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Ignition key needs to be released to get spark to start engine?
OK once again I need to rely on you experts on the forum. I have had my 1965 L76 for like 20 years since around 2000. I remember it had a touchy start problem from around 2010 but would start if I released the key once the engine was turning over. A hassle for someone else trying to start it (great anti theft device) so I can get it going. Needless to say nothing was really changed back in 2010. But I finally decided its got be the ignition switch or solenoid. Well I put a whole new solenoid on it and nothing changed. I have attached a current pic of the wires to the solenoid poles. I have been told by others far smarter than me that usually the small wires are crossed and the purple wire and pink/black wire needs to be swapped. But I believe per the pics I have seen on the web and the wiring diagram they are in the correct spot. I then even sprang for a correct 1965 year NOS #660 ignition switch thinking that could be it. Swapped it out but nothing has changed. I still need to let off the key to get fire. I can live with it and have so far but it takes the right touch to let off the key to get fire to start the car. Someone that does not know the trick will not start it and basically flood it. This a TI car so wondering does that have anything to do with this problem? Just finally figured I would get off my butt and ask you guys if you have any ideas. Others have said replace the solenoid again or swap the wires. I can easily swap the wires but they seem correct, but you never know. Also do not want to cause a short with TI. I don't think a swap of wires will do it but I blew a pulse amplifier once on this car. Anyway I was hoping someone that has more electrical knowledge than me can suggest what they would do.
Tux
I don't know anything about TI ignition, but you should have 12v going to the distributor via the black/pink stripe wire from the starter while the key is in the cranking position. This would be the first thing I would verify. I hope someone doesn't come right along and say you idiot that's not how TI works.
Do you have a 1963 Corvette Shop Manual and 1965 Supplement? If not buy them before you proceed. They will have proper wire diagrams. Don't believe what you read on the internet or some guy just guessing.
It sounds like the TI is not getting 12V power during cranking. So you need to understand the wiring, audit you car for conformance and do some trouble shooting like checking to see if there is voltage at the coil during cranking.
We are fortunate that these cars for the most part have simple DC electrical systems, and you can troubleshoot just about anything with the factory wiring diagrams and an inexpensive multimeter.
...would start if I released the key once the engine was turning over...it takes the right touch to let off the key to get fire to start the car. This a TI car so wondering does that have anything to do with this problem? J
More than likely.
Pull the harness connector from the TI amp and inspect terminals for corrosion, clean it up if necessary, some dielectric grease won't hurt and then press it back on being sure it is fully seated. Verify that the TI amp has its ground wire intact and grounded. There are two resistor wires on this system. Check both ends at the coil and connector to ignition.
I have the shop manual and supplemental and the multimeter to test the coil. So will review the diagrams in depth now that I am at this point. I should be able to check all that you guys mentioned this weekend. Another thing is about a year ago I had an NCRS guy that has a shop install a whole new set of wiring for the car since it had not been done since the early 90's. It did help to get rid of a lot of other electrical gremlins. This starting problem was already there before the rewire and its still there. So that's why I went with the solenoid and ignition switch first. I will check the purple wire and coil for fire while cranking and also the TI amp and harness etc. If I really can't figure it out I can take the car back to the rewire guy since he has messed with it before but he is about 150 miles away and he will have to work me in. I will post again once I know more.
If whomever worked on the car rewired it with a correct harness then you or a familiar assistant will be able to diagnose this with a 12 volt test lamp and a multimeter.
Whatever it is, its simple to fix but likely take some effort to find. Get out the wiring diagram and find the missing 12 volts to the coil during crank. The 65 shop manual has a detailed troubleshooting regimen for TI which is a fairly simple system. If you follow the instructions patiently and thoroughly you will find the problem.
This diagram shows BOTH TI and non-TI wiring, so follow the one you want. Notice that the + and - for the coil for TI is shown on the black wires from the TI instead of pink from ballast.
Just last week I fixed a 66 BB TI car with the same problem.
