New (to me) 2005 5.7l Grand Cherokee Limited. It's getting real shitty gas mileage... driven 160 miles & am at just over 1/4 tank. Granted it's been mostly in-town driving, but I've been driving it real easy. It has 121,000 miles & I figured I'd start with a tune up, not having any service records from the previous owner.
I've done some research & think I've got a complete list, but wanted to make sure I'm not missing anything.
1. Oil (5-20 Mobil 1 Synthetic)
2. K&N Oil Filter
3. Air Filter
4. Plugs (NGK V-Groove Copper Core/ Nickel Plated... 16 of em)
5. Plug Wires (Taylor 8mm)
6. New MAP sensor
I planned on checking the throttle body blade & cleaning it up. Seafoam makes an intake cleaning system that I've used on my Volvo & Chevy... works real well. I'm also looking at doing the Oil Catch Can mod to help keep the intake clean.
Looks like you're off to a good start.
1. Good choice
2. Or a Mobil 1 oil filter.
3. Consider a K & N or Trueflow filter element
4. Good choice. Be sure to torque them properly and DO NOT use anti-seize on new plugs. On used plugs, a little dab will do you. Also, while you have the plugs out, consider just removing one per cylinder first and do a compression check so you'll get a good idea where you stand with overall engine condition. Pull the fuel pump relay first.
5. Good Choice
Definitely get the catch can.
If the above items doesn't heal the fuel economy, change the O2 Sensors. With that many miles it's very probable that they are not working like they should. They wear out similar in fashion to spark plugs. You may not notice they're bad until your fuel economy tanks. If you end up changing them, get only NTK (OEM)......No. 23160 for pre-cat, and 23159 for post-cat.
Since this vehicle is new to you, I'd recommend doing a complete service, to include changing all fluids/filters....differentials, Xfer case, transmission. I just did the 90K service on mine and the fluids/filters alone will run you around $300. Consider replacing the coolant too, as it should be changed at 100K, or sooner. Use only HOAT compatible stuff. Also, check the brakes, and have the front suspension/alignment/tire balance checked. You're at the mileage where things start failing, unless the vehicle has previously received lots of TLC.
Changing all the fluids is next on my list. This jeep does seem to be in great condition. Good idea on the compression check. The engine has good throttle response, and I only have the P0700 code showing (Transmission Control Module). The suspension feels firm & tight. I don't see any evidence of leaks underneath. The diff covers are dry (unless it all leaked out ). Brakes are good, but not good enough. I'm going to get some power slots & ceramic pads for it. My DD is a 2005 Volvo S60R w/ Brembo's... I'm used to stopping quick!
This truck will rarely be put off road. I do live by Pismo Beach, CA... so it will go on the beach from time to time to keep the 4x4 equipment from drying up.
Anyone know if it matters whether or not the MAP sensor has a flange? There are two options listed. One has a flange w/ what looks like 2 bolt holes. The other has no flange Can't see very well which one I have. A lot of shit on these engines.. not nearly as easy as my 68 Plymouth.
You're right, not as easy (or fun) as the old iron. Your early Hemi uses the MAP Sensor without the bolt hole....if you can actually get one. The one with the bolt hole is for the later models, but is interchangeable (with a little work) and is normally the only one you can get anymore. I guess, by now, some of the aftermarket folks may be making both though. Do a search on changing the MAP Sensor, and you'll see what needs to be done. Basically, it requires breaking a tab off the intake. It's a bit of a pain, because of the location. On the PCV Valve, be careful that you don't break the old on off in its housing. It has been done, especially on vehicles that haven't had it changed in a long time....or ever.
On the PCV Valve, be careful that you don't break the old on off in its housing. It has been done, especially on vehicles that haven't had it changed in a long time....or ever.
Thanks jeepgcoman, I plan on soaking the EGR bolts w/ PB Blaster and letting it sit over night before I attempt.. remember... I have "Old Iron" too, and it rusts . Though, by now, I've pretty much replaced everything on that engine & don't need to worry about it too much.
Edit- just noticed you said "PCV" valve... not EGR. Any tips for the PCV valve?
14summithemi: I just ordered new O2 sensors. Weren't too pricey through Roch Auto & Summit. NGK sensors. Both were less than $35 ea. They're about $100 a piece for my Volvo, so it wasn't too bad.
That's like 10-12 mpg...possible but below what it should be unless you are racer rick.....check your O2 sensors. If they aren't throwing codes they can still be carboned up. Since they are pricey try this on all four. I know it ain't fun and you have to be careful not to break them but trust me it works. Did on my '02 4.7.
Remove them and spray the screen end liberally with contact cleaner. That will clean off alot of the carbon and not damage them. Then when you re-install do yourself a favor and use anti-seize on the threads for next time.
Also, use a good injector cleaner in your next tank and monthly for a while, bet yours are spraying like poo...that'll roach mileage...any rough idle or seeming like a possible cylinder miss? dirty injectors sometimes present that way too...
