Intermittent crank no start - '13 5.0

Gabe

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Went back, checked the voltage at that violet/green wire, with the key on I had 17.04V, so that must mean the BAP is working properly, I'm assuming.
Also, added a crimp just behind the metal section of the connector:

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A complete view of the BAP wiring:

35625681613_be7819dcf4_o.jpg
 

redfirepearlgt

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^^^^ Again the key here that I am homing in on is 1.) The car intermittently cranks with no fire, 2.) you state that you have not heard that familiar sound of the fuel pump priming, 3.) you have as an added measure verified the fuel filter is fine.

Therefore your check that confirms that voltage is on C4033 pin 1 on the FPDM connector insures that the fuel pump relay and the control circuit up to C4033 pin 1 is good.

So that leaves the output voltage to the pump and the pump itself as the two likely candidates.

The last thing to do is to verify you are getting voltage to the fuel pump. If regardless you get voltage out you do this by measuring voltage at the Fuel pump on C433 pins 3 and 4 (yellow w gray wire and white w brown wire respectively) or you can back probe the same two wires at the FPDM on C4033 pins 5 and 8. This will isolate the pump as the most likely failed component if the output of the FPDM is good each time you key on. Remember with pressure static in the line the pump at key on may not run as long each time because the pressure rail sensor has been satisfied. Pump bearings and/or brushes and such can fail causing intermittent issues even though the winding in the motor is fine.

Before replacing the pump if that is the likely component, make sure the tank hasn't gotten full of bad gas (real bad gas) or other contamination when you pull the pump to inspect it. Also insure the inlet of the pump isn't clogged....and again don't forget the fuel filter. It will let you know if you have water or crud sucked up in the system when you blow it out.

Best of luck to you. I hope this helps you out. Intermittent failures are the most dreaded for a technician to isolate. I've spent weeks trying to catch and isolate an intermittent symptom in order to isolate the problem and make the repair vice just throwing parts at it.

I had this problem on a 99 F150. 55K on the fuel pump. Crank at times and never start and then suddenly it would start fine. Turned out the fuel pump was bad. Verified it the same way I have had you check yours.Thankfully mine finally failed all together.
 

Gabe

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Thanks for all your help.
The car now starts every time.
I'm wondering if the poor connection was all it was, but I'm not naive thinking that it's definitely fixed with the new connector in there.
The 3 times it's done it, the car was warmed up good, sat for 1-2 hours, then did the crank-no-start.
So next time I drive it, I'm gonna attempt to recreate that scenario.
We'll see.
 

Gabe

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Quick update on this, I've put over 300 miles on the car in the last week, about 275 just on Sunday (mostly highway), car has been starting normally every time, regardless of how long it's been sitting.
So, at least so far, it looks like all my troubles were caused by that connector being wonky.
 

Gabe

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Haven't driven the car in about a week and a half, I take it out today to run some errands, one start was weird, it started but idled low like it was gonna stall then revived itself into a proper idle, didn't give it any more thought.

Take the car out tonight to dinner with the wife, all great till we go to leave, crank no start.
Couldn't hear the fuel pump priming, just kept cranking and not starting.
I go jiggle the wires at the BAP relay, still nothing.
After about 10-15 key turns to see if I would hear the pump priming, I finally heard that beautiful sound and cranked it one more time, and the car started.

Guess my problems aren't over. Gonna start by replacing the relay tomorrow and see what happens, since I have a spare and it's easy to do.

Anybody have any other thoughts?


.
 

skaarlaj

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I've had 2 vehicles that if they sat for a short amount of time, I'd come back and they'd be flooded. A few of the injectors would leak by while the vehicle was off, and relieve the pressure in the system into the engine over a short time. If it sat over night, it would start right up, I'm guessing the fuel that leaked by the closed injectors evaporated before trying to start the vehicle if it sat long enough.

I just made a rig to seal up the (rail) end of the injector to a can of carburetor cleaner, and while someone held the can open, I'd hit the injector on and off a bunch of times with a little power from a motorcycle battery I had in the garage, and I could see the culprit injectors sealing up in the closed position better than when I started. Very easy, just took a little time.

I guess a good way to know if this is happening with yours would be the duration of time the car sits in the off position when having trouble starting. If it's a short time, (under 4 hours) that causes the problem, I'd watch the tail-pipes while someone else tries starting it and see if black smoke (indicating a flooded engine) arises when it finally burbles to life. If so, I'd clean your injectors internally like I mentioned above, it'll cost nothing but a can of carb cleaner.
 
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Gabe

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I'm assuming when you did that you could probably hear your fuel pump priming though, right?
I don't hear mine when this is happening, except when it will actually start.
 

redfirepearlgt

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Hey Gabe, relay contacts have been known to stick, or build up carbon on the contacts enough to inhibit the voltage from making it to the device they are controlling though the coil is energizing. After several key cycles to the suspected relay the voltage drop across the carbon on the contacts will sometimes burn away enough to make enough contact to enable whatever they are to turn on/off. So the relay would be your next best bet in this case based on the description of the symptom. I would start with the aftermarket relay on the trunk being used with the BAP first. Then try replacing the fuel pump relay itself in the BEC. Best of luck.
 

skaarlaj

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I'm assuming when you did that you could probably hear your fuel pump priming though, right?
I don't hear mine when this is happening, except when it will actually start.
I'm guessing so, I couldn't really hear either of the two vehicle's fuel pumps too well honestly, never really paid much attention. Just knew they were flooded and took a lot cranking to start, but this was in the good old days when a throttle cable was attatched to the throttle body, and you could crank it and actually manipulate the throttle open to unflood an engine.
 
