QuestionThe LHS will not start when the outside temp reading is below 26 degrees F. If the reading is 27 degrees or above it starts right up. Occasionally I can get it to start by holding the gas pedal down or pumping it, but not always. When I do this it will sputter and pop but not always start. 4 mechanics and 5 different code readers but no error codes. I would appreciate any recommendations.
AnswerHi Barry,
Of course it is possible that the temperature sensors that are supposed to adjust the mixture to take account are inaccurate but not so much as to set a code. That could be measured: the resistance of each at the local temperature at the time. But before doing that may I recommend a common problem that is also something that can slip past the self-diagnostic capability?
I would take a look at the exhaust gas recirculation valve which is located behind the engine near the air intake throttle valve. It is mounted in a pipe that runs between passenger side exhaust manifold and the air intake manifold. The valve is mounted horizontally and has a valve stem between its round vacuum actuator top and the body of the valve attached to the pipe, inside the flange that connects the two parts. The stem has a slot into which you can insert the tip of a flat-bladed screwdriver so as to lever the stem back and forth against spring action which should move freely and close tightly. If the stem seems to be sticky so that stem doesn't close all the way by spring action, then you can try spraying some penetrating solvent like WD-40 on the valve stem to freeup its motion.
If the valve is sticking slightly ajar (which is more likely the colder it gets) it will make for a no start/rough idle such as you describe because the mixture is too dilute. It is one of the most common causes of this symptom.
So see if you can find the valve and check/lubricate the stem. To check it in motion you can rev the engine from idle to 2500 rpm and back to idle and watch to see if the valve stem moves freely in both directions to the extreme open and closed positions. It may be that the interior of the valve is cruddy so that might require that it be unbolted from the pipe where it it attached and cleaned. But chances are good it will only be a sticky stem. You will probably need to remove the corrugated air intake tube that connects the air filter housing to the throttle body air intake to the engine in order to visualize what I have described.
Feel free to write back with the results and other questions you might have.
Roland
PS By the way, you can read the fault codes yourself on the '96 LHS
by using the ignition key:"On-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light which remains 'on', to see it begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the procedure to assure the count set is accurate. The last two counts will be 5 flashes each. If there are other counts those would be meaningful as the 55 means 'end of readout'. Let me know if so.