With up to date maintenance and a few easy mods, I get 22.5 mpg at 65 mph, and have 105k on the OD. Remove the TB from the vehicle and clean every bit of black everywhere, not just the plate. I used rubbing alcohol with rags and q tips for crevices. Takes time but well worth the effort, and never have to do it again with a catch can installed. Also undo the battery neg terminal while doing this to reset the ECU.
Definitely do the Seafoam crankcase treatment, put 1/2 bottle in the oil, and run for 100-150 miles, (don't race the engine either) then change oil. This works great and loosens up the stuck MS lifters, (the cause of the Hemi tick) greatly improves throttle response and improves mpg. I've done this every oil change since 50k.
Do the EGR, but do not follow the how to instructions on this forum. It is very easy to do. Just remove the top EGR bolt, wiggle to loosen it up, then rotate the EGR down to the left and voila, the lower bolt is out in the open and easy to get to and remove. No cutting, alternator, belt removal, etc.....
Thanks for the tip on the EGR valve. I have a bottle of Seafoam ready to use. I think cleaning the throttle body is probably the right way to go. This jeep doesn't have a catch can, and I doubt anyone has paid any attention to the blade in any of the 121,000 miles it has. It's probably pretty crappy in there. I wonder if I should just replace the whole thing & start fresh.
If you want her to sound bad arse throw on the K&N FITPK....amazing sound, but your mpg will suffer do to the need to "hear" that sound every time you start off
Umm, sorry but I respectfully disagree. Been there done that with the CAI, and so glad to be rid of it. The noise is LOUD and unpleasant, not sweet Hemi sound, plus the worst part is it drives worse than stock after spending so much money. Did direct comparisons and low end / midrange torque is lost with the CAI, so you have to rev it to get going, plus tip in throttle response is worse so you have to mash the go pedal and downshift to pass.. IF there are any HP gains they are few and well up in RPM, where the Hemi spends very little of it's overall time. For a worthwhile mod, get an Intune with Hemifever CMR tune for not much more than a CAI.
OK.. I feel like an idiot now. I knew the car had coil packs... but I thought there was a plug wire involved somewhere. My Tahoe has coil packs... but use a plug wire to go from the pack to the plug. Plus, when Summit racing has plug wire options for a "2005 Jeep Grand Cherokee Limited 5.7l"... I figured I'd order a brand I'm familiar with (Taylor).
These trucks don't use any kind of spark plug wire... do they
Mine is in pretty good shape, so I don't mind it on there. Plus... it hides the rat's nest
SO... I should have the other two O2 sensors by Wednesday. Should have the catch can tomorrow. One thing I noticed was my throttle body was quite clean. Nothing caked on the blade... just a film on the backside. I wiped it clean with a rag & alcohol. I did forget to do the MAP sensor & will do that Wednesday with the O2 sensors.
I hope this all improves the mileage. If not... I may have to turn around & sell it. I can live with 15mpg city as long as I get around 20 or more on the highway.
For the catch can... the line from the PCV valve goes from the valve to the intake post throttle body. The old PCV had quite a bit of oil build up on it.. so it's obviously passing some oil into the intake. There is another line that comes from between cylinders 1 & 3 that runs to the air box between the filter & throttle body. It seemed to have oil build-up in the line as well. Should I run both of these through the catch can?
Did they use 8 year old little girls to install these in the factory? I had to contort my body & hands in ways they weren't meant to go. Nothing had anything resembling clear access... let alone enough room to cycle a ratchet, wrench, or any other tool. I used 3 different O2 sensor sockets as well as various 7/8" open & box end wrenches.
Once I loosened the first one (downstream passenger side) it came out & new one installed o.k. The next attempt (downstream driverside) took 2.5 hours to remove. The threads of the sensor were so jacked up. I tried to see if I could get the other one that came out clean to thread into the bung (didn't want to screw up a new sensor), but no go. I need to pick up an M18x1.5 thread chaser tomorrow to clean up the bung threads. The bung steel should be harder than the sensor threads, so the chase should clean out the crap left behind.
Hopefully the upstream sensors go easier. Really don't want any debris falling down into the cats. Any advice on how to get to these without killing myself? You're not supposed to drop the Y pipe to do these, are you?
Did they use 8 year old little girls to install these in the factory? I had to contort my body & hands in ways they weren't meant to go. Nothing had anything resembling clear access... let alone enough room to cycle a ratchet, wrench, or any other tool. I used 3 different O2 sensor sockets as well as various 7/8" open & box end wrenches.
Once I loosened the first one (downstream passenger side) it came out & new one installed o.k. The next attempt (downstream driverside) took 2.5 hours to remove. The threads of the sensor were so jacked up. I tried to see if I could get the other one that came out clean to thread into the bung (didn't want to screw up a new sensor), but no go. I need to pick up an M18x1.5 thread chaser tomorrow to clean up the bung threads. The bung steel should be harder than the sensor threads, so the chase should clean out the crap left behind.
