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Unread 10-11-2013, 09:35 AM   #1
bradkline
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1997 TJ Wrangler 
 
Join Date: Oct 2013
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Long crank before starting when cold

Hey guys. I just bought this Jeep a few days ago. 1997 Wrangler Sport, 4.0, auto, with A/C. Bone stock and 155,000 miles. In really good shape. I drove it at the guys house and everything went perfect. I get to my house and go to take the wife for a spin and it cranks for probably 6-7 seconds before firing. I kill it to try it again and it fires right up. It has sat for a few hours between starting. It has a CEL on but I checked it at his house before buying and it was an 02 sensor (which the cat and the sensors have been eliminated so I didn't stress about that too much.

I text the guy just to ask if he knows anything about it, he says "never happened to me." Well, BS because now every time I start it after it sits for more than 30 minutes I have to crank and crank for 7-10 seconds before it starts. So, this is my thought, and you guys tell me if I'm on the right path.

1. I should be checking fuel pressure while cranking after it sits. 50 PSI roughly from what I am reading on other starting problem threads?

2. Checking for spark while cranking.

If those two things are good, what is my next step? I wanted to get some feedback before I get into it this weekend so if those are both fine I know steps 3 and 4 to check. Drives fantastic once it starts, no cutting out, no stalling, etc. Just the cold starting issue. Brakes were pulsing when I test drove it so when I got home I pulled the front wheels to find the pads virtually gone and the rotors pretty worn. Installed brand new pads and rotors up front.

Thanks and any/all thoughts are greatly appreciated as I am a newbie to Jeeps and don't know if they have any "common problems" that cause this that I'm not aware of! Thanks guys and I hope one day I can contribute to the forum! Yeah, I still high five!

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Unread 10-11-2013, 09:37 AM   #2
bradkline
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Not sure if I made it clear that once it starts, I can immediately turn it off and it fires back up on the first crank. Personally makes me think fuel. Fuel is draining back towards the tank, has to crank to get it to the injectors, but once it has been fired it will fire right back up because the fuel is right there and ready to go.....
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Unread 10-11-2013, 09:43 AM   #3
seatown7
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I just went through this with my 01 TJ. Mine had a leaking injector...so it wouldn't hold the fuel pressure provided by turning the ignition on. Sometimes it would fire right up, other times it would crank several times until I'd have to put my foot in the gas like I had a carbureted jeep and not an injected one. Replaced the leaky injector and it fires with a tap of the key. Sounds pretty similar to your issue.
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Unread 10-11-2013, 09:48 AM   #4
bradkline
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That would be something I haven't encountered. How do I find the leaky one? Or, just replace them all at 155,000 miles and don't worry about it? Thanks for the input seatown7!!
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Unread 10-11-2013, 09:57 AM   #5
Jonny Jeep
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The combined fuel filter/pressure regulator that sits on top of the tank is known for causing a long crank when it goes bad allowing fuel to drain back to the tank. The fuel pump only runs for two seconds when the ignition is first turned on, or when the ignition is cranking or running. At the next cold start try turning the ignition on for a couple of seconds, off, back on for a couple of seconds and then turn to start.

A leaky injector could also cause a long crank issue but the filter/regulator is much more common. A good write up regards dropping the fuel tank is at DailyDrivenTJ-Fuel Pump Repair

It doesn't show replacing the filter regulator but it can be popped off with a couple of large screwdrivers, making sure both o-rings are removed. When I did mine I also replaced the two strainers in the bottom of the tank.
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Unread 10-11-2013, 10:55 AM   #6
seatown7
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I had a local shop dig into my leaky injector...I'm not sure id replace all 6 if the others are OK. If you had more than one bad one...then maybe I'd go for a whole new set.
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Unread 10-11-2013, 11:08 AM   #7
bradkline
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Thank you Jonny Jeep! So it sounds like I am on the right path thinking fuel first. I will bust into it this weekend and post my findings. Thanks guys! I will check back before I do to see it there is any other feedback. Have a good weekend all!
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Unread 10-11-2013, 11:35 AM   #8
bradkline
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Quote:
Originally Posted by Jonny Jeep View Post
The combined fuel filter/pressure regulator that sits on top of the tank is known for causing a long crank when it goes bad allowing fuel to drain back to the tank. The fuel pump only runs for two seconds when the ignition is first turned on, or when the ignition is cranking or running. At the next cold start try turning the ignition on for a couple of seconds, off, back on for a couple of seconds and then turn to start.

A leaky injector could also cause a long crank issue but the filter/regulator is much more common. A good write up regards dropping the fuel tank is at DailyDrivenTJ-Fuel Pump Repair

It doesn't show replacing the filter regulator but it can be popped off with a couple of large screwdrivers, making sure both o-rings are removed. When I did mine I also replaced the two strainers in the bottom of the tank.

So if I go tonight (As it has been sitting two days now) and cycle the key a few times and she fires right up .. you think the above is a pretty good shot at being the culprit? That would eliminate a leaky injector in theory?
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Unread 10-12-2013, 03:47 AM   #9
Jonny Jeep
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I've never suffered for a leaky injector so I'm not sure how it would affect the start. Priming the fuel line will just make the actual start up quicker. I don't think it would necessarily eliminate leaking injectors, as the only certain way to see if an injector is leaking is to pull the fuel rail and prime the fuel pump to see if any of them leak. I've never to my knowledge suffered a leaky injector so can't say for certain if it would result in the same long crank symptoms. From what I've seen though, the most common cause of a long crank due to lack of fuel pressure is a faulty regulator.

If you have the time, then for the cost of a set of injector o-rings you can find out if any injectors are leaking. Whatever you do, remember petrol vapour is extremely flammable.

If you need a filter/regulator they are available from Rockauto.com, Amazon, and ebay. They may be available in parts stores over there but you'd need to check into that yourself.
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Rockauto 5% discount code can be found here... http://www.markviii.org/LOD2/products_services.htm

Online factory service manuals (FSMs) and parts lists can be viewed at http://www.jeep4x4center.com/knowledge-base/index.htm
If the link doesn't work properly, look for the service manual link under Jeep Resources at the bottom of the page.
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Unread 10-12-2013, 07:08 AM   #10
elmoe
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My 98 did the same thing when I had the 4.0 in it now with 5.9 it still does it so I would look at the regulator first.
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Unread 10-12-2013, 07:22 AM   #11
bradkline
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Ok, I will hit that tomorrow guys. Thanks for the input! When I got home yesterday I cycled the key about 5 times and it fired on about the third crank (a lot faster than normal) so I would say fuel is the issue for sure. Time to get greasy!
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