Engine is hard cold start?

Tiny
LOWFLYER63
  • MEMBER
  • 1988 TOYOTA PICKUP
  • 4 CYL
  • 4WD
  • MANUAL
  • 175,000 MILES
Son's truck. Symptoms: Hard to start when even mildly cold; rough idle always, low power, dies when coasting or gearing down to stop, poor mileage.

History: Previous owner had engine rebuilt 8,000-10,000 miles ago; ran good. Buoght it, gave it to my son (who is pretty hard on vehicles) and problems began within a month. Good history with previous owner (50+ y/o, 99% highway user, took good care of vehicle).

What I know: Two immediate problems I see. The coolant temp sensor is broken (yes broken). The inside comes out with the connector and won't stay in place. Not sure if it actually works but I will be replaceing it when next I have access to the truck. The thermal time sensor connector also wont stay attached. Again, not sure if that's a factor (maybe for start) because it shouldn't play a role once the engine is running (right?).

My plan is (to troubleshoot the cold start issue) to connect a push to close switch diectly to the cold start valve from the battery and to ground (+ bat to terminal 1 CSW through push to close switch and ground wire directly to the terminal 2 of CSW), whereby bypassing the thermal time sensor completely. Pushing the button while cranking the engine (in my little mind) should tell me if the cold start issue is in either the thermal time sensor or the coolant temp sensor. Right? If the problem continues, it must be somewhere else. Right? More to follow on that if successful.

So, to the question: Should any of this affect the overall performance of the engine once it is started? And if not, where do I start?

Thanks in advance

Lowflyer
Thursday, December 10th, 2009 AT 3:43 PM

8 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check and test the cold start injector, coolant temperature sensor, Idle air control valve, EGR valve, TPS sensor and airflow meter to include a fuel pressure check. THis guide can help.

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting

Please run down this guide and report back.

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Thursday, December 10th, 2009 AT 4:49 PM
Tiny
JJSIMMONS
  • MEMBER
  • 1 POST
I had bad gas and had to get a new fuel pump but now my engine is running really good.
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Monday, November 16th, 2020 AT 8:41 AM
Tiny
MJADAMS5
  • MEMBER
  • 1 POST
  • 1986 TOYOTA PICKUP
Truck is hard to start. You have ato turn it over for a long time but it always starts right before the battery dies. I have repalced the fuel pump, filter, spark plugs. Once you crank it, it runs like a champ. As soon as you turn it off, you start the process over. ANy suggestions on where to start?
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Monday, November 16th, 2020 AT 8:41 AM (Merged)
Tiny
MIKEYBDMAN
  • MECHANIC
  • 623 POSTS
I believe that model has a cold start injector that may be bad.
Also not sure on that model what the boost pump is supposed to be doing during start. But I would check to see if you were getting good pressure during starting.
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Monday, November 16th, 2020 AT 8:41 AM (Merged)
Tiny
MIKE4
  • MEMBER
  • 1 POST
  • 1983 TOYOTA PICKUP
Engine Performance problem
1983 Toyota Pickup 4 cyl Four Wheel Drive Manual

when first starting my truck, it seems to take forever. It cranks fine, but seems as if no fuel is in the carburetor. I have a 2 bbl holley that I purchsed aprox. 2 years ago. Is it possible that it needs a rebuild, is the accelerator pump bad, or can it be electrical. Please help.
Thank you, mike
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Monday, November 16th, 2020 AT 8:42 AM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi mike4,

You need to check for leakage from the carburettor which would leave the float chamber dry after sitting for a period of time.

Does pumping the accelerator pedal one or 2 times make the engine start easier?

Check if the autochoke is out of adjustment, closed too much resulting in insufficient air going in.
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Monday, November 16th, 2020 AT 8:42 AM (Merged)
Tiny
LESAB98
  • MEMBER
  • 6 POSTS
  • TOYOTA PICKUP
I have a 1984 New Horizons Motor Home that has a toyota truck front end. I have two questions about this vehicle

1. Is there a 6 cyl engine that is a direct swap for the 22r 4 cylinder? Need more power This engine has 40,000 verified original miles.

2. When it is completely cold, or sets overnite, it's a stone s.O.B. To start, sometimes taking 15 to 20 mins of pumping the gas and cranking before it starts. After that it is fine until it sits for several hours.
Any suggestions?
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Monday, November 16th, 2020 AT 8:42 AM (Merged)
Tiny
LOSONE
  • MECHANIC
  • 1,616 POSTS
There is no swap from a 4 cyl to a 6 cyl.

Hard start is probably a fuel issue. 40K on an engine does not deter the fuel pump from being bad. Take the line off the carb and see if you have fuel. If so you may have a carburator issue. Let me know
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Monday, November 16th, 2020 AT 8:42 AM (Merged)

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