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My almost no cost solution to a Crank, but No Start condition --> with a bad MAP sensor and the fuel pump not coming on

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5.8K views 14 replies 10 participants last post by  Prospect62  
#1 · (Edited)
My Durango was experiencing an occasional Crank, No Start condition. Maybe once every other week, but it would eventually start. Concerning, but not terribly alarming. I knew I would eventually have to address.

Of course, after a month or so, this predictably deteriorated into a pesky Crank, No Start. Lucky for me it became stranded in our driveway and did not need a tow. It would crank over normally, but just would no longer start.

This is the story and troubleshooting approach I wanted to share. I saved myself a bunch of $$$ and hopefully you can too.

Apologies in advance for the length, I like to write.
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The Issue:
2017 Dodge Durango R/T 5.7L
95k miles on the odometer
Has lived its entire life in New Orleans --> pretty clean, no corrosion, never flooded, well-maintained. YMMV.
Simply starting to show some age
Aside from this occasional Crank, No Start nuisance it was operating perfectly normal.
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Context Alert:
I've been an automotive enthusiast since age 16. Mostly modded Ford Mustangs. I have a good set of tools, but nowhere near a pro level.

I'm self-taught. I love forums like this, certain YouTube channels, and just consider myself determined. If I can do this, so can you. Tip of the hat to South Main Auto YouTube channel right there. Check that channel out.

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My Troubleshooting Approach & Thought Process:
I will think before I act.
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Spoiler Alert:
I have learned that an intermittent (occasional) Crank, No Start condition is almost always an electrical gremlin with the wiring harness, harness connectors, crimped or chaffed wires, bad relays or things like this. Water intrusion that causes a temporary short circuit, but eventually evaporates. A loose wire that is wiggling around in a hot engine bay with chassis flex that eventually cools down, contracts, and re-establishes a complete wiring circuit. Crusty ground wire connection.

This may not be common knowledge for many. I wanted to share. Not 100% always true, but a very good thing to remember.

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I will not just randomly replace expensive parts like a fuel pump or starter without a technically valid reason to do so. I've also learned that guessing and randomly replacing parts is a very poor approach. "Firing the parts cannon" - as it is known in the auto repair shop trade - can actually make an issue worse. Especially when you inadvertently replace a part that is OK with some non-OEM equivalent junk from FleaBay that does not work straight outta the box.
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I also recall an instance about a month ago when it was cranking, but not starting. So I had opened the hood and briefly checked the underhood fuse box (aka TIPM - Totally Integrated Power Module).

I spent about 5 minutes identifying the fuel pump relay and fuse, using the diagram on the underside of the fuse box cover and a similar chart from the owner's manual. This can seem overwhelming - but it is not. Anyone can locate their fuel pump relay and fuel pump fuse.

Internet stock image shown below for reference only. YMMW.
Image


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I removed my fuel pump fuse - F70, 20 amp - in my case. It was not "blown" and so I just put it back in place.

I did the same with the fuel pump relay. Just a quick visual. Fuel pump relay was not burnt, not melted, not swollen, clean and dry. I plugged that back in too.

And right afterward when I went back inside the cabin less than 30 seconds later - VOILA - it fired right up. THIS WAS A BIG CLUE IN HINDSIGHT.
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Anyway, fast forward a month or so, and my Durango is now cranking, but not starting in my driveway. I know I have a good battery less <1 year old. It is holding a steady 12.3V while cranking as verified by my ordinary voltmeter. I have the battery by now on a trickle charger. There is no reason to believe I have a timing issue. There are also no lights on the dash. None. Zero.

Oil, coolant, belts, hoses, air filter, etc.... --> through visual inspection is all good. Nothing obvious. I am using my eyes & ears. I can hear that the fuel pump is not coming on when I press the start button (accessory mode) though. This is a big clue.

I am starting to conclude I have a fuel delivery problem. Basic questions:
1) Has the fuel pump failed? (See above -> I am not still replacing this with a technical reason to do so)
2) Is the fuel pump not getting 12V switched (aka Key On) power?
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I take a break and log back onto this forum. After about 20 mins, I learn older gen Durangos (2011-2014) have known issues with the fuel pump wiring harness connector right on top of the gas tank. This connector is there in case you actually need to replace the fuel pump. One can simply unplug the wiring harness connector to do so.

