Dreaded No Start fixed... for good (hopefully)
06-10-2006, 04:43 PM
#1
Melting Slicks
Thread Starter
Dreaded No Start fixed... for good (hopefully)
After the second stranding event, I finally decided to fix the problem once and for all.
I was never able to successfully diagnose the No Start to my satisfaction.
I'd chased wiring, changed relays, checked connections, checked the clutch safety switch, actually learned what the VATS system does and how to arm and disarm it, but in the end I never really felt that I had isolated the problem, or corrected it.
You just can't trust a car that won't start. Especially if you can't figure out why it won't start, only to have it start just fine a couple of hours later for no aparrent reason.
What's the sense of starting it, only to dread ever turning it off for fear of the Dreaded No Start?
It would almost be OK if I always drove it from home back to home. But gosh forbid if I ever wanted to take it to a car show or go for a long cruize and spend the night somewhere.
If any of you should experience the same frustration here's what to do.
Cut the purple wire inside the big loom just aft of the ECM. Run a hot lead and ground from the battery using #10 wire. Splice into the cranking circuit (it a yellow wire under the dash) using a #10 wire. I found the easiest place to access it is at the CRANK fuse in the secondary fuse panel under the hush panel on the passenger side. I ran a #10 wire through the door vent grommet and carefully hid it up against the firewall, zip tying it to the windshield washer tubes. I used black wire to help in hiding it.
I used a Bosch 5 pole 30/40A relay, here's a link to a common diagram:
http://www.the12volt.com/relays/relays.asp
Connect the purple wire from the starter to the normally open pole #87. Battery 12v goes to pin #30, ground to pin#86, cranking circuit (yellow wire) to pin #85.
I hid the relay just under the ECM, so that it's not immediatly visible, yet still accessable.
What my mod does is to use the 12v that originally triggered the starter to trigger a relay which allows 12v DIRECTLY from the battery to the starter solenoid. The current that triggers the starter solenoid does not wander all over BFE, under the dash, through the clutch switch, VATS, SIR, ECM, CCM, etc., etc.
When you turn the key, the starter WILL engage.
The VATS system can still shut off the fuel and the ignition so even though the car could crank, it won't start if the VATS is triggered.
The cluch safety switch is bypassed, so it is possible to start the car with the cluch out, but that's hardly a major drawback. Anybody that has starting issues usually wires that POS switch out right away.
Now if she won't crank, I've only got three possible things to diagnose. The relay I just installed, the starter/solenoid, or the ignition switch.
Cost of the project, approximately $25, and took about 3 hours to do. Hardest part was getting to the yellow wire under the dash and figuring how to get it through the firewall.
The peace of mind knowing that it will start every time I turn the key?
Priceless!
TomC
'90ZR1 #792
I was never able to successfully diagnose the No Start to my satisfaction.
I'd chased wiring, changed relays, checked connections, checked the clutch safety switch, actually learned what the VATS system does and how to arm and disarm it, but in the end I never really felt that I had isolated the problem, or corrected it.
You just can't trust a car that won't start. Especially if you can't figure out why it won't start, only to have it start just fine a couple of hours later for no aparrent reason.
What's the sense of starting it, only to dread ever turning it off for fear of the Dreaded No Start?
It would almost be OK if I always drove it from home back to home. But gosh forbid if I ever wanted to take it to a car show or go for a long cruize and spend the night somewhere.
If any of you should experience the same frustration here's what to do.
Cut the purple wire inside the big loom just aft of the ECM. Run a hot lead and ground from the battery using #10 wire. Splice into the cranking circuit (it a yellow wire under the dash) using a #10 wire. I found the easiest place to access it is at the CRANK fuse in the secondary fuse panel under the hush panel on the passenger side. I ran a #10 wire through the door vent grommet and carefully hid it up against the firewall, zip tying it to the windshield washer tubes. I used black wire to help in hiding it.
I used a Bosch 5 pole 30/40A relay, here's a link to a common diagram:
http://www.the12volt.com/relays/relays.asp
Connect the purple wire from the starter to the normally open pole #87. Battery 12v goes to pin #30, ground to pin#86, cranking circuit (yellow wire) to pin #85.
I hid the relay just under the ECM, so that it's not immediatly visible, yet still accessable.
What my mod does is to use the 12v that originally triggered the starter to trigger a relay which allows 12v DIRECTLY from the battery to the starter solenoid. The current that triggers the starter solenoid does not wander all over BFE, under the dash, through the clutch switch, VATS, SIR, ECM, CCM, etc., etc.
