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My 94 VDP is very hard to start at times. Usually after it's been sitting for several hours. I have cleaned the fuel system from the tank to the injectors. It has a new fuel and air filter. I recently changed the distributor cap, rotor button and plugs. The plug wires checked good on the ohmmeter. I cleaned the intake tubes and throttle body with throttle body cleaner (I did not remove the throttle body). Once the car starts, I get a puff of smoke from the exhaust, but it smells more like a lean burn than like burning oil, and it stumbles a bit, but it runs great and gets good mileage. At normal temp, it fires right up, no smoke or stumbling. Everything I have tested seems to be working right. What should I try next???? Thanks, Gunner

Reply to
Gunner
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I had a Mercedes that did exactly that.... turned out to be no voltage to the cold start injector. I Dan

Reply to
Dan Cassaro

You might want to verify fuel pressure at cold startup. I believe there is a residual pressure check valve to prevent quick leakdown of pressure back thru the pump after the engine is shut down. The pump should also run for a short time when the ignition is first turned on to pressurize the fuel rail. The pump then stops until the engine is cranked and running.

I don't think there is a cold start injector, but there is a temperature sensor which signals the Electronic Control Unit to enrich the mixture for cold starting.

Don Young

Reply to
Don Young

Don, You are correct. The 94 doesn't have one, or at least I can't find one on the web. The 93's and before do, apparently. His symptoms seem to be engine temp related, though. Maybe a bad thermo sensor somewhere?

Dan

Reply to
Dan Cassaro

I just checked the Intake Air Temp Sensor.....basically what your Mercedes had. It checks good. I'm going to bypass the fuel pump relay next and see if the 1/2 second pump run circuit may be bad. Thanks for the input.

Reply to
Gunner

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