Although unlikely given my Durango's somewhat pampered lifestyle, I decide to visually inspect this connector. If you live in an environment where it snows and road salt is used, this connector can fall apart. I look more online and discover this connector can be examined without even a rear tire removed. It just takes getting on your back and wiggling underneath, but you can put your hands on this fuel pump connector, unplug it, and look at it.

Well, in my case, the connector was pristine. Clean as a whistle. A thin layer of road grime on the outside, but no "green crusties" inside. I conclude this is not a reason my fuel pump is not turning on. I'm still not replacing my fuel pump.
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This retroactive info needs explanation here. It is very important context.

When I started troubleshooting in earnest, I plugged in my ordinary Innova handheld scan tool into the OBD-II port. This $100 tool has saved me thousands and thousands of dollars --> highly recommend as an aside.


Interestingly, there were no diagnostic trouble codes (DTCs) stored in the engine computer and displayed on my scan tool. None, zero, but again, I didn't even have a check engine light on my dash. Nothing. Not even a low tire pressure light.

Fuel gauge was sweeping normally and showing 3/8ths full. Everything else on the SUV is working such as the AC, all the lights, radio, seats, windows, door locks working A-OK. I reasonably conclude I likely do not have a major problem with the underhood fuse box (aka TIPM Totally Integrated Power Module). Ditto I have no reason to believe there is any issue with the Powertrain Control Module (engine computer).
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Meanwhile, while reviewing "live data" on my handheld scan tool, I noticed the MAP (manifold air pressure) sensor was way out of range and only reading 8 psi. That's like Mt Everest altitude BTW.

We live at sea level so the MAP sensor should be reading 14.7 psi. Basic high school physics. I was somewhat surprised there wasn't a DTC being displayed on my scan tool for something like "MAP sensor out of range" - but this is a 2017 Dodge and not a 2024 Ferrari. Context.

Long story short, I know this is a device that is not inhibiting a start . This sensor just finely "trims" or adjusts the fuel delivery for maximum MPG and minimum emissions depending on actual atmospheric pressure. FYI - my hand held scan tool was showing Short Term and Long Term fuel trims, both engine banks, at +/-2%. Almost perfect.

For $50 for and an OEM equivalent, made in the USA, MAP sensor from my local brick-n-mortar auto parts store I decide to proactively replace it. This is comically easy to do. See YouTube. I've made a step forward, but the SUV still won't start. The MAP sensor is now reading a correct 14.7 psi though. I feel OK.
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At this point, I was firmly concluding my Durango was not getting fuel.
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Time to check fuel pressure.
* Unfortunately, since around ~2011 or so, most manufacturers have discontinued the installation of a Schrader valve on the fuel rail on top of the engine. A Schaeder value is nothing more than the same type of valve on your tire where you add air, except on a fuel rail it would be all metal.

This valve, a $15 component, has been removed by virtually every manufacturer. I digress, but this is a shame because one could just put a tire pressure gauge on this valve to check fuel pressure. From above, my scan tool is pretty good for $100 but it was not displaying fuel pressure.

I look online again and quickly learn there is a quick connect / disconnect fitting on the fuel rail line on the driver's side of the engine towards the firewall. Like in case you ever need to de-pressurize the line like to change a fuel injector.

Some may consider this unsafe, but I'm an adult and I'm quite certain, I'm not getting fuel anyway. I disconnected this fitting to determine if the fuel pump is putting out pressure. Spec is 58 psi - which is like the faucet from your kitchen sink. There should be fuel readily flowing at this point with the engine cranking.

I crank a cold engine. Nothing is coming out of this fuel rail line. Not even a dribble. I reconnect the fitting.
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Spoiler Alert:
NOW I KNOW I AM NOT GETTING FUEL but I still need to figure out if :
1) My fuel pump has indeed failed

2) My fuel pump is not getting 12V switched power from the TIPM (fuse box underneath the hood)
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Time to check Powers and Grounds.
I go straight back to the fuel pump fuse and fuel pump relay in the TIPM under the hood. And, now, in broad daylight, with more clarity and focus I discover this below under closer examination. Look at that fuse.
Image

That ain't right. I chastise myself for not noticing this earlier, but whatever. Learn and improve and move forward.

