93 240 hesitation when weather is hot

240Dad · Post by **240Dad** » 11 Apr 2012, 19:31

Greetings all,
My daughter has her 240 back after I drove it for about a year. It now has 200,000 miles on it. I have done extensive work on it over the last 4 years and I have to say it is a fun car now and pretty reliable.
She has had a recurring problem that I have never experienced when I have driven the car.
The car is black which adds to the heat that builds up in it during hot weather. She says that, if she parks in a concrete parking garage on a lower level out of the sun it usually runs fine. However, if she parks in the hot sun (say 80 degrees F) she says it will start and run fine then will hesitate and stall. It will usually start again in a few minutes and run for a little while before doing it again.
If this is truly due to external heat what might it be? One guess I have heard is that the fuel hoses are old and tend to collapse in heat. I am not sure I buy that unless you experienced folks agree.
Thanks,
Bill

electech · Post by **electech** » 12 Apr 2012, 01:42

I am not sure about the hoses collapsing...I have heard of it on lawnmowers, but not cars. And not very familiar with the 240 fuel system, so I can't say for sure if it is reasonable. To me, it sounds more like an engine issue, which is not my strength. Check for any engine codes?

What I can say is that heat is killer on electrical parts. Most electrical components are designed and tested for 70 degrees C, so about 160 degrees F. But older components can fail much cooler, especially ones with moving parts like relays and motors. The fuel pump is cooled by fuel, so if it starts and gets worse, then I wouldn't think that is the issue.

First of all, check the battery condition- summer weakness precedes a winter failure.

Hmmm....just occurred to me. If it is parked in the heat, she is surely running the A/C. With the high temperature in the car, the A/C pressure could climb very high. High pressure in the A/C system can make the compressor really bog down the engine. Get the A/C system tested, or see if you can recreate the issue. Run the A/C on high blower, recirculate, and move the temperature control to halfway warm on a warm day. See how the A/C and engine react. It could be a failure in the A/C compressor pressure switches or too much refrigerant in the system.

240Dad · Post by **240Dad** » 12 Apr 2012, 18:12

Thanks, electech
The battery is new as of 2 months ago. I replaced the compressor a couple of years ago. Honestly there is not much that I have not replaced or repaired on the one.
Thank you for your comments. One thing I find is comments like yours can get me thinking about things that I had not previously considered.
I thinkI will be getting the car back soon so I can try the things you suggested.

electech · Post by **electech** » 12 Apr 2012, 22:27

Sure thing Bill. It's fun to think about other people's problems

An easy test might be to let her know that if it happens again, turn off the A/C and see if that "fixes" the problem.