Question-------------------------
Followup To
Question -
Roland, That narrows it down, thank you. Is the sensor accessible from the top of or from
underneath the engine? I have not yet found it from the top. By the way, the engine is a V6 3.5
L.
Steve
-------------------------
Followup To
Question -
My 94 New Yorker (192,000 miles) developed a starting problem for the first time today. The
engine cranks very well, but it simply will not start. The tank is over half full. The engine was
last run almost 24 hours ago, but we are experiencing very hot weather (90 F) today. Could this
classify as vapor lock? Or is there likely more to the problem?
Answer -
Hi Steve,
I don't believe that if the engine has not been run and gotten hot that there could be a vapor
issue. So lets do the typical approach to a 'no start' which is to determine if you have a spark.
Because I don't know which engine you have let me give you one approach that works for all:
take a phillips head screwdriver with a plastic handle and insert the metal tip of it into one of the
rubber caps that you can remove from a spark plug (don't pull on the wire, just grasp the cap
itself, rotate it back and forth while pulling to free it from the spark plug). Once the tip of the
screw driver is put in the cap so as to touch the wire clip at the bottom of the cap which normally
touches the tip of the spark plug, hold the 'assembly' via the plastic handle and position the shaft
of the screw driver about 1/4" from the cylinder head of other metal part of the engine which is
in contact with the head or block of the engine which serves as a ground. Then have a helper
crank the engine while you observe whether a spark jumps across the gap from the screwdriver
shaft to the metal ground point during a 5 second cranking period. See if you get spark for 5
seconds, 1-2 seconds or not at all. Then we can take the next step in diagnosing the no start,
based upon your observation.
You might also want to check the engine controller for any faults it may have observed and
stored as two digit code numbers. Try using the ignition key: turn it "on-off-on-off-on" and
leave it "on" (doing this quickly, no longer than 5 seconds). Then watch the 'check engine' light to
begin flashing, then pause, flashing, pause, etc. Count the number of flashes before each pause
and keep track of the numbers. Repeat the readout and verify the counts are correct. Then group
them in pairs in the order that they came out, thus forming two digit numbers. You may notice
that the pause is shorter between the digits of a given number, and longer between the numbers
themselves. Then send me a 'follow-up' question telling me the results of your readout. By the
way, 55 will be the last number (two groups of 5 flashes each) and that is the code for "end of
readout".
I have the troubleshooting manual for several of the engines and we can look up the possibilities
of what is wrong based upon what fault codes you show.
There is also an essay on fault codes at the site:
http://www.allpar.com/fix/codes.html
which gives the meaning of the code numbers. But then you need to get specific info for what
exactly might be the diagnostic tests or parts to replace to complete the repair. When writing
back tell me the engine and displacement if you happen to know it.
Roland
Roland,
The code was clearly 1,2,1,1,5,5, so the "code" must be 12-11. From the allpar.com site that
you referenced above, these codes refer to:
11 No ignition reference signal detected during cranking (bad Hall effect) OR timing belt skipped
one or more teeth; OR loss of either camshaft or crankshaft position sensor. Can cause the
engine to stop working entirely with no limp-home mode.
12 Battery or computer recently disconnected
There was no clear spark jumping from the screwdriver shaft to the engine at gaps of less than
1/4", so obviously the problem lies first and foremost with the spark generation and I guess this
explains the 11 code. Do you have any further suggestions?
I think I know the origin of the 12 code: The car has a short circuit that could not be identified
the last time it wss in the shop, so whenever I park the car for extended periods (>2 days or so),
I pull the fuse associated with the fuel efficiency/mileage readout (which evidently also connects
other peripherals including brake lights and trunk features) and that opens whatever circuit is
leaking when the car is not in use.
Answer -
Hi Steve,
The 11 code actually refers to the crankshaft position sensor which is located at the rear of the
engine on the passenger side. It has a 3-wire connector (orange, black/light blue, light blue/dark
blue) and is held in place by a bolt. You will find that a new one has a paper spacer mounted on
the tip so leave that in place and insert it into position touching the torque converter plate.
Tighten the bolt to 105 inch-pounds. But first you might want to inspect the wires as far as you
can just to be certain before you buy the new one. If it were the camshaft sensor it would have
been a code 54.
Roland
AnswerHi Steve,
It appears to be actually installed at the leading edge of the trans bellhousing rather than the rear surface of the engine, and it looks to be just above the level of the half-shaft on the passenger side so getting to it may be better from underneath. The Haynes manual concedes it is difficult to reach to do any electrical testing, recommending instead to use a diagnostic readout box if you really want to check it out before removing it. That is the best info I have on it. One last thought, make sure that when you turn on the ignition key to run that you do hear the fuel pump run for about a second so as to be sure that the ASD circuit isn't killing the voltage immediately rather than after a second or so. But I tend to believe the code readout, and the hall sensors do tend to give up after a few years.
Roland