Voltage to the TI system during crank is critical. The Solenoid R terminal ensures the crank voltage to the TI Pickup Coi(in distributor]) and TI Amp is at its highest potential. If voltage is low then it won't fire the system.
By design, a single Key-on or Key-off will produce one trigger pulse in the Amp and results in one spark to the IGN coil. That's why on a inoperative TI system it will try t.o start but won't. Any TI fault could exhibit itself this way...... a single spark like it's trying to start.
Since you get it to start on occasion it's likely a, low/marginal voltage problem during Crank.
During Crank, measure voltage at BAT, then Solenoid R(pink/blk). They should be identical/within a few tenths of a volt. I suspect your Solenoid internal contacts are corroded and you're getting a substantial voltage drop at R output, so much so that the Amp and PU Coil are not at proper operating voltage.
You could try a simple verification test. Jumper the Solenoid Bat and R terminal. Then Crank. It may start right up.
On that 66 I worked on we had 11.5V on BAT and 9.2 v on R during Crank,a Big drop in voltage through the solenoid. We changed the solenoid and car started properly.
Also, ensure your Battery is in top condition and always fully charged. TI requires optimal voltage to operate during Crank.
Rich
PS.TI IGN coil does not get battery voltage(12v) during crank. By design it's about 2.4v . Also with IGN ON, apx the same. At Crank, IGN Coils+ gets its input from the Amp, not the Solenoid R. R powers the TI Amp and PU coil only.
Just last week I fixed a 66 BB TI car with the same problem.
Voltage to the TI system during crank is critical. The Solenoid R terminal ensures the crank voltage to the TI Pickup Coi(in distributor]) and TI Amp is at its highest potential. If voltage is low then it won't fire the system.
By design, a single Key-on or Key-off will produce one trigger pulse in the Amp and results in one spark to the IGN coil. That's why on a inoperative TI system it will try t.o start but won't. Any TI fault could exhibit itself this way...... a single spark like it's trying to start.
Since you get it to start on occasion it's likely a, low/marginal voltage problem during Crank.
During Crank, measure voltage at BAT, then Solenoid R(pink/blk). They should be identical/within a few tenths of a volt. I suspect your Solenoid internal contacts are corroded and you're getting a substantial voltage drop at R output, so much so that the Amp and PU Coil are not at proper operating voltage.
You could try a simple verification test. Jumper the Solenoid Bat and R terminal. Then Crank. It may start right up.
On that 66 I worked on we had 11.5V on BAT and 9.2 v on R during Crank,a Big drop in voltage through the solenoid. We changed the solenoid and car started properly.
Also, ensure your Battery is in top condition and always fully charged. TI requires optimal voltage to operate during Crank.
Rich
PS.TI IGN coil does not get battery voltage(12v) during crank. By design it's about 2.4v . Also with IGN ON, apx the same. At Crank, IGN Coils+ gets its input from the Amp, not the Solenoid R. R powers the TI Amp and PU coil only.
Rich, as a K66 owner I appreciate your knowledge here.
Rich,
Thanks for giving me more intricate details on TI. I wish you were close to me as I would ask you to let me drive it over to your place. I will track it down but watching you do it and learning that way since you have been down this road before is right up my alley! I'm cautious with TI since when I shorted that old pulse amplifier 10 years ago I had pulled the negative battery cable while the car was running to check to see if the alternator was charging. That used to work for me on an old Z28 with points in high school pre computer day cars. But found out the hard way $$ that TI cars are another animal.
Tux
Yes original Delco TI Modules are very sensitive. The service manuals and even the AIMs frown on pulling more than one plug to check spark. Loose the coiled wire even worse.
It can be a challenge to diagnose faults on a TI system but experience helps.
So did you get a chance to test the solenoid? Please post back with your findings for future reference.
I recently went through an R terminal failure. It took me quite a while to diagnose it. The algorithms for the TI ignition would all come back to the pulse amplifier after all my multimeter tests showed within tolerance. Finally after speaking with Dave st TI Specialties, I found out you need a full 11 volts at the + side of the coil while cranking to start. To me it sounds like you are not getting your R terminal circuit to close until the solenoid is disengaging. It should close when your solenoid engages and remain closed until it disengaged. I would believe that the contacts in your solenoid are worn. Depending on how the bench test of the solenoid was done, it may show to be a functional starter since the R terminal circuit does close, just not for the entire time the starter is engaged.
