I have a 91 Bronco with 302 motor. It will only start when it is cold. it will not start when it is warm up. I have change the fuel pump, fuel pump relays, fuel filter, tune it up cap, rotor, wires, plugs, Map, the ignition module has been tested and passed when I am trying to start it when hot it will turn over fine but it sound like it is not firing but when I plug the plugs out and check them I am getting spark. after it seats about 30 min. it will start to try to start, I let it seat about 15 min. it will start up and run until I shut it off and try to start it back up again. I have about 30 p.s.i. on the fuel rail.
91 Will Not Start after it heats up needs o cool back down to start
- Thread starter breng5
- Start date
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yo BRENG,
WELCOME!
Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.com/topic/14269-code-reader/?&pid=74587&mode=threaded
Try for at least the KOEO portion, then if running and warmed up to normal operating temp, try the KOER.
WELCOME!
Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
http://broncozone.com/topic/14269-code-reader/?&pid=74587&mode=threaded
Try for at least the KOEO portion, then if running and warmed up to normal operating temp, try the KOER.
Seabronc
New member
That is a classic symptom of the TFI module shorting out when hot.
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yo,
It could be the Hall Effect (Profile Ignition Pick-up (PIP) Signal, Stator, RPM) inside distributor
DTC 14 & 18; Profile Ignition Pickup (PIP) & Troubleshooting; "...The top three leads (for PIP signal) can lose continuity with the back plate (ground) on the module when the unit is hot.
"the Hall Effect Signal is called the “Profile Ignition Pick-up” (PIP) signal. Corroded connectors between the Hall Effect PIP unit in the distributor and the TFI module on the distributor housing are common. Replacing the sensor isn’t as easy on these applications because you have to R&R the distributor shaft."
Source: by Wells Manufacturing
Overview & Wave Form; "...The stator is a Hall Effect device, which uses a magnetic field. It sits under the distributor cap and picks up a signal from a wheel with teeth. (miesk5 NOTE; this wheel is a rotary armature that has open areas called windows and tabs, called vanes). The wheel has the same number of teeth as cylinders in the engine and moves at the same speed as the distributor and camshaft. If you have a V8 then the wheel has eight teeth; seven teeth are the same and one tooth is smaller to identify cylinder #1. As the wheel spins with the distributor is breaks the magnetic field of the hall devise generating a sine wave. This sine wave is called the raw Profile Ignition Pickup (PIP) signal and indicates the engine status at 10deg. BTDC. Now some people think the TFI is responsible for this, but that is incorrect; the PIP signal passes threw the TFI unaltered to the computer. This sensor is so accurate that cam changes can be a bad thing. The computer is programmed when to open fuel injectors in relation to the valve timing from PIP. Changing the valve timing with a cam swap won't be noticed by the computer. So optimal performance and idle will not be to their true potential. As I've said on other pages this sensor is extremely important. Without it working properly the computer never senses the engine moving and the entire vehicle is a paper weight. If you have a distributor mounted TFI, it too can be the problem, because the PIP signal must pass through it to the computer. The stator and TFI both share the same grounds and power circuits, when one fails the other might be bad as well. It's a standard practice at dealerships and most quality repair shops to replace the TFI and stator at the same time. This prevents the problem from re-appearing a few weeks latter..."
