AK to HI engine code every new part gets worse

[Ecomike]

I got my TPS and MAP at Autozone. I switched to Murray T-stats recently, from O'reillys, made in Israel. Standard parts, made in Italy, from Rock Auto for the CPS (Autozones last one was bad, made in China I think). If it is heavy part like a brake rotor I try to use Autozone, but I inspect the part closely first. Light weight stuff (low freight costs) I try to use Rock auto, great selection of manufacturer sources there to pick from!!!

 

[SBpunk]

The ones I had from O'Reilly's didnt work. Both of them. WeRMopar was the cheapest place I found online with shipping to Hawaii. My CPS is already starting to act up too. Next payday i'm going to drop 300 bones on replacing all my sensors with mopar parts. I hate not knowing everything possible about my vehicle.

 

[Ecomike]

The ones I had from O'Reilly's didnt work. Both of them. WeRMopar was the cheapest place I found online with shipping to Hawaii. My CPS is already starting to act up too. Next payday i'm going to drop 300 bones on replacing all my sensors with mopar parts. I hate not knowing everything possible about my vehicle.

Have you considered the possibility it might not be the sensors? Sounds to me like it is time to back up and start over, and collect a new set of data, test the wires, get the sensor data with a meter, look for things that might have gotten knocked loose like vac lines.....even the PCM?

What exactly does this mean?

"CPS is already starting to act up too."

 

[Ecomike]

FWIW, I think I have bought 3 or 4 bad Renix parts the last few years (all at Autozone). One was a CPS, it finally showed infinite resistance one day during one of the random no starts (started fine 3 out of four times for weeks).

One early water pump bearing failure, took 12 months.

One bad out of the box, off set, not centered rear brake drum, it was obvious on visual inspection right out of the box.

And one visibly damaged, right out of the box IAC.

That is four out of probably 80-100 Renix jeep parts I have bought from AZ the last 3-4 years that was defective.

I have 3 running Renix rigs, and a 4th 1985 XJ that uses a lot of the same parts (non jeep engine).

I have yet to find a quality head light switch made by anyone for the 85-89 jeeps, so I switched to adding the harness relay set ups under the hood to move the load from the switch to the relays. And I went to CFS 3 row brass radiators, and the Volvo coolant bottle caps.

 

[SBpunk]

Sorry Eco was away from the computer a few days. My trans has been shifting hard since I put in the CPS and its getting worse. GOing to drop the pan and swap the fluid this weekend hopefully it helps a bit.

When it comes to the TPS's I replaced I was under the same impression. There was no way I couldve gotten 2 bad units off the shelf. Soon as I put in the MOPAR part my codes went away and the engine is running much smoother.

 

[ihscoutlover]

I used to work for Autozone. I won't bad mouth them. They have some good stuff and some bad. When they got rid of the Wells brand, well I am sure that changed things some. I bought my CPS from the stealership for 1 reason, high failure rate of ALL the chain parts stores parts. I got much better run out of that unit. Like the O2 sensors, I found that all your imports do better with the OEM vs a Bosch O2 sensor. Brother found out on his '90 Honda accord, where it was running like crap, we swapped out his O2 sensor, then his fuel mileage got worse. Took it to a mechanic that specialized in imports and found out that the O2 sensor was bad due to not being within the specs it should have been...brand new out of the box. I have seen parts come back, especially electrical ones that were bad. They even sent me to training to diagnose and test these sensors and components. Bottom line, lots of stuff is now made overseas in sweatshops to keep costs down, since we are keeping our vehicles longer. Keep doing what you are doing and if you run into another issue try the search and see what comes up. I am also a member over on cherokee forum, and there is some good information over there as well.

Jeff

 

[SBpunk]

Always do Chain stores are great dont get me wrong just not for sensors but thats my opinion and experience. In this case the issue wasn't just a sensor (if a sensor at all). After replacing pretty much everything I discovered my #1 injector wasnt getting a good ground / power source. Never figured out which since before I bought new connectors and started hunting the wires I found a complete harness for 35$. Running MUCH better now but still think my PCM is going out. Another project for another day tho.

 

[xeroOTG]

You can check the impedances of the lines to to the ecu, I wouldn't just guess it was on the way out. Did you ever get a FSM? Mine was indispensable in diagnosing a IAC circuit. I went from connector to connector with a multimeter and found my ecu A connector was damaged, one of the pins in the plug had bent. I took it apart and fixed it and been running good ever since. I'm glad you found a harness though! Those can be tricky...

