Overheating coil?
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
In that case, assuming all three coils are good, there is too much resistance upstream. Bad ballast resistor, faulty connections, etc. Table this concern for now and repeat the measurement during the failure condition.
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Posting Guru
Joined: Nov 2011
Posts: 1,302
Likes: 5
From: Burlington, WI
Ok just drove to the hardware store and back. Died twice in the parking lot. Just shut off kind of died. Twisted the key and she fired right back up though...twice in a row (within 30 seconds). Why is this happening? Same reason as the no spark issue?
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Posting Guru
Joined: Nov 2011
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Likes: 5
From: Burlington, WI
If it had no spark it wouldve kept cranking instead of starting back up the way it normally does. I'll reword my original statement.
---2 scenarios---
1. Truck dies. Turn key, cranks forever with no spark (gets gas because it wreaks of it).
2. Truck dies. Turn key, truck fires right up.
Both times the truck dies like the key is turned off. Only half of the time does it ever restart on command. The test given was for scenario #1. Since that did not occur, the test was not performed.
Better? Feel like I've confused a lot of folks so there ya go. Interesting issue isn't it?
---2 scenarios---
1. Truck dies. Turn key, cranks forever with no spark (gets gas because it wreaks of it).
2. Truck dies. Turn key, truck fires right up.
Both times the truck dies like the key is turned off. Only half of the time does it ever restart on command. The test given was for scenario #1. Since that did not occur, the test was not performed.
Better? Feel like I've confused a lot of folks so there ya go. Interesting issue isn't it?
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
I don't know what to tell you. I've given you measurements to take during the failure condition. You seem to only do one or the other: capture measurements in the absence of the failure, or neglect measurements in the presence of the failure. Nobody can answer vague questions like "why does this happen" or "why does it smell like this" without step-by-step troubleshooting. I'll check back in to this thread when you've got some useful data.
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Posting Guru
Joined: Nov 2011
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From: Burlington, WI
tell me: how do I take data readings for a failure for situation #2? Far as I know, there's none to be taken. Ive been told to gather numbers when there is no spark...aka situation #1. One of the 2 situations above always happens. Not both at the same time. Just one at a time. In this case, #2 happened. Why did it choose to run this time and not stay dead like before? Beats me. It's hit or miss as to what it does. Turning the key is the only way to find out what it will do. Thats about all I can say.
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MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Your goal should not be to try and gather explanations for all observed behavior and correlate them together the first try. It's very simple: the next time the engine will not start and simply cranks in the absence of spark, take this very basic measurement at the coil with the key left in RUN. This will tell you if the module is even trying to ground the coil in the first place.
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Posting Guru
Joined: Nov 2011
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From: Burlington, WI
Correct and that's what I want to do. However, as we all know, to even see if the engine will crank to determine if there is spark or not, the key must be turned. Sometimes turning the key starts the truck, sometimes not. I do not have control over that at all. I will get that measurement if/when it just cranks and does not restart.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
We must be getting a wire crossed somewhere. Please let me know if this is not clear: when you find yourself holding the key, the engine is cranking, but not starting after a reasonable amount of time, immediately stop what you're doing, and leave the key in RUN. Walk over to the front of the truck and take the measurement. It's literally as simple as that. Don't overthink it.
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Posting Guru
Joined: Nov 2011
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From: Burlington, WI
Sorry I was misunderstanding you guys yesterday...lots going on in my head lol. Anyways it stalled this morning. No spark at all. Performed test correctly this time.
Battery 12.86 volts
Coil to ground 4.97 volts
Battery 12.86 volts
Coil to ground 4.97 volts
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
All right, that's pretty useful information. You know the coil is getting power, the module is getting power, the coil has continuity, and the module is grounding the coil and is alive at the very least. Your voltage is too low, but it's not different from when it's running.
The next time it won't start, check for spark on the primary side of the ignition system. Connect a test light from the negative (TACH TEST) terminal of the coil to clean, unpainted metal on the engine (ground). Keep the coil connected and crank the engine with the key - the light should BLINK.
If it doesn't BLINK, the next thing to check is the pickup module.
The next time it won't start, check for spark on the primary side of the ignition system. Connect a test light from the negative (TACH TEST) terminal of the coil to clean, unpainted metal on the engine (ground). Keep the coil connected and crank the engine with the key - the light should BLINK.
If it doesn't BLINK, the next thing to check is the pickup module.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
If it BLINKs, then the entire primary side of the ignition system is in working order. If this is the case, yet you do not have spark at the plugs, then the problem is isolated to the secondary side of the ignition system, or spark is not being checked properly. Intermittent or heat-related ignition issues are more common to the primary side, however.