Interesting Problem
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Just a short up date yesterday I changed out the damper which was causing fast bleed off in the fuel line, now pressure holds 4 hours before bleed off to around zero. I also had a spare ICM here so I switched that out the old one had no dielectric grease under it, Ohm check injectors hot all checked out around 17 .1 - 17.5 I did find a bad connector on injector harness was loose no change on no start. Yesterday I also replaced cap and rotor was about 7 years old . I still have to reset IAC and base idle, will get some new plugs also. Runs great but still hard to start when hot after sitting. I just checked spark again on no start color is orange blue.
If it is orange it means it is not getting enough voltage.
I would first try changing your spark plug wires, if that doesn't work, then the coil. Needs a tune up anyway I suppose!
Le Mans Master
Joined: Jul 2004
Posts: 6,221
Likes: 697
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Thread Starter
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
The wires are Taylors and they might have 15K on them max, at night with clam open there is no arching. The spark looked strong and was a good 1/2 inch arch to valve cover. Wondering what would cause voltage drop when hot? may be the coil is bad although it looked ok when I changed out dizzy yesterday
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
The wires are Taylors and they might have 15K on them max, at night with clam open there is no arching. The spark looked strong and was a good 1/2 inch arch to valve cover. Wondering what would cause voltage drop when hot? may be the coil is bad although it looked ok when I changed out dizzy yesterday
Thread Starter
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
I am kind of leaning that way, will try to find out if the coil can suffer from heat soak, the cover on the dizzy dose get hot. That would be about an $ 80.00 good measure, I never just throw parts at this car unless I know they are bad. Not sure if there is a test for the coil will have to open another beer & the FSM again.
Last edited by floridamale; Jan 30, 2014 at 08:01 PM.
Melting Slicks
Joined: Jun 2013
Posts: 3,065
Likes: 39
Yes ignition coils can suffer from heat soak. Typically in regards to heat soak what happens is when the car gets warm, it will stall or run really rough. This is a symptom of a bad ignition coil. So, since it is hard to start when hot, it could be related to the coil. Which is why I suggested replacing it. They are very cheap, not even $50. If it hasn't been changed in a while, then I would change it.
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Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
Yes ignition coils can suffer from heat soak. Typically in regards to heat soak what happens is when the car gets warm, it will stall or run really rough. This is a symptom of a bad ignition coil. So, since it is hard to start when hot, it could be related to the coil. Which is why I suggested replacing it. They are very cheap, not even $50. If it hasn't been changed in a while, then I would change it.
Thread Starter
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
Yes ignition coils can suffer from heat soak. Typically in regards to heat soak what happens is when the car gets warm, it will stall or run really rough. This is a symptom of a bad ignition coil. So, since it is hard to start when hot, it could be related to the coil. Which is why I suggested replacing it. They are very cheap, not even $50. If it hasn't been changed in a while, then I would change it.
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
if it were bad it would fail or show signs of it when engine's running. I would do the ohm tests like the book says. if you have not verified that injectors are working, you should do that before replacing a part.
Thread Starter
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
Burning Brakes
Joined: May 2011
Posts: 838
Likes: 2
From: Louisville Ky
enough to see a strong blue spark turn to an orange one! 
as I said, I may have missed it but didn't see where you checked the signal to the injectors -you know the one, from the ECM?. checking ohms on the injectors is not checking signal.
In my previous message, I referred to checking ohms on the coil, which was the subject we were discussing.
for the record, NO one cares if you solve your problem or not, or how you do it. I'm always curious as to what the issue is, but the burden of communicating is on you, the communicator. your wise guy remark was uncalled for, but that goes with all forums, I reckon.
as I said, I may have missed it but didn't see where you checked the signal to the injectors -you know the one, from the ECM?. checking ohms on the injectors is not checking signal.
In my previous message, I referred to checking ohms on the coil, which was the subject we were discussing.
for the record, NO one cares if you solve your problem or not, or how you do it. I'm always curious as to what the issue is, but the burden of communicating is on you, the communicator. your wise guy remark was uncalled for, but that goes with all forums, I reckon.
Max G’s
Joined: Nov 2008
Posts: 2,751
Likes: 78
From: Monroe OH
NCM Sinkhole Donor
Reading back through this and the mention of the Vats jarred my memory. And this wasn't a Vats issue. I could start the car and drive and stop to get gas or something and it was hard to get started back up. This happened in 08 and last time was on the July 4th weekend and had to leave the car at work because couldn't get started back up. The issue ended up being the Neutral Safety Switch.
Thread Starter
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
Today I was able to test the impulse to the injectors under hot condition no impulse. Car still starts and runs great from a cold start still chasing hot no start condition. I tried plugging in my old CTS by no change although I didn't install it. I could drive this this thing to end of world as long as I don't shut it off.
Last edited by floridamale; Feb 2, 2014 at 11:21 AM.
Instructor
Joined: Aug 2006
Posts: 170
Likes: 0
no srart
Today I was able to test the impulse to the injectors under hot condition no impulse. Car still starts and runs great from a cold start still chasing hot no start condition. I tried plugging in my old CTS by no change although I didn't install it. I could drive this this thing to end of world as long as I don't shut it off.
I would find a good diag. tech. who can use a scope and tell him what is happening and have him scope this out it may safe you a lot of $$$ Well best of luck!
Thread Starter
Safety Car
Joined: Jan 2008
Posts: 3,939
Likes: 1
From: Vero Beach Florida
I believe if I disconnect the entire injector harness I should get an impulse signal from the ECM until I reconnect the injector that is bad if that is the case. Without the harness hooked up and no signal from ECM then I have to look else where. Ideas welcome Thanks 
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
Clean and inspect ALL sensor plug-ins under the hood. Set TPS to spec.
testing spark by grounding a plug is not a test....all that tells you if it has spark or NOT. Yours DOES...so move on. The spark color is going to change depending on the voltage going INTO the system...HEI turns 12v Hi-amp to 40,000V at the plug. That means the smallest drop in battery voltage especially when the alt is not turning will cause a voltage drop in the HEI output. As in ANY electrical circuit, the amount of energy is restricted by the quality of the ground.
get a NEW coolant temp sensor. That's the KEY to most mystery hard start issues.
problem solved.
testing spark by grounding a plug is not a test....all that tells you if it has spark or NOT. Yours DOES...so move on. The spark color is going to change depending on the voltage going INTO the system...HEI turns 12v Hi-amp to 40,000V at the plug. That means the smallest drop in battery voltage especially when the alt is not turning will cause a voltage drop in the HEI output. As in ANY electrical circuit, the amount of energy is restricted by the quality of the ground.
get a NEW coolant temp sensor. That's the KEY to most mystery hard start issues.
problem solved.
Last edited by leesvet; Feb 2, 2014 at 09:21 PM.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
I believe if I disconnect the entire injector harness I should get an impulse signal from the ECM until I reconnect the injector that is bad if that is the case. Without the harness hooked up and no signal from ECM then I have to look else where. Ideas welcome Thanks
You could do this test: disconnect all the injector connectors. Connect a noid light to one connector and plug one of the other connectors into an injector. Crank and check for noid light flashes. Unplug the injector and plug in another one. The noid light should flash with the same intensity. Do that for all the injectors, one at a time. If the noid light flashes are dramatically dimmer for one injector, then that's your problem. There could be more than one bad injector...