My '06 KJ CRD is stalling when I turn right at low RPMs. The original theory was that there could be air in the fuel system (still possible), and it's throwing a P0090 code (Fuel Pressure Regulator 1, a.k.a. Fuel Metering Solenoid). But now I've idled the Jeep for hours, and it ran fine, and I can drive it, but whenever I take a right corner at low RPMs, the engine stalls. Also stalls on a sideways incline, using gravity to simulate the same cornering acceleration. P0090 is putting the Jeep into limp-in mode, and won't clear (seems like it's an active hard fault that I haven't resolved).

===== Background =====

Everything was running fine on the Jeep. After driving with no issues, I pulled up to the diesel pump and filled up to full from 1/4 tank with standard ULSD. As soon as it was done filling, I immediately hung up the nozzle, closed the fuel cap, got in, cranked up the engine, and drove off. I got less than 1/4 mile before the engine died, while lightly accelerating at ~25 mph on level ground. CEL came on. I pulled over and was able to get it started, and pulled into the adjacent parking lot, but there it died again. For 20-30 mins it would crank but not run. Then it would idle, but stall if shifted into gear. Then it would shift in to gear, but would stall periodically while driving around the parking lot.

From that point until now, I've assumed that I got some air bubbles in with the fuel, and by immediately driving away, I sucked some of those air bubbles into the fuel filter, or even through and into the fuel pump or injectors. The fuel filter is brand new, installed ~6 weeks ago.

So, having got it home in limp mode, I bled the fuel head/heater/filter... again and again and again. Then I let it sit for 8 hours, and repeated. I bled it, and ran it, and idled it and stalled it and bled it again and repeated maybe 20 times. Still stalling on low RPM right corners, still showing P0090. I tried bleeding out of that top bolt on the fuel head (no change), and tried taking the hoses off the head and reinstalling them, and re-priming the head and filter (no change). When bleeding the regular bleed valve, after it had idled or stalled, it seemed like there was usually a little air in there, but really only some tiny portion of the volume of the filter - a few mL. But I don't have those handy transparent fuel hoses so despite all the bleeding, I can't say for certain there's no air in there. Code reader shows rail pressure, idling at 750rpm, around 5600psi, if that means anything.

I methodically unplugged all the injection-related wiring harnesses I could find, and confirmed that they all threw other codes when unplugged. The harnesses directly on top of the cylinders threw no codes when unplugged, FWIW. I even unplugged, inspected, and reinstalled the plug on the actual device theoretically throwing the error (the fuel metering solenoid on the back side of the fuel pump, deep down where you have to hire a team of tiny monkeys to get in there and remove/replace it). Removing that connector doesn't introduce any new codes - still just P0090. And of course, every time, I delete the codes with my code reader, turn off the key, pull the ground strap, short ground strap to + terminal, turn the key on, wait 2 mins for the caps in the ECU to drain, and then put it back together and re-check the codes. I've done that probably 20 times, too. Also unplugged ECU for 10 mins and then re-seated the ECU connections.

Finally, in desperation, I tried bleeding the connector on the front of the fuel injection rail, on the high pressure side. (I picked that one because it was the only one I could get a wrench on.) It sprayed and I thought maybe some bubbles might have come out, but it was hard to tell with the high pressure spray. Anyway, no change.

Of course, in this process, I've Googled everything I can think of, and I believe I've read every forum post and watched every YouTube video related to air in fuel or P0090 code on a KJ CRD that exist on the whole internet. And I've followed up on everything that seemed like it was related to my problem... But still P0090, still stalling on right corners.

So, I've exhausted all the ideas I can think of that make sense if I did in fact suddenly induce the problem by getting air in the fuel. Two other things I haven't done yet - I haven't bled fuel directly from the injectors, because there's too much stuff on top of them to get a wrench on them (and I assume everything covering them should stay attached if the engine is running), and I haven't gone through a complete fuel filter change process and re-prime (but I've primed it and bled it lots of times). I also know that people install Gen 2 fuel heads/heaters and in-line or in-tank lift pumps to help with these issues.

