AFMan

Anyone had this happen? I have an '01 Cherokee limited. When a diagnostic was ran, this is what came up. I took it in, (it's in now and I'm waiting to hear back) when I noticed intermittenly when I would accellerate hard, the check engine light would blink, and then stop blinking. Just curious if this has happened to anyone else? What needs to be done to fix something like this?

AFMan

Well, I guess I'm the only one. I had all the plugs changed, and they cleared the code, however when I accelerate hard, the "check engine light" still blinks on and off, then it finally goes out. So, it only seems to happen when I accerlerate hard. Any thoughts?

Jeep89JV

Probably just o2 sensors. I wouldn't be concerned if its running well.

Willys55

Blinking Check Engine light means that a cat damaging miss fire is occuring! Replacing the plugs is not always the answer. Carbon build up on valves can cause improper valve seating which will cause a clyinder compression drop resulting in a missfire. (common but not always the problem) High resistance accross the secondary coil windings can and will always cause a missfire which is more noticable after engine hot or under highrev load. Check compression accross the board.(not just the one missfiring) The correct way is to remove all 6 plugs , disable the fuel pump and crank the engine for 30 seconds to relieve fuel pressure.

I could go on for hours with this........95% chance that your coil pack is bad.....look for carbon tracking on the bottom side of the coil pack, because I am really sure you don't have the tools to test it. Also 99% of the time people change the stupid plugs but forget all about the boot insulators.

P.S. : Get a new shop mechanic. Because if they had a real good scanner and someone trained in using it,they would have accessed the Mode 6 info and discovered that injector pw was long and the number of cylinder missfires per cylinder..(also on some vehicles the pcm will not set a missfire code on a problem cylinder until it reaches a predetermined fail percentage and buy that time you are nearly stranded along the roadside.

Willys55

P.S. WELCOME TO CF FROM Russ in NJ

AFMan

Thanks *****. I guess I should check to see if the coil pack is bad now. I wonder if a general mechanic can do that. If it needs replacing, what do they run?

Willys55

about 145.00

AFMan

Unfortunately, it's in the dealer service dept now being fixed. I don't have a detailed description, but apparently it has to do with the 6 misfire and regarding valves being worn and needing to be replaced. I'll let you guys know as soon as I do. Not supposed to pick it up until Monday.

AFMan

Okay, so the dealer showed a fault code for a mis-fire in cylinder #6(as expected) so further tests found the valve needed to be inspected. They removed the valve cover and the valve was not rotating(not sure what this means) so they rotated all valves, reinstalled valve cover, added combustion chamber cleaner through intake and cleaned fuel injectors. They replaced a "gasket va 9001004." That's verbatum from the right up.

Comments from anyone that this has happened too? Why at 72K did this happen?

It seems to be running fine now. Nice and strong, so I'm hoping the dealer did the job right. Any inputs from anyone regarding this issue would be appreciated. Thx

96tudor

Valves rotate or spin to maintain a good seat and make sure hot spots don't develop. Did they fix the problem so that the valve will rotate normally, or were there deposits on the valve face or cylinder seat that kept it from rotating and the technician cleaned that away with their chemicals?

captainwoot

The repair is actually a chrysler TSB, a known problem the valves stop rotating and develop carbon deposits that stop them from closing completley at high rpm. They rotate the valves and add the cleaner in hopes of correcting the condition. If it doesn't work, you can keep running cleaners through it or bite the bulit and pull the cyl head for a valve job!
Good luck

AFMan

Yes, they fixed the problem. There were carbon deposits, so they cleaned them, replaced #6 gasket, rotated all of them, and cleaned them with chemicals. That seems to have worked.

AFMan

SO what does biting the bullet and pulling the cylinder head for a valve job run around parts and labor?

AFMan

Okay, so now the check engine light came on permanently. About 5 days after I got it back. WTF? What is going on with my jeep fellas? Anyone gone through anything similar? I have to take it in on Monday.

warthog

Any update on this?