Chrysler Repair: 92 LeBaron wont start, chrysler lebaron, vacuum line

Question
Hi,
I have a 92 Chrysler LeBaron convertible, 3.0L V6 with auto trans. While my wife was driving home, it quit running and hasn’t started since. This car has about 120K miles on it. The car has had a recent tune up (about a month ago) – new plugs, wires, cap, rotor, battery, and alternator. The alternator was replaced the same day this happened. After the alternator was changed the car drove fine for a 90 mile trip to the next town over and back. This car does not have the factory anti-theft system that has caused other people these problems.

After having the car towed home, I made sure the battery had a full charge and tested the battery with a hand held load tester. The battery tested to be good and my code reader pulls up no codes. I checked to see if the timing belt broke or slipped. I cranked the engine over and watched the rotor turn to eliminate a broken belt. I lined up #1 cylinder on TDC, the rotor was pointed to the #1 terminal inside the cap (which is not in the same location as the plug wire). I pulled the window cover to the rear cam and the marks were lined up there as well.
I verified that I have spark to # 6 cylinder by inserting a screwdriver in the plug wire and watching it arc to a bolt on the valve cover. I did not check each individual cylinder just a random wire check.
The fuel pump powers up when the key is turned on so I checked fuel pressure at the fuel rail. With the key on I have 45 psi and when cranking I have 55psi. The vacuum line was off the regulator so I could see that no fuel was leaking past the regulator diaphragm. With the key back in the off position, the fuel rails maintained the 45 psi for about five minutes before I released the pressure and removed the gauge. With everything hooked back up, we then cranked the engine over and listened to each individual injector with a stethoscope and verified they were pulsing. I also listened to the regulator to verify no fuel was leaking past it.
Having spark and hearing the injectors pulsing, I don’t think the sensor in the distributor is bad or that the ECM is bad but the car still will not start. The car cranks over easily just wont start.
Can you help me figure out this problem as this car is my wife’s daily driver?
Thank you
Herman


Answer
Hi Herman,
I would suspect mixture as the problem. Two possibilities: the MAP sensor could be inaccurate but not so bad as to set a code. You might want to probe between the dark green/red and black/light blue wires to see the reading with the ignition "on" and then when you are cranking it over. Another possibility if the vehicle was first delivered to California is that the egr valve is sticking slightly ajar. Thst is located in the crossover exhaust pipe. Check the movement of the stem by inserting the tip of a screwdriver in the slot of the valve stem and seeing if spring-action closes it firmly. If not, spray the stem with WD-40 and move it back and forth. This is not applicable to 49-state vehicles. The last thing to try is the throttle body. Clean its throat, both side of the throttle plate, and the by-pass passageway.
If you haven't tried the ignition key fault code readout do that: "On-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then count the flashes of the check engine light before each pause. Then repeat to be sure of an accurate count. Group the counts in pairs in the order of appearance to form the two digit fault codes. Then write back with the results or go to www.allpar.com/fix/codes.html for a code list.
Thanks for the very complete set of tests/observations. You are very deliberate, clear, thorough.
Roland