Engine cranks but does not start

Tiny
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  • 2008 DODGE AVENGER
  • 200,000 MILES
Battery is new. Alternator is good. We took out the starter and checked it. It turned so we put it back in. Thinking ignition switch is bad we bypassed the ignition on it. It cranked just didn't start. Kind of at a loss of what next. Any suggestions?
Sunday, July 10th, 2022 AT 6:54 PM

5 Replies

Tiny
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What is the problem and are there any clues or other symptoms that led to this? Is this a charging or cranking problem?
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Sunday, July 10th, 2022 AT 7:33 PM
Tiny
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It started with the engine light on and the wipers not working correctly. They were jerky. Then it wouldn't start. I tried jumping it didn't work so I bought a battery. It was an old 2014. So, then it still didn't start regularly. Started with checking fuses. None were bad. When it did start, I went to AutoZone to get a test done. The printout said evap so changed it. Then no starting at all. The mechanic couldn't find the starter. He watched a video on YouTube and found the starter, took it out and tested it. It was good so he put it back in. Then he set up a bypass if the ignition to see if it would crank. It did crank but wouldn't start even when I tried giving gas while he tried bypass. It still won't start. That's where we are.
He did say the tmip was covered with oil. Not sure how because I never noticed a leak.
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Monday, July 11th, 2022 AT 8:40 AM
Tiny
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This is really confusing. We'll have to sort out the details, then start fresh. The first problem is I need you to clarify "doesn't start". This in itself is confusing because to some people, not cranking means "doesn't start, and to others, cranking at normal speed, but the engine doesn't run means "doesn't start". I always call it a "crank / no-start" when the starter works normally, but the engine won't run, and "no-crank" when the starter doesn't spin the engine or it spins it too slowly.

The next problem is when the Check Engine light turned on, there was at least one diagnostic fault code in memory to lead us to the circuit that needed further diagnosis. It's important to have those codes read and recorded before that valuable information is lost. By disconnecting the battery, the memory in the Engine Computer was cleared, so now it's too late to see that information. It looks like you did get a code for the evaporative emissions system before it was erased, but that system won't prevent the starter system from working or the engine from running.

There's more going on than a simple defective starter motor. The worst possible way to test one is to remove it from the engine. Your mechanic should know that. Even a starter with badly-worn solenoid contacts can appear to work well on a bench test in a shop or auto parts store. That's like saying a piece of string is good, therefore it can be used to tow another car. We want to know if the starter is capable of rotating the engine. The only way to find that out is to test it while it's bolted to the engine. There's a number of simple, quick tests for that, but as I mentioned, there's more going on that just happens to include the starter system. Also, your title was the best description of the problem. The starter cranks the engine, so there's no need to waste time testing what is working.

To add even more frustration, some of the things that can cause this problem often do not set a fault code just from cranking the engine. The computer needs more time to detect the defect, as in when a stalled engine is coasting to a stop. Regardless, the place to start is by reading the fault codes in the Engine Computer. In earlier years Chrysler made doing that yourself much easier than any other manufacturer. Cycle the ignition switch from " off" to "run" three times within five seconds without cranking the engine, leave it in "run", then watch the code numbers appear in the odometer display. Remember, those codes were erased when the battery was disconnected. If you are lucky enough to have them set again, you can go here:

https://www.2carpros.com/trouble_codes/obd2

to see the definitions, or I can interpret them for you. It's important to be aware those codes never say to replace a part or that one is bad. If a sensor or other part is referenced in a fault code, it is actually the cause of that code only about half of the time. First we have to rule out wiring and connector terminal problems before spending money on a part. That code retrieval method no longer works in later year models. If it doesn't work for your '08 model, a scanner or a simple code reader will be needed to read the codes. The people at many auto parts stores can read codes in Engine Computers for free

I'm also confused about the "evap" part you mentioned. The evaporative emissions is a complete system of sensors, valves, solenoids, hoses, and includes the charcoal canister and gas tank. This is where we'd need to know the exact fault code number to know where to start looking. Some refer to a large leak or a small leak. Some refer to insufficient flow within the system. This system can be frustrating and time-consuming to diagnose problems in before we know which part(s) to replace. Toyota is one, for example, that puts almost everything on one giant, expensive assembly. You just replace that and have almost no diagnostic time. For most others, it takes longer to figure out which part is defective, but then we replace just that part.

You also mentioned you installed a used battery that is three years older than its expected life, (thank you for including that detail), then it "didn't start regularly". I don't know what that means.

