1987 190E Hard Start when warm

[jross1952]

Anyone have suggestions for my 190E 2.3 that has a hard start problem after getting warm? It will start fine after sitting for 30 minutes or more but if I stop for just a few minutes and try to start immediately it takes many revolutions for it to kickoff. Otherwise runs great!

Jay

[Mike Freeman]

Sounds like the pressure accumulator may be leaking internally!
After the engine has been off for 20 mins. loosen the fuel supply hose to the fuel dist. and see if any pressure exists, if not replace accumulator.
Mike

[saumil]

As mentioned by the previous message, there could be a leak somewhere in the fuel system causing the pressure to drop rapidly after the car is turned off. You will need a fuel pressure gauge to test this.

Also check the fuel injection temperature sensor, also called the coolant temperature sensor. It is the last sensor on the engine, closest to the windshield. Remove the connector, measure the resitance across the sensor terminals - it should be 2.5 to 3.5 Kiloohm at 20 deg-C and should go down to about 250-350 ohm at 80 deg-C. If the resistance does nto change by a factor of about 8 to 10 when engine temp changes from 20 deg-c to 80 deg-c, change the sensor.

The other possibility is the zero position of the airflow sensor plate. But I am assuming that you have not touched this.

[Jorge]

Where is the air flow sensor located at? At zero position, what is it indicating? My '85 190E will not start cold or warm. Good sparks and fuel pressure. How does EHA tied into starting? Thanks!

[saumil]

The air flow sensor plate is under the air filter box. EHA helps provide the fuel as soon as the ignition key is turned on. When you turn on the ignition key, 40 to 60 ma of current should flow through its coil. Check the coil resitance, it should be between 15 and 20 ohms. If you have not touched this plate and the car was working with the current plate setting, I would not mess with it.

Cold start problem could be related to a faulty cold start valve, though there has now been some doubt as to when this valve should function, some say it works only in extreme cold weather, but as far as I can recall, my valve works in Houston, and I have not rechecked it yet, but will do soon. Infact, when you crank and you get close to 12V on the cold start valve terminals, the computer is trying to use it, and when this occurs and no fuel comes out, I would think that it needs to be replaced.