QuestionQUESTION: Had a noise in the engine, on my 97 Chrysler Concorde, 3.5L engine, determined it was the water pump. Replaced the water pump trying very carefully not to move the cams. The engine will now crank but will not start. Had a friend come over with a scanner and it showed I was not getting a reading from the crankshaft position sensor. Replaced it and still have same problem. Got online and found a similar situation you helped a guy with on 1/13/2007. I checked voltages on the cam and crank sensor and have 8v (actually 9v.)on the orange wires. Have 5 volts on the tan/yellow and lt.blue/dk.blue with the plug disconnected. On the cam I back probed the tan/yellow wire and the voltage changed from 5 to 0, back to 5.when I rotated the engine by hand. (did not try crank position sensor since it was a new one) Checked for continuity on orange wire from both plugs, back to pin 44 at PCM and it was good. Tested for voltage at dk.green/orange wire at the coil pack with a 12v test light and it lit up when I turned the key on and continued to light as I cranked the engine. Do not have a neon glow lamp to test from the dk.green/orange with to other pins, but tested coil resistance to the other pins and got a reading of .6 on all of them. I hear fuel pump running every time I turn the key on. Only thought I have is, that maybe I did move the cams and they are out of time. Would that cause it not to start? I would think it would start, but run rough. Any help would be appreciated.
ANSWER: Hi Ken,
It appears that you have done a thorough job of checking things out. However, although the crank sensor is new, it might be faulty or possibly not installed with the tip of the sensor close enough to the surface of the rotating drive plate. Measure between pins 4 and 24 at the pcm while rotating the engine by hand.
Try disconnecting the battery to erase any existing fault codes. Then try to start it again. Then turn 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 process to be sure of an accurate set of flash counts. Then let me know what they are. Fault codes are two digit numbers, so you group the counts in pairs. The last number would be 55 which means end of readout.
If you get a code 11 then that would confirm a problem still with the crankshaft sensor. Otherwise let me know the codes.
of course you could verify the timing belt alignment since that might have slipped enough to cause the problem. The last possibility would be an egr valve that is sticking ajar which prevents starting and often won't show a code.
Those are the things I can suggest.
Please read the PS (below) and respond to it.
Thanks,
Roland
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QUESTION: I had actually done the check engine light thing,(that was the first thing I found searching on the internet) just forgot to add it in. It is a 12. I had actually done that at the beginning of all this and it has always been a 12. I did the fault code test twice today, but I had not disconnected the battery after I had done all of the other testing, would that make a difference??
What am I measuring for on pins 4 and 24 at the PCM, voltage or continuity? Is the connector unplugged when I do that test?
ANSWER: Hi Ken,
Disconnecting the battery erases all the codes, except for 12 which is "battery disconnected recently". If you don't get an 11 code after trying to start it a couple of times, then I wonder whether the friends reader was accurate because if it were you would expect an 11 code.
The 4 and 24 are the crank sensor signal and ground wire so if you put fine straight pins in the two wires you should see the voltage oscillate between 8 and 4 or so volts as you rotate the engine by hand, with the plug in the socket of course.
Roland
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QUESTION: Roland, Thanks for your help. I back probed the 4 and 24 pins (Pin 4 was a Turquoise color, and 24 was a black/green wire) with connector plugged in PCM and both cam and crank sensors plugged in with key on, only had .6 volts. I turned engine by hand and it never changed.
With PCM connector plugged in, I checked pin 4 to ground and had continuity.(I am assuming pin 4 is the ground wire.) I checked pin 24 to 5v pin on crank sensor plug(disconnected) and had 14.92 on 40K setting on my meter. Then checked pin 24 to 8v pin on crank sensor and had 10.8 on 40K setting. Plugged crank sensor back in and back probed into the 5v wire and got my 5v reading. Turned engine over by hand and reading would go to 0 and then come back to 5v. (noticed that voltage was jumping around a lot when turning, but would go to 0 or 5 when I stopped) Can you explain to me how the 5v and 8v systems work with the PCM? (Who sends what to where?) I was a service rep. for Ag. and Ind. equip. manufacturer for 24 yrs., but we didn't get into much of this stuff)
AnswerHi Ken,
The 8v on the orange wire is what powers the sensor. The black/light blue is a common ground wire for all the sensors and it goes to pin 4 or the PCM. The pulsing signal wire is light blue/dark blue and goes to pin 24 and it varies between 5v and 0.3v depending upon whether there is metal or an open slot opposite the tip of the sensors at the moment. There are 12 slots in the torque converter drive plate so there would be 12 oscillations per complete rotation of the crankshaft. It sounds like yours is working properly.
Are you getting spark at one of the spark plugs when you are cranking it over? Remove a plug and hold the threaded shell in contact with the cylinder head while a helper cranks over the engine. It you get spark then there is no issue with the crank or cam sensor. The fuel pump should be running while you are cranking it over.
If you have a no start with no codes, and you have spark, fuel pump, and I assume compression, then it has to either be mixture or significantly off-marks cam/crank sprocket settings due to replacement of the water pump without removal/install of the belt. So I would next check those timing marks. As to mixture, check that the valve stem on the exhaust gas recirculation valve is moving freely (move it via the slot in the valve stem, and is gummed up spray some WD-40 on the stem where it enters the valve body.
Thanks for the rating and nomination.
Roland
