Some of you may recall that I posted a week or so ago regarding my daughter's '90 244 (170K) which had been idling roughly. LH 2.4 OBD was giving me 1-1-3 (fault in fuel injectors) and 2-3-2 (fuel system compensating for rich or lean mixture at idle).

After chasing down numerous red herrings (IAC, TPS, AMM, ECU, cold start injector, coolant temp sensor) the problem turned out to be a bad fuel pressure regulator. I've experienced two failure modes for LH-jet FPRs; the first where inadequate fuel pressure is delivered and fuel comes out the vacuum line connection on the front of the unit, and the second (which occurred in this case) where the unit simply pressures up to the point that NO fuel is let out the return line side and excessive pressure is delivered to the injectors (hence the OBD code). Easy to test, just disconnect the return line to the tank from the back of the FPR and connect a couple feet of hose. Aim the hose into a gasoline safe container and turn on the engine. You should get a good strong stream of fuel from the return line at idle, probably something like a half gallon a minute or more. If you get little or no fuel, the FPR is bad, and your main fuel pump will run hot and start screaming for attention pretty soon.

Also found out that this same FPR (Bosch 0 280 160 294) is used on both the LH 2.4 in my daughter's '90 244 and the B230FT in my wife's '94 940T. Now I need to go by the pick and pull to get a "spare" for my "inventory." --
Mike W., four 240s and a 940T, Largo, FL