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Discussion Starter · #1 ·
Hey guys, I have a question regarding my 2001 TJ. It has the 5 speed and 4.0 in it, 102,000 miles. It has the usual problem with starting in that I have to turn the key on and off 2-3 times to get it to start. I'm guessing this has to do with the check valve in the fuel tank. What I am curious about is it also throws the check engine light with the codes for misfires in cyclinders 1 and 3. When it does start it idles pretty rough until I give it a little gas to get the revs up, then it idles fine. Could the check valve be related to these problems or could it possibly be something else entirely? Thanks for reading guys.
 

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doesn't have anything to do with the fuel pressure regulator. that sounds more like idle air control problems to me. does it always idle rough or just on start up?
 

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That symptom sounds exactly like the check valve inside the fuel pressure regulator is leaky. When that happens, the engine can misfire even once the fuel has made it up to the fuel rail, until the fuel has made it up/down the fuel rail to all the fuel injectors. Both of my TJs have had bad fuel pressure regulators and the misfire problem was common for both if I tried to start the engine before the fuel had made it to all the injectors.

My bet is replacing the fuel pressure regulator will take care of it. You may be better off replacing the entire fuel pump/fuel pressure regulator assenbly as there is actually a fuel check valve in both and occasionally both can leak and cause problems.
 

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Discussion Starter · #4 ·
It only idles rough right on start up until it warms up a little. If I don't give it a little gas to even out the idle it usually does it itself but it takes a minute or two.
 

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Discussion Starter · #5 ·
That symptom sounds exactly like the check valve inside the fuel pressure regulator is leaky. When that happens, the engine can misfire even once the fuel has made it up to the fuel rail, until the fuel has made it up/down the fuel rail to all the fuel injectors.

My bet is replacing the fuel pressure regulator will take care of it. You may be better off replacing the entire fuel pump/fuel pressure regulator as there is actually a check valve in both and occasionally, both can leak and cause problems.
Thanks Jerry, I appreciate it. One last question, do you think I should try resetting the codes and seeing if they come back or change before I go buy a new fuel pump/regulator?
 

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If it's misfiring, resetting the computer isn't going to help do anything but temporarily clear the misfire codes. The code will come back immediately so I wouldn't reset the computer until after you've replaced the FPR or fuel pump/FPR.
 

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Discussion Starter · #7 ·
If it's misfiring, resetting the computer isn't going to help do anything but temporarily clear the misfire codes. The code will come back immediately so I wouldn't reset the computer until after you've replaced the FPR or fuel pump/FPR.
Ok looks like I'll need to order a fuel pump/FPR. Any recommendations on brands?
 

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Best would be OE, followed by Omix-ADA or Bosh though I had good experience with the inexpensive AIRTEX Part # E7156MN In Tank Fuel Pump Assy-Module for only $143 from RockAuto Auto Parts. I was too broke at the time to go with the OE so, knock on wood, the Airtex has been working fine for about a year now.

If you order from Rockauto, PM me first and I'll give you my latest 10% off discount number that Rockauto just emailed me.
 
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