Jakers

Alright I'm going to do my best to explain my issues/concerns... I apologize for being long winded.

For those of you living in Arizona, I live in Gilbert and took a drive up to Payson. For those of you not in Arizona to get to Payson from my location you have to travel through the mountains. Its all highway but a good portion of the drive is uphill, not straight up and down uphill but if on the way back home there are those signs saying "6% - use lower gears" (not sure if that helps or not). BTW, its a 78mile trip - I drove it in my wifes tacoma and It only takes about an hr and a half.

On the way up the Jeep overheated and I had to pull over for about a half hour - 45 minutes. ~6 months before this trip I did a huge overhaul on the jeep. New headgasket, push rods, rockers, valve job, head inspection, mech fan, water pump, t-stat, housing, open cooling system, mounter mounts, cam shaft. So I assumed this trip would go flawlessly. I later found out that I had small leak in my t-stat to heater core hose. (installed one of the "flush" Ts). I have since replaced it with a single piece hose so hopefully that took care of that. But I wanted to add that information in case it has anything to do with my next problem.

Also, on the way up there It didn't seem like my Jeep even had the power to climb those hills (which my previous Jeep seemed the same way) and I never thought anything of it, but I saw a few other cherokees crusing up the hills with ease! Going 65-70mph while I'm barely able to go up it doing 45-55. To keep a speed of 55mph I have to keep the rpms around 2500. If I want to go any faster it feels like I'm just "flooring" the gas the whole time.

I'm not sure if I'm just paranoid or if I am having an issue with oil pressure. I've been reading around and I'm curious if I have a bad cam bearing. I have two videos posted below. The first video shows my oil/speed/rpms while going up one of the hills after about 20 seconds in you can see where the tranny shifted gears and rpms dropped down to 1500 but then my speed began to quickly drop as well, it was a never ending up/down/up/down with rpms and speed. The second video shows me in park with the rpms/oil pressure. I moved the video around a few spots in the second video to see if I could capture any of the sounds the engine was making. It's been a month or so since the trip so I can't remember if it was making this small knock or not.

I have 33" tires with 4.56 gears if that helps for the power issue. But I still feel like the jeep was just working too hard to go up those highway hills.

Any help would be appreciated. Thanks!

cruiser54

I wonder if you have a clogged catalytic converter.

Cruiser’s Vacuum Test for Exhaust Restriction

Your vacuum gauge should come with an instruction booklet outlining this procedure.

Hook the vacuum gauge up to a source on the intake manifold.
Start the engine and note the vacuum reading.
It’s usually 17 to 21 inches of vacuum.

Throttle the engine up to 2,000 to 2,500 RPM for 20 seconds or so and the vacuum reading should stabilize to the same reading you got at idle.

Let the throttle snap shut. The vacuum reading should shoot up about 5 inches of vacuum higher for a second and then come quickly down to the original reading.

If the vacuum reading stays high and comes down slowly with jerky needle movements, you have an exhaust restriction.

Jakers

Jeep just passed emissions (not sure if that would help/worsen emissions scores) but it's been about 2-3years since the cat was replaced. I do not own a vacuum gauge but have been needing a reason to buy one! Which one of those china freight ones would you recommend? Would I be able to use one of these brake bleeder/vacuum pump kits or should I just stick with the tester?

http://www.harborfreight.com/mityvac...ump-39522.html

http://www.harborfreight.com/fuel-pu...ter-93547.html

cruiser54

I'm thinking the Mity-Vac could be dual purpose.

Hurry up and fix that thing so it's reliable. At least to get to Prescott and back so you can buy me a few of those hundred beers you owe me. LOL.

Jakers

The wife was just asking yesterday when we are going to go up there to the lakes! At this point I don't even like driving it around town haha. Gonna head to HF right now, should be able to post the results in the next few hours.

Jakers

Alright, at idle mine is 15-16, when throttle is first pressed to 2250 vacuum drops to ~12 then immediately rises to and bounces around 18-19. Once throttle has been let off vacuum jumps up to 22 and then settles back down at about 15. I've attached a clip of the video.

Mine did NOT stabilize to the same vacuum as idle (15-16) while the engine was at 2250, it stayed steady between 18-19.


This is where I hooked up the vacuum gauge to



edit: Checked my oil while I was at it and noticed that the dipstick tube/oil on the dipstick tube smelled like gas I also did a compression test since I had the hood open.

Dry: Cyl 1: 106 Cyl 2: 105 Cyl 3: 105 Cyl 4: 114 Cyl 5: 107 Cyl 6: 106
Wet: Cyl 1: 135 Cyl 2: 136 Cyl 3: 149 Cyl 4: 149 Cyl 5: 142 Cyl 6: 142

cruiser54

Hmmm. Is the oil all gassy?

Jakers

Could you be more specific? Oil on the dipstick tube looks like regular oil, just smells like gas. What do you think of the compression results?

cruiser54

Pull the dipstick. Let a drop or more of oil drip on the piece of skin between your thumb and forefinger. Does it stay all together and run slowly or does it run quickly into the wrinkles in your skin?

syncview

Okay, is it only me or that Oil pressure at idle is too high?
IIRC the specs are 13psi MINIMUM at 600rpm to 37-75PSI MAX

now, I'm not saying that it should be around 13psi, I have seen them idle around 25+psi with good pumps

High oil pressure suggests a clogging or blocking, oil thickened by soot or oxidation etc

Also, your compression test results are very low, which suggests that the engine oil can be gassy as cruiser54 asked and can increase engine oil pressure

And, ref low power, it can be due to low compression AND have you confirmed if the fuel pressure is OK?

Radi

Your vacuum is a little low but it recovers properly when you rev the engine. I'd say the cat is OK but your rings are probably pretty worn. The low compression and contaminated oil are symptoms of that. Probably the reason the motor is out of breath on the hills.
Shorten the OCI's for now, gasoline wipes the oil film off the moving parts and accelerates wear. Long term you'll want do do a cylinder/ring job.

The high oil pressure is possibly a failing pressure sender. They tend to fail by reading too high.

Jakers

Perform this on a hot or cold engine?

Sender unit was replaced 2 weeks ago..cylinder/ring job sounds like something I won't be able to do myself lol and pricey.

I replaced fuel pressure regulator about 6mo ago or so but haven't checked pressure at the rail since. I'll check in the morning when I do the dipstick test.

syncview

Yep, check the fuel pressure
and while you're at it, go through the ignition system too, spark plugs, dizzy cap / rotor, spark plug wires.

Jakers

Just replaced all those as well, when I did the overhaul, been about 6months but I've only put maybe 1000-1500miles on it since they've been replaced

Jakers

Fuel pressure seems good, its 31-32. When I rev the engine it jumps up to 34-35 but then goes right back down to 31-32

Oil in the engine doesn't seem to run more slowly or quickly than new oil out of the jug. If there is a difference it seems small to me. Here are videos showing the difference. First video is engine oil cold. Second video is engine oil hot-ish (engine ran for about 15min, shut it off, waited 5min then tested oil), third video is oil right out of the jug. Washed my hands with gojo before each testing so there wouldn't be any oil slick left over. Used a zip-tie for the new oil so the results wouldn't be compromised from the dipstick.