3FE cold start woes

[TheElegantFox]

What's the ideal cleaner to use for the injector? I've seen some threads where they recommend carburetor cleaner, but a few others have a whole kit and special cleaner for the injectors. I think a few you pour into a tank of gas, not sure that's what I need though.

 

[Prairie Swamp]

I built this:

Injector Cleaning

• Prairie Swamp
• Dec 12, 2017

Just pipe fittings. Allows you to run the motor on straight injector cleaner. Or alternatively you can run your tank down as low as you dare and dump a couple or three bottles in and run it.

 

[TheElegantFox]

I built this:

Injector Cleaning

• Prairie Swamp
• Dec 12, 2017

Just pipe fittings. Allows you to run the motor on straight injector cleaner. Or alternatively you can run your tank down as low as you dare and dump a couple or three bottles in and run it.

Will that work with the cold start injector location? This guy has a photo of how he cleaned it: Clean your cold start injector

 

[DirtRoads]

What's the ideal cleaner to use for the injector? I've seen some threads where they recommend carburetor cleaner, but a few others have a whole kit and special cleaner for the injectors. I think a few you pour into a tank of gas, not sure that's what I need though.

Hoppe's gun cleaner if you have it. If not, carb cleaner or whatever is fine.

It would be a good time to do a fuel pressure check as well just to be sure everything is fine there, you're right there in the neighborhood. To me, it sounds like your cold start injector switch is faulty, that is located on the thermostat housing. Specter offroad has a pretty decent diagram showing what is what. I had the same problem and it cured mine.

Gents, I'm having the same type of issues. I have a 90 FJ62. I recently replaced a bad starter. Since replacing the starter, the engine seems to have a hard time cranking over. Not sure if this is a starter issue or something else. The starter was new from Cruiser Corp. Any ideas?

Please clarify. Engine cranks at a slow RPM or engine cranks for an extended period of time before starting?

Slow RPM = starter or starter electrical issue. Bad electrical connections are usually the problem.
Extended period of time is usually cold start system related or fuel supply related.

 

[Prairie Swamp]

Only if the injector is being told to fire by the computer. Not sure off the top of my head what those parameters are. I would start with cleaning the 6 primary injectors and go from there. I think you have issues other than the cold start injector.

 

[Seth S]

If you run the truck straight off of one of the various injector cleaners its a good idea to do an oil change when you are done. If any of that injector cleaner gets into the oil pan it will not mix well with the oil.

 

[YooperCruiser]

I just cleaned my 7th injector when I cleaned my throttle body and let me tell you the end of that thing was completed covered in crud so worth looking at.

 

[TheElegantFox]

Wanted to resurrect this thread as the truck has been exhibiting the same and worsening behavior as originally posted. I think replacing the coolant temp sender is next.

What I know so far:
Vehicle will eventually crank over after 4-5 goes, 10-30 attempts when it's below 40f. When cranked and running, CEL will persist for about 30m of operation, then light will go off. Idle is a tad high, usually around 900-1k rpms.

• Starter = good
• Battery = good
• Vacuum lines = good
• Cold start injector = good (just cleaned and was relatively clean)
• Spark plugs = unknown
• Coolant temp sender = looks real bad in this photo or at least the wires running to it.

• 

 

[TheElegantFox]

Maybe replacing the connector plug is in order Toyota Lexus 2-Pin Water Coolant Temp Connector Plug Kit 90980-10735 90980-11061 - https://www.ksvlooms.com/products/toyota-lexus-2-pin-water-coolant-temp-connector-plug-kit-90980-10735-90980-11061

 

[TheElegantFox]

Cleaned the contacts on the coolant temp sensor and tried a mostly cold start and got it first go and idle was closer to the stock 800rpms. The connector will probably need to be replaced at some point, but we'll see if a contact clean and reseat will pass the overnight cold start test tomorrow.

 

[Seth S]

Wanted to resurrect this thread as the truck has been exhibiting the same and worsening behavior as originally posted. I think replacing the coolant temp sender is next.

What I know so far:
Vehicle will eventually crank over after 4-5 goes, 10-30 attempts when it's below 40f. When cranked and running, CEL will persist for about 30m of operation, then light will go off. Idle is a tad high, usually around 900-1k rpms.

• Starter = good
• Battery = good
• Vacuum lines = good
• Cold start injector = good (just cleaned and was relatively clean)
• Spark plugs = unknown
• Coolant temp sender = looks real bad in this photo or at least the wires running to it.

• View attachment 2973372

Cranked over means start? Or cranked over means you cycled the key 10-30 times and for 9-29 of those attempts the starter didn’t do anything but eventually the starter engaged and the truck started?

 

[Seth S]

You can test the coolant temp sensor. You need an ohm meter and then just measure it’s resistance when cold and watch the resistance as the engine warms up. Or pull it out and put it it a pan of water in the stove and heat it up. The FSM should have the values.


But your harness looks a bit rough. You would t hurt to go through and inspect for chaffed or broken wires, dirty grounds, corroded contacts etc.

 

[TheElegantFox]

Starter engages every time and sometimes there's at least 1-2 cylinders firing once or twice, but getting the engine running is usually what it has trouble with.

 

[TheElegantFox]

Started this morning in 2 start attempts so it seems cleaning the coolant sensor contact helped it get a better read. CEL isn’t going away though the truck seems to be idling and driving well.

 

[Engineer8000]

3FE Coolant Sensors:

In my experience the cold start injector timer plug is the same as the one on the cold start injector. This is from the FSM, there is a whole process described for verifying functionality of the cold start injector and timer.

This explains how it works, in general. The temperatures and timing may not be exact for the 3fe.

 

[TheElegantFox]

3FE Coolant Sensors:

View attachment 2974344

In my experience the cold start injector timer plug is the same as the one on the cold start injector. This is from the FSM, there is a whole process described for verifying functionality of the cold start injector and timer.


View attachment 2974347

View attachment 2974348

View attachment 2974350

This explains how it works, in general. The temperatures and timing may not be exact for the 3fe.

Ah this is really helpful information, I need to check and clean that connection point as well then.

 

[TheElegantFox]

 

[TheElegantFox]

The cold start time switch looks melted, or held together with tack.

How can I access it? Do I need to remove the coolant pipe? Does that line hold coolant while the vehicle is off? I’ve never removed any coolant lines before so I’m not sure if this means a total system drain to access this or not.

 

[Engineer8000]

You will have to drain part of the coolant.

 

[TheElegantFox]

Managed to get it off it a deep socket with some light coolant drainage. I think I need to order a new one just because the PO rubber glued the wires with clamp ends to the plug contacts. I took it out and tried to get the gunk out to clean the metal contact area but it’s still pretty sketchy.