But none of that explains why the Jeep ran great, I put fresh fuel in, and then it wouldn't run. No other hardware changed - just fuel. That's why I keep coming back to air issues. It's like some fuel and air somewhere in the system are sloshing when I turn right, and fuel isn't making it to the fuel pump. Or something like that... But at this point, all I have to go on is the turning right thing.

So, my next step is to basically pretend to change the brand new fuel filter, but it's not going to do anything different - it'll still stall, and still be in limp-in mode, I have no doubt. So maybe while I stand out in the dark and the cold, some of you fine folks will come across this and have a better idea than I've had. Help, please!!

Sounds like it could be bad fuel. Was this a station you regularly fill up at? Have you pulled a sample from the tank to see what it looks like? It could be totally unrelated, but if the problem started right after you filled up, that would be the first place I would look.

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2006 Jeep Liberty CRD Limited
Gen2 Fuel Head - Magnaflow Exhaust - Ram transmission swap - In-Tank Lift Pump
Moab Wheels - 245/75/R16 LR E Cooper Discoverer AT3 Tires - OME Lift 790/90009 948/60069 - Etecno Glow Plugs - V6 Airbox
RUNNING B100
Pic of my Jeep!

I agree here with ebbnflow....maybe drain the tank an fill up again from another fuel pump.

The 2006 LHD CRD has the known problem with the cable harness getting trapped behind the Fuel Filter Head Mounting Bracket causing shorts through to chassis. Worth removing this Bracket and having a good look for wiring damage there.....could be shear coincidence the problem started when it did, maybe turning right twists the chassis a bit in that area and maybe all your pumping on the fuel head has moved any suspect wires there. Fuel Heater connector seated properly?

You may have a lead going to the CP3 Pump area chaffing through to engine/chassis somewhere so you need to trace those leads and if needed climb into the wiring diagrams available on this Forum.

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2002 Export CRD

Alright, thanks ebbnflow and BillyBob - those are good ideas I hadn't considered. At one point I "primed" about 10 oz worth of fuel through the fuel pump head, and bled it out into a bottle. It loomed normal, but who knows. Worth draining the tank and trying again. Now I'll have to find someplace to put 20 gals of fuel.
I wish that explained the turning right thing...

I'll also dig in and take a look at that wiring harness. I much prefer electrical problems to deep-seated mechanical ones...

Thanks again for your input. Will update.

You'll likely find a slightly burnt pin at the ecu for the FPS. If so, carefully scrape it clean, and give it an ever so slight bend for better contact (1-2 degrees), then coat with dielectric grease. I've seen this on 2 CRD'S now, and it was a permanent fix.

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05 CRD: H.D.S2 stat,WW Ironrock trilink&LCA's, OX rear,ARB front, 4.10's, ARB bumper, Suncoast,OME 3.5, JBA UCA,rock rails, Moabs&265/75 Duratracs, GDE tunes ,FFD fan,ARP's, 2 micron fuel, new valves,sasquatch battery tray & grid heater, tensioner relocated
Mech fan, VH & AC delete

If it really is bad fuel, you should change the fuel filter too.

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U.S. Army Retired

Could also be a bad connection at the fuel rail pressure sensor or the fuel quantity solenoid on the CP3.

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U.S. Army Retired

I disagree, actually. Bad fuel causes bad performance in all instances of operation, not just going around right hand corners at low rpm. Although I do agree it could be electrical, as others have said.

Some things aren't clear to me. I assume you do NOT have the Gen2 filter head OR a lift pump based on your statement toward the bottom of your original post? If not, then you have a little more work (or explaining) to do.

1) Have you checked the heater plug on the front of the filter head for leaks? If leaking it will, at the very least, smell like diesel. At worst it will be dribbling fuel. Either one is a bad thing and means you need to replace the filter head.

2) When installing the fuel filter, were you sure to remove the old gasket (o-ring) before installing the new filter? Many people have made this mistake because the old gasket can get stuck to the filter head underneath where you cant see it.

3) You say you have bled the head countless times, but what is the result? Do you get air every time you bleed it? Does it eventually become solid fuel with NO bubbles? After you run the motor for a minute or two, what happens when you prime it and open the bleeder again? More air? Solid fuel? We need to know.