When you turn the key, the starter WILL engage.
The VATS system can still shut off the fuel and the ignition so even though the car could crank, it won't start if the VATS is triggered.
The cluch safety switch is bypassed, so it is possible to start the car with the cluch out, but that's hardly a major drawback. Anybody that has starting issues usually wires that POS switch out right away.
Now if she won't crank, I've only got three possible things to diagnose. The relay I just installed, the starter/solenoid, or the ignition switch.
Cost of the project, approximately $25, and took about 3 hours to do. Hardest part was getting to the yellow wire under the dash and figuring how to get it through the firewall.
The peace of mind knowing that it will start every time I turn the key?
Priceless!
TomC
'90ZR1 #792
Last edited by Crabs; 06-11-2006 at 12:35 AM.
06-11-2006, 02:56 AM
#2
Drifting
My car has been doing the exact same thing for a few months now. For no apparent reason it just wont crank every once in a while, sometimes it will work after waiting a bit. It does however push start just fine when this happens. Already replaced the starter but that didn't help. Last time it screwed up I checked the voltage where the clutch safety switch is bypassed and sure enough got 12 volts with the key in start. Not sure what to make of it, some kind of occasional short in the purple wire maybe? Keep me informed on how your wire reroute works out, might just do the same if I can't get to the bottom of this.
06-11-2006, 08:35 PM
#3
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Very good workaround. Just to throw some toothless worthless advice in tho, make SURE you find the correct yellow wire under the dash, because yellow is also the SIR (airbag) wiring color code.
06-11-2006, 11:56 PM
#4
Melting Slicks
Thread Starter
Originally Posted by locobob
My car has been doing the exact same thing for a few months now. For no apparent reason it just wont crank every once in a while, sometimes it will work after waiting a bit. It does however push start just fine when this happens. Already replaced the starter but that didn't help. Last time it screwed up I checked the voltage where the clutch safety switch is bypassed and sure enough got 12 volts with the key in start. Not sure what to make of it, some kind of occasional short in the purple wire maybe? Keep me informed on how your wire reroute works out, might just do the same if I can't get to the bottom of this.
It appears to be a semi-common fault in ZR1's. Here's a link to a nice write up in the ZR1 Net Registry:
http://www.zr1netregistry.com/ZR1_nostart.htm
There's another article in the Trouble shooting area which to me made the most sense and which led me to making the mod that I did:
http://www.zr1netregistry.com/ZR1_tr...ting.htm#Start
If you read through it, toward the bottom is the gem which sent me to the Helms manuals and then down to the local Auto parts store:
install a start switch in the cabin that bypasses all the resistive areas.
Not wanting to have something so gauche as a button or toggle hid on a hush panel or in the govebox or the ashtray. I just wanted the key to start the car no matter what.
I did just that.
I'll keep you posted, but I seriously doubt that I'll have bad news...
If you need a little help I can scan the page in the Helms (page 8A-30-0) which has the nicest block diagram of the starting system, and hand draw in the mod that I made.
TomC
'90ZR1 #792
06-12-2006, 12:04 AM
#5
Melting Slicks
Thread Starter
Originally Posted by ZR1Rob
Very good workaround. Just to throw some toothless worthless advice in tho, make SURE you find the correct yellow wire under the dash, because yellow is also the SIR (airbag) wiring color code.
I'd hate to be responsible for somebody getting a face full of airbag just trying to start his/her car.
This is where the Helms manuals and a voltmeter are your friend!
Page 8A-30-0. (for the '90ZR1, probably different page for different year car).
Although this mod was fairly trivial, it does require a basic working knowledge of electronics and wiring.
It would be entirely too easy to fry a wiring harness if the wrong wire got plugged into the wrong place.
So, if you don't feel comfortable playing Sparky the Electrician, by all means have somebody else who knows what they're doing do it.
Please.
TomC
'90ZR1
08-23-2006, 02:09 PM
#6
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No Start fixed... for good (hopefully)
Originally Posted by Crabs
After the second stranding event, I finally decided to fix the problem once and for all.
I was never able to successfully diagnose the No Start to my satisfaction.
I'd chased wiring, changed relays, checked connections, checked the clutch safety switch, actually learned what the VATS system does and how to arm and disarm it, but in the end I never really felt that I had isolated the problem, or corrected it.
You just can't trust a car that won't start. Especially if you can't figure out why it won't start, only to have it start just fine a couple of hours later for no aparrent reason.