Source: by Ryan M (Fireguy50) at http://oldfuelinjection.com/?p=10
Misfiring, Rough Idle, Surge, & Ping-Knock Symptoms, due to a Magnetized Shutter Wheel, (Bronco & all Fords w/EEC IV & TFI); "...Inside the TFI distributor is a Hall-Effect sensor that provides an RPM and POSITION signal to the Ignition module and ECM for fuel and ignition control. Mounted to the distributor shaft is a "shutter-wheel" that passes through the Hall-Effect sensor. The slots or windows cut in the shutter-wheel are what makes the Hall-Effect sensor switch on/off to create the signal it sends out. The shutter-wheel is supposed to be a piece of "dead" steel but can become magnetized. A magnetized wheel can cause very erratic operation of the Hall-Effect and resulting erratic output signal. The Test: There are a couple of ways to check for this condition. One is to simply pull off the distributor cap and see if something steel will "stick" to the shutter-wheel. Make sure that whatever you are using to check the wheel with isn't magnetized itself. A more accurate method would be to watch the wave-form on the "SPOUT" wire with a Vantage or Lab-Scope. The SPOUT is the wire with the connector in it that you unplug to set ignition timing. Monitor the wave-pattern on the SPOUT with the timing-connector in. If there is anything erratic about the wave-form, unplug the timing connector and re-check the wave-form. If the pattern "cleans up" all of a sudden, chances are good that you have a magnetized shutter-wheel. The Fix: Most shutter-wheels can be removed from the distributor shaft with a couple of screws. Everybody seems to have their own way of de-magnetizing the wheels but good success has been had with bulk audio-tape erasers or by placing the wheel in an engine parts cleaning oven and baking it. That last one sounds weird but it works..."
Source: by snapon.com via archive.org
No Start and or Misfire, etc.; Thick Film Ignition (TFI) Testing, Overview & Diagrams, Distributor Mounted Ignition Control Module (ICM); "...Part I; In This Fast Test you'll be able to pinpoint the problem to the Ignition Control Module or the Ignition Coil or the Profile Ignition Pickup Sensor (PIP Sensor) in four easy test steps. This test will only help you in a Cranks but Does Not Start Condition. http://easyautodiagnostics.com/ford_ignition_module/distributor_mounted_module_1.php
It could be the Hall Effect (Profile Ignition Pick-up (PIP) Signal, Stator, RPM) inside distributor
DTC 14 & 18; Profile Ignition Pickup (PIP) & Troubleshooting; "...The top three leads (for PIP signal) can lose continuity with the back plate (ground) on the module when the unit is hot.
"the Hall Effect Signal is called the “Profile Ignition Pick-up” (PIP) signal. Corroded connectors between the Hall Effect PIP unit in the distributor and the TFI module on the distributor housing are common. Replacing the sensor isn’t as easy on these applications because you have to R&R the distributor shaft."
Source: by Wells Manufacturing
Overview & Wave Form; "...The stator is a Hall Effect device, which uses a magnetic field. It sits under the distributor cap and picks up a signal from a wheel with teeth. (miesk5 NOTE; this wheel is a rotary armature that has open areas called windows and tabs, called vanes). The wheel has the same number of teeth as cylinders in the engine and moves at the same speed as the distributor and camshaft. If you have a V8 then the wheel has eight teeth; seven teeth are the same and one tooth is smaller to identify cylinder #1. As the wheel spins with the distributor is breaks the magnetic field of the hall devise generating a sine wave. This sine wave is called the raw Profile Ignition Pickup (PIP) signal and indicates the engine status at 10deg. BTDC. Now some people think the TFI is responsible for this, but that is incorrect; the PIP signal passes threw the TFI unaltered to the computer. This sensor is so accurate that cam changes can be a bad thing. The computer is programmed when to open fuel injectors in relation to the valve timing from PIP. Changing the valve timing with a cam swap won't be noticed by the computer. So optimal performance and idle will not be to their true potential. As I've said on other pages this sensor is extremely important. Without it working properly the computer never senses the engine moving and the entire vehicle is a paper weight. If you have a distributor mounted TFI, it too can be the problem, because the PIP signal must pass through it to the computer. The stator and TFI both share the same grounds and power circuits, when one fails the other might be bad as well. It's a standard practice at dealerships and most quality repair shops to replace the TFI and stator at the same time. This prevents the problem from re-appearing a few weeks latter..."
