don't think a bad check valve in the primary causes any other issues. So, if you have one pump with a bad check valve, and you don't have a replacement, install it on the primary. Or install a primary/secondary reverse wiring harness until you can get a proper repair. I keep one of these harnesses in my Z now. Last edited by mhobtr; 01-02-2019 at 04:44 PM. |
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