2.6L 190E answers to some problems
It was hard to start and the idle, upon warm-up, surged between 1200-1500 RPM. These are common problems and this board lead to a couple of answers. Starting in the back end, new check valves were installed. My 1988 190 E has two fuel pumps, so, two check valves. The fuel line between the primary and secondary pump was leaking, to the extent that when the plastic pan covering the pumps was removed, it was filled with fuel. Fuel line was replaced. I knew I wasn't getting the gas mileage I should be getting! Up front, the black rubber breather tube from valve cover to aircleaner box was cracked underneath and it was replaced. I had previously put silicon goo on it, but I figured, with everything else I'm doing, I might as well replace that, too. With the aircleaner box removed, there was, on the intake runner closest to the firewall, a vacuum valve that was open. For automatic transmission models, this is a vacuum connector for the kick-down. Since I had a 5-Speed, I capped it close. Idle control valve, in front of the plenum, was cleaned. But it still would not start. Now, it wouldn't start at all! After checking all the vacuum lines (a vacuum meter was installed as soon as work moved up to the motor and there was a leak somewhere), the culprit was found - the EHA. The ElectroHydraulic Accuator is up stream of the fuel distributor: it is a small black plastic rectangular box about 3 x 1.5 inches. First of all, it was leaking (this car has 240,000 miles on it) and testing indicated it 's values were off. That $225 part was the main problem. I also installed a new (Bosch) coil (long story short - it was running a PepBoys coil just big enough for a lawn mower) and adjusted the CO. It starts and runs good, now. I hope some of this is helpful to those with 2.6L motors.