Crank no start and shuts off, low idle

Chrysler has never used a mass air flow sensor on their domestic vehicles, so you replaced something else. The crankshaft position sensor is a good suspect, but so is the camshaft position sensor. Your best observation is loss of spark. Where people get in trouble is they stop looking for other things when they find that. In this case, about 95 percent of crank / no-starts are caused by loss of spark, fuel pump, and fuel injectors. You have to check all of those, but they're harder to do. Instead, lets jump to the middle and check if the automatic shutdown, (ASD) relay is turning on. Knowing that will tell us which way to go next.

Look for the dark green / orange wire at the ignition coil, at any injector, or either smaller terminal on the back of the alternator. Use a test light for this as most digital voltmeters don't respond fast enough. You will see the test light turn on for one second when you turn on the ignition switch. What is important is if it turns on again during cranking. If it does not, the cam and crank sensor circuits are the best suspects.

These sensors often don't get detected right away when a signal is missing during cranking, but it is still proper procedure to read the diagnostic fault codes first. If you disconnected the battery or ran it dead recently, any fault codes will have been erased and that valuable information will have been lost, so you can skip this. Disconnecting the battery will also cause the low idle speed. That has a real easy solution once we get the engine running. Until then, you may need to hold the accelerator pedal down 1/4" to get the engine started or to keep it running.

Chrysler made reading the fault codes 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. You can go here to see the definitions:

https://www.2carpros.com/trouble_codes/obd2/p0400

or I can interpret them for you. It's important to understand those codes never say to replace a part or that one is bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a sensor or other part is referenced in a fault code, it is actually the cause of that code about half of the time. First we have to rule out wiring and connector terminal problems, or mechanical problems associated with that system.

There's two different sets of symptoms to be aware of. The first involves the idle speed being too low. That can cause cranking with a failure to start unless you hold the accelerator pedal down 1/4", you won't get the nice "idle flare-up" to 1500 rpm at start-up, and the engine will tend to stall at stop signs. That problem has an easy fix and will not cause stalling while driving. It is caused by disconnecting the battery, and is solved by coasting down from highway speed. That triggers the conditions needed for the Engine Computer to relearn when it must be in control of idle speed.

The other problem can cause stalling while driving, a crank / failure to start, but low idle speed is not related. This is the one where you'll find spark is missing, as you mentioned originally. The clinker is when this is intermittent, you have to do the testing while the problem is occurring. Since you found a good test point, leave the test light connected so you can see it when the problem occurs next time. I've already run a wire under the rear edge of the hood, then through the passenger's window, so I could watch the test light inside the vehicle. This works especially well when you have one that only acts up for a few seconds, then resumes working.

This is starting to sound like a failing fuel pump, but I'm wondering if you don't have two different problems. Unlike GM fuel pumps that fail while you're driving, leaving you sitting on the side of the road, Chrysler fuel pumps almost always fail to start up, but if they do, they keep running until you stop the engine. A common clue is the engine will run for one or two seconds on the residual fuel pressure in the line, but it will only do that for two or three starting attempts. That's long enough to show you have spark.

When this happens, bang on the bottom of the gas tank while a helper cranks the engine. These pumps fail due to worn brushes. If the intermittent connections occur when you stop the engine, you'll have the crank/no-start next time. Banging on the tank can jar the armature enough for the brushes to make contact, then, once the armature is spinning, the brushes will continue working for that drive cycle. That problem will get progressively worse over the next weeks and months.

Do you have a fuel pressure gauge that you can run out of the hood and clip to the radio antenna?

I've run into two vehicles, both minivans, where the plug to the fuel pump assembly developed weak connections after the pumps were replaced, then one terminal overheated and burned away. Those caused intermittent operation.

We need data to analyze to know where to start looking. Check for a fuel pressure gauge at some local auto parts stores. Many of them rent or borrow tools. Those in my area make us buy them, then they give us a refund when we return them. If we want to keep a tool, they exchange it for a new one that we get to keep.

I mentioned the MAP sensor is the biggest contributor to fuel metering calculations. When you're getting too little fuel, or so much that you can smell it, a failing MAP sensor is a good suspect. The tool for this is a scanner with "record" capability. Most of the better ones have that. An experienced engine performance specialist knows what to look for with the sensor readings. For the rest of us, we need to see what the typical values are when the engine is running right, then compare that to when the problem is occurring. The "record" function lets you make a recording for a few seconds when the problem acts up, then you can play that back slowly, later, to see what changed. This is especially useful with intermittent problems and when there are no related diagnostic fault codes to steer you to the circuit that needs further diagnosis.

