I've got a 92 2Dr s10 with 4wd, and 150k miles on it, it has the v6 TBI (Throttle Body Injection). It's been sitting for a year or so.

I would drive it, or run it for 10-20 minutes (Runs and accelerates just fine, till it warms up I suspect), and then the engine idle gets fast, and when I step on the pedal the engine chokes on the fuel and dies (When choking, smells like sulfur.), unless I very slowly open the throttle. After it dies, it will not immediately restart, it just cranks. If you let it sit overnight, it'll restart and the cycle is repeated.

I don't know offhand how to check the fuel pressure, but I think it's fine.

After digging into the problem online, I replaced the fuel pressure regulator gaskets, which didn't help.

One other thing to note, When the car is running well, the SES is on, When the SES light goes out, the car starts it's fast idle and then I have the flooding/stalling issue.

I forgot how to check the OBD code on that car (with a jumper and by counting SES flashes I think, the details are fuzzy.)

Anything about this problem sound familiar?

I've also got a 92 Vortec Bravada with AWD and no reverse (Gradual loss over the years, just learned to park uphill), but that's a problem for another day...

 

Have you checked the codes?

 

I'll have to check that out again, I found the info on how to do it here, for future reference and DIY-ers http://www.troublecodes.net/GM/

The codes for my vehicle are these I think, http://www.troublecodes.net/GM/92-93_43Z_tbi.shtml

Expect a reply sometime tomorrow.

 

The only code it flashes is 15, which according to the link above is "Coolant temperature sensor signal indicates a temperature colder than -27� F for 30 seconds after the engine has been running for at least 30 seconds."

It flashed 12 three times, 15 three times, and 12 three times again.

I find it hard to believe this has to do with the cooling system, but at this point, I'm open to suggestion.

 

thats wierd the same thing is hapenning to mine right now every thing you explained to the tee. i have a 91 four door and les than 30,000 miles on it and it just bogs down i cant get over 20 mph ive checked the fuel pump, egr, egr cylinoid dist. map and i just cant figure it out the carb was also rebuilt when the motor was. could this be a computer problem maybe, or just a bad sensor some where thats afecting the comp. what ever it isit must comon if i get it ill shurly let ya know

 

I wouldn't be surprised if it was the computer. Given that it runs like a champ untill the SES goes out makes me wonder if when the SES is on, the car runs at some default settings, and when it goes out, it runs on some screwed up setting.

 

The coolant temp sensor is used to determine whether to come out of fuel enrichment mode. If it is shorted to ground, the ECU is sensing that the engine is VERY cold and adding fuel to try to heat the engine up. If the ECU does not see the engine temp increase, it does not know to drop off of enrichment mode.

The fact that it works for a bit, then doesn't would reinforce that the ECU is working properly and that a sensor issue is the root of the problem. There is a period of time while the engine will be operating in open loop mode prior to entering closed loop operation. When in open loop mode, the ECU is working off of predetermined fuel/spark maps. Once it enters closed loop mode, it uses sensor data to regulate fuel & spark.

 

Sounds perfectly logical. So am I looking to just replace the coolant temp sensor, or is there a surefire way to troubleshoot it with a multimeter?


I appreciate your help with the matter, sounds like you really know your stuff!

And come to think of it, as long as we've had the car (probably put 30-40k miles on it) that coolant temp gauge needle never seemed to leave the bottom of the scale, so maybe it did manage to short itself out once and for all. Looks like the sensor is only $12 at Autozone.

Thanks

 

Here's the run down on the sensor.

The ECT (engine coolant temperature) sensor is used to control:

• EGR (exhaust gas recirculation) valve
• Fuel Delivery
• IAC (idle air control) valve
• IC (ignition control) - spark advance
• TCC (torque converter clutch)

The ECT sensor is a thermistor that is located in the engine coolant flow. Given a low coolant temperature, the sensor produces a high resistance (100,700 ohms @ -40*F). At high temperature, the sensor produces a low resistance (70 ohms @ 260*F).

The control module sends a 5.0 volt signal to the ECT through a resistor in the control module and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot.

I would first inspect the wiring to ensure that it is connected at that both wires show good conductivity from the sensor back to the ECU. With the key on, engine off, you should get +5V on the yellow wire and show good ground on the black wire.

The ECT is located near the front of the engine quite close to the thermostat housing.

If you really wanted to test the ECT, here are the proper resistance readings for a given coolant temperature:

• 177 ohms @ 212*F
• 467 ohms @ 158*F
• 1800 ohms @ 100*F
• 3520 ohms @ 68*F
• 7500 ohms @ 40*F
• 13500 ohms @ 20*F
• 25000 ohms @ 0*F
• 100700 ohms @ -40*F

 

ok ive been on this all day and still nothing i thought it might have been the fuel pump so i replaced it and now i get diferent codes 12, 22, 33, 34, 43,prety much sounds like the same thingim just not sure the cool. temp switch is it though whem it starts it runs fine whene its warmed up i give it gas and it just bogs down like its a lawnmower in high grass somthin got to give