Jeep 2009 one day just wouldn't start. While talking to m...

Hello and welcome! My name isCustomerand I can assist you with your question. I am a former master tech and I have worked in this field for 20 years. I specialize this type of problem you are experiencing so I am confident I can assist with this issue. I am sorry you are having this issue and I understand this can be frustrating so I will try my best to help. While we are working on this issue together, please allow up to 30 minutes (or more) between replies as I might be online helping other customers or offline spending time with family. Please understand I can only see what is on this page and what you have already shared with me. Please keep in mind, I don’t know the history of the vehicle and I don’t know your mechanical ability, however, I will try my best to help. The phone call prompts are automatic and are coming from the web site, not from me. If you would like to speak on the phone, please request a phone call on your end and I will call you right away. I am going to start by asking some basic questions to get up to caught up to where you are at with this situation so I can assist you in a timely manner. I appreciate your time and patience while we are working together on this issue. My goal is to provide you with a pleasant experience and ensure all of your questions are answered. Please reply back at anytime so I can fully answer or address any questions or concerns you may have. _Please download or save any documents or images I may send you as they will automatically expire after 7 days._ Can I start by getting your first name? Thank you

Without knowing all of the information like the vehicle history, the components that have been tested or replaced, the results of any tests that need to be run and without being there myself looking at the vehicle, it is hard to say exactly what is going on. I can only give you a general answer, but I hope this helps. You are going to want to start by checking all fuses and check for codes in the computer using a compatible scan tool [like this one](https://www.amazon.com/Autel-AutoLink-AL319-Scanner-Automotive/dp/B007XE8C74/ref=sr_1_7?dchild=1&keywords=obd2+scanner&qid=1589589090&sr=8-7). If there are codes in the computer, you can reply back to me on this page with the code number or numbers and I can help you pinpoint the root cause. If all fuses are good but there are no codes in the computer, we will have to pinpoint what the engine is missing when this no start condition occurs… Spark Fuel Compression First is the fuel system. There are two way of checking the fuel system. First, there is the fuel pressure up to the fuel rail. Normally this is checked using a fuel pressure gauge. You simply hook it up to the fuel rail, turn the key on or crank it over and take a reading. Most older vehicles have a fuel pressure test port. This means you can simply screw the fuel pressure gauge onto the fuel rail with ease to check fuel pressure. If not, you can tap the fuel pressure line going to the throttle body or fuel rail (depending on your system) and take a reading that way. The newer vehicles use a fuel rail pressure sensor. It will take a pressure reading off of the fuel rail and turn it into a digital signal that the computer will see and understand. You can see this under live data in the ECM or PCM using a compatible scan tool under “live data”. The second part of the fuel system would be the injector pulse. This is the signal from the computer to the injectors to tell them when to open up to allow fuel into the engine. Normally this is tested using a tool called a noid light. You simply plug the noid light into the injector connector after disconnecting the injector connector from the fuel injector and watch it while an assistant cranks it over. It should blink if it has power and a ground signal trigger from the computer. This is a good signal. Both parts of the fuel system are very important and must be present for the car to start. Next would be the ignition system. On a standard ignition system, the secondary ignition components should be able to deliver strong bright blue spark that can jump at least a half inch of a gap while cranking the engine over. You can check this on more than one cylinder to be sure the ignition system is working normally like it should. Depending on your set up, you could have ignition wires that send the ignition to each cylinder or you could have coil over plug (which is very common). Either way, simply access the wire or coil and insert a spark tester or screw driver in place and ground the other end. Watch for night blue spark while an assistant is cranking the engine over. There is also the primary ignition system too. This is the engine speed sensor or sensors (cam or crank sensor). Some vehicles use just the crank sensor and others use both the cam and the crank sensor to produce spark. On some more complex vehicles and engines, there might be 2 or more camshaft position sensors that can affect spark. Both the primary and secondary ignition system can fail (and even intermittently) causing a no spark condition. If there is no spark while cranking, be sure to check for power to the ignition coil or coils with the key on and while cranking the engine over. Yes this could be a blown fuse or relay causing a no spark condition. Some vehicles or ignition systems use an ignition module as well as the coil or coils, and others are triggered directly from the engine computer but will still need a separate power source for the ignition coil(s) to work. As far as compression goes, low or no compression could be caused by base engine mechanical issues such as a broken camshaft or timing chain. You can check engine compression, remove the front timing cover and take a look at the timing marks or possibly pull the valve cover to see if there is any visual damage that you can see. Checking compression requires a compression gauge. Simply screw the tester into the spark plug hole after removing the spark plug and crank it over to take a reading. While the compression specifications vary a bit depending on the engine, basically you want to ensure compression is relatively the same in all of the cylinders. All three of these are tested when the engine is being cranked over. A compression tester, spark tester, fuel pressure gauge and noid light are all accessible at your local auto store or online. All three tests play a very important part in diagnosing a no start condition. Be extremely careful when doing these tests. You could also see if it runs on starting fluid once you know the engine has spark. If it does, then you know you have spark and compression and you simply have a fuel delivery problem. Here is a video explaining how to check for spark and fuel on a car that cranks but does not start. [https://www.youtube.com/watch?v=064Ilsz8Fzg](https://www.youtube.com/watch?v=064Ilsz8Fzg) Glad I can help. Please let me know if you have any further questions. Thanks and have a great day!

It is not a fuel or spark issues. It is electrical. The fuel pump does not get a signal to turn on all the time. Some times it does then for no reason it doesn't. For instance it sat all day Sunday, I went to start it to go to work, it started no problem, went to work 7 miles down the road. I thought if I disconnect the battery it might help, well no it di.dn't. Got out of work and it would not start

Hello and thank you for the reply. Since the fuel pump is not powering up due to an electrical issue, it turns into a fuel issue preventing the engine from starting. Have you checked the fuel pump circuit? Would a wiring diagram of the fuel pump help? Have you checked for codes in the computer? Can you send me the VIN?

It is a brand new fuel pump it was put in this past Friday. I thought that would help but no still the same problem. Fuses are fine and so is the relay. VIN \*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*\*.

Thank you. And what about codes in the computer?

no trouble codes for that comes up

Ok does the fuel pump fuse have power on it when cranking?

didn't think of it, all appear to be good that I have checked

Ok may want to check that next. It should have 12 volts on it while cranking. If not and there are no codes in the computer, this could be an issue with the main fuse block or integrated power distribution module. If you did the battery disconnect procedure without any results, the fuse box may need to be replaced. You need to have a mechanic look at it and diagnose it correctly before you start replacing parts on it.

I'm not with the vehicle now but how can I check the fuel box to see if there is a problem?

This is done using a compatible scan tool

ok thank you very much

You are most welcome!