Not sure where I should post, but I've got a question about our 89 TBI 350 Suburban.

The truck starts fine when cold. However, if you turn the truck off and try to restart it (after you've driven it) the motor will turn over, but has real trouble firing. If you crank it long enough while manipulating the throttle, you can get it to fire. Once it does, it runs like crap until it burns off all the extra gasoline. (Black smoke out of the exhaust)

I figured it was ignition related because once you get it running, you see all the black smoke from the exhaust. So, we tried replacing the ignition coil first, which didn't help the problem. Tommorrow I plan on pulling some of the wires to make sure it's getting spark to the plugs. Until then, does anyone have any ideas why the truck only has the problem when hot?

BTW, we did get an SES light, but it was for low coolant temp sensor or open circuit. Sounds unrelated, but the light did show up right before the truck starting running like crap.

Any ideas?

 

If the code is for coolant temp sensor, when you start the vehicle warm the coolant temp sensor may be telling the ECM that the engine is cold and giving it too rich of a mixture.

 

Thanks for the reply...Guess I'll give it a shot

 

replace the sensor and the connector for it

 

Is this the sensor that screws into the side of the cylinder head (on the driverside)?

Thanks again!

 

If your TBI 350 is like mine on my 92 Buick Roadmaster, the sensor in the head is for the temp gauge and the temp sensor for the computer is in the intake manifold next to the thermostat housing.

 

Thanks, that's what I needed to know.