Source: by Ryan M (Fireguy50) at http://oldfuelinjection.com/?p=10
Misfiring, Rough Idle, Surge, & Ping-Knock Symptoms, due to a Magnetized Shutter Wheel, (Bronco & all Fords w/EEC IV & TFI); "...Inside the TFI distributor is a Hall-Effect sensor that provides an RPM and POSITION signal to the Ignition module and ECM for fuel and ignition control. Mounted to the distributor shaft is a "shutter-wheel" that passes through the Hall-Effect sensor. The slots or windows cut in the shutter-wheel are what makes the Hall-Effect sensor switch on/off to create the signal it sends out. The shutter-wheel is supposed to be a piece of "dead" steel but can become magnetized. A magnetized wheel can cause very erratic operation of the Hall-Effect and resulting erratic output signal. The Test: There are a couple of ways to check for this condition. One is to simply pull off the distributor cap and see if something steel will "stick" to the shutter-wheel. Make sure that whatever you are using to check the wheel with isn't magnetized itself. A more accurate method would be to watch the wave-form on the "SPOUT" wire with a Vantage or Lab-Scope. The SPOUT is the wire with the connector in it that you unplug to set ignition timing. Monitor the wave-pattern on the SPOUT with the timing-connector in. If there is anything erratic about the wave-form, unplug the timing connector and re-check the wave-form. If the pattern "cleans up" all of a sudden, chances are good that you have a magnetized shutter-wheel. The Fix: Most shutter-wheels can be removed from the distributor shaft with a couple of screws. Everybody seems to have their own way of de-magnetizing the wheels but good success has been had with bulk audio-tape erasers or by placing the wheel in an engine parts cleaning oven and baking it. That last one sounds weird but it works..."
Source: by snapon.com via archive.org
No Start and or Misfire, etc.; Thick Film Ignition (TFI) Testing, Overview & Diagrams, Distributor Mounted Ignition Control Module (ICM); "...Part I; In This Fast Test you'll be able to pinpoint the problem to the Ignition Control Module or the Ignition Coil or the Profile Ignition Pickup Sensor (PIP Sensor) in four easy test steps. This test will only help you in a Cranks but Does Not Start Condition. http://easyautodiagnostics.com/ford_ignition_module/distributor_mounted_module_1.php
Seabronc
New member
Agree with miesk5. On older ignitions it was usually the pickup.
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>-I had the same problem of not starting until it cooled down. In my case it was a faulty coolant temperature sensor. On my older 302 it is on the connector for the heater hose under the throttle body. I also agree that the ignition module can act that way.
I am not sure if I have fix it 100 % yet but I found so far I had a bad fuel pump relay, and I just change the coolant temperature sensor and I have tested the truck in the garage and right now it is starting up and running and after I shut it off it is now starting up again. maybe Friday I can take it out for a real test ride and see how it does on restarting after it has had some harder run time on it. thanks for all the help so far. can anyone tell me what the timing is to be set at and the tester I have now says the spout connecter is open should this be open or closed to run right.
Seabronc
New member
Timing is normally controlled by the computer. If the SPOUT connector is not hooked up, the engine defaults to basic timing. Normal is for the SPOUT connector to beclosed, it is a jumper wire. The basic timing and procedure should be on the emissions control sticker. IE, you set the basic timing to spec without the spout connector hooked up and then when it is hooked up the computer takes over control of the timing.
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ok I finally had time to work on it some more and what I found out is the water coolant temperature sensor had been pull out and hide on top of the motor a manual gauge for temperature had been put in the wrong spot. move the manual gauge to the right spot and put in a new coolant temperature sensor and it runs again I did have to reset the computer and right now its learning what the setting are again.... now the only time it stalls out is when I am stopping while the motor is under a heavy load when I am pushing snow. it has never stall out when I have been plowing with it for the last 3 years this is something new so I hope after a few more time out driving and plowing that will clear up as the computer learn again or is their something else I should be looking out at ... when I am driving it down the road and stop its does not stall out ... if I let up on the gas paddle easy and slow it will not stall out when I am plowing .. but if I just take my foot off of it and let the weight of the snow stop the truck I am pushing it will stall
Thanks again for all the help you all have given
Thanks again for all the help you all have given
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