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Topic Review (Newest First)
03-15-2012 11:34 PM
compshooter I'll chime in here, though may not be benifical. My Jeep does the same thing. When the engine has been sitting for more than 10 minutes, I turn the key to the on position for about 3 seconds, then off. Do this 3 three times. She fires right up. If I fail to do this, she cranks for 10-12 seconds before firing.

However, I have replaced the fuel pump, in which I believe the "regulator" is included in, and did not change the issue. Since my Sexy Babe (and my wife) spent 3 years in Uruguay, South America, I am wondering if the posts above about injectors and Seafoam may help out. Gas quality may be different there than in the U.S. Guess I've got nothing to lose by trying.

Reckon I'll give it a try and post results.....
03-15-2012 10:04 PM
Kevbz
Quote:
Originally Posted by Hammerdown
If the idea is to turn on the fuel pump why not just leave the ignition on for a some time. What does cycling do?
I believe the pump only cycles for a small amount of time at first key turn on. Presumably to push/pull fuel up to the check valve and put pressure on the lines. If the check valve isn't holding pressure from it to the fuel rail and injectors there is alot of line to prime. Cycling the key makes the pump cycle more than once.

I would assume that after it is running the ECU controls the pump and injectors based on throttle position. So cycling the key only gets it primed so the ecu can take over.

I am only talking in assumptions, i haven't ever dove deep into the fuel system of a Wrangler, but that's how other vehicles over the years have worked
03-15-2012 07:58 PM
Hammerdown If the idea is to turn on the fuel pump why not just leave the ignition on for a some time. What does cycling do?
03-15-2012 07:26 PM
CoyoteOn2 Yes Sir, everything you say makes for
Great points, none the less.
And I thank- you.
03-15-2012 07:07 PM
Kevbz theirs always the potential for a weak spark, ECM not retarding the spark on first fire up. Dirty injectors. Usually if the key off/on trick works it falls under the fuel lines not maintaining fuel, but in that sense if you cranked long enough then it should fire eventually.

sometimes even turning the key and and waiting...giving the ECU, fuel pump time to initialize, maybe pumping the gas before key start to make sure the throttle body butterfly isnt sticking. I too am just throwing things out there, but pumps are finiky when they decide to act up
03-15-2012 06:08 PM
CoyoteOn2 Seems MOST here are hung up on this Pressure Regulator/ Check Valve being the culprit, why is that?
(and it could very well be the cause in MOST cases)
BUT, as stated earlier, as in my case, IT'S NOT ALWAYS the issue.
So then, are there any other causes with all the SAME symptoms ?
First cranking NO START -
Second crank, immediate start up -
or
cycling of Ignition renders NO CHANGE -
No loss of pressure in line or rail after sitting hours -

I'm leaning towards Dirty injectors / Throttle Body and components
in SOME cases, such as in mine.
But I'm not the expert here, and I'm guessing that may be my issue.
Enough so that, this will be my next step in trying to narrow down my
issue, or cause, as far as trouble shooting. A complete cleaning of
Fuel System and related components.
I would go with replacing the Regulator idea IF it were losing pressure,
but without that system, or lacking there of, I feel a couple of hundred
dollar expense is not completely justified at this stage.
Makes sense to me anyways that if it ain't a lack of pressure, it can't be
a pressure issue ~~~~ OR CAN IT ?
Sometimes MY common sense aint too common.
Comments or Bashing are Always WELCOME, and in this case, encouraged.
03-15-2012 10:21 AM
geiman
Quote:
Originally Posted by Hammerdown View Post
What does cycling the ignition key do?
Pretty much this:

Quote:
Originally Posted by Kevbz View Post
fuel pump starts pumping when you turn the key to the acc position before starting, cycling the key pumps the lines with fuel
If you're check valve isn't working correctly, fuel leaks back into the tank and the line is no longer pressurized with fuel after turning off your Jeep and letting it sit. Cycling the key gets gas up to where it needs to be before starting the Jeep.
03-15-2012 10:18 AM
Kevbz fuel pump starts pumping when you turn the key to the acc position before starting, cycling the key pumps the lines with fuel
03-15-2012 08:41 AM
Hammerdown What does cycling the ignition key do?
03-15-2012 08:25 AM
Peepers
Quote:
Originally Posted by Hammerdown View Post
It cranks quite a few times but doesn't fully start. I switch off and try again and this time it catches instantly. What is happening?
Mine does this, but I'm not sure what causes this.

