Do I Need Engine Work On My 89 YJ? -
LinkBack Thread Tools
post #1 of 6 Old 07-21-2013, 01:23 PM Thread Starter
Registered User
1989 YJ Wrangler 
Join Date: May 2013
Location: Burnsville
Posts: 52
Do I Need Engine Work On My 89 YJ?

I have recently been through multiple sets of spark plugs. What happens is I will replace the plugs with brand new ones and all four cylinders in my 2.5L will fire properly and it will run better for about a day, roughly. I'll frequently pull the plugs and make sure they are burning the proper color since I have been having problems with my jeep running rich lately.

Usually, my plugs will burn black. If it isn't burning black, the plugs will burn a very dark brown color... But usually, more often than not, all plugs will come out black. Sometimes, but rarely, one or two of the plugs will come out wet. Every time I put brand new spark plugs in my 2.5L, the plugs will burn a light tan or greyish white color for a period of time (about a day or two), and then days later I'll check the color they all are burning, and they all come out extremely dark or black, once in a while one or two will be wet.

I've done a compression check on the cylinders a couple times now. I've got these levels of PSI:

Cylinder One: 105 PSI
Cylinder Two: 125 PSI
Cylinder Three: 107 PSI
Cylinder Four: 124 PSI

Knowing these numbers, I was told that the valves and rings are fine. They aren't perfect, but supposedly "no need for a valve job". I know these levels on the compression tester gauge should ideally be extremely close to each other in PSI levels, but am wondering if these readings are OK, knowing the fact that every other cylinder is higher than the other two, like my readings above show.

Also, I have black "soot" lined in the inside of my exhaust pipes. The exhaust smoke comes out normal though. It's just a thick lining inside the exhaust pipes that are covered in black.

If I had taken the down pipe off, which I have done before to diagnose some other miscellaneous things, I can start the car up and intermittently, but extremely frequently, see small flame coming out of my exhaust manifold. I was told by multiple people, including Que89yj, that this abnormal flame coming out of the manifold itself is caused by a car running so rich that the excess unspent fuel sucking into the engine is spit out of the manifold and down the exhaust itself. On its way out, it can and/or will ignite.

Also, when I very recently replaced my entire exhaust system including the exhaust manifold, down pipe, catalytic converter, muffler and tail pipe, after about 200 miles or less on brand new exhaust my catalytic clogged so much and so quickly that it started glowing redish orange and started smoking like crazy. I took the catalytic off and replaced it with a test pipe so I was able to drive to work without it happening again, knowing I never cured the root of the problem, which would be my car running so darn rich.

Currently, I am stuck getting 13 miles per gallon in a 4 cylinder TBI with 30 inch tires. I should be getting way more.

Another thing... Every time I turn the car off, seconds later I will hear some type of fluid dripping internally from inside the engine. To follow this, right when the fluid starts dripping internally I will hear a light ticking noise that eventually slows and dies down to a stop. The ticking noise and fluid dripping noise last roughly ten or 15 seconds, and stop at roughly about the same time of eachother. My engine is always lobing. Sometimes it will lobe a lot more than other times, but it always does it.

Lastly, not every time, but maybe 40 percent of the time at random, I will shut off my car and hear a loud pop, like a fire cracker go off, and it is coming from the tail pipe. It seems to have started ever since the exhaust was replaced completely, especially when I replaced the brand new clogged catalytic converter with a test pipe for some reason.

What do you think this all could be? Here's what I replaced that may help you all understand:

-New EGR Valve, now tested and new one works fine
-Fixed all vacuum leaks
-New Exhaust
-ALL NEW Sensors, every single one of them besides the CPS...
-Brand new "OLD STOCK" discontinued, never had fuel in it TBI unit, factory part from chrysler. Not an aftermarket part. Costed me a fortune, but worth it...
-New injector
-New fuel pressure regulator
-Cleaned out EGR Tube, wasn't clogged
-New ISA Motor
-Tested canister purge control solenoid, works fine
-All new spark plugs, of course
-New plug wires
-fairly new rotor and distributor cap
-WOT Switch tested and works perfectly fine
-New vapor canister filter
-New air filter
-tested compression, readings are above
-tested vacuum pressure, running at about 15 PSI at IDLE (Is this normal or do I still have a leak in the vacuum somewhere?)
-New fuel filter
-All new gaskets wherever there is a gasket needed under the hood

I've done a lot more to this jeep in the last few months than what is listed above, but the rest of it does not have anything to do with any of my current problems I've listed in this thread.

