bad cold start!

[firemut1]

I have a 93 talon dl 1.8 1g DSM new bone yard motor has trouble starting after sitting for 8 or more hours. worse when it is cold. have checked injectors and they look good. will start on starting fluid first time. sorry I am new to this type of motor. but I have replaced the vacume return line thing and it still dose the same thing, however that was off a bone yard motor also. changed the fuel filter plenty of gas there. when the vacume line thing was remove not a lot of gas there could it be the problem? did the code read with a volt meter and it said 12 which I think is the MAS sensor. The motor runs great after brief warm up but if you try to step on the gas before warm up dies out. not sure what to try next the MAS is 200.00 + and if it is not the problem then what. please help.

 

[femmeDSM]

Could be a fuel pressure problem, or could be an ECT (coolant temp sensor) on its way out.

Get a hold of a fuel pressure gauge/tester, and check the pre-rail, post-filter fuel pressure. Not sure what the specs are for N/A cars, but if you can't find it, I will look it up for you.

If your fuel pressure is too low, this would likely be caused by a problem with the fuel pump (check/replace the pump) or the fuel pressure regulator.

Your coolant temp sensor is located on the bottom of the thermostat housing, next to the fuel gauge sending unit. It's the larger of the two sensors, located farthest from the engine block (I believe it's the same location on a N/A car). Check the wiring to this, as the 2 wires going to it can start to break or deteriorate, especially on an older car.

If you have a service manual (a Haynes or Chilton will do), they will demonstrate the proper way to test all of the components I listed. If you need help, just ask.

 

[firemut1]

thanks for the info will check coolent temp sensor and see what the reading is what should I be looking for?

 

[femmeDSM]

thanks for the info will check coolent temp sensor and see what the reading is what should I be looking for?

I would recommend first just making a visual inspection of the wires and plug for corrosion/broken pieces/etc. If the wiring looks okay, you can check voltage and resistance. I don't have my tech manual in front of me at the moment, but IIRC you should see approx 4 - 5 volts to the plug with the key in ON (not running, car probably won't start w/ this unplugged anyway).

Resistance is checked between the two prongs on the sensor. As the engine temperature increases, resistance decreases. So a cold engine should have a high resistance, and after you've warmed the engine up the resistance should read much lower. I can get the specs for you later, but I believe cold = approx 2500ohms and operating temp = approx 250. I could be wrong, I'll double check that when I get home.

 

[1fast97gsx]

my bet is coolant temp sensor .. hook it up to a scantool and see what the sensor reads.

 

[firemut1]

you have been very helpful I will check it on saturday when I get home again.
thankx again

 

[firemut1]

Went out today changed coolant sensor and it started right up and it is 28 degrees out here thanks you saved me a lot of time and money

 

[femmeDSM]

Went out today changed coolant sensor and it started right up and it is 28 degrees out here thanks you saved me a lot of time and money

Awesome, glad I could be of help Hard to believe such a small part can keep your car from starting, huh?