Notice the fuse, while still intact, is almost melted and scorched brown on one side. THIS IS CLEARLY AN ELECTRICAL PROBLEM THAT MUST BE ADDRESSED. I use my voltmeter and RUH ROH I am not getting switched 12V power to the fuel pump fuse. Why?

I check the upstream fuel pump command relay and it looks fine. I swap that with "known good" from another slot in the TIPM that controls the HVAC unit inside. (Life hack) Using my simple voltmeter, I learn am not getting 12V switched power to the fuel pump relay. The fuse and relay are inline BTW.

Key Point:
I might have a bad fuel pump. I might not. But I am still not changing the fuel pump until I figure out why it is not getting switched (key on) 12V power.

Spoiler Alert:
Many people can get this far. Hallelujah. If you reach this point, and you need to get your SUV to a shop, you have greatly reduced the potential of getting ripped off.

But if you can get this far, with just a little more grit and determination, you can punch the proverbial football across the goal line like I did and save yourself a bunch of $$$. Keep reading.

At this point, I personally know I need an OEM equivalent wiring diagram. I do not know this Durango inside out, upside down, backwards and forwards like I do my 2014 5.0 GT supercharged Mustang. I need a wiring diagram to see how this fuel pump gets power. Well, I know it gets power from the TIPM - but which wire is it underneath?

I am going to unfasten the entire fuse box so I can access all the wires (and there are dozens and dozens) underneath. I need to know at a minimum which one to look at. What color is it? Because I am now 99% certain I have a wiring issue - remember from above the instance where I got it to start by basically "fiddling" with the TIPM. BIG CLUE.


Context Alert:
Wiring diagrams can be very hard to find online. This is proprietary information that tends to "force" one - for lack of a better term - to a dealership for service. Even if you can find one online, they are often wrong and not specific to your vehicle. And not interactive - meaning you cannot zoom in and things like that.

Also, Chilton's & Haynes manuals for these generation vehicles are generally unavailable in your public library. A Ford F150 from the 1990s? Maybe. Not a 2017 Durango.

I go online to my preferred Pay-Go site called AllData. There are other Pay-Go options, but AllData offers DIY level access to resources. I paid $19.99 online for 30 day access to everything related to 2017 Durango R/T. Recall notices, service procedures, and - the complete wiring diagram.

If I can do this, so can you. AllData also has a bunch of online tutorials and how-to videos. Including how to read a wiring diagram.

About 30 minutes later, I have the entire fuel pump electrical circuit on my laptop. I've annotated the critical part of the graphic below for illustrative and sharing purposes. YMMW.
Image


I have the information I need. See the yellow box in particular. There is a Dark Blue wire plugged into the bottom of the TIPM. It is labelled pin #25 and it is on connector #3 (C3). This wire comes from the engine computer and should be providing 12V when the start button is pushed.

I unfasten the TIPM and turn it over. It takes some minor effort to undo the plastic clips, but there is enough slack in all the wires to do so and continue troubleshooting.

It took me about 15 mins and a magnifying glass to confirm the right connector, the location of this Dark Blue wire, pin #25. The markings are tee tiny and very hard to see.

I gently "back-probe" this wire with an automotive T-pin and connect the lead to my voltmeter. AND DISCOVER I AM ONLY GETTING LIKE 6-8V TO THIS CONNECTOR (to the fuel pump relay) and IT IS FLUCTUATING TO ZERO VOLTS.

THIS RELAY NEEDS TO BE GETTING 12V PRETTY MUCH EXACTY.

I start wiggling that wire and pressing it gently into its socket and I instantly get 12V on my voltmeter.

THIS IS MY LOOSE WIRE. RIGHT HERE. RIGHT AT THAT PIN. THIS EXPLAINS WHY I WAS ABLE TO "WIGGLE" THE TIPM PEVIOUSLY AND GET THE DURANGO TO START.
This is what it looked like.

Image


I spritzed everything with a shot of dielectric cleaner from a rattle can, tightened the pin and PRESTO I was getting 12V from the engine computer. Steady. Wiggle test no longer disturbs the voltage.

PRESS THE START BUTTONG AND BBRBBBRVROOOOOM. My Crank, No Start condition is resolved.

