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350 Tbi Issues

terminator0723

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terminator0723 New Member

terminator0723

Posted
Posted

I have a 2500 with a 350 TBI motor in it. The thing runs fine when you fire it up cold. When you shut her off and refire it, it idles roughly and shoots out a little bit of black smoke, or it idles realllllly low like the motor is still trying to catch on, and if you give it gas it'll cut off, or it won't start at all. After you let it still for like 3 or 4 hrs it will start back up but still put out a little black smoke. I just did a small tune up( air filter, oil and oil filter, and new plugs) on it to see if it would help. It idles smoother, but didn't solve my problem. I also noticed the temperature isnt going up on the temperature gauge. I dunno if its a stuck thermostat or if its part of this problem. Any input would be appreciated!

 

Thanks

Heavy Cruiser Enthusiast

Heavy Cruiser

Posted
Posted

If upper radiator hose is not hot to the touch, then I would suspect the thermostat is stuck in the open position, or semi-open.

 

The temp gauge should read just to the left of the center mark of the gauge, 210°F is the center mark, if engine has a 195° thermostat. A 180° thermostat will place the needle on the first mark from the left.

kuhl_530 Enthusiast

kuhl_530

Posted
Posted

Your engine problem has nothing to do with your thermostat, I'll put my money on that. I suspect your engine's running too rich. Could be a bad fuel pressure regulator, or bad injectors. Most likely the reg though.

superjim Senior Enthusiast

superjim

Posted
Posted

Check the fuel pressure regulator.

Pull the vacuum hose off and check for fuel.

There should be NO TRACES of fuel in the vacuum hose.

Mike G Enthusiast

Mike G

Posted
Posted
Check the fuel pressure regulator.

Pull the vacuum hose off and check for fuel.

There should be NO TRACES of fuel in the vacuum hose.

 

What vacuum hose would you be referring to? On the 92, the FPR should be attatched to/part of the TBI unit on the top back side. I am interested to know this trick as my truck suffers from this now-and-again.

--Mike

superjim Senior Enthusiast

superjim

Posted
Posted
Check the fuel pressure regulator.

Pull the vacuum hose off and check for fuel.

There should be NO TRACES of fuel in the vacuum hose.

 

What vacuum hose would you be referring to? On the 92, the FPR should be attatched to/part of the TBI unit on the top back side. I am interested to know this trick as my truck suffers from this now-and-again.

--Mike

 

 

 

I am not familiar with the 92 FPR specifically, but other ones, 95 and up, all had a vacuum hose attached to them.

bbwb Enthusiast

bbwb

Posted
Posted

Could also be your fuel pump...been there done that on the poor start-up

 

bbwb

ZZ327 Senior Enthusiast

ZZ327

Posted
Posted

check your EGR valve up on the passenger side of the intake Right behind the TB. make sure that little rubber piston moves freely.

  • 1 month later...
citydriver Enthusiast

citydriver

Posted
Posted

Sounds alot like the CTS (Coolant Temp. Sensor) may be going bad, this is the small sensor mounted in the top of the intake manifold next to the thermostat housing and has a 2 wire connector on it with a yellow wire and a black wire. Only about $14-$16 at your local auto parts store, may not be a bad idea to change your thermostat out also. I change out the CTS everytime I change the engine coolant, I call it cheap insurance.

  • 3 months later...
kundog Enthusiast

kundog

Posted
Posted

Check the coolant temp sensor (on manifold) my engine did this to me...i hooked my laptop up to it and the pcm saw the coolant temp at like -40 deg due to a corroded pin/connector at the sensor.

  • 2 weeks later...
VRSCA1 Enthusiast

VRSCA1

Posted
Posted
Check the coolant temp sensor (on manifold) my engine did this to me...i hooked my laptop up to it and the pcm saw the coolant temp at like -40 deg due to a corroded pin/connector at the sensor.

 

I agree have it checked out otherwise you are throwing darts....

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