No pulse when warm?
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New User
Joined: Jun 2016
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No pulse when warm?
88 F250 with 460 - Several mechanics and myself have been trying to track down why there is no spark and no pulse to the fuel injectors when you try to start the truck warm. When the motor is cool it starts very easy, idles smooth and has plenty of power but if you drive it to Lowes or something to pick up what you need you have to wait for the motor to cool back down before it will start. Does anyone have any suggestion on where to start? Thanks.
Parts replaced:
Solenoid
Starter
Fuel pump
Distributor
Clutch fan
ECM - Double-checked, had the new one tested by the local ford dealership and it tested fine.
Both relays
Battery
Ignition control unit
Plugs and wires
Coil pack
Alternator
Parts replaced:
Solenoid
Starter
Fuel pump
Distributor
Clutch fan
ECM - Double-checked, had the new one tested by the local ford dealership and it tested fine.
Both relays
Battery
Ignition control unit
Plugs and wires
Coil pack
Alternator
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
When you get the no spark situation, unplug the SPOUT connector and see if spark returns. The SPOUT connector will isolation the ignition system from the fuel injection system. If spark returns when you unplug the SPOUT, the issue is somewhere with the EFI system, if the spark still does not come back, the problem is in the ignition system.
Does the truck die at all while driving, or it just refuses to start after you turn it off?
Does the truck die at all while driving, or it just refuses to start after you turn it off?
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Update
So, the truck has been in the shop for 8 weeks this past Monday while they have been trying to figure out what the issue is hence not replying about the test, I did pass the information on to them. When I last talked to them whatever was causing the issue when the truck has warmed up has completely broken as there is now no pulse or spark at all.
The reason they have had the truck so long is because the owner is a friend of a friend so they are working on it as the have time but they have replaced all of the same stuff I have (warrantied it all out thank god) plus they replaced the ignition switch and the issue persists. They have had a regular customer bring in an older ford truck with the same issue where they have replaced the same parts and no luck so we are hopeful that when they figure one out then they will be able to fix them both simultaneously.
If anyone perusing this post happens to have had an issue like this please let me know about any solutions you may have come across so that I can pass the information on to me mechanic, thanks.
The reason they have had the truck so long is because the owner is a friend of a friend so they are working on it as the have time but they have replaced all of the same stuff I have (warrantied it all out thank god) plus they replaced the ignition switch and the issue persists. They have had a regular customer bring in an older ford truck with the same issue where they have replaced the same parts and no luck so we are hopeful that when they figure one out then they will be able to fix them both simultaneously.
If anyone perusing this post happens to have had an issue like this please let me know about any solutions you may have come across so that I can pass the information on to me mechanic, thanks.
Lead Driver
Joined: Jul 2007
Posts: 7,868
Likes: 9
From: Rhode Island
Sounds like the shop really doesn't know what they're doing. The ignition system on these trucks only has three main components - distributor PIP, TFI module and the ignition coil.
The ignition system can be completely isolated from the computer system, and shouldn't take more than a day tops to completely diagnose it.
The ignition system can be completely isolated from the computer system, and shouldn't take more than a day tops to completely diagnose it.
New User
Joined: Jun 2016
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I am also having a somewhat similar issue. When my engine is fully warmed up it has a very hard time starting. Luckily I have not had to wait for the engine to cool down as you have, at least not yet...
When I did a search I came across a lot of heat soak issues with some 460's pertaining to the starter and battery cables. I know you mentioned no spark and no injector pulse, but I know when electrical cables are hotter due to ambient temp they carry less current.
Could the heat soak that effects the starter system also be causing your issue? If so maybe some heat tape or shielding could resolve the issue?
Sorry if my thinking is wrong on this, just thought I would throw this idea out.
When I did a search I came across a lot of heat soak issues with some 460's pertaining to the starter and battery cables. I know you mentioned no spark and no injector pulse, but I know when electrical cables are hotter due to ambient temp they carry less current.
Could the heat soak that effects the starter system also be causing your issue? If so maybe some heat tape or shielding could resolve the issue?
Sorry if my thinking is wrong on this, just thought I would throw this idea out.
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