I was trying to fix an evap leak that I had and ended up breaking one of the fuel lines from the pump to the frame, and the replacement parts were as bad as my broken ones, so I had to wing it myself.

While testing for leaks, I noticed that my fuel pump would not turn on by turning the key to the on position (Woo Hoo! it doesn't leak!). Watching the line, the second my jeep started to turn over fuel started spraying out everywhere.

I think there is an electrical gremlin that starts the fuel pump when the engine is cranked, rather than turned to the on position. Kind of like a retractible pen, once you push the button (the start position), you can write with it (on), until you push the button again (off).

This is why it starts easier the second time. I don't know if this would be an ecu or ignition issue.
03-15-2012 08:09 AM
yoopone My 99 did this for years also. I leave this Jeep in Florida at our condo sitting in a car port. I have someone who comes and starts it a couple times a month and drives it a little but for the most part it sits months at a time. So after reading everything I could on this forum, I was convinced it was the fuel pressure regulator. When I came down last April I bought 4 cans of Sea Foam. I ran 2 through just normal driving then I put two in on a full tank before I left. The Sea Foam sat all summer long and my daughter came down in the fall and put another can in for me.The Jeep starts first time every time now! I am pretty pumped about that. I would not disagree with the poster above that ethanol is the culprit. Do you ever see how it gums up a small 2 cycle motor?
03-15-2012 08:01 AM
MickeYJ Mine starts right away on first try
03-15-2012 07:58 AM
Kevbz
Quote:
Originally Posted by Iceman View Post
My 97 did that a bit while I was running E10 but stopped after I found a station that has pure gas.
here in my neck of the woods its blended E10 almost all the time
03-15-2012 07:54 AM
geiman Very common problem, like already mentioned it's probably the check valve. Use Google to search this site and on JeepForum; that should give you a ton of information on the subject. As a short term fix, you can cycle the key from off to on a few times (without trying to start the vehicle) and then start the Jeep.
03-15-2012 05:46 AM
cork1958 I kind of always just turn the key to the on position first and listen for fuel pump to quit on any vehicle, before cranking it all the way. Vehicle's ALWAYS starts instantaneously!!
03-15-2012 05:35 AM
Iceman My 97 did that a bit while I was running E10 but stopped after I found a station that has pure gas.
03-15-2012 05:26 AM
CoyoteOn2 Yeh, My 2000 4.0 Auto does the same thing, BUT, I don't think it's the Pressure Regulator
on mine. I put a Pressure Regulator Gauge on the Fuel Rail to observe what kind
of bleed down I was getting, and to NO AVAIL, after setting for aprox. 32 hours,
maybe I had a 2 psi drop in pressure. So to me, THAT ruled that out. It's really
not all that big of an issue to me at this point. But maybe, one day in the future
I'll take a day and do a more detailed trouble shooting process on it.
03-15-2012 04:32 AM
flipped73 Sounds like a fuel pressure regulator at the tank. It has a back flow preventer in it to keep fuel in the fuel rail. When it fails the fuel pump must refill the fuel line and rail as the fuel drains back to the tank. You have to drop the tank to replace it but it is done on the outside of the tank on the top of the fuel pump. There is a post on here somewhere with pics and everything. By the way mines been doing that for about 3 years. I replaced mine with a faulty one and haven't done it again yet. HTH
03-15-2012 04:13 AM
killroy3 Sounds like the same trouble I was having try turning the key on (not to start just on) for like 5sec or so then try starting it
03-15-2012 02:26 AM
Hammerdown
Does your Jeep start this way?

It cranks quite a few times but doesn't fully start. I switch off and try again and this time it catches instantly. What is happening?

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