Hopefully the upstream sensors go easier. Really don't want any debris falling down into the cats. Any advice on how to get to these without killing myself? You're not supposed to drop the Y pipe to do these, are you?
Not just blood sweat and tears man.. buy some PB blaster and spray it on before hand the day before and again a hour before you do it. Should help a lot.
PB blaster helped... forgot I had a bottle of that in the garage. Got a thread chaser & cleaned up the O2 sensor port. Got all the O2 sensors installed.
New problem. P0032 and really shitty idle. Bank 1 sensor 1 voltage high. All sensors are new NTK's. I connected to the harness after I tightened the sensors to avoid twisting the wires.
I always get confused... Which side is bank 1? I know sensor 1 is the upstream sensor.
That's the last one I installed then: Driverside upstream. The harness connector was broken previously, it won't click into the connector from the sensor. It still connects, just doesn't lock... that's how it was before, but it didn't throw any codes before. I wonder if I need to replace the whole harness.
Maybe since it wasn't securely and tightly clicked there is some corrosion in there? Spray some contact cleaner in there and clean with a toothbrush then blow it out with compressed air (can or compressor) and then use contact grease on the contacts. Those connectors have a rubber ring seal to keep elements out so maybe the loose fit is source of issue?
I'll see what I can do. The harness on these things were not well thought out in terms of service. I can only get 1 hand on this connector. I was giving thanks that the old one slipped right off. I guess it was a double edged sword since it's probably the reason for the code right now. As far as corrosion, I could see right into the connector & it looked very clean. It was positioned to where I could shine a light right into it, & I checked it for that very reason. High voltage reading would indicate some kind of short... right?
I just can't believe how horribly it ran. All because of one sensor.
I'll see what I can do. The harness on these things were not well thought out in terms of service. I can only get 1 hand on this connector. I was giving thanks that the old one slipped right off. I guess it was a double edged sword since it's probably the reason for the code right now. As far as corrosion, I could see right into the connector & it looked very clean. It was positioned to where I could shine a light right into it, & I checked it for that very reason. High voltage reading would indicate some kind of short... right?
I just can't believe how horribly it ran. All because of one sensor.
Does anyone have a PN for the o2 sensor harness? I can't find one. I just don't see how to check anything on this harness with it installed. Too f***in tight. I do see that the convoluted tubing they use as protection for the wiring is about gone. I wouldn't doubt there is a wire grounding out somewhere.
You wanna talk f***in tight? You are gonna have to come up with a whole new vocab to replace that harness. HOLY GOD! That spaghetti mess is one giant octopus! It's all interconnected between O2 Sensors, injectors, ECM and other "stuff". No separate wiring runs.
p/n 56044237AF (Wiring, Injector)------> Item 1 in pic below.
Retail $1,100, Street $775
And the kicker, can you imagine getting at all those clip brackets, etc...?
Jeez... I was hoping they had one just to replace the O2 sensor harness. Screw that. Any other ideas on how to fix a broken connector? I'll try the zip tie idea Sleeps mentioned. Not sure I can do it one handed.
So I got the brilliant idea last night to remove the O2 sensor I just installed & put the old one back in to see if it gets rid of the code (no code prior to changing out the part..and this was the only side I didn't have to pull & mess with the harness to disconnect the connector due the clip being broken). If it doesn't throw a code, then I know I just got a bad one from RockAuto. If it does, then I know it's in the wiring.
I'll give it a go tonight when I get home from work. Thankfully, it's still in the 60's & 70's here.
Otherwise... if anyone has any other bright ideas... throw them in the pot.
Is there a "Moron of the Year" award on this forum? If so... I humbly nominate myself
So, after removing the new sensor... and installing the old one... I was still getting the code. I tried clearing it, but it came back. I jiggled the harness, hoping whatever contact was being made would cease, but the code remained. I brought out the test light to see if any power was getting to the pigtail. It must only power up with the engine on because I was getting no signal from any of the pins... and I wasn't about to stick my hand up there with it running. Finally, I reached up there at an odd angle and decided to see if I could get any better connection. I felt it compress just a tad bit more. I cleared the code & restarted the engine.
YAHTZEE! Of course, had I tried that before, I wouldn't have wasted any of your guy's time.
Thanks for all the help. I do have another mystery though. A disconnected ground strap dangling from the transfet case. I'll post a pic.
Ok, cool. At one point a I was hoping it had something to do with the sensor failing! Lol.
Next job is replacing the front passenger CV axle boot. It's torn & is splattering grease everywhere. Plenty of room around that part... but I have faith it'll be a pain in the ass as well.
Ok, cool. At one point a I was hoping it had something to do with the sensor failing! Lol.
Next job is replacing the front passenger CV axle boot. It's torn & is splattering grease everywhere. Plenty of room around that part... but I have faith it'll be a pain in the ass as well.