[EB_Bucky]

I have a 1995 EB Bronco with the 5.8L engine and about 182k on the odometer. Recently I've been having issues with it not wanting to start (cranks but doesn't start) after leaving it outside overnight (temps between 35~45°F. The car runs absolutely fine if parked in a garage with higher temp, but lately it just doesn't want to start ever since it was parked outside a couple of days ago.
I pulled some OBD1 codes through KOEO test and received the following errors:
114 - IAT sensor out of range
116 - ECT sensor out of range
636 - Transmission oil temp (TOT) out of range

Any suggestions on what could be a possible fix?

 

[BroncMom]

I bet @miesk5 will have the info you need. It make take him a bit to reply but he's our tech manual wizard 😊

 

[Rob_64-365]

I'd be looking at the
(113) intake air charge temp sensor
and the
(116)engine coolant temp sensor.

And when I say I'd be looking at them, I don't mean blindly replace them, I mean to meter the resistance on each sensor and see if they fall within the specified range, because most likely it is one of the two, and replace just the bad one because today's sensors are nowhere near the quality of the original Motorcraft sensors that came on the truck. If you do find one of them out of spec, or reading Open, aka shorted out, replace it. I suspect your 636 is one that is thrown when the truck doesn't know the air temp, so it things the trans temp should start of somewhere near that, and it's not, because ine of those other sensors listed above is bad. That's my guess anyway.

If you do buy a sensor or two, buy Motorcraft if possible, I've had non Motorcraft sensors fail in just over 90 days, so buy the best one you can.

 

[rla2005]

All of those KOEO codes indicate the engine and transmission were not warmed up to operating temperature before running the KOEO tests and Stored Code display.

 

[EB_Bucky]

@rla2005 unfortunately since I'm unable to start the engine, I cannot bring it up to operating temp before the test. Do you have any recommendation on what I could do to mitigate this?

 

[EB_Bucky]

@Rob_64-365 I'll check those two sensors. When cranking, it sounds like the engine is almost about to start for a fraction of a second but then just returns back to cranking. Sometimes, it also feels like the engine is partially running when cranking it and shuts off when I turn off the ignition.

 

[EB_Bucky]

Thanks @BroncMom, I'll keep an eye out for their reply

 

[rla2005]

Do you have any recommendation on what I could do to mitigate this?

Measure the sensors with a meter as previously suggested.

 

[jermil01]

Agree with the above. my $$ is on the coolant temp sensor.

 

[miesk5]

Yo EB,
Welcome to our Big Bronco DIY Community!

DTC 112 to 114; Intake Air Temp (IAT); (Air Charge Temperature [ACT] prior to 1992) Troubleshooting & Possible Causes; Codes 112 to 114 will set a IAT sensor code in the EEC, remove and inspect the sensor it could get contaminated by engine oil , K&N oil (although in their site, they vehemnetly deny this is a cause... they picked and chose to "prove" the point) or dust. Clean the sensor with isopropyl alcohol. If the sensor still fails replace the unit
Cleaning w/Carburetor Cleaner in a 90 5.0; "...also noticed the intake air temperature (IAT) sensor was reading on the cool side, compared with the ambient air temp, so I pulled the sensor out of the intake and found Figure 5: a dirty IAT. I cleaned it with some spray carb cleaner and the truck passed the emissions test!..."
Source: by Brian M at asashop.org

Overview & Testing; "...This measures the temperature of the air entering the engine. Which impacts the fuel ratio; the cooler the incoming air is the denser it is. Denser air can utilize more fuel, giving us even greater accuracy in obtaining our desired air to fuel ratio. Before you start blaming the air charge temperature sensor and replacing it make sure the rest of the coolant system is in good condition. All of the following items will affect the ACT; Coolant level, Radiator Fan, Engine Temperature, read more @ Fuel Injection Technical Library » Air Charge Temperature (ACT)
Source: by Ryan M
Location in an Edelbrock Perfomer Lower Intake Manifold Diagram in a 90 5.8

Source: by SeattleFSB (Seattle FSB)
...

DTC 116 Engine Coolant Temperature (ECT) Sensor Troubleshooting & Possible Causes; "...The ECT sensor is a thermistor, basically a resistor that changes voltage accordingly to temperature changes. It provides a reading that's used by the EEC to change fuel delivery at engine startup to reduce emissions and monitors the temperature of the engine. If you see some rust in it clean it by sanding the surface using a fine grit sandpaper, Also check the connector and wiring..."
Overview & Testing by Ryan M (Fireguy50) @ Fuel Injection Technical Library » Engine Coolant Temperature Sensor (ECT)
...

