1988 240GL 124,000 miles non-turbo 2.3L

After about 5 months of intermittent starting I finally found out that the source of all my headaches was the bad Fuel Pressure Regulator. The car first gave me major problems starting at about 10800 feet above sea level here in Colorado on a trip but seemed to start a little easier at my home of 7000ft. I would have to disconnect the first injector wire, keep the gas to the floor and crank forever. Once it started under the power of 3 cylinders I would have to quickly reconnect the wire fitting back into the injector and be on my way. If I shut the car down for about an hour it would usually start again fine but if left to sit it for over 1.5 hours it was a 50/50 chance of go or no go. It didn't make a difference either hot or cold outside for the crazy conditions to manifest. Once I realized that it was a pressure issue and not a sensor issue it all made sense, hidesight 20/20 I guess. When looking for the problem I had to find my fuel pump relay which is NOT behind the center console like many manuals describe it was actually located on the passenger side firewall below the glove box but above the foot well. You have to take off the cover that is under the glove box section of the dash to find it. My fuel relay was white.

**************** STATIC ELECTRICITY KILLS!!! DISCONNECT YOUR BATTERY WHEN DEALING WITH GAS LINES, FILTERS and RELATED FUEL LINES/HOSES!*****************

Since the Fuel Pressure Regulator is a mechanical item and does have seals that wear out be smart and replace it. It takes 2 screws to EASILY remove from the top of the fuel rail and I would suggest you replace this first if your brick is exhibiting the same sort of issues when starting then move on to the fuel filter under the driver side before the rear wheel which probably needs replacement anyway. I've included the part I purchased that might help if you have the same Bosch number 035-17-064 stamped on the regulator as I had, the FPR cost about $45.00 and was worth every cent for a perfect start every time.

Niehoff Ignition 21849
Fuel Pressure Regulator: LH-Jetronic; O.E. No. 3517064
****************** DISCONNECT THAT BATTERY!!! *********************************