What's the sense of starting it, only to dread ever turning it off for fear of the Dreaded No Start?
It would almost be OK if I always drove it from home back to home. But gosh forbid if I ever wanted to take it to a car show or go for a long cruize and spend the night somewhere.
If any of you should experience the same frustration here's what to do.
Cut the purple wire inside the big loom just aft of the ECM. Run a hot lead and ground from the battery using #10 wire. Splice into the cranking circuit (it a yellow wire under the dash) using a #10 wire. I found the easiest place to access it is at the CRANK fuse in the secondary fuse panel under the hush panel on the passenger side. I ran a #10 wire through the door vent grommet and carefully hid it up against the firewall, zip tying it to the windshield washer tubes. I used black wire to help in hiding it.
I used a Bosch 5 pole 30/40A relay, here's a link to a common diagram:
http://www.the12volt.com/relays/relays.asp
Connect the purple wire from the starter to the normally open pole #87. Battery 12v goes to pin #30, ground to pin#86, cranking circuit (yellow wire) to pin #85.
I hid the relay just under the ECM, so that it's not immediatly visible, yet still accessable.
What my mod does is to use the 12v that originally triggered the starter to trigger a relay which allows 12v DIRECTLY from the battery to the starter solenoid. The current that triggers the starter solenoid does not wander all over BFE, under the dash, through the clutch switch, VATS, SIR, ECM, CCM, etc., etc.
When you turn the key, the starter WILL engage.
The VATS system can still shut off the fuel and the ignition so even though the car could crank, it won't start if the VATS is triggered.
The cluch safety switch is bypassed, so it is possible to start the car with the cluch out, but that's hardly a major drawback. Anybody that has starting issues usually wires that POS switch out right away.
Now if she won't crank, I've only got three possible things to diagnose. The relay I just installed, the starter/solenoid, or the ignition switch.
Cost of the project, approximately $25, and took about 3 hours to do. Hardest part was getting to the yellow wire under the dash and figuring how to get it through the firewall.
The peace of mind knowing that it will start every time I turn the key?
Priceless!
TomC
'90ZR1 #792
I was never able to successfully diagnose the No Start to my satisfaction.
I'd chased wiring, changed relays, checked connections, checked the clutch safety switch, actually learned what the VATS system does and how to arm and disarm it, but in the end I never really felt that I had isolated the problem, or corrected it.
You just can't trust a car that won't start. Especially if you can't figure out why it won't start, only to have it start just fine a couple of hours later for no aparrent reason.
What's the sense of starting it, only to dread ever turning it off for fear of the Dreaded No Start?
It would almost be OK if I always drove it from home back to home. But gosh forbid if I ever wanted to take it to a car show or go for a long cruize and spend the night somewhere.
If any of you should experience the same frustration here's what to do.
Cut the purple wire inside the big loom just aft of the ECM. Run a hot lead and ground from the battery using #10 wire. Splice into the cranking circuit (it a yellow wire under the dash) using a #10 wire. I found the easiest place to access it is at the CRANK fuse in the secondary fuse panel under the hush panel on the passenger side. I ran a #10 wire through the door vent grommet and carefully hid it up against the firewall, zip tying it to the windshield washer tubes. I used black wire to help in hiding it.
I used a Bosch 5 pole 30/40A relay, here's a link to a common diagram:
http://www.the12volt.com/relays/relays.asp
Connect the purple wire from the starter to the normally open pole #87. Battery 12v goes to pin #30, ground to pin#86, cranking circuit (yellow wire) to pin #85.
I hid the relay just under the ECM, so that it's not immediatly visible, yet still accessable.
What my mod does is to use the 12v that originally triggered the starter to trigger a relay which allows 12v DIRECTLY from the battery to the starter solenoid. The current that triggers the starter solenoid does not wander all over BFE, under the dash, through the clutch switch, VATS, SIR, ECM, CCM, etc., etc.
When you turn the key, the starter WILL engage.
The VATS system can still shut off the fuel and the ignition so even though the car could crank, it won't start if the VATS is triggered.
The cluch safety switch is bypassed, so it is possible to start the car with the cluch out, but that's hardly a major drawback. Anybody that has starting issues usually wires that POS switch out right away.
Now if she won't crank, I've only got three possible things to diagnose. The relay I just installed, the starter/solenoid, or the ignition switch.