DTC 636 indicates the output of the Transmission Fluid Temperature (TFT) sensor was out of Self-Test range. The sensor output shows a failure occurred at either the low or high end of the acceptable range. The correct range of measurement is from 0.76 to 4.69 volts for Escort/Tracer and from 0.21 to 3.50 volts for all others.
Possible causes:
Fluid levels not to specification.
Transmission fluid not at operating temperature.
Sensor resistance out of limits.
Damaged Powertrain Control Module (PCM)
●
See How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L) by Abraham Torres-Arredondo @ How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L) by Abraham Torres-Arredondo
●
ASAP, find out if speed control recall work, if equipped was completed. If you still have concerns about Recalls, please contact the Ford Customer Relationship Center:
US: 800-392-3673 | CA: 800-565-3673
Note: 3673 spells "FORD" on phone keys
For the hearing- or speech-impaired: Please contact the Telecommunication Relay Service by dialing 71
"Summary: ON CERTAIN PICKUP TRUCKS, PASSENGER VEHICLES, SPORT UTILITY VEHICLES, AND MOTOR HOMES CHASSIS, THE SPEED CONTROL DEACTIVATION SWITCH MAY, UNDER CERTAIN CONDITIONS, LEAK INTERNALLY AND THEN OVERHEAT, SMOKE, OR BURN. THIS COULD RESULT IN AN UNDERHOOD FIRE."

Here's:
1995 Bronco Dealer Brochure @ 1995 Ford Bronco

1995 Bronco/F Series Drivetrain, Powertrain Service Manual - Google Drive
The eight Groups found in this manual are:
00 - Service Information
02 - Engine and Transmission Mounting
03 - Engine
05 - Driveline
07 - Transmission
08 - Clutch
09 - Exhaust System
10 - Fuel System
Each Section covers a component or system. The second set of numbers on each page
indicates the Section.
If the vehicle has more than one type of component, such as two types of engines or power
steering systems, alphabetical suffixes are used.
&
1995 Bronco/F Series Chassis, Service Manual - Google Drive
To switch between folder list & grid views, click the button to the right of the "DOWNLOAD ALL" button in the upper right corner of the window) by HawkDriver
The twelve Groups found in this manual are:
00 - Service Information
01 - Body
02 - Frame and Mounting (Body)
04 - Suspension
06 - Brake System
11 - Steering System
12 - Climate Control System
13 - Instrumentation and Warning Systems
14 - Battery and Charging System
15 - Audio Systems
17 - Lighting
18 - Electrical Distribution
Each Section covers a component or system. The second set of numbers on each page
indicates the section.
If the vehicle has more than one type of component, such as two types of engines or power
steering systems, alphabetical suffixes are used.

See 1995 F 150 Powerstroke 7.3 Turbo Diesel Service Manual @ Ford Service Manuals - Google Drive
In pop-up, click "Drive"

Haynes Red Manual for 80-95 Bronco & F Series @ Hanes guide 80-96 bko f series.pdf via BroncMom!

See my mostly recovered View attachment 202203
site by member schwim @ Ford Bronco And F-150 Links - FORD BRONCO

For any Bronco questions or to chat about it's planned modifications or build, it's better to post each seperately in Noobie Bronco Tech Questions. Flame free zone. This will get more attention and you can build up your post count to get into other sections such as Bronco and Ford Parts/Accessories (50 non-padded posts required to participate, due to scammers who preyed on our members).

Our Forum FAQs includes for example, How to:
Post images
Save (Bookmark) Threads Or Posts
Search The Site
What is the Difference Between the Showcase and Gallery
How To Find Subscribed Thread and more tips!

See How to add your 95s Signature @ Bronco Forum - Full Size Ford Bronco Forum by BigBlue 94

➡ Baba Looey's Favorite FSB Links (lots and lots of tech links)
... Includes such as, How do I fix my back window?

Take time to participate in our current Full-Size of the Month & later in the new year, Full-Size of the Year Contest @ Voting
You will get ideas by those competing.
Prizes are awarded to the winner!; a full spread in Bronco Driver Magazine is the top prize, in addition to a years subscription, once the article is submitted; and a years worth of premium FSB membership.
Al

 

[94Wronco]

Have you checked your basics like fuel air and spark as well?

 

[BroncMom]

Yo EB,
Welcome to our Big Bronco DIY Community!