 

[SBpunk]

Yup got a FSM awhile back. I need to read thru it a few times. Like I said its running better but something still doesnt feel right. The motor is still shaking pretty good which is making me feel like its not firing all 6

 

[Ecomike]

You know how to pull the injector connectors, one at a time, to look for the miss firing cylinder right? If it gets worse when you pull one, that is a good cylinder, if there is no change, that is the one that is not firing.

Then you need to find out what is missing, compression, spark or fuel.

 

[SBpunk]

Thats how I figured out my number 1 wasnt firing. Its running better but still not firing. I've checked the compression, spark and injector so it leads me to believe that the PCM is bad itself. The OBD2 will pop a code when I pull the number 1 off but there is not change in the engine. The new harness helped refresh some of the other connections which is making it seem like its fixed until I start playing with the number 1 injector. Maybe I'll recheck the compression again this weekend. Might have missed something.

 

[Ecomike]

Swap a spark plug with #1, in one of the tests. Does this rig have plug wires???? If yes, test or swap it too!!! Then check the CAP for a crack on the #1 post.

 

[Jamie57]

Thats how I figured out my number 1 wasnt firing. Its running better but still not firing. I've checked the compression, spark and injector so it leads me to believe that the PCM is bad itself. The OBD2 will pop a code when I pull the number 1 off but there is not change in the engine. The new harness helped refresh some of the other connections which is making it seem like its fixed until I start playing with the number 1 injector. Maybe I'll recheck the compression again this weekend. Might have missed something.

I'm having very similar problems with my 2000. My cylinder is #6 though.
There was a tech bulletin from Chrysler about some bad valve springs causing the symptoms you and I are seeing. Unfortunately with a foot of snow on the ground and no garage, I'm waiting for nicer weather to change out the springs. It's an easy job with the right tools and the springs are rather inexpensive. You could try that and let us know.

 

[Ecomike]

I have read some recent posts here saying the new springs solved their problems on the late model 4.0s!!! Short of replacing, not sure how determine if that is the problem.

I'm having very similar problems with my 2000. My cylinder is #6 though.
There was a tech bulletin from Chrysler about some bad valve springs causing the symptoms you and I are seeing. Unfortunately with a foot of snow on the ground and no garage, I'm waiting for nicer weather to change out the springs. It's an easy job with the right tools and the springs are rather inexpensive. You could try that and let us know.

 

[SBpunk]

Ill have to google how bad they are to swap. I'm sure I have all the hand tools but if it takes certain spring pressure and what not that worries me hahaha. I'm off the next few days so ill give it a shot

 

[Ecomike]

There is a thread here from about 8 weeks ago, cruiser54 guided me into replacing the valve stem seals on mine. It was almost too easy, LOL. Here is the tool you need:

http://www.summitracing.com/parts/otc-4573/overview/

Just push a long 5/16" polypro or nylon rope into spark plug hole to fill up the area above the piston, then manually turn the crank shaft with a socket and ratchet or breaker bar. That supports the valve so they do not fall into the head.

Dig up that 8 week old thread, it has all the anal details in it, LOL. Blow by blow, LOL :gag:

 

[Ecomike]

This might help some too.

http://www.youtube.com/watch?v=ob_4-F-m1FI

 

[SBpunk]

Ok so I redid the compression test. Number 1 was 135 and the rest were between 150 and 165. Within 30 so I'm guessing the lifter is good. Gonna throw on some better motor mounts this weekend see if it helps with the engine shaking at all. Sorry for the short reply at work lol

 

[Ecomike]

Adjacent cylinders must not be more than 20 psi different per the FSM. If it is, it causes vibration. What was each cyl number and value?

I do not understand the good lifter comment?

 

[SBpunk]

#1 145
#2 160
#3 155
#4 165
#5 160
#6 165

Not the exact PSI since it went in 5lb increments. My train of thought was if the compression was good on the cylinders then the valve lifters should be. Might be wrong of course but thats why I ask all you more educated folks hahaha. I didnt do a wet compression test since the numbers were pretty close together. The number 1 is the only one that was low but still within the acceptable range. Honestly what it comes down too is why its shaking and why when I pull the number 1 injector off its still not showing any change in the engine. I'll poke around some more since I'll be taking it around the island this weekend.