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-   -   4.0L Rough Start (http://www.wranglerforum.com/f210/4-0l-rough-start-37573.html)

Axiom 10-05-2009 06:10 PM

4.0L Rough Start
 
Having a weird issue with my 4.0L. When it's parked over night facing up hill and I go to start it in the morning, it struggles to start. It doesn't happen all the time, but most of the time it does. When I park it facing down hill and leave it over night, she fires right up just fine.

Now, just this morning I went to start her up while she was parked facing down hill and she had a hard time starting.

Couple things worth mentioning. I've let her sit for about a week and a half straight before without starting her on level ground. She fired right up without issue. Also, for the first week after I change the oil she never has issues starting regardless of how she's parked.

On a side note, the negative terminal on the battery seems to collect some sort of white powdery deposits. It gets so bad I have to take a wire brush to it or else it won't start.

Thanks!

specbill 10-05-2009 06:47 PM

When you say it won't start..is it because it does not turn over fast enough to start (electical ) or does it turn over fine but just doesn't want to fire (Fuel or electrical)?

Jerry Bransford 10-05-2009 07:04 PM

Leaky anti-drainback valve located inside the fuel pressure regulator that sits on top of the fuel pump. Its job is to keep the fuel rail and fuel injectors pressurized with fuel for a fast start and when it leaks, it lets that fuel instead drain back down into the gas tank.

That it allows the fuel to drain down into the fuel tank when the Jeep is heading uphill but not when it is facing downhill makes perfect sense. :)

Axiom 10-06-2009 10:07 AM

Quote:

Originally Posted by specbill (Post 454169)
When you say it won't start..is it because it does not turn over fast enough to start (electical ) or does it turn over fine but just doesn't want to fire (Fuel or electrical)?

When you first turn the key it sounds like it's going to turn over just fine, then a half second later it starts struggling. It does sound like it doesn't turn over fast enough.
Quote:

Originally Posted by Jerry Bransford (Post 454180)
Leaky anti-drainback valve located inside the fuel pressure regulator that sits on top of the fuel pump. Its job is to keep the fuel rail and fuel injectors pressurized with fuel for a fast start and when it leaks, it lets that fuel instead drain back down into the gas tank.

That it allows the fuel to drain down into the fuel tank when the Jeep is heading uphill but not when it is facing downhill makes perfect sense. :)

Plausible. However, yesterday when I went out to start it up. It was facing down hill over night. It struggled to start in the morning. First and only time it's ever done that though.

Jerry Bransford 10-06-2009 10:12 AM

Quote:

Originally Posted by Axiom (Post 454482)
When you first turn the key it sounds like it's going to turn over just fine, then a half second later it starts struggling. It does sound like it doesn't turn over fast enough.

Plausible. However, yesterday when I went out to start it up. It was facing down hill over night. It struggled to start in the morning. First and only time it's ever done that though.

Ok but uphill or downhill, it still sounds like the anti-drainback valve is leaking... a very common problem with our Jeeps.

meyers 10-06-2009 10:16 AM

When you say you take a wire brush to your battery, do you pull the cables right off and give them a good cleaning or just brush off the tops? If you don't you may want to take them off and clean them. Jerry is dead on with the drain back issue though, very common on the Jeeps

Axiom 10-06-2009 10:32 AM

Quote:

Originally Posted by Jerry Bransford (Post 454488)
Ok but uphill or downhill, it still sounds like the anti-drainback valve is leaking... a very common problem with our Jeeps.

I'm assuming I'll have to drop the tank for this. I know in the Dakota's the fuel pump is inside the tank. :banghead:
Quote:

Originally Posted by meyers (Post 454491)
When you say you take a wire brush to your battery, do you pull the cables right off and give them a good cleaning or just brush off the tops? If you don't you may want to take them off and clean them. Jerry is dead on with the drain back issue though, very common on the Jeeps

I remove the cable and take a wire brush to it. The crap still comes back though. Haven't found a way to completely get rid of it.

Wind_Rocker 10-06-2009 10:49 AM

Read my thread below on starting problem. At first it was not too bad, intermittant like yours, after two months it took two or 3 cranks to start. I replaced my regulator yesterday, when I popped it out fuel ran out of it full stream, check valve was totally shot. Starts like it should now.

Axiom 10-06-2009 02:41 PM

Quote:

Originally Posted by Wind_Rocker (Post 454504)
Read my thread below on starting problem. At first it was not too bad, intermittant like yours, after two months it took two or 3 cranks to start. I replaced my regulator yesterday, when I popped it out fuel ran out of it full stream, check valve was totally shot. Starts like it should now.

Good to hear. Any thoughts on the battery?

Jerry Bransford 10-06-2009 06:37 PM

Quote:

Originally Posted by Axiom (Post 454496)
I'm assuming I'll have to drop the tank for this. I know in the Dakota's the fuel pump is inside the tank.

You have to drop the tank but the regulator sits on top of the fuel pump external to the tank and it can be replaced without pulling the fuel pump.

Wind_Rocker 10-07-2009 09:38 AM

Quote:

Originally Posted by Axiom (Post 454646)
Good to hear. Any thoughts on the battery?

I would get the battery tested first, I think you said something about the battery being suspect? You can usually get it tested for free. I've never had the problem of the white stuff on the terminals.

I started having cranking problems during the time I was having the starting problems, took the Jeep to nearest Sam's (where I bought the battery) and it had a bad cell. Interstate Megatron 34 months old, supposed to be the best battery you can buy, twice as good as #2. It still had 38 months on the warranty so only costs $28 to replace.

If the battery is good I would disolve all the white stuff with baking soda and water, careful not to get any in the battery. Then remove the cables and make all the contact surfaces shiny like chrome. Then I would spread the terminals a little so you get a good clamp when reinstalling and avoid beating on them.

I use battery terminal spray on mine, small can of red stuff works good. When I was in the Army we used grease on all the battery terminals or you could use vasoline. If you go to auto parts store for battery spray, but a couple of those little impreganated felt washers to go under the terminals. I don't know how good they work but only about a buck.

To summarize, I would check condition of battery, make sure I had 100% terminal to battery post contact, smear on some protective coating and fix the starting problem so the battery is always above 90% charge like a lead acid battery likes to be.

Axiom 10-07-2009 04:06 PM

Quote:

Originally Posted by Wind_Rocker (Post 455054)
I would get the battery tested first, I think you said something about the battery being suspect? You can usually get it tested for free. I've never had the problem of the white stuff on the terminals.

I started having cranking problems during the time I was having the starting problems, took the Jeep to nearest Sam's (where I bought the battery) and it had a bad cell. Interstate Megatron 34 months old, supposed to be the best battery you can buy, twice as good as #2. It still had 38 months on the warranty so only costs $28 to replace.

If the battery is good I would disolve all the white stuff with baking soda and water, careful not to get any in the battery. Then remove the cables and make all the contact surfaces shiny like chrome. Then I would spread the terminals a little so you get a good clamp when reinstalling and avoid beating on them.

I use battery terminal spray on mine, small can of red stuff works good. When I was in the Army we used grease on all the battery terminals or you could use vasoline. If you go to auto parts store for battery spray, but a couple of those little impreganated felt washers to go under the terminals. I don't know how good they work but only about a buck.

To summarize, I would check condition of battery, make sure I had 100% terminal to battery post contact, smear on some protective coating and fix the starting problem so the battery is always above 90% charge like a lead acid battery likes to be.

I'll go get the battery tested first and see what they say. Thanks.


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