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Robert
Robert, ASE Certified Master
Category: Dodge
Satisfied Customers: 4275
Experience:  Dodge Master Certified, Dodge Sprinter Certified
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2000 caravan 3.3 no spark. Have 11+ volts on green orange

Customer Question

2000 caravan 3.3 no spark. Have 11+ volts on green orange wire at coil while cranking, however. No spark or fire. No response to starting fluid. No idea if fuel is being injected. No codes. Friends van. They need it to run. Im a bmw tech. It just died without warning as they drove across a paking lot and then would not restart.
Submitted: 1 year ago.
Category: Dodge
Customer: replied 1 year ago.
I have read elsewhere that the asd relay that powers the ign coil and injectors, will not be activated by the pcm if the crank sensor and cam sensors are not sending.
Customer: replied 1 year ago.
So i don't know if i should try replacing one of these 2 sensors or which one. I see another big module (besides the pcm beside the battery)....this other module sits on the right side inner fender and has a long single connector with a 10 mm bolt that holds the connector in. Looks like an ignition or transmission module....just not real familiar with these dodge systems.
Customer: replied 1 year ago.
If one of you can help me diagnose and get it running for them, i will give a good tip. I am doing this to help a family in need and will probably be donating the parts required to fix it, so
Expert:  Robert replied 1 year ago.
Hello, welcome and thanks for asking your question. My name is***** a Certified Auto Technician with 28+ years experience. I will do my best to assist you. please keep in mind that I may need to ask questions of you before I can answer. When you reply please feel free to add as much detailed information as possible pertaining to your concern.
The best thing to do at this point is to scan for the "Diagnostic Trouble Codes" (DTC's) from the onboard computers. The DTC's are used as the Starting Point for diagnosis. They let you know which system(s) the fault is in. This information is of great value for correct diagnosis. As a Technician, my first course of action is normally to scan for the DTC's. If you can obtain these codes, we can more accurately and efficiently diagnose the problem. You can rent a code reader for FREE at your local auto part store (AutoZone, O'Reileys, Advanced, etc.). If you post these Diagnostic Trouble Codes here, I can obtain the most accurate information to help you diagnose the Concern, and then point you towards the correct repair.
Keep me posted...
Thank you,
Robert
Customer: replied 1 year ago.
i already checked, and surprisingly, no codes. owner said engine light was never on.
Customer: replied 1 year ago.
that's one of the first things i did was check for codes.
Expert:  Robert replied 1 year ago.
Hello,
Sorry for the delay...
What is the make and model of the scanner?
We need to be certain that the PCM is powered up and online with the key on, that's why I need to know what type of scanner was used....
Cam and or crank sensor will usually set codes if either was bad so that would rule those out as long as the PCM is in fact online....
One thing that you can do is to disconnect the MAP sensor and check the 5 volt feed for 5 volts. If there is not 5 volts present, you may have a shorted sensor somewhere bringing down the PCM...
Basically we need to verify 5 volts and also that PCM is online and operational....
A Capable scanner will be able to help determine this....
Keep me posted and let me know if you have additional questions...
Thank you,
Robert
I also need to let you know that my responses may be delayed because I may be helping another customer, or I may be temporarily offline. Your understanding is greatly appreciated.
Thank you...
Robert
Customer: replied 1 year ago.
I know that the pcm is "alive" because the 5V signal is going to the sensors that I checked. My personal scan tool is just an inexpensive code reader like the Autozone has down the street. It does not do live data or anything besides engine DTC's. Also, as I said, the automatic shutdown relay is being activated momentarily when I turn on the ignition switch because I have system voltage on the green/orange pwr wire to the coil and injectors momentarily when the ign is switched on, and then I have voltage there again while the engine is turning over, trying to start. The way I understand is that the pcm must see crank and/or cam sensor signals before it will send the ground to the automatic shutdown relay to pull it in, sending power out on the green/orange wires. If the pcm was dead or not powered, then I believe it would not be functioning by sending out the 5V reference signal and the ground signal to the ASD relay. What can I check next?
Customer: replied 1 year ago.
i read that a bad crank or cam sensor does not always throw a DTC, maybe only if it has open or shorted circuit inside or wiring to sensor? So it will always throw a code if it is not functioning? i know I have had bad sensors on BMW's, but no code
Customer: replied 1 year ago.
I am not against renting a better scanner that will tell more maybe. maybe you can recommend one from one of those stores. I have all 3 of those stores nearby.
