My brick starts perfectly when the outside air temperature is < 50 degrees F. For the last 5 years or so, as the temperature starts to go up in the spring, summer and fall the car is more difficult to start. Sometimes I have to crank for 15-20 seconds while pumping the gas to start and then the car will run roughly for 20 seconds or so and then all is ok. This is followed by a large puff of smoke that smells of gasoline. With spring and summer approaching I would like to diagnose and fix this issue.

Car is 1990 240 DL, 200K miles 1 owner and nearly everything on the engine is original.

Currently no codes to report and check engine light is not on, but I am having the start issues as the weather is warming up.

Thoughts on how to trouble shoot this?

Thanks for any and all help.

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Make something idiot proof and someone will invent a better idiot.

This is usually a sign the starting mixture is too rich. You'll hold the pedal to the floor and make it easier to start, when this occurs.

Several causes, none of which would set the EPA-mandated OBD codes. A leaky injector would flood a cylinder, or more than one. A faulty engine coolant temperature sensor (ECT) will adjust the mixture very rich. Also, your 1990 has a cold start injector. It could be leaking as well.

Two checks are in order. First the easy one. Check the resistance toward the ECT from the ECU plug, or check the voltage at key on before attempting to start the car. Check the 7/9 FAQs for details on doing this.

The more difficult one is checking residual and working fuel rail pressure. Difficult because you don't have a gauge. But an alternative exists if you pull the plugs and sniff for fuel. Not always as conclusive as the residual pressure testing, but sometimes the leak is so bad you can't mistake the wet plugs.

How's your fuel consumption?
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Art Benstein near Baltimore

Life is like a roll of toilet paper.
The closer you get to the end the faster it goes.

Thanks for the reply Art.

I disconnected my Fuel Pressure Regulator vacuum side last night and it had a very strong smell of gas and actually dripped a bit onto my finger. I have ordered a new FPR from FPCEuro and will replace next week.

I know that can explain what I am seeing, but I would say my fuel economy is consistently around 21 MPG city driving / 24 Highway. That is not to far off of what I have experienced over the life of this car. Also if it was my FPR I would expect to be triggering 2-3-1 or 2-2-1 codes (Compensating for rich or lean air/fuel mixture at cruise), right?

After replacing my FPR I will try your recommended tests and report back.

Thanks again for your your time.
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Make something idiot proof and someone will invent a better idiot.

Your mpg numbers look right. I think you found the trouble, but it was a small tear in the diaphragm. Remember the feedback and adaptive mixture can compensate silently for small issues. Your residual pressure leaked all that gas into the manifold to make it hard to start overnight.


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Art Benstein near Baltimore

"To do is to be." - Descartes
"To be is to do." - Sartre
"Do be do be do." - Sinatra

The fuel pressure regulator did the trick. My son and I changed the old one out on Saturday and the car has started perfectly (without touching the gas) every start since then.

Thanks for your prompt reply and assistance.
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Make something idiot proof and someone will invent a better idiot.