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My limp issue...out of ideas
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=90016		 Page 1 of 1
Author:  BlueCRDinAZ [ Tue May 14, 2019 11:22 am ]
Post subject:  My limp issue...out of ideas
Howdy folks,
So now that it is getting warmer in Phoenix my ride has developed a tendency to blip surge the motor to about 1500 RPM and go into a limp mode whether the engine is up to temp or not. This will happen when I am idling/ at a stop, and didn't happen when the weather was cooler. To clear it I have to D/C the neg battery cable and reconnect. I cant figure this one out-I am not an electronics whiz.
My history of upgrades is

Rebuilt head with new exhaust valves and rockers
head gasket and arps
New timing belt, water pump etc
deleted egr/fcv with Weeks2
replaced the mech fan with the GM clutch and 11 blade
The beautiful chunk of HDS' Tstat
Eco tune from GDE with programmer
Hemi t/c
Steel 7v plugs
Silicone charge hoses
Provent kit

When I pull the codes with the GDE programmer I get P0299, and the 671-2-3-4 codes for the plugs, which I attribute to maybe the old harness (I have a new one coming)but I could be wrong? I also recently removed the turbo and cleaned it out by opening it up and cleaning out the sludge-yikes. The turbo vacuum lines seem to be in good shape and I made sure that the actuator rod was free to move next to the oil line on the turbo. There is zero play in the compressor bearings. Since reinstalling the turbo I can now hear the turbo spool from a dead stop, whereas before I could only hear it at about 2k RPM. The heat shields are in place.
The only real issue I had when swapping the motors was when I pulled the block out I damaged the Crank sensor connection and I had my mechanic repair that for me (I don't have a lift).
Overall the Jeep runs great, just a bit smokey if I get into the pedal. I'm stumped....
Author:  flash7210 [ Tue May 14, 2019 12:00 pm ]
Post subject:  Re: My limp issue...out of ideas
P0299 is a underboost code, meaning the turbo isn't putting out any pressure.
So its either a turbo problem, a boost leak problem, or a MAP sensor problem.
This will make the engine under powered, push black smoke out the exhaust, and feel like limp mode.

I cant really explain the "blip surge" part other something else is occurring at the same time.
Like maybe the AC compressor is cycling off (which is periodically does naturally) and causing a rise in rpm.
Author:  BlueCRDinAZ [ Wed May 15, 2019 4:41 pm ]
Post subject:  Re: My limp issue...out of ideas
New MAP sensor will be here tomorrow. Stay tuned.
Author:  Billua [ Thu May 16, 2019 9:58 pm ]
Post subject:  Re: My limp issue...out of ideas
Are you sure the plastic line to the turbo actuator is good? I just found about a half inch rub through on the bottom of that plastic line while I am changing turbos on my new (to me) jeep. This jeep had a history of under boost codes according to the PO-previous owner..

I am not sure that I would have discovered this if I hadn't flipped this line up and inspected it after I removed the old turbo.

Good luck!
Author:  TKB4 [ Fri May 17, 2019 10:28 am ]
Post subject:  Re: My limp issue...out of ideas
I also had a hole in about 1/4 inch vacuum line going to turbo near the rear of exhaust manifold when I had a boost problem. I solved it temporarily by cutting a piece of plastic straw and cutting the damaged area out and forcing the resulting two ends into the straw tight and wrapping copiously with electrical tape till I could fix permanently.
Author:  connolcj [ Fri May 17, 2019 11:49 am ]
Post subject:  Re: My limp issue...out of ideas
I had the P0299 code and was able to fix it by taking the turbo apart and cleaning out all carbon build up. Brought the pep back to the jeep in no time. A bit time consuming but was better than dropping the $$$ after I had already bought a new(used) engine and did the whole nine yards to it. Studs, rockers, EGR delete, muffler delete, DIY tune, full gasket set etc.
Author:  BlueCRDinAZ [ Mon Jun 03, 2019 1:29 pm ]
Post subject:  Re: My limp issue...out of ideas
An UPDATE

Been several weeks now and I have since replaced the MAP sensor and glow plug harness-which cleared the 0672...codes. I also dumped 2 cans of seafoam together into the tank. The smoke production is ALOT better now, I only see it when I accelerate from a dead stop but even then if I use a light foot I can keep that down too.

Unfortunately this limp issue is still popping up occasionally; only now instead of disconnecting the neg terminal on the battery to clear it, it now clears with just turning the key off and restarting. And no codes are popping up on the programmer.
Still stymied..
Author:  APC9199 [ Mon Jun 03, 2019 2:42 pm ]
Post subject:  Re: My limp issue...out of ideas
Just for giggles, reach down past the turbo actuator and feel for the small adjusting nut on the actuator rod. Try to twist it and see if it moves at all. It should NOT move under any amount of force you can apply with your hand. I had that nut come loose on my CRD after a long drive on some washboard back roads up in Flagstaff and it took awhile to figure out what was causing my underboost.

Make sure you do this with the engine fully hot so you burn yourself, then throw a tool and cuss at the Jeep like it can hear you. Your ascension to shade tree Jeep mechanic will then be complete. (<-- Just kidding, don't do that! :ROTFL: )
Author:  BlueCRDinAZ [ Tue Jun 04, 2019 1:18 am ]
Post subject:  Re: My limp issue...out of ideas
APC9199 wrote:
Just for giggles, reach down past the turbo actuator and feel for the small adjusting nut on the actuator rod. Try to twist it and see if it moves at all. It should NOT move under any amount of force you can apply with your hand. I had that nut come loose on my CRD after a long drive on some washboard back roads up in Flagstaff and it took awhile to figure out what was causing my underboost.

Make sure you do this with the engine fully hot so you burn yourself, then throw a tool and cuss at the Jeep like it can hear you. Your ascension to shade tree Jeep mechanic will then be complete. (<-- Just kidding, don't do that! :ROTFL: )


now that's some funny stuff right there!
Author:  TKB4 [ Thu Jun 06, 2019 1:27 am ]
Post subject:  Re: My limp issue...out of ideas
Make sure to check the intercooler hoses for cracks oily residue or loose clamps especially if you don't have Samcos or silicone intercooler hoses. The ID parts silicone hoses have also had some problems.
Author:  Billybob [ Thu Jun 06, 2019 3:46 am ]
Post subject:  Re: My limp issue...out of ideas
Fuel supply problems can cause engine to go into Limp mode or to die completely without posting any codes.
I had this with my 2002 Export 2.5 CRD due to a blocked fuel filter.

Sudden surge maybe caused by the throttle circuit or the butterfly flap?

Problems showing up only when engine is hot or cold often caused by the cam or crank sensors failing but this usually posts a code. :?

Remove the Aircon relay to stop AC clicking ON/OFF which may cause a surge.
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