FJ62 Replaced fuel pump now idling high (1 Viewer)

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Aug 16, 2018
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So I just replaced my fuel pump as it died on me the other day. I did the cut a hole in the floor trick which in hind sight is a PIA if you dont cut that hole big enough. You will need to really wrangle that thing out of the tank and bend your lines a little. Good luck! I definitely broke stuff, but anyways got it back together. Truck started and seemed to run great. Started and let it run a bit, shut it down and after tinkering and buttoning everything back up I started it and soon noticed its idling high. I did mess around with my accordion air intake hose inspecting for cracks which it def has and put some more duct tape on it for good measure. Right after that I noticed the high idle. Checked to see if I damaged the accordion hose further or disconnected a vac line. All looks good.
If everything is normal and unchanged why is it idling high? Beyond that I dont think it idled high the immediately upon first start with the new pump. I think it increased rapidly at some point. It never had a high idle issue before, always settled back down after a couple minutes after cold start. Since it now has good fuel pressure from the pump is it possible the FUEL PRESSURE REGULATOR is bad now that it is seeing good fuel pressure and causing the high idle? Not positive, just freestyling here. I'm more of a monkey than a wrench. Thanks in advance.
 
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Feb 5, 2020
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Harpers Ferry, WV
Not that any else has changed, I’d still double check timing, accelerator cable, spray some starting fluid around everywhere to check for vacuum leaks. Also, drive it around for an hour and give the computer a chance to adjust.

More than likely your old fuel pump wasn’t working at 100% for a while, so everything was adjust for that old pump. I’d have to look at the manual but there’s probably a way to measure the pressure on the rail.
 

cruisermatt

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Easy stuff first, is the throttle closed all the way?

main intake hose should really matter for idle since it's before the throttle body. But you should replace it with a fresh one because it's after the MAF sensor
 

3_puppies

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Helena MT
So I just replaced my fuel pump as it died on me the other day. I did the cut a hole in the floor trick which in hind sight is a PIA if you dont cut that hole big enough. You will need to really wrangle that thing out of the tank and bend your lines a little.


I don't get the cutting the hole either, just did the fuel pump in a 1990 this past Sunday, 3 hours start to finish, dropping the tank. not a difficult job at all.
might be easier here than other areas around the country, as all the bolts come out without breakage.
 
Joined
Aug 16, 2018
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Mass/NH Border
There is more rust and frozen nuts under there than I cared to deal with. It was annoying but I know it was still the right move to cut that hole.
I will mention she started and idled at about 650-700 after mostly cooling down later last night. It was in the 30’s. But after starting to drive high idle resumed. I’ll check more today. I think I have a spare FPR and may put it in. Don’t know if it’s good but I believe it was changed out on a previous cruiser of mine by po to try to remedy something. Don’t think it was the cause so I may chuck it in
 
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Mass/NH Border
UPDATE: May have resolved itself. @poptart was probably right! After having to go spend $80.00 picking up my dog from the groomer(to look good for thanksgiving that will be just my wife and newborn!) the trip altogether took like 40 minutes with some extended idling here and there. That must have been enough time for the CPU to learn whats going on now. After I started it this morning the RPM's were high like normal at first and when I came back outside was steady at 650. Before the fuel pump I always had to tend the throttle right after start up until it got steady and ran smooth. I no longer have that issue with the new fuel pump and overall acceleration seems smoother. Hoping I can put the high Idle to bed for now and keep enjoying it before the snow flies.
 

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