I own a 1987 760 Turbo wagon. My car has been sitting for about a month while I was doing some unrelated suspension work to it. When I parked the car a month ago it was running perfectly, now it wont run ? Yesterday I tried to start the car and it would not start. I checked for spark and that was fine so I began looking for fuel related problems. I checked my pre pump even though it was running and found that the bellows hose that connects the pump was ripped. I ended up replacing the pump and the hose because I came into lots of spare parts. The car was still hard to start, but it started, but now is running awful. I replaced my main fuel pump and checked the FPR and radio relay. Still runs terrible. I ran through all my normal tests and cannot find the problem ? The car is hard to start, it stalls and will not keep running no matter what RPM. It is running very rough as well. I have swapped FPR, checked AMM, checked for vacuum leaks, cleaned Throttle body...nothing has helped....Its almost like the engine is being starved for gas, but there is plenty of fuel pressure and a good flow of gas Any thoughts or suggestions would be appreciated ! Thanks, Mark

The only time we had issues with any of our 4 high mileage 740s was when they sat.

Driven daily, they seemed to thrive on mileage.

My theory is inactivity is not good for the many aging connectors in the car. When you drive and go over bumps, the wiring and connectors jiggle, cleaning themselves.

Try to give all the connectors a cleaning, or at least a good shaking.

One of the service writers at my dealer was a 740 buff, he told me to clean every connector as much as I could, add some dielectric grease, and zip tie any that I could. I did one a week so that if I had a problem, I knew where to look.

You might try to start the car after you clean each one.

In the late 60's I was stationed at SHAPE (Supreme Headquarters Allied Powers Europe) ((bragging)) near Brussels.

It rained almost every day before lunchtime. One afternoon, when I was trying to start my Ducatti 160, which was giving me a hard time, an Army General stopped and asked me what was the matter.

I explained the bike's dislike for being wet.

He told me, sometimes you just have to give it a good shake.

I did and the bike started!
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'96 855R,'64 PV544 driver, '67 P1800 basket case, '72 Yamaha Rd400, '68 Honda 350-4, '12 XC70, the first 5 are mine, heh, heh, 525,000 miles put on 10 bricks James A Sousa

Are the plugs wet? Check that line that goes around, under the intake to that little box on the left (drivers) fender. That one got me once. It took me weeks to find it.

Sitting for a month?

Could be lazy or stuck fuel injector(s). You can buy a mechanic's stethoscope for next to nothing and listen for a sharp tick on each injector as they cycle. Then, I would wonder if there was a stuck valve or low compression cylinder which you could diagnose with a compression gauge. Also, look for signs of a head gasket leak. That block test fluid stuff, which you can get at parts houses, actually works pretty good.

Last resort... buy a can of Sea Foam.
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Try some gas additive, like Heet, for water in gas problems. Is your car in wet climate right now?