Cost of the project, approximately $25, and took about 3 hours to do. Hardest part was getting to the yellow wire under the dash and figuring how to get it through the firewall.
The peace of mind knowing that it will start every time I turn the key?
Priceless!
TomC
'90ZR1 #792
91 woultdnt't start:
SOLENOID IS HOT ? After about a 10 or 15 minute engine shut down period
- Installed a Start switch FIRE DIRECTLY = NO VOLTAGE DROP:
Relay 30A The starter solonoid 12V battery - purple wire.
I CONTINUE WITH THE SAME PROBLEM.
CORRECTIVES MEASURES:
- Starter motor affected by water intrusion ? changed by one new !
- Clutch switch ? = Bypassing the switch !
- Battery ? = changed by a new one !
- VATS system ?: "Security" lamp on the cluster should be off when the
ignition is on = New Key =OK!!
SOLUTION ?
He car can be pushed by hand with the ingnition key in the RUN position
and the gearshift in the Second gear = ok!
Some solution idea to the problem?
Thank you
Frank ZR1 91
08-24-2006, 07:16 AM
#7
I went through all of those symptoms and components several years ago. Push start worked, but was embarassing as hell. I finally had the entire secondary (aftermarket) alarm and remote door/lock system removed. I have not had a no start since. Just one more thing to consider. 
08-24-2006, 03:24 PM
#8
Pro
I did almost the same thing about 3-years ago. Same issues, and also had an aftermarket alarm and remote door locks. Like Tom, I started troubleshooting, but never really found the problem.
I don't recommend bothering with the yellow wire under the dash, just for fear of using the wrong one and detonating your airbag. Instead, just use a 4-pole relay and bypass the purple wire just the same. You can do it all next to your battery and it literally takes 10-minutes.
I did this over 3-years ago, and my Z has always started ever since, so for those of you with the same problem, you can do this mod and it should fix your problem.
Nice part is, I still have my aftermarket alarm/door locks, VATS, and clutch switch all working, and she still starts.
I don't recommend bothering with the yellow wire under the dash, just for fear of using the wrong one and detonating your airbag. Instead, just use a 4-pole relay and bypass the purple wire just the same. You can do it all next to your battery and it literally takes 10-minutes.
I did this over 3-years ago, and my Z has always started ever since, so for those of you with the same problem, you can do this mod and it should fix your problem.
Nice part is, I still have my aftermarket alarm/door locks, VATS, and clutch switch all working, and she still starts.
08-24-2006, 05:45 PM
#9
Melting Slicks
Thread Starter
Originally Posted by jaymitchell01
I don't recommend bothering with the yellow wire under the dash, just for fear of using the wrong one and detonating your airbag. Instead, just use a 4-pole relay and bypass the purple wire just the same. You can do it all next to your battery and it literally takes 10-minutes.
I'm assuming that you took the starter engage signal from the purple wire itself and then used it to open the circuit from the battery to the starter solenoid. It makes sense as it takes much less current to switch the relay than it does to engage the solenoid.
I chose getting the signal from the yellow wire under the dash because I was not absolutely positive that there wasn't a wiring problem between the ignition switch and the ECU. My goal was to reduce the number of variables as best I could.
You can be sure that I was VERY careful on which yellow wire I spliced into.
TomC
'90ZR1 #792
08-24-2006, 06:32 PM
#10
Pro
Originally Posted by Crabs
Jay:
I'm assuming that you took the starter engage signal from the purple wire itself and then used it to open the circuit from the battery to the starter solenoid. It makes sense as it takes much less current to switch the relay than it does to engage the solenoid.
I chose getting the signal from the yellow wire under the dash because I was not absolutely positive that there wasn't a wiring problem between the ignition switch and the ECU. My goal was to reduce the number of variables as best I could.
You can be sure that I was VERY careful on which yellow wire I spliced into.
TomC
'90ZR1 #792
I'm assuming that you took the starter engage signal from the purple wire itself and then used it to open the circuit from the battery to the starter solenoid. It makes sense as it takes much less current to switch the relay than it does to engage the solenoid.
I chose getting the signal from the yellow wire under the dash because I was not absolutely positive that there wasn't a wiring problem between the ignition switch and the ECU. My goal was to reduce the number of variables as best I could.
You can be sure that I was VERY careful on which yellow wire I spliced into.
