Need your ideas - LT5 won?t turnover - Page 2 - ZR-1 Net Registry Forums

Mikey · 02-12-2022

3 months??

Innovation Performance Technologies in Aberdeen, NC (near Pinehurst) is owned by a friend of mine.. might want to have them do future work. They're not LT5 gurus but anything else C4 is pretty much all the same and they are very competent. Ask for Jon or Crimson and tell them I sent you.

tf95ZR1 · 02-12-2022

Keeping it simple (KISS) are they depressing
the clutch pedal all the way to the floor?

richarde · 02-13-2022

It sounds as though the problem is linked to the Clutch Safety Switch, in particular the Clutch Neutral Start Switch Rod. As it can be difficult to bleed all the air from the clutch hydraulics after replacing both the master and slave cylinders, an over aggressive use of the clutch pedal (repeatedly side slipping it when fully depressed in an attempt to rid the system of air) can sometimes break / disengage the switch rod. This would lead the no start situation described. The part number of the Switch Rod is 14080260.

-=Jeff=- · 02-13-2022

Have you tried to unplug the clutch safety switch put a jumper across the terminals and try to start it? Also you can add a relay (in an older post here) that will use all the switches to power the relay then the relay runs from battery directly to the starter.

It is also possible the starter contacts are carbon covered but I think it is the CSS and related circuit

lfalzarano · 03-01-2022

Update, the mechanic did test the clutch safety switch Feb 4 and tested OK. He retested it again on the Feb. 21 and had to replace it. It starts fine now!

Thanks for all your suggestions and ideas. The mechanic at Chevy is questionable.

When I went to pick it up shifting was laborious and the clutch didn?t engage until an inch from the firewall. (This all started with the clutch hydraulics going out and shattered the clutch, which was the original repair request to the dealer!)

Add to that the idle wouldn?t come down below 2000rpm. It was impossible to drive with both conditions.

So it remains in the shop. [emoji20] we?re approaching the 4 month anniversary of no ZR-1[emoji35]

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richarde · 03-02-2022

So, the clutch pedal needs to be depressed to the floor before disengaging. A few suggestions spring to mind.
The most obvious one is whether the clutch hydraulics have been successfully bled to rid all air from the system.
Another visual check - both the clutch and brake pedal should be very close to being the same height from the floor when looking into the car. If the clutch pedal is appreciably lower than the brake pedal, the problem could be that the full stroke of the clutch master cylinder is not being obtained. If you find this to be the case, the reason could be a bent clutch pedal bracket or pushrod, or even an incorrect specification master cylinder. Having a new clutch with lots of meat on the centre plate can exaggerate this issue.
If the above checks out OK, moving to the clutch slave cylinder, ensure that it is of the correct specification for both bore size and stroke.

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lfalzarano · 03-02-2022

Quote:

Originally Posted by richarde

So, the clutch pedal needs to be depressed to the floor before disengaging. A few suggestions spring to mind.
The most obvious one is whether the clutch hydraulics have been successfully bled to rid all air from the system.
Another visual check - both the clutch and brake pedal should be very close to being the same height from the floor when looking into the car. If the clutch pedal is appreciably lower than the brake pedal, the problem could be that the full stroke of the clutch master cylinder is not being obtained. If you find this to be the case, the reason could be a bent clutch pedal bracket or pushrod, or even an incorrect specification master cylinder. Having a new clutch with lots of meat on the centre plate can exaggerate this issue.
If the above checks out OK, moving to the clutch slave cylinder, ensure that it is of the correct specification for both bore size and stroke.

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Thanks for your ideas. I?ve been forwarding your comments to the Chevy service manager.

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lfalzarano · 03-02-2022

Another mystery is why an apostrophe being replaced by with a ? mark on this forum?[emoji16]

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A26B · 03-02-2022

A bent clutch fork can also cause a low pedal disengagement. Bent and broken clutch forks are an infrequent but known occurrence in the ZR-1.

Lets see an apostrophe '', and a Question mark???
Showed up fine from my keyboard

secondchance · 03-02-2022

Quote:

Originally Posted by A26B

A bent clutch fork can also cause a low pedal disengagement. Bent and broken clutch forks are an infrequent but known occurrence in the ZR-1.

Lets see an apostrophe '', and a Question mark???
Showed up fine from my keyboard

Bent clutch fork happened to me about 10 years ago. Apostrophe being replaced with question mark happens when I use iPad for posting.

02-12-2022	#11
Mikey Join Date: Jul 2020 Location: Nashville TN Posts: 323	Re: Need your ideas - LT5 won?t turnover 3 months?? Innovation Performance Technologies in Aberdeen, NC (near Pinehurst) is owned by a friend of mine.. might want to have them do future work. They're not LT5 gurus but anything else C4 is pretty much all the same and they are very competent. Ask for Jon or Crimson and tell them I sent you.

