Long crank

Joseph

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Hey all, started the Jeep cold this morning no issue. Only thing is that i’m the first 20 seconds the idle will dip down briefly for a second or two then go back up.
I went to start it at work again about 4 hours later and it had this really long crank before it started.
I already replaced the entire fuel pump assembly within the last 6-7 months, including the pressure regulator. I replaced all this because of having a long crank, as well as a totally inaccurate fuel gauge.
Haven’t checked the IAC or throttle body yet because I didn’t have a long enough torx to fit in there. The Jeep has a decent list of dealer maintenance and I’m not sure if it’s already been done or not.
Spark plugs were done around 115k, I just rolled over 140k.
Should I start with the IAC? Planning on doing a tune up and all that stuff this weekend anyway.
Thanks.
 

ranger101

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I’d start with checking fuel pressure at the rail. Just because it’s a new pump doesn’t mean it’s still functioning properly.
 
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Joseph

Joseph

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I’d start with checking fuel pressure at the rail. Just because it’s a new pump doesn’t mean it’s still functioning properly.
True. I have not had a long crank at all since, so who knows. I’ll see if I can get a pressure tester from advance auto this weekend too.
 
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tquig01

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Could it possibly be my injectors?
While it could be, it isn't as likely. It is also way easier to start with the simple things to check first. Rule out fuel issues from the rail back before you start turning wrenches. There are only two places to lose pressure, the pump or the injectors. A bleed-down test will help you isolate the issue to 50% of the system.
 
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Joseph

Joseph

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I’ll just stick with the plan of pressure testing then. I’m gonna do the IAC and sparkplugs anyway. Won’t hurt to change the oil either now that I’ve hit 4k since the last. Gonna be gorgeous out all weekend
 
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Goatman

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If replacing the fuel pump cured the long crank issue I would think the injectors should be ok. After you get the fuel rail pressure tester you will have a better idea where to look.
 
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Joseph

Joseph

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I did the throttle body and IAC and boy was it dirty. The IAC housing sprayed some cleaner right back into my eyes so that was fun.

The long crank didn’t come back so I haven’t bothered yet.

Yesterday though, I discovered my rear main seal is finally making some drips out onto the driveway. More fun stuff. Later that night, my check engine came on for p0456.. Might explain the long crank! Last time I had it, changing out the entire fuel pump assembly fixed this. Looks like the Delphi units might not be so great. It’s getting harder and harder to daily drive this thing..

F4D73583-0EEE-41B8-B544-4C8A13538DA3.jpeg
 
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Joseph

Joseph

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The long crank went away and came back for the colder weather. I just did this fuel pump in March, is it really possible that less than 7k miles/6months later it’s gone bad again?

Went to start last night at the bar, long crank for 7-8 seconds and died. Fired up right after that. Leaving the next bar, same thing only it didn’t die. This morning again, same thing. Except when I started taking off, it felt a little hesitant. Maybe I’ll just get a subaru lol

Does anyone have a recommendation for an assembly?

cbec1b36-27ab-4a11-bc82-93e8614aeee9.jpg
 

Chris

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Bosch is the best fuel pump replacement out there, but since they no longer make them, you have to look for them as leftover old stock (eBay usually has some).

However, Delphi I've heard good things about, and it's highly unlikely the fuel pump would fail again after 7 months. At that point it has to be something else I would assume.
 
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Joseph

Joseph

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Bosch is the best fuel pump replacement out there, but since they no longer make them, you have to look for them as leftover old stock (eBay usually has some).

However, Delphi I've heard good things about, and it's highly unlikely the fuel pump would fail again after 7 months. At that point it has to be something else I would assume.
I guess I’ll actually be checking the pressure this time. The issue went away originally so I didn’t bother..
What else could it be, if the pressure checks out?
 
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astjp2

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Crank position sensor or a coil. I have had both be a problem with modern EFI vehicles
Cam position sensor also...
dont work well when cold, but once warm, they are ok.
 
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Joseph

Joseph

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Crank position sensor or a coil. I have had both be a problem with modern EFI vehicles
Cam position sensor also...
dont work well when cold, but once warm, they are ok.
I’ll start the Jeep an hour later and it’ll still have the long crank/dying issue. It runs fine once it’s started. I’ve also replaced the crank sensor with a MOPAR one. Definitely feels like inadequate fuel at start. I’m thinking maybe the check valve is dumping the gas back into the tank. I still have to get to the parts store to get the tester.
 
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astjp2

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Turn the key on for 5 seconds, do not start, turn it off, do it again and again, after the 3rd time see if it starts, if it does, it could be the check valve.
 
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Joseph

Joseph

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Turn the key on for 5 seconds, do not start, turn it off, do it again and again, after the 3rd time see if it starts, if it does, it could be the check valve.
Well I just let it rest for 20 mins between starts then headed out again and it started right up. I’m gonna let it sit for an hour or so and see if it does the same thing. $150 to rent the tool from autozone!
 
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Joseph

Joseph

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I tried it. Turn the key to the on position, primes right up to 49 and then slowly drops down. Start the Jeep, good fuel pressure consistently. Shut it off, the pressure drops again. Assuming check valve?