No crank condition - need suggestions - ZR-1 Net Registry Forums

KFoster · 10-22-2015

I haven't found this issue, but I bet someone has covered it. 1990 ZR1 will not crank at times. Did it a few times this summer and I thought it was temp related as it cranked fine cold, but then it would not engage starter. No cranking, but all electrics worked fine. Leave it to cool over and it would fire right up. Now, it does it cold. Leave it alone for a few hours and it will crank right up. Maybe a sticking relay? Clutch switch? Any ideas? In my experience, relays won't just unstick. You can tap on them and get them to work, but in this case I did not do that. Did nothing more than leave it alone and try it later. Now I'm afraid to turn it off anywhere but home. Help.

RussMcB · 10-22-2015

I think the first step would be to prepare for bypassing a lot of things the next time it happens, so you can send 12v directly to the starter from the battery. That will tell you if it is starter-related or not.

To prepare, you need to locate the "purple wire" that goes from the ECU (correction - UNDER the ECU) to the starter. Make some kind of jumper connection so you can connect 12v to that wire. You will, of course, need to make sure the car is out of gear.

If the starter works with your jumper wire, then you can start debugging the other possibilities, such as VATS, clutch switch, etc. If the jumper doesn't solve the problem then you'll need to remove the plenum and troubleshoot in the starter area.

If you do a search for Purple Wire in this forum you will get plenty of details and pictures.

Oh, and park on hills. :-)

Off topic: Can we see a pic of your Pantera?

KFoster · 10-22-2015

Hopefully this will show up.

RussMcB · 10-22-2015

Nice! I like how you two dressed to match the car. :-)

We Gone · 10-22-2015

http://www.zr1.net/forum/showthread.php?t=21388

Check the sticky at the top of the page lots of great info.

http://www.zr1.net/forum/showthread.php?t=16778

RICHARD TILL · 10-23-2015

The contacts in the solenoid would also be a likely suspect. Fixed mine twice with the same problem. Cheap fix. I`m about 75 miles east of you. Shout if you need any help.

KFoster · 10-23-2015

Richard, I appreciate it. I didn't think about the solenoid. Never had one act like that, but could be. I will try to bypass the clutch switch when it does it again and then check the solenoid. Good ideas from everyone.

Dynomite · 10-23-2015

Exactly as Richard, Steve, and Russ suggest.....but messing with the Starter requires a bit of surgery requiring you put the car to sleep (that is my euphemism for removing some coolant) which is required unless......unless....you block TB Coolant

Starter, Starter Relay, Wiring Harness, Battery, and Plugs Tricks

Electrical Ground Connections and Installing Starter Relay

See this link for TB Coolant Blocking drilling and threading details Injector Housing TB Coolant Blocking

I have blocked TB Coolant in an LT5 without removing the Injector Housings (recommend removing the two Injector Housing Coolant Manifolds however).

Paul Workman · 10-23-2015

Quote:

Originally Posted by KFoster

Richard, I appreciate it. I didn't think about the solenoid. Never had one act like that, but could be. I will try to bypass the clutch switch when it does it again and then check the solenoid. Good ideas from everyone.

Marc Haibeck presented these procedures at the Bowling Green spring gathering, one or a couple years ago. This and much more info is also on his site. For you reading pleasure...

Z51JEFF · 10-23-2015

THE PURPLE STARTER WIRE DOES NOT COME FROM THE ECM. The wire runs UNDER the ECM. Misinformation will only add to the confusion here folks.

10-22-2015	#1
KFoster Join Date: Jan 2015 Location: Decatur, AL Posts: 93	No crank condition - need suggestions I haven't found this issue, but I bet someone has covered it. 1990 ZR1 will not crank at times. Did it a few times this summer and I thought it was temp related as it cranked fine cold, but then it would not engage starter. No cranking, but all electrics worked fine. Leave it to cool over and it would fire right up. Now, it does it cold. Leave it alone for a few hours and it will crank right up. Maybe a sticking relay? Clutch switch? Any ideas? In my experience, relays won't just unstick. You can tap on them and get them to work, but in this case I did not do that. Did nothing more than leave it alone and try it later. Now I'm afraid to turn it off anywhere but home. Help. __________________ 1990 ZR1, 1987 Mustang GT (since new), 1973 DeTomaso Pantera, 1987 928S4 Passed on: 1984 930S (gray market), 1988 Mustang Coupe Trooper car(drag)

10-22-2015	#2
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,160	Re: No crank condition - need suggestions I think the first step would be to prepare for bypassing a lot of things the next time it happens, so you can send 12v directly to the starter from the battery. That will tell you if it is starter-related or not. To prepare, you need to locate the "purple wire" that goes from the ECU (correction - UNDER the ECU) to the starter. Make some kind of jumper connection so you can connect 12v to that wire. You will, of course, need to make sure the car is out of gear. If the starter works with your jumper wire, then you can start debugging the other possibilities, such as VATS, clutch switch, etc. If the jumper doesn't solve the problem then you'll need to remove the plenum and troubleshoot in the starter area. If you do a search for Purple Wire in this forum you will get plenty of details and pictures. Oh, and park on hills. :-) Off topic: Can we see a pic of your Pantera? Last edited by RussMcB; 10-24-2015 at 09:03 AM. Reason: Z51JEFF yelled at me for spreading misinformation.

10-22-2015	#4
RussMcB Join Date: Jan 2015 Location: Marietta, GA USA Posts: 1,160	Re: No crank condition - need suggestions Nice! I like how you two dressed to match the car. :-)

10-22-2015	#5
We Gone Join Date: Apr 2004 Location: ATL. GA. Posts: 2,170	Re: No crank condition - need suggestions http://www.zr1.net/forum/showthread.php?t=21388 Check the sticky at the top of the page lots of great info. http://www.zr1.net/forum/showthread.php?t=16778 __________________ Steve 1990 Steel Blue/Black #2355 1990 Red/Red #1473 1991 Quasar /Black #118 Sold 1991 Turquoise/Black #766 Parted Out 1993 Yellow/White #179 Sold 1990 Black/Gray #1361 Headers/4:10s Sold

10-23-2015	#6
RICHARD TILL Join Date: Aug 2005 Location: Iuka, Mississippi 38852 Posts: 756	Re: No crank condition - need suggestions The contacts in the solenoid would also be a likely suspect. Fixed mine twice with the same problem. Cheap fix. I`m about 75 miles east of you. Shout if you need any help.

10-23-2015	#8
Dynomite Join Date: Aug 2009 Location: South Dakota/California Posts: 3,797	Re: No crank condition - need suggestions Exactly as Richard, Steve, and Russ suggest.....but messing with the Starter requires a bit of surgery requiring you put the car to sleep (that is my euphemism for removing some coolant) which is required unless......unless....you block TB Coolant Starter, Starter Relay, Wiring Harness, Battery, and Plugs Tricks Electrical Ground Connections and Installing Starter Relay See this link for TB Coolant Blocking drilling and threading details Injector Housing TB Coolant Blocking I have blocked TB Coolant in an LT5 without removing the Injector Housings (recommend removing the two Injector Housing Coolant Manifolds however). __________________ 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; 10-23-2015 at 01:52 PM.

10-23-2015	#10
Z51JEFF Join Date: Dec 2007 Location: Fremont,Ca Posts: 3,068	Re: No crank condition - need suggestions THE PURPLE STARTER WIRE DOES NOT COME FROM THE ECM. The wire runs UNDER the ECM. Misinformation will only add to the confusion here folks. Last edited by Z51JEFF; 10-23-2015 at 11:15 PM.