My 88 240 has two new fuel pumps and a filter. I also just replaced the fuel pressure regulatorand MAF sensor. The car starts and runs in the morning for a few seconds then stalls. I restart the car and it is fine all day.Next morning it stalls again.I am thinking it might be the fuel line has a air leak that allows the fuel to recede in essence overiding the work of the fuel pressure regulator. When I changed the filter and pump under the car I noticed the fuel line was a type of black plastic????? It took alot of work to get the old filter and pump replaced and I think it is possible that twisting the fuel line may have created an air leak-I dont see any fuel leakage though. Anyway has anyone replaced their fuel line from pump/filter all the way up to the engine??? Do I need to find this plastic fuel line or can I use standard rubber fuel hose?

 

I would use the plastic line.
But that might not fix the problem.
Is there any codes?

 

Being a 1988 I dont have a diagnostic box under the hood-anyway to read a trouble code from the computer????????

 

Sorry my bad forgot what year it was when I posted about the codes.(Was going through alot of posts)

 

Not sure about newer 240s, but my former 1982 244 stalled out every morning because of either a faulty cold start injector (replaced) or thermal time switch (did not replace and likely the cause). After 3 minutes of pressing on the accelerator, it warmed up and ran like a champ.

 

Hey I think I found the problem and it wasnt the fuel line after all-I checked the air cleaner and at the bottom where there is a hose coming in from the engine (with what I guess is preheated air) I found a rag stuffed in blocking the air flow. I asked a few mechanics and they said that is a trick to reduce NOx emissions levels at test time-evidently my 240 was throwing high NOx levels before the fuel pumps were changed-unfortunately noone ever removed the rag from the air cleaner intake. My guess is that when cold started the computer expected airflow from this preheater hose andbecause it wasnt getting through past the rag the car was flooding.Once the car warmed and the valve in the air cleaner closed, the airflow was normal and the fuel ratio was where it should be.Anyway -it is running okay now-Thanks to everyone for the suggestions.

 

I have the pre-heat hose blocked on my car and it runs fine. I've never heard of that causing a problem. Nor have I heard of it fixing high NOx problems.

When (not if) the thermostat fails in the air box, the default position for the flapper valve is "cook the AMM." To protect the $250 AMM I (and many others) blocked the heated air duct permanently by gutting the inside workings of the air box with a Dremel and gluing a lid from a tin can over that hole. By outside appearances the pre-heat tube is connected to the air box and everything looks fine. If some inspector wants to open the air box, by first removing the AMM, then he'll discover that I've been a bad boy. That's unlikely. Besides the car easily passes emissions tests.