At this point, since we haven't done any diagnostics yet, the best suspect is an intermittent problem in the TIPM, but that's only a guess for now. The TIPM, (totally integrated power module), is the under-hood fuse box. I don't know how oil could get on that, but I'm sure it can't help if any got inside onto the circuitry.

The TIPM is also involved with the wipers. Lets wait with that for now. If the TIPM has to be replaced to solve the first problem, it might also solve the wiper problem.

See what you can come up with for the diagnostic fault code numbers. If we're able to go further, I'll need to know the engine size too, to find the right wiring diagrams and sensor locations.
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Wednesday, July 13th, 2022 AT 3:52 PM
Tiny
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It wouldn't start. That's what started all this. My engine light came on when we did get it started with a new battery. I work nights some first thing in the morning I was going to AutoZone to get things tested. The car wouldn't start. When the mechanic got there it started and had the engine light in, so we went to AutoZone.
The evap code came up with that specific part I had put on.
It won't start from key. It will crank out without starting as if it's not getting fuel to starter.
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Thursday, July 14th, 2022 AT 11:11 AM
Tiny
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Dandy. Your last sentence was the key. This is a "crank / no-start" which means the starter motor and that entire system is okay, and we can move on.

Did you try reading the fault codes again the way I described by cycling the ignition switch three times? I'd like to know if that still works on '08 models. If it does, you won't have to run back to the auto parts store to have them read.

Next, have you identified anything you can do to get the engine running after it won't start? One thing in particular comes to mind. Fuel pressure should remain high for days or weeks when the engine isn't being run. In case it does bleed down a little, the fuel pump is going to run for one second when you turn on the ignition switch. That will ensure fuel pressure is up for starting in case it bled down a little. If it bleeds down too much, that one second may not be enough time to get the pressure back up. That can result in a crank / no-start. The way to identify that is by connecting a fuel pressure gauge that you can look at when trying to start the engine. I run the hose under the back of the hood, then clip the gauge under the right wiper arm where I can see it from inside the car. You can usually borrow a fuel pressure gauge from an auto parts store that rents or borrows tools. Here's a link to an article on how to use one, if you need it:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

An alternate method that could provide a clue is to turn the ignition switch to "run", wait a couple of seconds, turn it off, then turn it to "run" again, wait another couple of seconds, then crank the engine. That will cause the pump to run twice as long and build more fuel pressure. If it always starts and runs that way, that's a pretty good indication fuel pressure is bleeding down too quickly. There's three possible causes of that. The most common is a leaking fuel injector. The less common causes are a leaking fuel pressure regulator and a leaking check valve in the pump itself. For those last two, the fuel leaks back into the tank. A leaking injector will dump raw gas into the intake manifold. You might be able to smell it under the hood. While making the engine hard to start, the amount of fuel that drips from the injector isn't really excessive. The pressure will drop off quickly, then the dripping will stop.

The second common cause of a crank / no-start is a loss of signal from the crankshaft position sensor or the camshaft position sensor. This is where the diagnostic fault codes are very helpful. In particular it is real common on all car brands for those two sensors to fail by becoming heat-sensitive, then they work again after cooling down for about an hour. The typical symptoms are the engine runs fine until you stop for a short time, as in when stopping for gas. Heat from the engine has time to migrate up to the sensors, causing one to fail, then you'll have the crank / no-start condition. As long as you're driving, natural air flow keeps those sensors cool.

When the signal is lost from one of those sensors, the Engine Computer still turns the automatic shutdown, (ASD) relay on for one second to run the fuel pump, as before, but it doesn't turn it back on when the engine is rotating, (cranking). That relay also powers the ignition coils, so you'll also have no spark along with no injector pulses and no fuel pump. The loss of spark is the clue to look for. The next time the no-start occurs, check right away for spark before the defect goes away. Here's a link to an article on how to do this:

https://www.2carpros.com/articles/how-to-check-for-ignition-spark

If you do find spark is missing, it is possible to have an intermittent problem in the ignition system alone, but by far it's much more common to lose spark, fuel pressure, and injector pulses all at the same time, and that's almost always due to one of those two sensors.

The problem with those sensors is if there's no diagnostic fault code stored in the computer related to them, we'll need a scanner to see which one is missing. Once we know that, the loss of signal is caused by that sensor around half of the time. We also have to consider its connector terminals and wiring. One check you can do yourself is to gently wiggle the wires while the engine is running. If doing that causes the engine to stall, the connector is the better suspect, not the sensor itself.

A connector or wiring problem will also cause the engine to stall while you're driving. If that doesn't happen, a failing sensor is most likely to show up when restarting a hot engine.

Tell me what you find with those suggestions, then we'll figure out where to go next.
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Friday, July 15th, 2022 AT 1:19 PM

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