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travelers

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If it is the relay, we started using ones from Standard from a local parts store. We found that they didn't hold up very well. So we picked up some with the same rating from the International/Peterbuilt dealer. They are a better grade of relay and they are the same size and type.

I would also use a digital volt meter to test the leads to the relay to make sure it's getting voltage telling it to activate the relay. If so then if its going out the relay. and then to the rest of the system if need be.

I have the Roush setup in my car.
 
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Gabe

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Thanks guys, I installed a new relay this morning, just in case.
This evening on the way back from a car show where I drove it there about 45 minutes after which the car sat for 3 hours, I leave and I'm a few minutes away when just slowly accelerating from a stop the car died and cruised to a stop on the side of the road. Took a few tries to restart but it finally restarted and drove away.
Drove home the rest of the 45-minute drive just fine.
So I'm thinking either there was nothing wong with the BAP relay or I installed a not-so-great replacement.
I will buy a new one and pop in a new fuel pump OEM relay as well, and see what happens.
Certainly don't think the OEM fuel pump is going bad, but it might be, as it could be the BAP crapping out, but haven't heard of either one being common.
 

travelers

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You might want to data log your fuel system to see if your loosing fuel pressure. also google how a boost a pump works as there is a lot of good info to read
 

Gabe

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You might want to data log your fuel system to see if your loosing fuel pressure. also google how a boost a pump works as there is a lot of good info to read

Well, today I went and checked all the wiring to the BAP, the S&H fpdm wiring upgrade, and all the grounds.
Also swapped the underhood little square fuel pump relay with the identical relay in the A/C compressor location, 2 spots over (locations 41 and 43 I think).

Then went and opened up the electrical tape I had taped over the original connection I made to the violet/white FPDM connector wire when I installed the wiring upgrade, seemed a bit flmsy so I un-did it and replaced the connector, and put new heatshrink on it, then replaced the connector I replaced a couple/few weeks ago (earlier in this thread), did a better crimp on the new connector and used heatshrink also. Checked and re-routed some of the other wiring back there, to make sure there's no unwanted contact.
Also popped out the rear seat cushion and checked all the fuel pump wiring under there, since I found a TSB that related to '11-'13 cars that might have the driver side harness under there chafing between the body and the bottom of the seat.
No chafing found.
Tested the relay, with the 86 hooked up to the positive terminal of the battery and the 85 hooked up to the negative, I had values of zero showing up on my multi-meter when I was touching the 87 and the 30 terminals with the probes, multi-meter in ohm mode (2k or 200 ohm I think). Supposedly that's a good thing, going by what I was finding on the internet on how to test an automotive relay. Also, the thing was clicking instantly as soon as it was getting power.

And the car started up just fine of course, and drove fine when I took it up and down the road.

Tonight/tomorrow it's gonna rain, so no chance to drive it till at least Saturday.
I think I need to start carrying some parts/tools and my multi-meter with me every time I drive the car now ...
 

redfirepearlgt

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It's beginning to sound as if the problem resides in the Fuel pump itself. If both of the relays are working (sounds like they are) and all of your connections are good, then that can only leave the BAP itself or the fuel pump. I had a fuel pump intermittently fail like this on my 99 pickup. Of course that pump was about 16 years old and had about 55000 miles on it when it did fail. The truck would crank and crank and crank. The relay feeding the FPDM was working fine. Disconnected the fuel filter and cranked the engine and nothing was produced into the bucket I had the line dumping into in spite of having 13VDC+ feeding the pump from the relay. So that left the FPDM and/or the Fuel pump. Put it all back together, and the truck suddenly started (oddly enough). Drove it up to the corner station, filled it up all the way with gas (that was a mistake), started it back up, drove it home, parked it, shut it off, waited 30 minutes, came out and tried to start it again and wouldn't you know...BUH, BUM, BAH! No start condition again. Replaced the fuel pump and it has been fine ever since.
 
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travelers

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If you can borrow a manual fuel pressure gage you can put it on the shredder valve on the fuel rail and see what your pressure is at when it hard to start. That will tell you the story.
Or maybe I'll have to have a road trip.....LOl
 

Gabe

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Bringing this back up since my lovely car decided to intermittently start the crank-no-start B.S. again this summer.
First time it did it, the car had sat all day in hot temps, after work I go to start and got nothing.
And same symptom, no fuel pump priming.
I'm finding that there's finally an aftermarket high-volume pump available for these 5.0's, I'm contemplating installing one, removing the BAP and the aftermarket fuel pump wiring upgrade, to eliminate things that might be causing it.
Unfortunately, the issue doesn't seem to happen at home, where I always have more tools than I might carry, so I can run tests better.
 

Gabe

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One thing I've noticed for sure, problem seems to happen during high ambient temperature.
Hot day, car sits all day, most likely this shit happens. So something heats up and causes the problem.
 

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