3FE hard start in cold temps

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A new problem with my '88 FJ62. Engine does not like starting in cold temperatures. Good strong starter but tough time firing up. After numerous tries it will eventually start but CEL stays on until it gets up to temperature and goes away. Truck runs fine after that. Seems like the ECU is not adjusting the choke. Checked coolant temp sensor wiring connections and don't see issue.
I don't have a code reader that fits the plug so I can't get a code number. Seems like something straightforward like bad sensor. Appreciate any ideas and recommendations.
 

Godwin

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A new problem with my '88 FJ62. Engine does not like starting in cold temperatures. Good strong starter but tough time firing up. After numerous tries it will eventually start but CEL stays on until it gets up to temperature and goes away. Truck runs fine after that. Seems like the ECU is not adjusting the choke. Checked coolant temp sensor wiring connections and don't see issue.
I don't have a code reader that fits the plug so I can't get a code number. Seems like something straightforward like bad sensor. Appreciate any ideas and recommendations.

Actually you do have a coder reader, you are it. There is no instrument that plugs in to translate a code like with OBDII. You use a jumper wire such as a length of stiff wire, paper clip, or this Diagnostic Port Jumper Wire for OBD equipped vehicles - https://absolute-wits-end.com/diagnostic-port-jumper-wire-for-obd-equipped-vehicles/, plugged into the TE1 and E1 spots in the diagnostic port under the hood. Turn on the key and read the number of flashes that the CEL outputs. That will be the code that you then take to the FSM to know if you have a detectable electrical issue or not.
 
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Actually you do have a coder reader, you are it. There is no instrument that plugs in to translate a code like with OBDII. You use a jumper wire such as a length of stiff wire, paper clip, or this Diagnostic Port Jumper Wire for OBD equipped vehicles - https://absolute-wits-end.com/diagnostic-port-jumper-wire-for-obd-equipped-vehicles/, plugged into the TE1 and E1 spots in the diagnostic port under the hood. Turn on the key and read the number of flashes that the CEL outputs. That will be the code that you then take to the FSM to know if you have a detectable electrical issue or not.
Thanks Godwin, I just ordered the port jumper wire. While I'm waiting, any ideas on what might be the issue?
 
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The cold start injector can clog (especially in moderate climates where it doesn't get used as much). If it's clogged, it won't throw a code. You might search 'cold start injector' here for suggestions on testing/debugging. It can either be clogged or fried - both will result in hard starting in cold weather. It's easy to get to on the side of the intake manifold.
 
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Thanks SteveH.
Right after I made original post I found the thread on Cold Start Woes and it was very informative. I pulled the cold start injector- vey easy. Some black crud on it so I cleaned injector and intake hole with intake cleaner. It's not that cold out now so the truck cranks and starts normally. Still have a lit CEL until the temp gauge gets about the middle of the range then it goes out.
 

HemiAlex

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I would check your main coolant temperature sensor and the cold start injector switch. It’s on the thermostat coolant housing.

Those two sensors do a lot. What you’re saying about the CEL staying lit could be related to that.

Be warned. The thermostat housing can become a big mess quickly. All of those bolts and nipples are just waiting to break. Plus the wires will be super brittle.

Be prepared to do it all at once. Upper and lower thermostat housing, thermostat and o rings, bolts and all all the sensors you can afford to do all at once. Plus the connector ends. You can pull all the sensors and check them with a heat source and multi meter but by the time you pull them out, you might as well just do it all at once. Buy once and cry once.

The figure below is from an 80 series with a 3FE but the orientation and layout is the same. Double check the part numbers one by one for your year and month of truck. Several vendors sell complete packages do do this.

3CE262F7-800F-4767-AEBC-7D10C1958439.jpeg
 
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I would check your main coolant temperature sensor and the cold start injector switch. It’s on the thermostat coolant housing.

Those two sensors do a lot. What you’re saying about the CEL staying lit could be related to that.

Be warned. The thermostat housing can become a big mess quickly. All of those bolts and nipples are just waiting to break. Plus the wires will be super brittle.

Be prepared to do it all at once. Upper and lower thermostat housing, thermostat and o rings, bolts and all all the sensors you can afford to do all at once. Plus the connector ends. You can pull all the sensors and check them with a heat source and multi meter but by the time you pull them out, you might as well just do it all at once. Buy once and cry once.

The figure below is from an 80 series with a 3FE but the orientation and layout is the same. Double check the part numbers one by one for your year and month of truck. Several vendors sell complete packages do do this.

View attachment 2907067
Appreciate the reply, comments and picture. Well noted on the "Be warned" It's always the "that looks easy" project that goes to hell.
 

Spook50

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The cold start injector can clog (especially in moderate climates where it doesn't get used as much). If it's clogged, it won't throw a code. You might search 'cold start injector' here for suggestions on testing/debugging. It can either be clogged or fried - both will result in hard starting in cold weather. It's easy to get to on the side of the intake manifold.
My first suspicion as well. If the battery is good, the cold start injector can get absolutely caked with funk from the EGR and the PCV together. Easy to clean, luckily. If you still have EGR and/or don't have a PCV catch can, cleaning the CSI should be a yearly job done every fall before the weather gets cold.

If the CSI is good, then the switch like @HemiAlex recommended is the next thing to look at.
 

Spook50

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I added a catch can to my 2F in the 60 and it works great. $15 on eBay well spent.
Mine's a modified air system dryer from Home Depot for I think like $20 :lol:

More than worth every penny though. Holds three ounces, but since doing a good thorough top end cleanup including my valve cover, it takes about 3K miles to fill it.
 

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