Have not had a chance to check anything other than visually. Wires all "look" good and in the right place. I hope to do it tomorrow otherwise I will be delayed for a couple weeks. As you know I can get it it to start and it runs fine once I get her up and running. Yesterday she cranked right up but I had the "touch" with the key. This coming week the extra house I have that is my man cave is being sold. This is the car's home. So I am moving some stuff over to another place. So having to pack up stuff and getting crunched for time. While this diagnosis should really not take that long, right now I have to find somebody handy to turn the key for me. Also no access here to a lift. Got jack stands but not into that like I used to be. Solenoid was replaced less than a year ago and I was having this problem before that and still do. Could still be the problem, but after changing the ignition to an NOS 660 I also still have the problem. Based on that I think its somewhere in between. But will still run the test you all mentioned. Dave Fielder had sent me a new pulse amplifier when I blew the old one several years back. I will put my multimeter on it tomorrow when it running to check for volts at the battery, coil and so on. I just got to find a helper to turn the key and if I had a lift I would be golden. Can use my self starter and jump start it off the battery and neutral switch purple harness wire but not sure if that will mess it up with TI. I just remember we could do that with points cars. I like this TI buggy but I would not mind right now having a point system!
Thanks to you all for giving me sound advice. I feel embarrassed to say it was an easy fix but I learned a lot more about TI. Since the wife was not around to turn the key I went ahead and did the easy one man stuff yesterday. I went with Dan's suggestion of pull the harness connector from the TI amp. Also did it at the distributor. Both looked seated and fine but I still roughed the spades up a little and put some dialectic grease on them. Then seated them again. I turned the key and it fired up the normal way. I did it several more times so I could believe it. Then went for a cruise and was still working correctly after that. Just got back from a Sunday drive and still starting correctly. So it was a very easy fix and I got lucky. Once I get someone around that can turn the key I am still going to test the volts off the coil at crank and volts down at the solenoid. Its amazing how sometimes its something very simple. I should of got off my butt and messed with it a long time ago. Just seems like I was not getting any or enough volts at crank based on the connection. Will know more when I test at crank when I get a key turner and go with the two man job.
I went with Dan's suggestion of pull the harness connector from the TI amp. Also did it at the distributor. Both looked seated and fine but I still roughed the spades up a little and put some dialectic grease on them. Then seated them again. I turned the key and it fired up the normal way. I did it several more times so I could believe it. Then went for a cruise and was still working correctly after that. Just got back from a Sunday drive and still starting correctly. So it was a very easy fix and I got lucky.
You were not lucky. You were the average case. In most cases a problem such as the one you experienced is simple and easy to correct. That's why I said what I did in post #4. Its not that the posts that followed weren't valid, its that more often than not you need not go that far. Bad connections have plagued mankind since the beginning. You are the third case I know of here with a similar TI difficulty resolved after re-seating connectors.
So... This is good. But as I mentioned in my earlier post, ANY TI fault can result in a no start during crank and once the key is released you get a SINGLE spark, by design. When the Amp is powered up, or down, this is what occurs.
Now, if it was in fact a intermittent in one of the two re-connections you made, keep a eye on them for a while if the problem reoccurs. However, for future diagnosis, its best to do only one at a time. You did both at once. I'm in the realm in my experiences to always try to find "root cause", meaning to be confident in the test result, make one change then retest, then the next change, retest.
Years ago I had a no start, one spark key off fault as yours. It happened to be on a 427/435 break in after a complete rebuild. Distributor was NOS. All testing yielded pass. Harness ohmed pass, known good Amps, verified harness to Amp internal connections, etc. Particularly suspect was then the PU coil in the distributor as that's all that was left. I measured across the 2 leads and got the 500 to 700 ohms, static, ie, at rest. I pulled it and clamped in a vice. Reran test rotating it. Still good. Then it got intermittent, occasional open circuit. Wiggling the wire as it entered the bottom, same intermittent fault so the wires were not shorted to ground or each other. It was open somewhere.