If anyone that has an idea of what my problem(s) could be can please post back and help troubleshoot this, that would be very appreciated by myself.

I know it is a very long and detailed post, but I figured I'd need to give as much info as possible for this...

Thanks guys, you've always helped me figure it out before, I know we can do it again.

wrangleryj89jp is offline  
Sponsored Links
post #2 of 6 Old 07-21-2013, 01:54 PM
Registered User
1991 YJ Wrangler 
Join Date: Jul 2012
Location: Modesto
Posts: 325
CPS, why did you not change that?

Timing chain could be stretched, causing your timing to be off just a bit, causing you to be running rich. I had a chain guide fail (different car) and I was running really rich and backfiring, because the proper tension wasn't on the chain anymore.

Your piston rings could be going, have you done a leakdown test? That wouldn't cause it to run rich, but it would be causing your plugs to foul. Do they smell like fuel or oil?
caoboy is offline  
post #3 of 6 Old 07-21-2013, 02:32 PM Thread Starter
Registered User
1989 YJ Wrangler 
Join Date: May 2013
Location: Burnsville
Posts: 52
I haven't changed the CPS because I didn't think it would start if the CPS was faulty. I haven't checked my timing chain at all. I had someone run a timing light on it in my garage and he said that the timing is off the smallest amount, but not by much. I don't know the amount it was off, but does the timing have to be perfect? What are some other symptoms of a failing timing chain or guide?

Never done a leak down test. How do you do a leak down test and what does it involve?

I'll have to check the plugs and get back to you on that later today to see if they smell like fuel or oil. If the rings were going wouldn't my compression read a lot lower than that?
wrangleryj89jp is offline  
post #4 of 6 Old 07-22-2013, 10:05 AM Thread Starter
Registered User
1989 YJ Wrangler 
Join Date: May 2013
Location: Burnsville
Posts: 52
wrangleryj89jp is offline  
post #5 of 6 Old 07-22-2013, 01:36 PM
Registered User
1995 YJ Wrangler 
Join Date: May 2011
Location: Baltimore
Posts: 3,776
Those numbers are really low and two of the cylinders are out of spec. These engines are considered toast and in need of a rebuild when they get below 110 psi or there are more than a 10% varience between cylinders. Your CPS should be fine. This is not a sensor issue and timing would not cause all of these issues. Your rings are worn and your plugs are black because of the oil getting by. That is also what is coating your tail pipe. Its time for a rebuild my friend.

1995 YJ. 2 inch BDS Spring lift. 1 inch shackle lift. 1.25 inch JKS Body Lift 33x12.5x15's. Engo 10,000 pound winch.

Originally Posted by Magnum View Post
I gave the Jeep the required offering of $$, sweat, and blood, and everything works fine now. -- Jim
Originally Posted by ldso View Post
. It started with a $200 axle, and a few thousand dollars later I was done :)
Originally Posted by Luuca View Post
diagnose the real issue before you start going all Obama on it - spending mad cash you'll need for other important things.

Ask me how I know...
Originally Posted by Overhead View Post
this is also my second set of RC springs this year. I'd rather spend the money again and get something that will last.
Siva283 is offline  
post #6 of 6 Old 07-23-2013, 04:02 PM Thread Starter
Registered User
1989 YJ Wrangler 
Join Date: May 2013
Location: Burnsville
Posts: 52
Good to know... Thank you I figured that I probably needed to do a rebuild, but at the same time, I just needed someone else to verify it and help me make sure of it before I pulled the engine. I will most likely not be rebuilding my current engine... Instead I am going to invest in a remanufactured engine. Quadratec and sell Reman "ATK brand" 150 AMC stock engines on their website. They are not too bad for a complete reman engine in price. Would anyone give me some knowledge on ATK Brand reman engines, and if they are quality and reliably done? I know Jasper has a good reputation, but for ATK's price, it's worth looking into one of theirs'....

Also, when I do the reman engine swap, I'm just going to put a reman transmission or maybe I'll throw a brand new Transmission in it... Mine is starting to be on the fritz and is acting up more and more. Anyone know of a good reliable quality brand for the reman transmission too?

This will be my first engine swap on any car, ever. Hopefully things go smoothly...

Any more knowledge on my questions would be extremely helpful! Thanks.

Also, is the problem you listed with my rings causing the weird "ticking sound and fluid dripping internally" sound that I described. Obviously if I replace the entire engine I shouldn't have those internal problems anymore, but I'm just verifying this all beofre I get my hands dirty...
wrangleryj89jp is offline  

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome