rdr8887

Hi. I've been lurking this forum for years now. So, thank you all for contributing when needed. This website is a great reference tool. I finally needed to create my own post to ask for some help.

Now, this post will be long. I'm going to try and use a few bullet points to make this easier to read. I'll explain more as needed...

Thank you all in advance and thanks for having me.

The Basics

• 1994 Jeep Cherokee 4.0L
• Motor is OEM.
• 189,000 miles not well maintained
• Overheated 3 years ago and shut off from heat
  • Noticed a good amount of coolant leaving system onto pavement.
  • Drove it rather than waiting for it to cool down and put water in
  • Never verified problem. Assumed it was waterpump and drover his other jeep.
• Sat from then until about a week ago
• 1/2 tank of gas.
• Bought this from friend as a project
• Time to get it running again.

The Symptoms

• Wont Start
• Intermittent chugging and trying...but never starts. Most of the time the start just spins.
• Rust everywhere in coolant system
• No codes on jeep self test. 12 and 55

Steps Taken

1. Cooling System
   1. Filled system with tap water. Bone Dry. No visible leaks
   2. Tested pressure. Failed. Leaked out within 3-4 minutes. Attempted 5 times. Found leak at thermostat gasket and water pump. Could never recreate a visible pour of fluid.
   3. Replaced Waterpump and thermostat complete with gaskets and silicone. Refill with water. Pressure tested and passed.
   4. Drained as much of the rust out of system I could without the car running.
   5. Reinstalled hoses cooling system fine. Will come back to system once car is running.
2. General Maintenance
   1. Cleaned and charged K&N Filter
   2. Oil Change. No water visible in oil. Appeared fine
3. Starter
   1. No started included.
   2. Replaced started with used version from salvage yard.
   3. Works
4. Battery
   1. Put in a newish battery. Holds charge. Left on trickle charge. Reset computer.
   2. Currently disconnected to reset computer.
5. Fuel System
   1. Checked for pressure are rail. Put a flat head in test valve and squirted fuel. Pressure was in rail.
   2. Engage fuel pump with ignition.
   3. Rechecked Fuel Rail and found pressure again. Fuel pump is verified to be working. Test repeated 5 times.
   4. Starter Fluid in Throttle body. Sprayed for 3 seconds. No Start. Repeat process 2 times first day, 1 time second day.
6. Spark
   1. Pulled all spark plugs. Dirty. Coated with carbon? Completely covered. Cylinder 4 had rust.
   2. Spark weak through buildup. Checked worst and best
   3. Compression Test Each Cylinder
      1. 86
      2. 33
      3. 47
      4. 54
      5. 84
      6. 84
      7. Numbered in order. Retested several times on lower compression cylinders.
   4. Replaced all spark plugs and wires. Better spark. No fire. Tried to start a few times....but now back to only starter
   5. Rechecked spark...looks good. Only checked one plug in the No. 2 cylinder.
7. Things I know
   1. Crankshaft Position Sensor was replaced within 15k miles of the vehicle overheating
   2. Leaking oil at rear main seal
   3. According to owner, an extra court per week required.
   4. Wasn't maintained well
   5. Fuel System is okay to rail.
   6. Crank turned when checked
   7. Everything moving correctly when spark plugs were out. Specifically looked at 2, 3, and 4 when attempting to crank. Will recheck tomorrow
8. Things to try
   1. Going to remove oil filler cap and check to see if I can see the rocker arms moving. As many as I can at least
   2. Pressure test cooling system with spark plugs out.
   3. Running out of ideas...

Again...sorry for the long post. Tried to list everything. Will answer questions and try to update the list accordingly. I want to get this thing running again. However, I'm not going to spend much to do so. If that's the case, I'll strip and sell the motor (what's still good at least).



I'd hate to part this thing out...so, can anyone help? I'm getting close to being out of my trouble shooting knowledge. Maybe I've missed a step? I want to exhaust all options before tearing into the motor to find whats going on.



Thanks in advance. And again, thanks for having me

Turbo X_J

Three year old fuel is probably no longer even flammable but in a nutshell, the motor is trash.

MtnHermit

Suggest to me that you have a project, like it or not. Have you considered a used engine? Either that or rebuild the one you have. If the body is good, worth the effort.

rdr8887

Yes, that's probably true. In fact, I'll check tomorrow. However, wouldn't the starter fluid start it? At least make it try then it chug out?

rdr8887

I might rebuild it. Just depends on the cost I guess. I'd want to narrow it down first. I believe even with those numbers the jeep should start. I'd like to know what's failed and why it won't start.

I'd rather rebuild then find a new motor.

JeepsMyName

I got a complete motor for my 91 for 250 it had 110k on it. If you shop around you can find deals.. rebuilding that motor could turn into your worst nightmare and a huge money pit.

1995liftedxj

My jeep is doing the same blew a head gasket so got a 93 4.0 in it and it try's and trys but won't I've tried starting fluid still nothing gets amazing spark new crank sensor but I pulled the fuel regulator on the fuel rail and all the o-rings was wasted so I'm going to pick up a new regulator and see what it does

MtnHermit

On 2nd thought, those compression numbers are as likely from the valves as piston/rings. There are additives that will clean the valves, do a search. Also sometimes weak valve springs are a problem.

Agree, should start with three good cylinders. As to bad gas, weak BS. Gas per see doesn't go bad, except it has alcohol in it and that attracts water. Known good gas is always better when your trying to sort out so many issues.

Good luck.

MtnHermit

You didn't mention the injectors. I assume a `94 has injectors? The TB just modulates air into the manifold. Would seem injectors would gum up in 3-years. Clean? Replace?

PocketsEmpty

If it sat for three years, and there's rust in the cooling system, you might as well just pull that engine and start over. And put a new rad / hoses in there when you do.

Firestorm500

Simply put, an engine needs these things to run:

Fuel
Air
Spark
Timing
Compression

If it has those in proper quantities, it will run. An engine wants to run.

Your compression looks very weak to me, especially on 3 of the six cylinders.

After the severe overheating episode, I think a complete teardown would reveal scored cylinder walls, possible broken rings and pistons. This is why little compression is observed.

Don't worry about radiators and peripherals like that. Get a borescope, pull the plugs, and look into the cylinders before going any further. Rotate the engine to get a good look at all of them top to bottom.

I'm like an earlier poster in that I think the engine is toast. Sorry.

rdr8887

I was hoping the low numbers were just from a stuck valve that might work itself out. The jeep ran fine before overheating and turning off. I know it's a possibility that this caused my problems...but I'm holding out hope.

Does anyone know what PSI I should expect in each cylinder?

rdr8887

No...that is one of the items on my list to check. I figure the injectors could very well be clogged. However, I also thought the starting fluid would fire it up anyway. Wouldn't the throttle body bypass the injectors? Meaning it would fire then bog down when the injectors tried to work?

I'm going to try to pull them this weekend and sit them in transmission fluid or something to get clean....

rdr8887

I don't think it would be that bad. I won't replace it until I know for sure it's needed. For now, it works as my toy...rust and all. I will flush it out real good. I'm pretty sure the rust is from running straight water in the coolant system.

rdr8887

It definitely could be. I've had a vehicle overheat before...but never to the point of shutting itself off. I will get one of these....hopefully autozone has one to rent. And I will check everything.

Still holding out hope...but the compression test lowered the chances of this being a quick fix...