DTC 112 to 114; Intake Air Temp (IAT); (Air Charge Temperature [ACT] prior to 1992) Troubleshooting & Possible Causes; Codes 112 to 114 will set a IAT sensor code in the EEC, remove and inspect the sensor it could get contaminated by engine oil , K&N oil (although in their site, they vehemnetly deny this is a cause... they picked and chose to "prove" the point) or dust. Clean the sensor with isopropyl alcohol. If the sensor still fails replace the unit
Cleaning w/Carburetor Cleaner in a 90 5.0; "...also noticed the intake air temperature (IAT) sensor was reading on the cool side, compared with the ambient air temp, so I pulled the sensor out of the intake and found Figure 5: a dirty IAT. I cleaned it with some spray carb cleaner and the truck passed the emissions test!..."
Source: by Brian M at asashop.org

Overview & Testing; "...This measures the temperature of the air entering the engine. Which impacts the fuel ratio; the cooler the incoming air is the denser it is. Denser air can utilize more fuel, giving us even greater accuracy in obtaining our desired air to fuel ratio. Before you start blaming the air charge temperature sensor and replacing it make sure the rest of the coolant system is in good condition. All of the following items will affect the ACT; Coolant level, Radiator Fan, Engine Temperature, read more @ Fuel Injection Technical Library » Air Charge Temperature (ACT)
Source: by Ryan M
Location in an Edelbrock Perfomer Lower Intake Manifold Diagram in a 90 5.8

Source: by SeattleFSB (Seattle FSB)
...

DTC 116 Engine Coolant Temperature (ECT) Sensor Troubleshooting & Possible Causes; "...The ECT sensor is a thermistor, basically a resistor that changes voltage accordingly to temperature changes. It provides a reading that's used by the EEC to change fuel delivery at engine startup to reduce emissions and monitors the temperature of the engine. If you see some rust in it clean it by sanding the surface using a fine grit sandpaper, Also check the connector and wiring..."
Overview & Testing by Ryan M (Fireguy50) @ Fuel Injection Technical Library » Engine Coolant Temperature Sensor (ECT)
...

DTC 636 indicates the output of the Transmission Fluid Temperature (TFT) sensor was out of Self-Test range. The sensor output shows a failure occurred at either the low or high end of the acceptable range. The correct range of measurement is from 0.76 to 4.69 volts for Escort/Tracer and from 0.21 to 3.50 volts for all others.
Possible causes:
Fluid levels not to specification.
Transmission fluid not at operating temperature.
Sensor resistance out of limits.
Damaged Powertrain Control Module (PCM)
●
See How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L) by Abraham Torres-Arredondo @ How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L) by Abraham Torres-Arredondo
●
ASAP, find out if speed control recall work, if equipped was completed. If you still have concerns about Recalls, please contact the Ford Customer Relationship Center:
US: 800-392-3673 | CA: 800-565-3673
Note: 3673 spells "FORD" on phone keys
For the hearing- or speech-impaired: Please contact the Telecommunication Relay Service by dialing 71
"Summary: ON CERTAIN PICKUP TRUCKS, PASSENGER VEHICLES, SPORT UTILITY VEHICLES, AND MOTOR HOMES CHASSIS, THE SPEED CONTROL DEACTIVATION SWITCH MAY, UNDER CERTAIN CONDITIONS, LEAK INTERNALLY AND THEN OVERHEAT, SMOKE, OR BURN. THIS COULD RESULT IN AN UNDERHOOD FIRE."

Here's:
1995 Bronco Dealer Brochure @ 1995 Ford Bronco

1995 Bronco/F Series Drivetrain, Powertrain Service Manual - Google Drive
The eight Groups found in this manual are:
00 - Service Information
02 - Engine and Transmission Mounting
03 - Engine
05 - Driveline
07 - Transmission
08 - Clutch
09 - Exhaust System
10 - Fuel System
Each Section covers a component or system. The second set of numbers on each page
indicates the Section.
If the vehicle has more than one type of component, such as two types of engines or power
steering systems, alphabetical suffixes are used.
&
1995 Bronco/F Series Chassis, Service Manual - Google Drive
To switch between folder list & grid views, click the button to the right of the "DOWNLOAD ALL" button in the upper right corner of the window) by HawkDriver
The twelve Groups found in this manual are:
00 - Service Information
01 - Body
02 - Frame and Mounting (Body)
04 - Suspension
06 - Brake System
11 - Steering System
12 - Climate Control System
13 - Instrumentation and Warning Systems
14 - Battery and Charging System
15 - Audio Systems
17 - Lighting
18 - Electrical Distribution
Each Section covers a component or system. The second set of numbers on each page
indicates the section.
If the vehicle has more than one type of component, such as two types of engines or power
steering systems, alphabetical suffixes are used.