TomC
'90ZR1 #792
08-24-2006, 07:57 PM
#11
Burning Brakes
I did the exact same thing to my car and it fixed the no start problem once and for all. The only difference is that I put my relay under the intake right beside the starter. When I started to investigate the issue I would have 12.5 volts at the battery but only about 11 volts up at the starter soliniod. the relay took car of all the issues and with it at the starter itself I only had about 6" of wiring.
08-24-2006, 11:41 PM
#12
Pro
Originally Posted by trophystock
I did the exact same thing to my car and it fixed the no start problem once and for all. The only difference is that I put my relay under the intake right beside the starter. When I started to investigate the issue I would have 12.5 volts at the battery but only about 11 volts up at the starter soliniod. the relay took car of all the issues and with it at the starter itself I only had about 6" of wiring.
08-25-2006, 11:50 AM
#14
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After the relay of 30A in the purple wire is 12,3V. measure made in the package of cables beside the ECM and I continue with the problem without starting up warm.
There are three yellow 10 gage wires on the relay socket.
I have taken out the 3 yellow bridges and I have put in their place a relay.
Is this operation correct?
There are three yellow 10 gage wires on the relay socket.
I have taken out the 3 yellow bridges and I have put in their place a relay.
Is this operation correct?
09-18-2006, 04:18 PM
#15
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Originally Posted by jaymitchell01
Instead, just use a 4-pole relay and bypass the purple wire just the same. You can do it all next to your battery and it literally takes 10-minutes.
I have been having the curious No-start RPO in my 91 a couple of times a year, last time this sunday.
I plan to do the modification during this week and also help my friend Francisco (he lives just 20 miles from me here in Spain) do the same.
thanks!!
09-18-2006, 04:21 PM
#16
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Originally Posted by jaymitchell01
Instead, just use a 4-pole relay and bypass the purple wire just the same. You can do it all next to your battery and it literally takes 10-minutes.
I have been having the curious No-start RPO in my 91 a couple of times a year, last time this sunday.
I plan to do the modification during this week and also help my friend Francisco (he lives just 20 miles from me here in Spain) do the same.
thanks!!
09-18-2006, 05:31 PM
#17
Melting Slicks
Thread Starter
Originally Posted by JordiZR1
Hi Jay, could you please elaborate a bit your description of the bypass?
I have been having the curious No-start RPO in my 91 a couple of times a year, last time this sunday.
I plan to do the modification during this week and also help my friend Francisco (he lives just 20 miles from me here in Spain) do the same.
thanks!!
I have been having the curious No-start RPO in my 91 a couple of times a year, last time this sunday.
I plan to do the modification during this week and also help my friend Francisco (he lives just 20 miles from me here in Spain) do the same.
thanks!!
In it's most simple form, here's a rough drawing of the starter bypass.
Simply cut the purple wire in the main loom and install the relay, wiring in 12V and ground directly from the battery.
Hope this helps!
TomC
'90ZR1
09-19-2006, 02:20 AM
#18
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From the drawing, I assume the purple wiring goes from the ECM bundle to the starter, and what we are doing is cutting it and installing the realy in between, so the purple wire now triggers the relay sending 12v directly from the batery to the solenoid via the rest of the same purple wire (if it is the one that is connected to the solenoid).
Am I right? am I mising something?
thanks for the scheme.
Am I right? am I mising something?
thanks for the scheme.
09-19-2006, 01:00 PM
#19
Melting Slicks
Thread Starter
Originally Posted by JordiZR1
From the drawing, I assume the purple wiring goes from the ECM bundle to the starter, and what we are doing is cutting it and installing the realy in between, so the purple wire now triggers the relay sending 12v directly from the batery to the solenoid via the rest of the same purple wire (if it is the one that is connected to the solenoid).
Am I right? am I mising something?
thanks for the scheme.
Am I right? am I mising something?
thanks for the scheme.
If if the current/voltage supplied to the solenoid via the wiring harness drops below a certain threshold value, the solenoid will not engage the starter and the car won't start when the motor is hot.
The suspected cause of this current/voltage drop is a temperature related increased resistance somewhere in the wiring harness, electrical connections, relays, VATS, or ECM.
When the engine cools and the resistance drops below that threshold value, the engine will restart.
The 4 pole solenoid effectively bypasses the resistance issue by using the voltage supplied via the purple wire to open a circuit directly between the battery and the starter solenoid.
TomC
'90 ZR1 #792
09-23-2006, 03:00 PM
#20
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OK, last night I installed the relay, at least in cold the car starts without problems, so I guess the wires are installed right
Time will tell if the problem is definitely solved.
Time will tell if the problem is definitely solved.