Heat Soak Solutions??

[vtboy51]

My bronco starts great cold, but struggles to re-start when hot (after being shut off for 15-20 mins or so). I had it into a very reputable shop this week and they confirmed it is suffering from heat soak. I don't really want to add louvers in the hood for added ventilation (not sure that would even work). Are there any solutions?

 

[DirtDonk]

How much does it struggle? Does it start after just a little extra cranking? Or does it risk draining the battery?

 

[Viperwolf1]

If you're having hot start issues with EFI you need to do some tuning and/or troubleshooting. A leaky injector can cause hot start problems. How does the fuel pressure hold after shutdown?

 

[vtboy51]

How much does it struggle? Does it start after just a little extra cranking? Or does it risk draining the battery?

It struggles a lot and drains the battery quite a bit, so much that when it does start I get some good belt squealing. I do have the Fitech EFI and was wondering if there are some settings I can change to help with this.

 

[DirtDonk]

They all heat soak. But there can be different aspects to deal with.
If it’s just the carb getting hot, maybe an insulated gasket an heat shield will cure it.
If the pump is weak a new one “might” fix it.
Or it might not…
Gas evaporating out of the bowl? The previously mentioned insulators and a sealed air cleaner maybe? What air cleaner are you running?
Weak spark not helping?

Speaking of which, just how are you set up?

 

[vtboy51]

If you're having hot start issues with EFI you need to do some tuning and/or troubleshooting. A leaky injector can cause hot start problems. How does the fuel pressure hold after shutdown?

Sorry for the stupid question, but I don't have a pressure gauge on the fuel line, does the FiTech report the pressure on the handheld?

 

[Viperwolf1]

I don't know. I'm a Ford EFI user. I'm sure they have some tech help at the end of a phone number somewhere.

 

[omureebe]

You're asking a simple question with a complicated answer. I have FiTech and had a host of issues that needed to be resolved before getting into the tuning - MAP sensor gasket failure, sticky injector, non-synchronized butterflies.

But if I were you, I would data log and review the data (plus post on the FB FiTech EFI Users group). You'll get some good places to look. And to answer your question on fuel pressure, need to put a mechanical gauge on the supply line at the unit and see something like 60lbs.

 

[vtboy51]

I've been doing a lot of reading on the different Fitech sites and one topic mentioned was the source of my 12v supply (Fitech white wire). I have mined connected to the + of the coil, how about the rest of you?
I've got grab my volt meter tomorrow and see if I get a voltage drop on crank at the coil, I believe they said I need to maintain at least 7volts.

 

[DirtDonk]

Maybe I missed it, but what main wiring harness are you using? And what ignition coil?
If it’s a factory harness then that might not a good place to source reliable voltage.
If it’s an aftermarket harness it depends on whether or not you installed a voltage reducing ballast resistor.

 

[vtboy51]

Maybe I missed it, but what main wiring harness are you using? And what ignition coil?
If it’s a factory harness then that might not a good place to source reliable voltage.
If it’s an aftermarket harness it depends on whether or not you installed a voltage reducing ballast resistor.

The wiring is factory and the coil is a "Flame Thrower", but I don't recall the specs on it. You can see the white wire on the coil terminal, that is what's coming from the Fitech harness.

 

[DirtDonk]

Because the red with green wire to the coil is a reduced power source when running I think it’s too close to the 7v to play with.
You need to find a different source.

 

[nvrstuk]

I know little about FiTech except when connected EXACTLY as their instructions, exactly is the key word here, most people have zero problems. I have a good Bronco buddy that has installed 18 FiTech's on Broncos. He has not had a single issue.

I have 3 buddy's that installed them and they run like crap. Their wiring looks like a hornets nest also-so there ya go!

 

[vtboy51]

I feel like my wiring is pretty clean, for me it was a lack of options as to where the Fitech white "key" wire should connect. For my stock wired '68 the only place I found was the + of the coil. After struggling with warm start issues for a while someone turned my onto the possibility that my voltage source was "dirty" and not adequate, and that is what got me searching for a new source.
Based on all you guys feedback and some google searches I just installed a 4 pin relay, which is triggered off the + of the coil, but now my Fitech gets a clean and constant 14.5v directly from the battery. I'll find out tomorrow if it makes a difference....

 

[nvrstuk]

Hope it's the ticket!

Keep us posted- best of luck.

 

[vtboy51]

Just wanted to update whom ever cares. The relay rewire was pretty straight forward, but I am still having issues with warm starts. My next step will be to get the report log from my Fitech and possible add a fuel pressure gauge. All that is going to need to wait since my sprung a leak in my radiator (original based on the stamping). That set of questions will be posted soon.

 

[DirtDonk]

Looking for a switched power source that’s hot in both ON and START gives you literally only two choices on on early bronco. The red with green wire on the coil like you tried, and the green with red wire on the voltage regulator.
Those are literally the only two circuits that work that way from the ignition switch.
And over all these many years of looking for a source like that, the voltage regulator was always considered the go to connection rather than the ignition wire.
It’s the only one of the two that is 12 V and the only one that would not directly affect the ignition system by drawing power meant for the ignition coil.

By the way, do you still have the radio noise suppression capacitors on the positive side of the ignition coil and the yellow wire to the voltage regulator?

 

[ksagis]

Somewhat obvious thing to try, have you tried opening the hood and taking off aircleaner when you shut down hot to see if problem persists? Might guide to towards heat management and fuel conditions in fuel rail. I've also seen electronics that intermittently act odd when they get hot, where is your computer? If under hood, you might try cooling it off to isolate fuel from electrical issues.

 

[vtboy51]

Looking for a switched power source that’s hot in both ON and START gives you literally only two choices on on early bronco. The red with green wire on the coil like you tried, and the green with red wire on the voltage regulator.
Those are literally the only two circuits that work that way from the ignition switch.
And over all these many years of looking for a source like that, the voltage regulator was always considered the go to connection rather than the ignition wire.
It’s the only one of the two that is 12 V and the only one that would not directly affect the ignition system by drawing power meant for the ignition coil.

By the way, do you still have the radio noise suppression capacitors on the positive side of the ignition coil and the yellow wire to the voltage regulator?

I do have the yellow wire still on the regulator, but am not sure about the capacitors. I don't think so unless they are located under the dash.

Somewhat obvious thing to try, have you tried opening the hood and taking off aircleaner when you shut down hot to see if problem persists? Might guide to towards heat management and fuel conditions in fuel rail. I've also seen electronics that intermittently act odd when they get hot, where is your computer? If under hood, you might try cooling it off to isolate fuel from electrical issues.

I blew a hole in my radiator Sunday, but I plan to try what you suggested once I get things put back together.

 

[DirtDonk]

I do have the yellow wire still on the regulator, but am not sure about the capacitors. I don't think so unless they are located under the dash.

Nope. The capacitors for reducing radio interference are located directly on the voltage regulator and the other one directly on the ignition coil bracket.