See 1995 F 150 Powerstroke 7.3 Turbo Diesel Service Manual @ Ford Service Manuals - Google Drive
In pop-up, click "Drive"

Haynes Red Manual for 80-95 Bronco & F Series @ Hanes guide 80-96 bko f series.pdf via BroncMom!

See my mostly recovered View attachment 202203
site by member schwim @ Ford Bronco And F-150 Links - FORD BRONCO

For any Bronco questions or to chat about it's planned modifications or build, it's better to post each seperately in Noobie Bronco Tech Questions. Flame free zone. This will get more attention and you can build up your post count to get into other sections such as Bronco and Ford Parts/Accessories (50 non-padded posts required to participate, due to scammers who preyed on our members).

Our Forum FAQs includes for example, How to:
Post images
Save (Bookmark) Threads Or Posts
Search The Site
What is the Difference Between the Showcase and Gallery
How To Find Subscribed Thread and more tips!

See How to add your 95s Signature @ Bronco Forum - Full Size Ford Bronco Forum by BigBlue 94

➡ Baba Looey's Favorite FSB Links (lots and lots of tech links)
... Includes such as, How do I fix my back window?

Take time to participate in our current Full-Size of the Month & later in the new year, Full-Size of the Year Contest @ Voting
You will get ideas by those competing.
Prizes are awarded to the winner!; a full spread in Bronco Driver Magazine is the top prize, in addition to a years subscription, once the article is submitted; and a years worth of premium FSB membership.
Al

Thank you @miesk5 ❤

 

[EB_Bucky]

Thank you @miesk5 for sharing all those pointers!

I just pulled out the IAT sensor and it was pretty dirty and covered in oil. Cleaned it up and tested the resistance, it was around 55k ohms at room temp which was almost the same as the new IAT sensor.

Also pulled out the ECT sensor, cleaned it and tested the resistance. It was around 24k ohms at room temp whereas the new ECT was around 46k ohms. Replaced it with the new ECT since it seems like the original one was bad but the Bronco still wouldn't start.

Do I need to reset the PCM by disconnecting the batteries before trying to crank? Also, it now has a weird whirring sound when cranking.

 

[miesk5]

Yo EB,
If your 95 cranks well, see my above post #10 "How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L) by Abraham Torres-Arredondo @ Part 1 -How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L).




●

 

[Rob_64-365]

So the codes didn't lead you to answers, so lets start with the basics.

Is there spark? Pull a plug & comfirm and also note the condition of the spark plug.

Then put a fuel pressure guage on the schrader valve & confirm 40psi key on, engine off.

 

[EB_Bucky]

Yo EB,
If your 95 cranks well, see my above post #10 "How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L) by Abraham Torres-Arredondo @ Part 1 -How to Troubleshoot a No Start (Ford 4.9L, 5.0L, 5.8L).




●

Wanted to share an update regarding some recent developments - conducted a fuel pressure test yesterday and in KOEO, I was getting a pressure of 20psi which would drop pretty quickly to 0 when the key was turned off. If I turned the key on several times, then the pressure would build up to 40psi but drop almost immediately to 0 when the key was turned off.

Today I unplugged and checked the FPR vacuum line but there was no fuel in it. Suspecting that my check valve could be bad, I decided to conduct a spark test before moving forward.

Plugged a test light to one of the spark plugs, disconnected the Fuel Pump Relay and cranked, and the Bronco surprisingly TURNED ON without any hesitation!? Turned off the car, plugged the Fuel Pump Relay back in and cranked again, and it started almost immediately without any issues.

I'm quite surprised with this and wondering what might be causing the issue earlier. I'm wondering if it might be a bad and unreliable check valve? I'm planning on conducting another fuel pressure check over the next couple of days to see if the pressure holds

 

[Rob_64-365]

Sounds like youre on to something with that fuel pressure thing. Sounds like it might just be the fuel pump acting up as it's on its way out.

 

[jermil01]

For reference, you shouldn't smell gas in the FPR vacuum line. If you do, that means there's a problem. If I remember correctly, these pumps have a valve that's supposed to hold pressure on them when the pump is primed. It's not uncommon for them to go bad. If that happens, you can the pump primed by turning the key a couple of times. If your pump is losing pressure that fast I'd expect that's probably the issue and as @Rob_64-365 advised that pump might be on it's last leg.

 

[miesk5]

Yo ,
My 96 had symptoms of a faulty Supply Check Valve. The valve is not repairable, so some owners have installed aftermarket external check valves in the return line. .