1988 Jetta cold start

[redwine]

Need some help, 88 Jetta 1.8 digifant fuel system, 175,000 miles
intermitent cold start, turns over but no start. Sits a while
and it will start and then runs fine no hesitation no stalling
gas mileage good. I looked for some sort of cold start injector
but I dont believe this fuel system uses one. It's a 5 speed
and recently replaced starter altenator and ign switch. thanks

[boschmann]

Try some of these checks with an ohmeter. On the air flow meter (on air filter housing) test between pin 3 & 4 (1 is closest to the engine & 4 is closest to the air filter) should be 500 - 1000 Ohms, this is the air temp sensor. You can also test between pin 3 & 4 while you move the internal flap & resistance should vary throughout it's range. Also, check resistance on the coolant temp sensor. It's a two pin sensor located where the upper radiator hose connects to the cylinder head, on the underside. It should be a blue connector. Resistance will vary w/temp, about 2000-3000 Ohms @ 68 F or 200 to 400 Ohms at operating temp. Higher resistance at colder temps.

[redwine]

thanks, will test during next no start condition

[boschmann]

You can run those checks anytime, usually if the sensor is bad it stays bad or if it's off calibration it stays off. Are you sure you're getting a spark during the no start event?