I disassembled the unit and removed the original Delco PU coil. I then dissected it. The lead going to the internal micro-wire winding inside was a cold solder joint. I repaired it, reassembled, and ran fine. Car has been fine over 9 years now.
Any fault can send you on a journey. Yes always best to start simple, but your initial fault still leads me to think it still may be a good idea to verify your voltage at Solenoid R during crank. TI is very sensitive to voltage input and the slightest variation can confuse it.
This action would also give confidence that one of the 2 connections you touched was the final correction.... Or not.
That TI car I helped with a few weeks ago had a very similar outcome. Battery was not 100%, with intermittent start and key-off single spark. New solenoid fixed it after measuring high voltage drop at R during crank.
If I were you I'd want to verify this last item before I could close out the repair, feel confident about the testing, and ship the car back to the owner.
So... This is good. But as I mentioned in my earlier post, ANY TI fault can result in a no start during crank and once the key is released ...
Now, if it was in fact a intermittent in one of the two re-connections you made, keep a eye on them for a while if the problem reoccurs....for future diagnosis, its best to do only one at a time. You did both at once. I'm in the realm in my experiences to always try to find "root cause",
If I were you I'd want to verify this last item before I could close out the repair, feel confident about the testing, and ship the car back to the owner. Rich
Rich, again, I appreciate your knowledge of TI systems and I agree heartily with your tip about finding the cause by checking one thing at a time. However in this case I would not want to unnecessarily worry the OP. TI systems are generally reliable as evidenced by its production essentially unchanged from 1964 to 1973, beyond early transistors (less of a problem than many claim) and a poor weather seal. All of the things you write are valid and worth knowing. But more times than not it's a simple matter of the harness connection to the amp as it likely was in this case, a few cases earlier, and my own case about 8 years ago which has not returned.
Rich, again, I appreciate your knowledge of TI systems and I agree heartily with your tip about finding the cause by checking one thing at a time. However in this case I would not want to unnecessarily worry the OP. TI systems are generally reliable as evidenced by its production essentially unchanged from 1964 to 1973, beyond early transistors (less of a problem than many claim) and a poor weather seal. All of the things you write are valid and worth knowing. But more times than not it's a simple matter of the harness connection to the amp as it likely was in this case, a few cases earlier, and my own case about 8 years ago which has not returned.
Dan
Dan I'm in full agreement with simple first, but I'd hate to see the OP get stranded some night. Maybe I'm too **** about root cause. 30 years in electronics engineering I guess. lol
I am in agreement on do one thing at a time and then test to see if that's the fix. You all know I am in the process of moving. So was in the cars garage and I decided to check the easy stuff as described. It was a spur of the moment thing but should have been done one at a time. I replaced that specific pulse amplifier harness back in 2007 from M&H as the original had resistance in it and I could not get spark back then . I actually forgot I did that. The engines harness was replaced not by me but by a retired NCRS guy that has a shop and works on these cars. That was done less than a year ago, along with a new starter and solenoid. I bought a pulse amplifier back in 2012 from Dave Fielder when I stupidly pulled that battery cable and toasted the other one. I think got this problem after 07or after 2012??? Seems like it had slowly gotten worse and then I learned to have the touch to let off the key and get it to fire up. Lived with it but got tired of even some other guys or mechanics that drive these cars have a hard time starting it and flood it. Anyway its "fixed" but I am going to run the tests described above. I am still cautious and wary and want to check the volts. Once I get this move out of the way, and have someone turn the key that will be the next thing. I don't want to mess with it anymore right now as I need it to start for sure so I can drive it over to our other place. We sell this house on Friday so I got this deadline looming and boxes all over the place packing stuff. I will let you know in a few weeks how I come out on those tests. Thanks for your help and listening to my TI saga.
04-14-2021, 07:27 PM
Ignition key needs to be released to get spark to start engine?