I did not needlessly replace the fuel pump. I did not needlessly replace the engine computer. I did not needlessly replace the TIPM. I only replaced a faulty, purely coincidental MAP sensor. $50 repair.

I consider Pride an unflattering human characteristic. But I was really stoked that I solved this problem. This is about as difficult as an intermittent condition can be to resolve.

BUT IF I CAN DO IT SO CAN YOU.

HTH
Andy
 
#2 ·
This is a solid post that will be helpful for many folks in the future. Crank/no-start is a super common issue on this board, and replacing a fuel pump kinda sucks because there is no access from the top. You either have to drop the tank or cut a hole in the floor.
 
#3 ·
At first I noticed the length of the post and thought, uh oh... but honestly read through it all, nice write up.

When you mentioned, "tightened the pin", what exactly did that entail? Did you re-crimp something, did you push up the wire into the bottom of the #25 connector again from it being loose?
 
#5 ·
Funny you said you pulled the relay and looked at it but it’s soldered internally to the board and the relay k10 you are pointing to in one picture is for the Rear Window Defogger. Also the PCM doesn’t supply power to the relay. It supplies ground. 12 volts comes from the battery through the run/start relay to the fuel pump relay.
 
#6 ·
Dude- Time for you to improve your reading comprehension skills and not be a sanctimonious douchebag.

1) The picture of the TIPM clearly states something like "typical Internet stock image". And "typical fuse location". And "typical relay location". "YMMV" Good grief.

2) And I can guarantee you my fuel pump relay is NOT soldered to the TIPM board. I pulled it out with my hand, like my thumb and index finger. If I could do it again, I would raise my middle finger in your direction.

3) Fair point on the PCM providing switched ground instead of 12V switched power. I spent an hour writing that up and made one oversight. But you - and everybody else - got the f**king point, right? My fuel pump wasn't getting power.
 
#7 ·
All Durangos have the fuel pump relay soldered to the printed circuit board starting in 2011 and continue in to this day hence the notation (ON PCB) in the relay description on the wiring diagram. The only exception would be the 2011-2013 that had the relay relocation recall or someone if install an aftermarket relocation kit both of which have a relay holder that gets mounted nearby for an external relay. It’s also another thing to note that the TIPM (Total Integrated Power Module) is only used up until 2013. Beginning in 2014 the TIPM was replaced with a PDC (Power Distribution Center) and a BCM (Body Control Module). The PDC in which your 2017 has also has a fuel pump relay soldered to the PCB. As for the hot leg on the fuse you are seeing and possibly the loose pin you claim to have (if it wasn’t a slightly burnt pin) is caused by the fuel pump continuously drawing higher than normal amperage. A device should continuously draw no more than half the rating of the fuse as a rule of thumb. If you have a 20 amp fuse and you are drawing above 10 amps continuously the pins in connectors and fuse legs will be the first to get hot. A healthy fuel pump should draw several amps below 10.

You seem very proud to find this loose pin issue that probably could have been found in 10 minutes and seem very hostile when being corrected as well but there is quite a bit of misinformation in your write up and I was letting you know.
 
#11 ·
you are correct on relay . but loose wire seems to be common and a lot of dealers have parts changers not real mechanics . mine spent a month at local dealer they had no clue decided it was aux battery changed it said all good three days later crank no start in morning then in hot afternoon starts fine. at this point I am willing to check wires as dealer is useless and will not stand behind their work
 
#8 ·
Be nice Brandon. He worked hard on this and the average DIY may not have even gotten as far as he did in the time he spent.
 
#10 ·
man this sounds a lot like my problem did you have any other issues besides the crank no start ? mine will do strange things like stop start acting up or auto lights not coming on no codes then crank no start next morning. then in afternoon it cranks fine. I have a 2020 with warranty but dealer is useless
 
#12 ·
Nice work and quality write up.

I fired the parts cannon at my Durango for something and replaced the map sensor about a year ago and it started running "better".

It all comes down to time and money. If you have lots if time diagnosing the exact failure makes sense. If you have lots of money but no time firing the OEM parts cannon makes sense.

I usually start with the OEM parts cannon. If things start working great. The issue was fixed quickly and already good parts replaced by new parts isn't going to hurt anything. If the OEM parts cannon fails I start being more methodical in figuring out what the issue is.