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I have had My Bronco for 10 years and that whole time it has not been dependable. The latest problem that has been going on for about 2 years now is it will just shut off. When it does everything still works except the engine will not run. Until recently if I was going down the road when it happened and kept it in gear it would usually start back up and may or may not run fine again after a few seconds.Now when it happens I have to wait 1-3 minutes but it always starts back up. It usually has a slight loss of power and will spark knock under acceleration when its going to act up or after it has. This is happening almost everyday now............

When I first start it everything is normal. After I drive it more than @ 3 miles and shut it off and restart it the Volt gauge will read less than 14 volts. and usually will not go up over 14 again until it sets awhile.( but not always) I have used a multimeter and everywhere under the hood has 14.3 volts.( ALt. Fuse, Batt. Solenoid) Its getting fuel and the pressure is good.
Twice in the last 2 weeks I have turned the key and the volt gauge did not work but the others did. Those times the truck would not start. This is a new symptom. Also when I turn my heater fan on my volt gauge drops to almost 13 volts.

I have done a 3g install, replaced the cap rotor and wires with ford racing and motorcraft parts.
New TPS. New TFN. I have cleaned the AIC and taken it back apart a couple times to see if I missed anything.

Do any of You have any ideas where to check next? :whiteflag
 

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Yo bluesuper74,
Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
Post Code(s) here according to:
KOEO & KOER

A helper can assist you by counting the codes. Some use their smart phones to record them.
BEWARE OF FAN, BELTS, PULLEYS, HOT HOSES, IGNITION HIGH TENSION WIRES, AND ENGINE COMPONENTS
Or ask local mom and dad parts stores if they will test it for you. The majority of parts chain stores tests just OBDII vehicles now.
Or purchase a coder reader such as;
"Innova ODB-1 and we generally recommend getting the extension cord with it, so you can work the ignition key in the cab while watching/holding the reader. It will save the codes but knowing when to go through the cycles and ensuring you get it right the first time can save time and hassle, especially if you're working on it by yourself, as most of us do." by BikerPepe`


Next is, Cranks but How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L) @ https://troubleshootmyvehicle.com/ford/4.9L-5.0L-5.8L/how-to-troubleshoot-a-no-start-1


VOLTAGE;
Battery that is fully charged produces 12.6 volts at rest with engine off and all lights and accessories off.
Inspect the terminals for loose or corroded connections.
Are battery connections including grounds to frame, intake manifold etc., clean and tight?

by El Kabong @
"Cheesy clamp on end. Do not use for a long term repair. Only to get you home when nothing else is available. If you have one of these, suspect it before anything else" El Kabong @ https://www.fullsizebronco.com/forum/21-noobie-bronco-tech-questions-flame-free-zone/165569-common-replies-faqs.html

When you turn the key to "RUN/START" and there's no spring resistance feeling it usually because the actuator inside steering column is broken or ignition switch is loose.
Overview; "...The ignition rod is attached the upper ignition actuator by a 3/32 x 38 roll pin ($0.12 each) and the rod needs to be straight so it travels enough to trigger the igniton switch but it's a chore to take it off as you need to remove the steering wheel and tear it down to the (Tilt or Non-Tilt) knuckle, usually down when you replace a broken upper ignition actuator. The ignition switch located on the lower part of the steering column has slots so it can be adjusted by loosening the 2 -7/16 nuts and move it up or down but a lot depends on what's wrong up top with some of the other parts, ie: ignition rod, key cylinder, lower igniton actuator and upper igniton actuator. These parts are timed so when you turn the key to RUN they all need to move forward/downward so the rod triggers the igniton switch to START the BKO..."

Accessories that fail to operate with the key in RUN, or that remain on when the key is turned off, may be the result of a misadjusted ignition switch rather than a malfunctioning ignition switch.