4) If you are getting good fuel with no air then you will need to crack the #4 (farthest rear) injector feed line AT the injector just enough to leak fuel under pressure but not suck air back in rapidly. Cover it with a towel and crank the motor for 10 seconds at a time, two or three times, then rapidly tighten the feed line nut.

If all of that checks out and you still have the same problem, I am going to strongly suggest adding a lift pump. They are not just for solving fuel delivery problems, but prolong the life of the injection pump and injectors by preventing air from ever entering them in the first place. They will also point out any leaks that may be present in the fuel lines, causing air ingress.

Let me know if my assumptions are incorrect and if you have already rectified any of this!

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2006 Limited CRD: Frankenlift II, Fumoto Drain Plug, DIY Stage 1 Tune, In-Tank Lift Pump

Hey APC9199. Thanks - all good points, and I tend to agree with you. To answer some questions: Correct - Gen 1 fuel head, no lift pump. The heater plug seems good... but I wouldn't mind replacing with a Gen 2 filter head anyway. When I bleed the head, I get either just fuel, or sometimes just a little air - maybe ~3mL - a few bubbles (sorry - thought I had added that in an edit). It varies, but it seems there's more likely to be air the longer I've run it. So, frequently some air, but rarely more than a tiny bit. I don't know exactly what t expect there...?

I think you are on the right track by assuming that the left-hand inertia (right corner/leftward slope) condition means that bad fuel less likely. That always kills the engine, even if there's throttle being applied. When it's dying at idle (about half the time), adding a little throttle smooths it right out.

I also like the idea of bleeding the rear-most injector. I wasn't able to get at it, so I bled the connection on the front of the manifold. But I'll see if I can get back there with a wrench. I assume everything that's attached around there needs to remain attached if I want to crank the engine and pressurize the injectors?

Then, some mechanic friends have suggested that there could have been an issue with the sender in the tank since I made my post. That at least keeps it narrowed to an issue with the only thing I had changed (the tank - I added a lot of fuel), and also could explain the inertial issue. Any thoughts on that?

Very intriguing. I will check out the ECU in the next 24-48 hrs and update. I did re-seat the ECU in its harnesses, but I didn't take it out to examine the pins.

Any thoughts on the inertial issue - only on right corners? Maybe those wiring harnesses are swaying just a tiny bit and that one pin is losing contact?

A new filter head is not a bad idea either way. I would recommend it. You can remove the black plastic cable track from the top of the motor to get better access to the injector nut. Just be careful, it is more brittle than old peoples' hips. You should be able to barely reach it without removing anything. An angled wrench might help with the odd angles. I don't think the sender can cause a failure to run condition. It would mess with your fuel gauge, but that's about it. The sender in our vehicles is really nothing more than a potentiometer (or equivalent) to show the fuel level and incorporates NO fuel-sending ability. No pressure, as it where.

Just for giggles, crawl under the rear of the vehicle and inspect the fuel connections between the tank and the rear suspension boomerang. A few members have had those connections rot out and fail, causing huge air ingress. That isn't likely since you seem to have decent fuel at the head, but it is easy to check and free.

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2006 Limited CRD: Frankenlift II, Fumoto Drain Plug, DIY Stage 1 Tune, In-Tank Lift Pump

Yup, one I had died mostly when going down hill. The pin will just look darker than the others. Takes a good light and look close

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05 CRD: H.D.S2 stat,WW Ironrock trilink&LCA's, OX rear,ARB front, 4.10's, ARB bumper, Suncoast,OME 3.5, JBA UCA,rock rails, Moabs&265/75 Duratracs, GDE tunes ,FFD fan,ARP's, 2 micron fuel, new valves,sasquatch battery tray & grid heater, tensioner relocated
Mech fan, VH & AC delete

Unlikely, but possible. A couple people on this forum have had the in-tank fuel pickup module (basically a plastic fuel pump module minus the fuel pump) randomly pop apart. One person heard a clunking/rattling sound from the tank when rocking/moving the vehicle, and another was having issues running out of fuel when the fuel gauge was clearly not near empty. Couldn't hurt to try rocking the vehicle and listening for moving parts in the tank.

If the issue is caused by a bad connection at the PCM as Mountainman suggested, here's some good info on replacing pins in the PCM connector:

http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?p=912003#p912003