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Unread 06-15-2013, 05:18 PM   #1
highjenks
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Wj Slow crank, not fuel pump

OK, I bought a 00 WJ with 230k. It had a slow crank and assumed it was a fuel pump. I had the fuel pump and filters replaced. Jeep runs a little better but no change in the slow crank. Checked fuel pressure at the rail and it's good. No injectors leaking or anything visible. Took it to a mechanic who said maybe a Camshaft sensor? No error codes. Anyone have any ideas? I also think the engine is only firing on 5 cylinders. The only time the thing starts quickly is when it's been sitting for a weekend or longer. Otherwise it doesn't matter if it's hot, cold, pump the gas or not, takes a few seconds to start.

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Unread 06-15-2013, 05:50 PM   #2
cykaaro
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If it's slow cranking, I'm thinking maybe starter or battery? If it's slow catching and cranks fine, then you'd need to look at fuel to the rail and are you getting spark? How are the coil packs?
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Unread 06-15-2013, 06:11 PM   #3
99WJ539918
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+1 for battery or starter. Mine was slow to crank before I replaced the starter. It sounds like your mechanic is guess and throwing parts at it. First thing you always check is battery voltage. Your Jeep will not run properly with a weak battery.
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Unread 06-15-2013, 06:16 PM   #4
cykaaro
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It NEVER hurts to always first thing disconnect your battery and clean the connectors, battery posts and tighten those puppies up. If you want to go a step further, which I do now after the problem I had, is disconnect the ground battery to block cable. Clean the block where it goes, the connectros and other grounds and tighten it back up. Made a huge difference. Especially since the battery cable should be the one against the block and mine wasn't. With mine they had them reversed which caused ground issues. Who'd a thunk!
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Unread 06-15-2013, 07:18 PM   #5
highjenks
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Not the battery. I've cleaned all terminals and replaced connectors. Always have good voltage per the dash meter. Will check the ground though.

I did replace all the spark plugs. I didn't do anything with the coil packs but that's what I'm suspecting. Really had to yank the thing off when I replaced plugs. Will search for a write-up on coil packs.
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Unread 06-15-2013, 07:24 PM   #6
cykaaro
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So did it do this AFTER the spark plugs? Maybe reseat the coilpack and make sure everything is plugged in properly and try.
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Unread 06-15-2013, 07:47 PM   #7
highjenks
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Did it before and after. But the coil pack did stick when I took it off, will check the boots and reseat it and see if that helps.
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Unread 06-15-2013, 08:00 PM   #8
99WJ539918
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The coil pack will usually stick, especially if no dielectric grease was use. Check for carbon tracking on the coil boots. I don't think that the slow crank is the coil pack, though. Are you referring to a long duration of cranking?
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Unread 06-15-2013, 08:58 PM   #9
cykaaro
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I would agree, especially since the condition existed before the change. Starter would be what I'd be looking at then. Also try to pause on ON before you hit START with the key. Does this have any effect at all, or does it do the same thing?
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Unread 06-16-2013, 09:19 AM   #10
highjenks
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Let me clarify. It's not a slow crank, it cranks, just doesn't catch and fire for a few seconds.
Pausing in ON before START doesn't do anything, tried this as I thought it may have needed time for fuel pressure to build. Read a write up on greasing the coil packs when I changed the plugs but I cut that corner.
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Unread 06-16-2013, 09:47 AM   #11
99WJ539918
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A long crank time can very well be the CKP your mechanic was talking about. As long as you didn't hit or move your distributor, of course. My 4.0L takes about three to four seconds to turn over for the first start off the day and usually 2.5 - 3 seconds after that. Although sometimes it takes longer (very rare, one or twice every couple months). As long as fuel pressure its good and injectors are working properly your mechanic might be on to something. With the high failure rate of the CKP's in our WJ's I wouldn't be surprised.
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PSA - It would be nice if people made an attempt while typing to discuss their problems or opinions instead of one long sentence with no punctuation. Maybe I'm cynical, but that really pisses me off. Rant over.

"It's like saying I had a car I got that was painted by the previous owner. I had an accident so painting a car is unsafe." - cykaaro
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