Test the ignition system mechanical operation by rotating the ignition switch lock cylinder through all positions of the ignition switch. The movement should feel smooth with no sticking or binding. The ignition system should return from the START position back to the ON position without assistance (spring return). If sticking or binding is encountered, check for the following:
burrs on the ignition switch lock cylinder
binding ignition switch lock cylinder
shroud rubbing against ignition switch lock cylinder
burrs or foreign material around the rack-and-pinion actuator in the housing of the ignition switch lock cylinder
insufficient lube on actuator
binding ignition switch

The ignition switch can be adjusted by loosening the mounting screws, and sliding as described in above link.
 

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I have had My Bronco for 10 years and that whole time it has not been dependable. The latest problem that has been going on for about 2 years now is it will just shut off. When it does everything still works except the engine will not run. Until recently if I was going down the road when it happened and kept it in gear it would usually start back up and may or may not run fine again after a few seconds.Now when it happens I have to wait 1-3 minutes but it always starts back up. It usually has a slight loss of power and will spark knock under acceleration when its going to act up or after it has. This is happening almost everyday now............

When I first start it everything is normal. After I drive it more than @ 3 miles and shut it off and restart it the Volt gauge will read less than 14 volts. and usually will not go up over 14 again until it sets awhile.( but not always) I have used a multimeter and everywhere under the hood has 14.3 volts.( ALt. Fuse, Batt. Solenoid) Its getting fuel and the pressure is good.
Twice in the last 2 weeks I have turned the key and the volt gauge did not work but the others did. Those times the truck would not start. This is a new symptom. Also when I turn my heater fan on my volt gauge drops to almost 13 volts.

I have done a 3g install, replaced the cap rotor and wires with ford racing and motorcraft parts.
New TPS. New TFN. I have cleaned the AIC and taken it back apart a couple times to see if I missed anything.

Do any of You have any ideas where to check next? :whiteflag
Out of curiosity have you checked the relays on the harness over the driver front wheel well? I had a similar issue for years on my 91 and it tuned out that the fuel pump relay was bad and shorting out under certain conditions causing stuttering and the engine to quit for a few minutes before starting back up like nothing happened.

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a couple things come to mind
ignition module getting hot and crapping out, coil , you need to see what part of the holy trilogy is missing when it dies,fuel ,spark ,or compression(not likely)
or even a bad connection heating up

could also be a fuel filter clogging up after you run it a bit, fuel tank not venting and not allowing fuel, cat converter?exhaust plugging up not allowing engine to exhale ,
a lean mixture will cause power loss and pinging

so many possibilities ,but you need to narrow down to what is missing when it dies

by chance,do you have an aftermarket tach?
I have seen them fail when hot in such a way they ground out the ignition acting like a kill switch

also check for a vacuum leak
my wives Chrysler town and country minivan 3.8v6 has started stalling out every once in a while with no reason when she lets off the throttle
turns out it has a vacuum leak at the intake to head gasket and would suck air in more when throttle plates were closed and cause a lean stall out
it would always restart right away for her
 

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I would absolutely start at the tfi ignition/distributor. If you have a spare Motorcraft tfi, swap it in. Mine did same when I initially bought it, new tfi fixed. I've relocated the tfi to a heat sink mounted on the inner fender to aleviate the heat issue with the tfi.. Easy just to buy replacement /rebuilt distributor with new tfi and see if that fixes it.

Bratcop

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speaking of the TFI, did you use a good layer of the heat sink paste on the entire back contact surface when you installed it?

if not you can fry a new one in a short time and it can do exactly as your truck is doing
 

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And non Motorcraft ones are always touchy and you have to be sure to get the right color gray or black typically your big box auto parts store has no idea there's any difference

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After going through the electrical and ignition system as noted above, you may want to check your ECU. Here was my ordeal, skip to the last page to see the details.\


https://www.fullsizebronco.com/forum/21-noobie-bronco-tech-questions-flame-free-zone/464665-hot-weather-stall-something-another-thing-4.html



If this is the case, you can just solder in new capacitors, just make sure they are a good name brand and you can use a higher voltage, just same uF.

BTW, I laughed when I cut the sticker on the ecu that voided the warranty.
 

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