QuestionQUESTION: I have a 1993 chrysler concorde 3.5 I just hade the heads redone i put all back together and now i have nospark. I did put timeing marks where they are to go on the cams and the crank and no spark. can you help? james florida
ANSWER: Hi James,
Try using the ignition key to see what fault codes may be recorded in the engine controller memory. "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 begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then repeat the process to assure you have the counts accurately. Then combine them in pairs in the order of appearance to form the 2-digit fault codes. The last code is always 55 which means 'end of readout'. Then either write back a follow-up question telling me the numbers or go to www.allpar.com/fix/codes.html for a code list. That is the best way to start.
Roland
---------- FOLLOW-UP ----------
QUESTION: HI i got the codes but some maby old how do you reset the computer 11,12,21,23,24
ANSWER: Hi James,
You reset by disconneting the battery for a few minutes, which appears to have been done in the past 50-100 key cycles because that is what the 12 code means. So when you 'reset' you will always get a 12 code to start.
The only code relevant to spark is the 11 code which points to the crankshaft position sensor not getting a signal to the pcm, more likely due to it failing but check its wires too. You can verify no signal by rotating the engine by the crank pulley bolt with the igntion set run position and measuring for voltage between the light blue/dark blue and black/light blue wires. It should oscillate between 5V and 0.3V several times per revolution. If not, and you have 8V on the third (orange) wire, then the sensor is no good or it has been moved too far from the flex plate that it is set in close opposition to via a paper spacer being in contact with the plate. You could try a new paper spacer and reset it in contact or just buy a new sensor as you choose.
The other codes are for the engine coolant sensor, the throttle position sensor, and air intake temp sensor showing voltages outside the range of normal. So check their plugs and harnesses. But they would impact mixture, not spark production so get the spark going first.
Roland
---------- FOLLOW-UP ----------
QUESTION: HI roland just to let you know the wires on the crank senser were loose thanks for the help. but now when you take your foot off the gas it will stal the only code is 21,12,55 I checked all vac lins and wires all ok it also starts on the first hit not hard at all it also runs a little rough at idle can you help with this? james
AnswerHi James,
I would suggest that you follow up on the earlier 23 and 24 codes: First see if you have a 5 volt supply on the violet/white wire on the plug that goes to the throttle positon sensor, and then also measure the smoothness (no discontinuities) of the resistance reading as you move the throttle, measuring between the middle pin and either end pin of the socket on the sensor. You seem to have a mixure issue. If you haven't done it yet, I would suggest cleaning the throat and side passageway of the throttle body and also both side of the throttle plate.
The 23 code says that the intake air temp sensor is out of the expected range. Measure to see if its resistance is around 10,000-14,000 ohms when cold, and then it should drop when the engine warms up to full temp to around the 1-2,000 ohm range. If not then replace it, and also check its wires.
Check the egr valve by moving the stem (using the slot into which you insert the tip of a screwdriver) back and forth to be sure it comes to a dead stop via the spring-action. That valve has to be closed or it won't idle. Lubricate the stem where enters the valve body if it seems to sticking ajar.
The 21 code (one of the heated oxygen sensors) will need to be corrected, but it doesn't come into play until the engine warms up, so I doubt it has anything to do with the problem shortly after you start it.
Keep checking for other fault codes. I am pleased you fixed the spark problem by correcting the crank position sensor.
Roland
