QuestionQUESTION: Up until this morning it was fine (albeit fine for a vehicle with 211,000 miles on it).
When I went to start it this morning it 'appeared' to want to start and then nothing. Continual cranking produced nothing.
I suspected a timing belt issue, but that appears to be OK. (Replaced the belt 2 months ago) Rotor turns fine and is in proper position in relation to TDC.
I've checked for spark at plugs and there is. Did a DVM impedance check on the coil and it appears to be within tolerances.
.8-1.0 ohms on primary and secondary terminals.
12.5k ohms between both primary and secondary terminals to the high tension terminal.
Fuel pump is priming fine. The odor of gas is present, but not overpowering.
I did a key on/off code read and got the following the first time; 12, 24, 55. I reset the code by removing the negative terminal for about 30 minutes and tried to start the vehicle again. Nothing. Did another code read and only get 12 and 55 now. During the cranking process, following some other advise, cranked for about 15-20 seconds max. Let it sit for a minute and got the 12 and 55 code again.
I'm stumped at this point.
I've looked for where any associated parts are located, but haven't been satisfied with any answers yet. Like; where is the crank sensor located, etc.
Roland, any help or advice you can offer will be greatly appreciated.
Thanks in advance.
Michael
ANSWER: Hi Michael
The 24 code meant at that time that the throttle position sensor signal was out of the expected range (either too high or too low a value which would be due to a short or an open situation).
It has a 5v supply so the signal should vary smoothly from 0 to 5 when measuring between the orange/dark blue and black/light blue wires as you move the throttle.
I suspect since you have fuel and spark that you may have a mixture problem due to a slightly stuck ahar exhaust gas recirculation valve. Try moving its stem back and forth using the tip of a screw driver inserted in the slot of the valve stem. Spring-action should close it tightly to a stop. If it is sticky, then spray some WD-40 on the stem where it enters the body and then exercise it some more.
The 3.0L doesn't have a separate crank sensor, as the photo-optic sensor located in the distributor does the job. If that were an issue you should see an 11 or a 54 code.
Thanks for the good history and readings. I hope this will help you solve the problem.
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QUESTION: Once again, thanks for your input Roland.
I have checked the EGR as you suggested and it appears fine as far as the travel on the rod. I gave it a good soaking with WD40 anyway to be sure.
I followed your advice and did a voltage check at the TPS and I *think* this is the problem piece.
The wire color is different from what you stated, mine are black/light blue stripe, dark blue(or black)/orange stripe and what appears to be solid black.
With the harness removed from the TPS I get the expected 5 volts with ignition on. But when the harness is attached to the TPS the voltage range is from .523 vdc to 1.543 vdc.
So I am going to assume (we know where that usually goes) that it is the TPS. I probably won't get to it until tomorrow since the sun is going down and the temps are in the low 30s.
Michael
ANSWER: HI Michael,
On the wire color discrepency, those two different sets of color wires are used with an automatic or with a stick shift transmission, so that is the explanation.
On the TPS the voltage range should normally be about 3 volta from minimum to wide open. I wonder however if there might be a partial short of some sort in the harness, so you might want to check the signal wires for that; verify you have 5V, and that the ground wire is solidly connected. The black/light blue goes to pin 4 and is the common sensor ground, the dark blue/orange is signal goes to pin 22, and the 5 volt supply comes from pin 6, all at the pcm. Of course it could be a defective TPS.
Roland
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QUESTION: Roland,
I was able to replace the TPS yesterday but it does not appear to have been the problem unit.
I re-verified spark from coil and at plugs. Now, I read other forums re: spark from coil and they mention a "bright blue" spark. When I perform that test the spark produced is an orange/yellow spark. Held 1/4 inch from grounding point the spark appears strong, but yellowish in color.
I will troubleshoot the harness in the event that there is a short or intermittent grounding issue.
Is the PCM on my vehicle located on the driver's fender-well under the primary fuse and relay block? I have yet to find a reasonable answer to that one. :)
I'm guessing that's where it is since there appears to be 2-3 harnesses terminating there.
Again, thank you so much for your time and your expertise in this matter.
18 degrees here this morning so it's going to be an interesting day for me. :)
- Mike
AnswerHi Mike,
Yes the pcm is in front and below the power box and has a 60-wire plug. You also might want to take some solvent and clean both sides of the throttle plate, throat of the throttle body and the idle air by-pass passageway on the side of the throat. Crud can make for imprecise fuel/air mixture and hard starting.
Roland