Expert:  Robert replied 1 year ago.
Hello,
You stated: "What can I check next?"
Basically I'd recommend for you to obtain a "Noid Light" and check to see if the injectors are getting the Pulse Signal while cranking. If you are seeing a constant timed pulse while cranking I would assume that cam and crank sensors are being read properly and you are getting a valid reference signal to cause the injectors to fire. If this tests good you can start concentrating on the ignition coil circuits.... Everything you stated above that question seems correct and is functioning as designed from what you described....
You stated: "i read that a bad crank or cam sensor does not always throw a DTC, maybe only if it has open or shorted circuit inside or wiring to sensor? So it will always throw a code if it is not functioning?"
For the most part, any thing that can cause the Cam and Crank Signals to be out of sync with each other or of one or the other signal is intermittent or missing WILL cause a code to set. Yes, if one or the other is not functioning, it will set a code...
None of the mentioned stores would have a better scanner than you already have. You would probably need a "Full Fledged" scanner that can read the datastream and also actuate circuits.. Hang tight on getting a better scanner until we run out of options.....
Keep me posted and let me know if you have additional questions...
Thank you,
Robert
Customer: replied 1 year ago.
Hey Robert, on the way home stopped and picked up the noid lights. connected to injector harness in 2 different places: did not see any light flashes while cranking. I did quite a bit of internet research last night on diagnosing this issue and one of the things I walked away with is that the crank sensor signal is required by the pcm before it will pull in the asd relay, which it is doing. Also, I read that the pcm will not fire the coils or injectors without a camshaft sensor signal because it uses this signal to know whether the crank is on TDC for spark and fuel, or on TDC exhaust stroke. One reference did say once the engine is running, that it can remain running without the cam sensor signal, but that idle may be higher than normal, etc. So I am going to use the method they described to check the digital hall-effect 3 wire cam sensor. It should have 5v reference coming in on one wire, ground to the pcm on another, and the last wire should be the one that the on/off signal goes back to the pcm. I will have to figure out with my meter which wire is which unless you know that info. I am also going to just check the availability of an new cam sensor should we decide it needs replaced. I hope I am on the right track
Customer: replied 1 year ago.
I also read somewhere else that the pcm will pull in the asd relay while cranking regardless of crankshaft signal, but will drop out after 5-10 secs if no crank sensor signal detected, so I will test that too. I have a batt charger on this van that kicks on as needed. It had 10.5 volts on batt when I first got to it a few days ago.....
Customer: replied 1 year ago.
ok, checked the 5 volt signal coming into both sensors was ok, then the middle wire was ground back to the pcm and was ok, then checked signal on the middle wire. It seemed to have about 8 or 9 volts on this wire while cranking on both sensors. I back-probed the connector passed the water seal with a very small gauge pin to check the voltage/ground signals on these wires. I also verified that the pwr stays on on the green/orange wire to the ignition coil and injectors while cranking for more than 10 seconds with the crank sensor disconnected even. It seems like i got 11 volts or so on the orange signal wires of both sensors with key on, and about 8 or 9 volts on the signal wire while cranking. I still don't know whether the sensors are working correctly or not. One guy said to check the output switched signal with the frequency setting on a meter. I did not have frequency on the meter I was using. I looked at all the wires in the engine bay area and found one branch sitting on an exhaust heat shield, but the only damage was to the outer sleeve and some burned insulation on one wire, no copper showing . I re-wrapped the harness branch and tied it up with a tie-strap. Looks like the guy that did the tune-up a year ago left that cable harness retaining screw off. So I am not sure what to do. I can get both sensors new for $73 total, but don't want to waste money on them if they are not the real issue. At this point I think either a sensor or the pcm is at fault, but not sure.
Expert:  Robert replied 1 year ago.
From your tests, it seems that cam and crank sensors are ok.
There is one thing that just came to mind. These are notorious for breaking the Flex Plate. This is fairly easy to test if you can remove the transmission dust cover and use an 18mm wrench to rotate the flex plate by the torque converter bolts, while rotating at that point check to see if you get any amount of rotation of the flex plate before the crank pulley begins to rotate. IF there is slack there, it means that the flex plate may be cracked/broken causing the no start issue....

Let me know what you find....
Thank you,
Robert
Expert:  Robert replied 1 year ago.
Hello,
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Robert