There is always a range of sensor signal voltages that are acceptable to the computer. Anything outside that range is one of the strategies that sets a fault code. For explanation purposes, temperature, position, and pressure sensors are most commonly fed with 5.0 volts, then their range of signal voltages is between 0.5 and 4.5 volts. The clinker is you can have a sensor send the wrong value, but if it falls within that acceptable range, the computer will act on it and accept it as valid. A few tenths of a volt means a real lot to a MAP sensor as far as engine performance. This is where the signal voltage can look okay to us, and not set a fault code, but it can cause an engine performance problem. Fortunately, when MAP sensors fail gradually this way, it doesn't take very long before they get bad enough for the computer to detect it and set a fault code.

Just saw your last reply. What do you mean by "kick over"? We run into a lot of trouble with confusing terminology, and a lot of people do not understand, for example, that "doesn't start" can mean a multitude of symptoms and causes. "Crank" seems to be another one that has meanings we never thought of.

To be clear, "crank" means the starter spins the engine. "Turns over" is the same thing. Some people think "turns over" means the engine runs.

When you say, "didn't even kick over once", I get visions of a starter that is not spinning the engine, and that is a totally different, but very common problem. If you have the little silver Nippendenso starter, those have a real common problem with internal solenoid contacts that arc and burn away. The symptom is you'll hear the fairly loud single clunk as the solenoid pops the drive gear into mesh with the ring gear, but the starter motor will not spin at all. The clue here is when you cycle the ignition switch between "crank" and "run" repeatedly, you'll hear that loud clunk each time, and eventually the starter will work and the engine will start. This first acts up perhaps once a week or two, and gets progressively worse over weeks and months. In the case of my mother's '95 Grand Caravan, I ignored it so long, she finally lost count after 700 tries and a blister on her thumb, but it did finally start. You can be sure I heard about it that night!

The fix for that is to replace the contacts. I can describe that further if necessary. Most people just replace the entire starter.

If the starter does not spin the engine but you do not hear that loud single clunk, the neutral safety switch is a good suspect for a no-crank problem. Cycling the ignition switch repeatedly, as in the previous problem, is not a solution or a clue. For this one, you might get the switch unstuck by shifting between "park" and "neutral" a few times, and trying to get it to crank when in either position.

Please let us know what you find. We are interested to see what it is.

A 1998 model is getting close to when they started where the engine, once running, could continue to run if one sensor failed, the crankshaft position sensor or the camshaft position sensor, but as with the older models, the computer needed to see signals from both sensors to start running. What we need to do next is connect a scanner to look at the state of those two sensors during cranking. Cranking by itself is usually not sufficient for a missing signal to set a fault code, so we can't assume anything just because there is no related code right now. We need to verify both signals switch from "No" to "Present" when cranking the engine. If they are both present, the next suspect is the injectors are being shut down by the security system. When that happens, the engine should run a few seconds if you spray in starting fluid.

This is not a true scanner and I don't think it is going to do what you need. If you look at the main menu, select "Live Data". That's where the sensor data will show up, but there is a major problem with these. I bought a couple of them too, and while they do display sensor readings, the display takes a few seconds to update the readings. That makes them useless when looking for tiny glitches from failing sensors, or for catching short-lived events. Those that I had didn't display the cam and crank sensors or their states. They only showed sensor readings that develop a signal voltage.

My first scanner was a Monitor 4000, but those require a cartridge that covers at least up to the year vehicle it is being used on. Mine was good through 1992. The advantage of those is one cartridge covers Chrysler, GM, and Ford. I bought mine because they offered a bonus cartridge just for Chrysler's new computer-controlled transmission.

Next I had a Chrysler DRB2 given to me that had been sent in twice for repair, without success. I repaired it, then bought a better cable for it. These look like the Monitor 4000 because they're built by the same manufacturer. They also need a cartridge, but it's different from that for the Monitor 4000. These only work on the older OBD1 emissions system, meaning up to 1995 models.

My next scanner was Chrysler's next step newer, the DRB3. The kits were available online from the manufacturer for $6200.00, but I bought mine for a whole lot less through the dealership I used to work for. No cartridges are needed, but then they only work back to '96 or '98 models, depending on when you bought it. With the extra plug-in cards I have, it will work on all Chrysler products back to '83 models. Also, with one of those cards, it will do emissions-related stuff on any brand of car sold in the U.S. Starting with '96 models. For that reason, a lot of independent shops bought them. Those went obsolete on all Chrysler products by 2008, and on the Dakota / Durango starting with 2004 models. Ask around at some local shops to see if anyone has one to sell when they want to buy something newer.

