Chrysler Repair: 88 Chrysler New Yorker Landau, chrysler new yorker, yorker landau

Question
Hello Roland:
    I spoke with you about a year and a half ago it was about this car you asked me to let you know how things turn out... I am pleased to say I now have my car back  and running thanks to you I had to replace a water pump and a timing belt to get the engine running then just recently I replaced all of the front brakes as they had rusted to the rotors from the vehickle was parked for 6 years and not running...I eliminated all of I think 4 or 5 trouble codes except for one code is still left code number 81 something I am told having to do with possibly the oxygen sensor ... I replaced the sensor and still no luck it also said to put dieclecric greese on all of the wire sockets and pins and IDE ect... did that and no luck I tested the fuel pump rail pressure look out that stuff really has a lot of pressure behind it come to find out code 52 was eliminated by replacing a small piece of rubber fuel line that had a pin hole in it but still have not got rid of code 51 it also says use the fuel pressure testor to do test for injectors and the such I think is part of the fuel rail pressure test I have not did that part yet so I think that it may be something in the fuel rail pressure or something it says that the gas tank or around that area to be tested. So that is how things have turned out ...
I have one question for you I have a turn signal on the left side that when the headlights are turned off will light up manually but will not flash 5unroon and off with the flasher system and when the head lights are on it will not light up at all... any suggestions on how to fix this?
Sincerely,
MR Tom Carlson

Answer
Hi Tom,
The 51 and 52 say that the oxygen sensor detects either a too lean (51) or too rich (52) mixture. Did you show those simultaneously or after you fixed one did the other appear? They should be mutually exclusive, only one or the other at any time, never both. If you are truly lean now then you might begin by searching for an intake manifold leak using small squirts of starter fluid while the engine is idling, squirting at the margins of the manifold and the vacuum hose attachment points and far ends in order to see if you can detect a leak, which would cause a momentary increase in the idle speed when you struck paydirt. But only use very short bursts of starting fluid as it is highly flammable.
I would believe the sensor and therefore consider how to increase the fuel in the mixture. Perhaps one or more of the injectors is partially blocked from the long storage experience? Those are some ideas. I surmise that you have the 3.0L V-6 as my shop manual wiring diagrams for the '88 Landau show only that engine as being available.
On the turn signal, I would look at the turn signal bulb/socket interfaces for possibility of poor connnections. Also check the cornering light bulbs on that side. For the flasher to work there has to be low but normal resistance in the circuit, so when you have some extra resistance the bulb will light but not draw enough current to fire the flasher. And when the voltage of the system is dragged down by the headlamps it further exacerbates the problem, thus no light at all. Be sure also to check the black ground wires from each of the turn signal socket to make sure there is not a poor connection to the body which would also cause the same extra resistance.
Those are my best ideas at this point. I'm glad to learn of your progress in keeping this near classic going!
Roland
PS Please rate my answer, thanks.