Hey all, so my Bronco is exhibiting even more starting trouble. It is an '86 5.0 EFI Manual trans.

It still starts normally when it has sat and is cold, but it still doesn't start when it gets hot. Usually only after getting off the freeway. It has to cool for 30-45 minutes before it'll start. If I try, it turns over really slowly, as if the battery is almost dead.
This is an obvious safety problem, being a manual transmission.
I thought the starter was bad, so I replaced it. No avail. I thought it might be overheating the starter, so I put titanium header wrap on the exhaust by the starter. Still nothing helped.

Last night, I was teaching my girlfriend how to drive my Bronco, so I made sure it didn't get hot so if she killed it, it would turn over regularly. She killed it in the middle of state street, and it was nice and cold. However, it would build fuel pressure, turn over very powerfully, and crank for a long time, but it didn't even seem to be firing. No matter if I gave it gas or not, the pitch didn't change, and it just wouldn't start.
Embarrassingly, a cop in a Charger pulled up and luckily his brush guard lined up with my hitch, and he pushed me until I could pop start it.

It's getting to the point where it's scary to drive my Bronco because I don't know if it'll get me where I'm going. The 6" lift, 35" tires, and stock 3.73 gearing doesn't make it easier not to kill anyway.

Does anyone have any suggestions?

 

Is this the tfi ignition system or duraspark? I dont remember

 

I have no idea, but I don't think the ignition would account for the starter's difficulty when hot. After getting off the freeway, it will usually turn over 2 or 3 times somewhat normally, but really slows down after that. It reduces to 1 cycle every couple seconds, which is not nearly fast enough to start the engine.

 

Can you pull the EEC codes? That might be able to narrow it down a lot more

 

However, it would build fuel pressure, turn over very powerfully, and crank for a long time, but it didn't even seem to be firing.
Not ignition related?
Okie Dokie.

 

Why is cranking RPM reduced, that's the key? Let us know what you find!

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Next time it does this check the positive cable going to the starter and see how hot it is. It may be as simple as changing it to a larger gauge cable. It takes more power to turn a hot engine over so it may be too much voltage drop. You also should check your ground cables. Chassis and engine ground. Make sure they are clean and tight. Make sure all connections are clean and tight in the starting circuit from the batt to solenoid and to starter.

 

I'm sorry, I meant no disrespect. In my reply, I meant to state that there may be two separate problems that coincidentally have to do with starting.

The problem you're referring to sure is boggling, considering it would turn over like a champ but wouldn't fire, but fired right up as soon as i pop started it.

I apologize if is sounded like I was undermining your opinion, I greatly value your input.

I will pull any codes ar my auto parts store, take the freeway back, and inspect the wire. I'll let you guys know how it goes

 

No appology necessary. I have very thick skin. And this is an online forum.

 

Alright, just ran the codes. It pulled:
DTC 44: Thermactor air system fault
DTC 34: Evap control system fault; High voltage - Defective EGR transductor sensor
DTC 77.

I heated my Bronco up quite a bit before I went in, and it had a very hard time starting, but it did start. However, as I had my hood up for the code reader, I noticed that something was smoking in the engine bay as I was cranking the starter. I immediately got out and felt all the wires, starter, solenoid, etc and everything was cool or luke-warm. I have no idea what was smoking, but I will have a friend try to look down and pinpoint it.

 

So, I had a buddy help me today. I heated it up, shut it off, and had him crank it as I looked for the source of smoke.

There was none. I don't know if I was just seeing things, or if the smoke fixed itself, but no smoke came out.

I once again checked for excessive heat at the battery, solenoid, the entire wire, and the starter. All were relatively cool or warm.

Also, as I was having him crank it, for the very first time it stopped cranking all together. It became so overwhelmed that it wouldn't even chug a full cycle.
I waited half an hour, and it fired right up with no hesitation.

I'm getting frustrated, and I'm about to the deadly point of blindly replacing ****. Does anyone have any ideas?

Thanks for the ongoing interest in my POS Bronco

 

Smoke will not "fix itself", although the magic smoke may have been used up! Ha ha, seriously - It may be simply a loose connection. Maybe.

This is not only inconvenient it can result in expensive repairs.. The voltage and current that should be going to the starter is taking a different path. Hopefully it's just roasting cables, and not something unpronounceable, difficult to get at and expensive. Voltage drop testing with a meter will show this. If you measure 0.8th of a volt between one cable that is too much, for example.

The electrical demands at startup are somewhere between 500 and 1000 ampere hours. Means practically all of the rated battery current is drawn upon in a split second when you turn the key. If any connection in the path is loose or corroded it will produce lots of heat instead of going to the starter itself. Clean all the ground connectors and the block and frame, and/or replace cables would be generally a good, ah, start. A file, wire brush, scotch-brite, wire wheel, grinder. Use what you have but bend a wrench on all the major connections and see if that helps.

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Okay, that's what I'll try. Should I only clean the onections that have to do with the starter system, or try to find them all?

 

Think about installing new cables - it's easier unless you're stuck in the woods. Just replaced the solenoid/switch to starter cable for my old truck, this (finally) makes for all cables new on the F100.

Cable was 50 years old.

Too lazy to post a link here but there is a photo of it in my garage.Your truck isn't too far behind. Found a big ole gouge, probably from before the truck was bought by me, out of the insulation that never noticed or forgotten about, it's all corroded from the middle and the ends. Turns out t's just as much trouble to remove and clean, as it is replace them, the crimping corrodes too, and the copper wire gets brittle as they get smoked.

Speedway, ordered it online yesterday, installed it this afternoon. 16 bucks plus shipping.

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This sounds an awful lot like battery cables to me. The rubber coating on them breaks down over time, allowing moisture into the cables where they corrode and carry less and less current. Heat can definitely affect this problem.

If your battery cables are original, they ought to be changed by now anyway.