The last scanner I bought about six months ago is a Snapon Solus Edge. I haven't bought all the cables and adapters yet to work on my older vehicles. I bought it because I needed something for my 2014 Ram.

You can find all of these on eBay. The disadvantage to anything built by Snapon is they get you with the very high cost of annual updates. You do not have to buy those updates if you never plan on using it on newer vehicles, but if you do, you can't skip any years. If you find a Solus Edge updated to 2013, for example, you must buy the 2014 update before you can buy the 2015 update, and so on. Five annual updates cost more than the cost of a brand new scanner, so the out-of-date ones lose their value to a repair shop very quickly. That's good news for you as long as it covers what you need it to. Mine was updated through 2018, and I paid less than half of what a new model would cost.

A lot of auto parts stores rent or borrow tools, so that would be a good place to start. The problem is the stores in my city make you buy the tool, then they give you a full refund when you bring it back. If you decide to keep it, you return theirs, then they give you a new one. It still doesn't hurt to ask.

Check at some local pawn shops too. To get a good deal, you have to look for those in online auctions, like eBay and Ebid. I've found items in their stores are priced almost as high as a new version. You can negotiate in the stores, but it's still uncommon to come away with a good deal. Look for a Solus Edge that is far out-of-date. As I mentioned, to bring one up to the latest updates to work on 2019 models, you'd have to buy every single year that is missing, and that can easily cost a real lot more than buying a new scanner that comes with the latest software. Also, these come with U.S. Domestic, Asian, and European software packages that you select individually. If you can find one in a pawn shop that doesn't have the European package, pretend that's what you really need, as a bargaining chip. They'd rather have your cash than a scanner sitting on the shelf, so they should be willing to deal. They know about the real high cost of updates. They're hoping someone buys it who is not aware of that. In your case, we don't care how far out-of-date it is as long as it works on a '98 model. More commonly you're going to find these for less than $1000.00 updated through 2014 to 2016.

Ask around at some local repair shops, and even at the Chrysler dealership, to see if they have a DRB3 they are willing to borrow. I just dug mine out last Saturday for the first time in about a year, and I solved a whole string of issues going back to the previous owner, on my '94 Grand Voyager. I solved intermittent failure to up-shift, intermittent slightly high idle speed, and an intermittent crank / no-start, by just watching the signal voltage from the throttle position sensor. Never would have figured that out without a scanner.

When I worked at the dealership, the owners were real good about helping out regular customers by borrowing out special tools and service manuals. The service advisors also were allowed to send service manuals or photocopies to other dealers in the area. We repaired each others' trade-ins at times too, so we had real good relationships with customers and with all the other dealerships except the Chevy dealer. There were times I was asked to hunt down one of our shelved DRB2s to borrow to a customer, once the DRB3 came out. If I wasn't real busy with a customer's car, I was allowed to show the person how to use the scanner and what to look for. The dealership owners' thinking was teaching a customer how to diagnose their own car was not going to put us out-of-business. It was only going to make them like us that much more.

Not having access to a scanner is like a doctor not having a stethoscope. There's just so much you can do before you have to call someone else. I can offer a few comments of value related to the two sensors. The distributor pick-up assembly, (camshaft position sensor), is a "Hall Effect" sensor, the same type of disc that was used on the 2.2 / 2.5L engines. Those had a very high failure rate. That would be a real good suspect if you put in a used one previously, but they usually were not intermittent. Once they failed, they failed.

The crankshaft position sensor for your engine is an improved design over the original ones. The first ones needed to be installed with a special paper spacer to set the critical air gap. Yours has a redesigned mounting bracket that makes it impossible to set wrong. There have been some stories about the magnet core cracking, causing a popping or back-firing problem. I've never run into that myself. This sensor does have internal electronic circuitry, as evidenced by it having three wires instead of two. That circuitry lends itself to failing by becoming heat-sensitive on all car brands. A common symptom is they work fine as long as you're driving, but cause a crank / no-start right after a short stop, such as when stopping for gas. While standing still with no natural air flow, heat from the engine migrates up to the sensor, causing it to fail. We call that "hot soak". The sensor usually works again after cooling down for about an hour.

The crank sensor on your engine is somewhat hard to get to. It's in the transmission bell housing, right behind the right cylinder head. I would only replace it as a test if I already had a new one on hand. The problem with intermittent problems is when you do replace a random part, you will never know if that solved it. You will only know it did not solve it if it acts up again. I wouldn't want to drive to another state and risk it acting up again. If you can find a missing signal on a scanner, that would give you the confidence to at least know you're in the right circuit.