02-12-2022	#12
tf95ZR1 Join Date: Aug 2005 Location: Northridge, CA Posts: 1,461	Re: Need your ideas - LT5 won?t turnover Keeping it simple (KISS) are they depressing the clutch pedal all the way to the floor? __________________ 1995 ZR-1 #106 Blk/ Blk Owned by me since 2000. 93K miles, but not on motor :-) Mods the way I want it, Not afraid to drive it!

02-13-2022	#13
richarde Join Date: Sep 2012 Location: United Kingdom Posts: 68	Re: Need your ideas - LT5 won?t turnover It sounds as though the problem is linked to the Clutch Safety Switch, in particular the Clutch Neutral Start Switch Rod. As it can be difficult to bleed all the air from the clutch hydraulics after replacing both the master and slave cylinders, an over aggressive use of the clutch pedal (repeatedly side slipping it when fully depressed in an attempt to rid the system of air) can sometimes break / disengage the switch rod. This would lead the no start situation described. The part number of the Switch Rod is 14080260. __________________ Richard 1990, numbers 1821 and 2391 1821 - owned since Nov 2002, charcoal / Gray, Stainless headers, B&B system, 4.10's 2391 - owned since Jan 2019, Black / Black, have completed restoration. Jeal headers, Corsa system, 4.10's, Aluminum flywheel with Carolina clutch.

02-13-2022	#14
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,169	Re: Need your ideas - LT5 won?t turnover Have you tried to unplug the clutch safety switch put a jumper across the terminals and try to start it? Also you can add a relay (in an older post here) that will use all the switches to power the relay then the relay runs from battery directly to the starter. It is also possible the starter contacts are carbon covered but I think it is the CSS and related circuit __________________ 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

03-01-2022	#15
lfalzarano Join Date: Feb 2011 Location: Clayton, North Carolina Posts: 1,133	Need your ideas - LT5 won?t turnover Update, the mechanic did test the clutch safety switch Feb 4 and tested OK. He retested it again on the Feb. 21 and had to replace it. It starts fine now! Thanks for all your suggestions and ideas. The mechanic at Chevy is questionable. When I went to pick it up shifting was laborious and the clutch didn?t engage until an inch from the firewall. (This all started with the clutch hydraulics going out and shattered the clutch, which was the original repair request to the dealer!) Add to that the idle wouldn?t come down below 2000rpm. It was impossible to drive with both conditions. So it remains in the shop. [emoji20] we?re approaching the 4 month anniversary of no ZR-1[emoji35] Sent from my iPhone using ZR-1 Net Registry __________________ Lou[COLOR="Red"][B][SIZE="4"][/SIZE][/B][/COLOR] Last edited by lfalzarano; 03-01-2022 at 01:32 PM.

03-02-2022	#16
richarde Join Date: Sep 2012 Location: United Kingdom Posts: 68	Re: Need your ideas - LT5 won?t turnover So, the clutch pedal needs to be depressed to the floor before disengaging. A few suggestions spring to mind. The most obvious one is whether the clutch hydraulics have been successfully bled to rid all air from the system. Another visual check - both the clutch and brake pedal should be very close to being the same height from the floor when looking into the car. If the clutch pedal is appreciably lower than the brake pedal, the problem could be that the full stroke of the clutch master cylinder is not being obtained. If you find this to be the case, the reason could be a bent clutch pedal bracket or pushrod, or even an incorrect specification master cylinder. Having a new clutch with lots of meat on the centre plate can exaggerate this issue. If the above checks out OK, moving to the clutch slave cylinder, ensure that it is of the correct specification for both bore size and stroke. Sent from my iPad using ZR-1 Net Registry __________________ Richard 1990, numbers 1821 and 2391 1821 - owned since Nov 2002, charcoal / Gray, Stainless headers, B&B system, 4.10's 2391 - owned since Jan 2019, Black / Black, have completed restoration. Jeal headers, Corsa system, 4.10's, Aluminum flywheel with Carolina clutch.

03-02-2022	#19
A26B Join Date: Dec 2003 Location: Arcadia,OK Posts: 3,394	Re: Need your ideas - LT5 won?t turnover A bent clutch fork can also cause a low pedal disengagement. Bent and broken clutch forks are an infrequent but known occurrence in the ZR-1. Lets see an apostrophe '', and a Question mark??? Showed up fine from my keyboard __________________ Jerry Downey JERRYS LT5 GASKETS & PARTS http://www.jerrysgaskets.com 1994 *ZR-1*, Black/Black, Lingenfelter Aerobody, 416cu in, 3.91 gears, coil-over susp, Brembo brakes, etc. 2016 Black-Red, 3LT-Z51 Auto 8-speed.